SEE Upset characteristics of BRAM in 28 nm Bulk FPGA by Pulsed Laser Test
 doi: 10.11728/cjss2024-0007
Abstract(5) [PDF 787KB](0)
Abstract:
In order to research the Single Event Effect characteristics of block RAM in SRAM based FPGA, pulsed laser test were performed on 28 nm bulk Kintex-7 XC7K410T-FFG900 FPGA. The Single-cell upset (SCU) and Multiple-cell (MCU) upset induced by pulsed laser were observed during the test, and the cross section under different laser energy was tested. Besides, we have analyzed the Multi-cell upset patterns of BRAM in FPGA. The result shows that the proportion of Multi-cell upset climbs up with the increasing laser energy, while the proportion of Single-cell upset goes in the opposite way. Two to eleven bits MCU may be induced by one pulsed laser, but without MBU in any logical word. Some SEE mitigation methods were suggested at the end of this paper according the result of SEE test to improve the reliability of SRAM based FPGA in space application.
Deep learning prediction method based on ionospheric parameter similarity features
 doi: 10.11728/cjss2023-0110
Abstract(5) [PDF 533KB](1)
Abstract:
The ionospheric critical frequency foF2 is one of the important ionospheric parameters, and conducting foF2 parameter prediction has important research significance and application value. This article proposes a deep learning prediction method that integrates the variation characteristics of foF2 parameters, using a bidirectional long short time memory neural network BiLSTM network and a model that combines ionospheric parameter similarity features to achieve 24-hour advance prediction of the ionospheric critical frequency foF2 parameters. The results indicate that the relative error of BiLSTM combined with ionospheric parameter similarity model in predicting foF2 parameters is around 8%~10%. The prediction results of detection stations at different latitudes indicate that as the latitude decreases, the difficulty and error of prediction increase, and the prediction accuracy decreases. The analysis of the prediction results of foF2 parameters during geomagnetic storms shows that the prediction effect during geomagnetic storms will be affected to a certain extent, and the prediction error will increase. During geomagnetic storms, compared to LSTM and BiLSTM models, BiLSTM combined with ionospheric parameter similarity feature models performs better in predicting foF2 parameters.
Research on on-board application of FlexRay bus
 doi: 10.11728/cjss2023-0124
Abstract(4) [PDF 1246KB](0)
Abstract:
The on-board data bus is the "nerve centre" of satellite integrated electronics. In view of the fact that the existing on-board buses represented by 1553B and CAN bus cannot meet the increasing demand for satellite bus data transmission, this paper carries out the research on the starboard application of the ground-mature high-reliability and high-speed FlexRay bus. Firstly, the technical advantages of FlexRay bus applied to satellite integrated electronics are analysed, and the hardware and software design of FlexRay star-carrying communication node is carried out; taking into account that FlexRay bus is used as an extension or supplement to the traditional CAN bus when it is applied in the orbit, the gateway function of CAN bus and FlexRay bus is designed and implemented, and the sequential order of the bus messages is achieved by adopting the rotational mapping algorithm. The rotational mapping algorithm is used to realise the sequential exchange of bus messages. After the BER test, the data are sent and received continuously, and the data of different bus messages in the network are exchanged normally without frame loss or frame error, and the BER is lower than 10-9. The test result verifies the validity and reliability of the design of the on-board FlexRay bus system.
Study on the active regulation mechanism of laser photothermal effect on thermocapillary convection of double-layer fluid
 doi: 10.11728/cjss2023-0036
Abstract(5) [PDF 915KB](0)
Abstract:
Active control of thermocapillary convective instability is a frontier scientific issue in the field of microgravity hydrodynamics and heat and mass transfer. In order to achieve effective control of thermocapillary convective instability of double-layer fluid, this paper innovatively proposes to use laser photothermal effect to actively control flow, The regulation mechanism of laser photothermal effect parameters (laser beam position, laser power and spot size) on the instability of double-layer thermocapillary convection is also studied. The calculation results show that the adjustment of laser power and spot size can significantly change the convective vortex structure in the spot area and weaken the vibration amplitude of temperature wave; The adjustment of the laser position can affect the position of the local convection vortex in the liquid layer, and then change the convection intensity on both sides of the laser position, so as to realize the control of the oscillating and unstable flow in the local region; The effective control of thermocapillary convection of double-layer fluid can be realized through the reasonable selection of photothermal effect parameters.
Review of the Development of Space Rodent Experiments
 doi: 10.11728/cjss2023-0096
Abstract(35) [PDF 1252KB](12)
Abstract:
Human beings have never stopped exploring the unknown universe. Since the twentieth century, human activities in outer space have become more and more frequent, and with the development of manned space engineering, astronauts have stopped in space for longer and longer, and various health problems brought by it need to be solved urgently. To this end, various countries have successively carried out space rodent experiments to study the impact of the space environment on living organisms. This paper investigates the mainstream foreign space rodent culture technologies and devices, and analyzes the space rodent experiments that have been carried out internationally, in order to provide reference for the design of space rodent experimental devices in China.
International Lunar Research Station CommunicationBased on Satellite Double Relay
 doi: 10.11728/cjss2023-0129
Abstract(20) [PDF 794KB](5)
Abstract:
After the construction of the international lunar research station where astronauts/scientists may reside is completed, maintaining high reliability and seamless communication with China's ground control center will be an important requirement. In the long run, The foreign stations of China’s deep space TT&C system maybe have the following risks: reducing the reliability of China’s deep space TT&C system, and affecting the highly reliable communication between the international lunar research station and the ground control center. Therefore, based on the introduction of the current situation of lunar exploration in China, and drawing on the design, construction, application, and development practices of the TDRSS (in chinese), a concept of satellite double relay communication is proposed. Firstly, coverage simulation analysis under various conditions was conducted from the perspective of geometric visibility; Secondly, research and exploration were conducted from various aspects such as microwave/laser frequency band selection, transmission system, link design, system composition, capture and tracking, overall positioning, and performance comparison with deep space TT&C system. Through connecting the past and the future, innovative ideas, and top-level argumentation, a preliminary exploration on the highly reliable communication of the international lunar research station based on the satellite double relay has been completed. Under the unified control of the ground control center, through the comprehensive utilization of China’s deep space TT&C system and the satellite double relay, the highly reliable and seamless communication between the international lunar research station and the ground control center will have a fully realized technical foundation. In addition, this idea can also provide reference for other spacecraft communication in Earth Moon space and interplanetary exploration, and further promote the integration and innovation of China's ground-based, space-based, and deep space TT&C system.
Research on interfacial flow and thermal stratification of cryogenic liquid nitrogen in variable gravity
 doi: 10.11728/cjss2023-0111
Abstract(8) [PDF 3268KB](2)
Abstract:
In order to study the effects of g on the flow, phase distribution, temperature distribution, and pressure distribution of liquid nitrogen tank during self-pressurization, the self-pressurization process of liquid nitrogen tank under different g was numerically simulated by the Volume-Of-Fluid (VOF) method. The results show that under the condition of large g, the fluid pressure in the tank increases gradually along the direction of residual gravity, and the temperature of the ullage in the tank increases with the continuous heat leakage of the tank wall, and the gas temperature near the wall is the highest, and the gas temperature near the liquid is the lowest, while the temperature in the liquid bulk zone of the tank changes little with time. With the decrease of g, the liquid in the tank is more likely to climb along the wall of the tank with better infiltration, and the temperature difference of the fluid in the tank is gradually reduced. In the case of a small g, after the fluid flow in the tank is stable, the ullage will be wrapped in the middle of the tank, forming a spherical bubble. The difference of the fluid temperature in the tank gradually increases and then decreases with time. In zero gravity environment, the presence or absence of heat leakage (qw = 0.5 W/m2) on the tank wall has no significant influence on the fluid movement and phase distribution in the tank, and within the initial time interval ∆tf (0 s ≤ ∆tf ≤ 40 s), the influence of the presence or absence of qw on the temperature distribution of the fluid in the tank also is not significant except near the wall of the tank. Numerical simulation results are expected to provide references to further study the on-orbit pressure control technique of cryogenic liquid tanks and space cryogenic fluid management.
Space Radiation-Induced Impacts on Gut Flora, Metabolitesand Multisystem Diseases
 doi: 10.11728/cjss2023-0126
Abstract(17) [PDF 615KB](6)
Abstract:
Maintaining the homeostasis of gut flora is of great significance to protecting human health. Gut flora plays a key role in regulating body functions, such as digestion, metabolism, immunity, and cognition. These physiological functions often depend on the diversity of gut flora, the stability of the bacterial flora structure, and the balance of the microecology. In the outer space, astronauts face many special environmental factors including the space radiation. Space radiation can cause imbalance of gut flora and changes in metabolites, damaging the intestinal barrier function, and further lead to pathological injury to multiple systems such as the intestine, cardiovascular, brain, and lungs. This article reviews the characteristic changes in gut flora homeostasis and its metabolites under space flight or simulated space radiation, as well as the interaction between gut flora and intestinal damage and other multi-system diseases under radiation effects. It is expected to provide a reference for the further study of the pathological mechanisms upon space radiation and radiation protection measures.
Analysis of the nighttime variation characteristics of mesospheric ozone and correlation with solar activity
 doi: 10.11728/cjss2023-0061
Abstract(23) [PDF 940KB](4)
Abstract:
The satellite ozone data of ENVISAT-1/GOMOS (Global Ozone Monitoring by Occultation of Stars) and TIMED/SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) are analyzed to provide a statistical analysis of the distribution of ozone in the tropical mesosphere (60-110 km) at night (local time 20: 00-24: 00) and explore its correlation with the 27-day solar cycle with HAMMONIA (Hamburg model of the neutral and ionized atmosphere). Both observations and model indicate that the nighttime ozone in the mesosphere peaks at 95 km and there is a semiannual oscillation in the upper mesosphere; in the upper mesosphere (above 80 km), the ozone variation is inversely correlated with the solar rotation variation. Although the observations and the model results share some common features, significant differences are found, where the amplitude of ozone sensitivity is greatly underestimated by the model.
The occurrence and infrared absorption spectra of Martian water
 doi: 10.11728/cjss2023-0118
Abstract(30) [PDF 2510KB](7)
Abstract:
After nearly half a century of exploration, the researches of Martian water have made important achievements, which provides essential information for understanding the historical information of Martian water and the evolution of the Martian environment, especially arousing the enthusiasm of human beings to search for life on Mars. The study of the occurrence and host minerals of Martian water is of great significance for understanding the composition of Martian surface materials, the evolution of Martian environment and climate, and the livability of life. Infrared spectroscopy is an important method to identify the occurrence of water on the Martian surface and the host minerals. At present, water vapor, water ice and various aqueous substances such as sulfate, clay minerals, hydroxides and hydrated silica have been identified on the Martian surface, indicating that there were several periods of aqueous activities in different water environments in Martian history. In this paper, the occurrence of Martian water and the information of Martian historical environment are summarized, and the infrared spectral characteristics of different water-bearing minerals and the main influencing factors including the type of host minerals, temperature, grain size and mixture are synthetic analyzed. Finally, the changes of infrared spectral absorption characteristics of groups such as H2O and OH are generalized. Regarding the origin and evolution of Martian water and the livability of Mars, China's ongoing exploration of "Tianwen-1" and future "Tianwen-3" are expected to gain breakthrough.
 doi: 10.11728/cjss2023-0121
Abstract(23) [PDF 465KB](6)
Abstract:
The National Center for Space Weather (NCSW) has been providing space weather forecasts for the next 24h, 48h and 72h since July 1, 2004. In this paper, we use the average error, the average absolute error, the skill score, the median error and the interquartile range of error to verify the forecasts of F107 index and Ap index of NCSW from 2005 to 2022. It was found that the F107 index forecasted by NCSW for the next 24h, 48h, and 72h are usually smaller than the observed F107 index; the Ap index for the next 24h is usually higher than the observed Ap index, while Ap index forecasted for the next 48h and 72h are usually lower than the observed Ap index. The higher the level of solar activity, the greater the forecast error of the F107 index is. However, the maximum forecast error of the Ap index occurs in the declining period of solar activity. In addition, we compared the forecasts of NCSW with the simple numerical models such as the persistence model, 14 days recurrence model, 14 days corrected recurrence model, 27 days recurrence model, and 27 days corrected recurrence model, and found that the forecast performance of NCSW is usually better than that of five simple numerical models. For the F107 index, the forecast performance of NCSW is slightly better than that of the persistence model, and significantly better than that of the four recurrence models. However, when the solar activity level is high, the persistence model's performance of the F107 index for the next 72h is better than that of NCSW. For the Ap index, in most cases, the performance of NCSW is significantly better than that of numerical models. However, when geomagnetic disturbances are severe, the Ap index forecasted by the 27 days recurrence model is more accurate than that forecasted by NCSW.
Analysis of sea surface backscatter coefficient errors and its effects for the CFOSAT scatterometer
 doi: 10.11728/cjss2023-0144
Abstract(34) [PDF 1377KB](8)
Abstract:
Noise is a key factor that affects the accuracy of spaceborne scatterometer backscatter coefficient (σ0), as well as the retrieved sea surface wind quality. In general, the scatterometer σ0 measurement error is attributed to both instrumental noise and geophysical noise, which are expressed in terms of normalized standard deviation (Kp). In this paper, the instrumental noise (Kpc) and the geophysical noise (Kpg) are analyzed as a function of sea surface wind speed, incidence angle, spatial resolution and offshore distance for the China-France Oceanography Satellite Scatterometer. The result shows that the variability of sea surface wind field is large under low wind conditions, so the geophysical noise dominates the measurement error of radar backscatters. Notably, the larger the grid size of wind vector cell (WVC), the more inhomogeneous the sea surface wind, such that the Kpg value increases as the WVC size. While under high wind conditions, the variability of sea surface wind is small, and the contribution of instrument noise and geophysical noise is similar. Moreover, the relationship between the σ0 error and the offshore distance is studied, which shows that the observation error generally increases as the offshore distance decreases, indicating that the near-shore geophysical noise is non-negligible for the scatterometer measurements approaching to the coastal line. In summary, the results presented in this paper reveal the influence factors of scatterometer σ0 measurements, which are relevant for better understanding the wind inversion and quality control of CSCAT, notably near the coastal areas.
Application of deep clustering algorithm in target echo classification of SuperDARN radar
 doi: 10.11728/cjss2023-0136
Abstract(26) [PDF 911KB](5)
Abstract:
SuperDARN radar target echoes usually contain echoes of various types of scattering, such as ionospheric irregularities, ground/sea scatter echoes, polar mesosphere summer echoes, and meteor trail echoes. The ionospheric convection map made by using the ionospheric echoes collected by SuperDARN is of great significance for space weather research. The scattered ionospheric echoes received by SuperDARN are often mixed with the scattered echoes from the ground or the sea, resulting in inaccurate ionospheric convection maps. Therefore, cluster analysis of SuperDARN target echoes is of great significance. In this paper, the graph embedding deep clustering algorithm based on autoencoder network is applied to SuperDARN target echo data for the first time, and SuperDARN echo data is effectively classified. In addition, the model is compared with traditional algorithms and machine learning clustering algorithms. The application of this model to sample data shows that the deep clustering algorithm can capture the deep structure features of echo data and improve the precision of echo clustering.
Research and prospect of in-situ construction materials on Mars
 doi: 10.11728/cjss2023-0137
Abstract(18) [PDF 1711KB](7)
Abstract:
Martian regolith is an important in-situ natural resource for building habitats and infrastructure on Mars. Based on the extreme environment of Mars and the special properties of pyrosol, the physical and mechanical properties of in-situ construction materials on Mars are reviewed in detail in this paper. The research progress in two aspects of pyrosol concrete materials, pyrosol melting and sintered in-situ curing materials is emphasized. The problems and limitations of these materials in Mars construction are pointed out, and the development direction of in-situ construction materials on Mars is prospected, in order to provide reference for the realization of in-situ construction on Mars.
Comparison between temperature data detected by ICON/MIGHTI and TIMED/SABER
 doi: 10.11728/cjss2023-0094
Abstract(29) [PDF 760KB](8)
Abstract:
The ICON satellite provides data for environmental characterization, modeling, and forecasting in near space. In this paper, the ICON/MIGHTI and TIMED/SABER temperature datasets were compared and analyzed in the range of 90~105 km, and the mean temperature deviation and root-mean-square error of both were calculated. The distribution of monthly mean temperature deviation with altitude and latitude in different months were also analyzed to provide a reference basis for MIGHTI and SABER temperature sounding data in modeling and forecasting applications of the near-space atmosphere. The results showed that ICON/MIGHTI and SABER temperature-sounding data can be used as references for modeling and forecasting applications. The results also showed that the ICON/MIGHTI and TIMED/SABER vertical profile detections agreed. The global mean temperature deviations with altitude were positive at 90~93 km, with a maximum deviation of approximately 2.5 K and negative at 93~105 km, with a maximum deviation of approximately 10 K. The deviation was usually higher during the day than at night. The mean temperature deviation varied significantly with season and latitude and had the largest mean deviation range and the largest root-mean-square error of temperature in summer.
Comprison of FY3D/GNOS atmospheric occultation detection temperature with TIMED/SABER detection temperature and NRLMSISE00 model temperature
 doi: 10.11728/cjss2023-0072
Abstract(22) [PDF 775KB](5)
Abstract:
The accurate detection of atmospheric temperature data is of great significance for the study of the structural characteristics and dynamic processes of the upper atmosphere. Launched in November 2017, China's Fengyun-3D satellite Discovery Explorer(GNOS) conducts a global exploration of atmospheric temperatures. The purpose of this study is to evaluate the atmospheric temperature data products of the FY3D satellite. We used the FY3D occultation observation data from January 2019 to December 2021, and the TIMED/SABER detection data and NRLMSISE00 atmospheric model data to compare and study the atmospheric temperature data in the range of 12~100 km. The temperature deviation of SABER-FY3D(TSABER-TFY3D) and NRLMSISE00-FY3D temperature deviation (TNRLMSISE00-TFY3D) and their distribution with latitude, season and northern and southern hemispheres were analyzed. The results show that the three temperature data are generally consistent with the height change trend, SABER-FY3D temperature deviation is positive deviation in the altitude range of 12~30 km, close to 0 K at about 30 km, and the negative deviation above 30 km is mainly negative, and with the increase of altitude, the negative deviation is increasing overall. NRLMSISE00-FY3D temperature deviation is positive deviation in the stratosphere and negative deviation in the mesosphere and low thermosphere. Both temperature deviations have obvious characteristics with latitude and season. Below 60 km, the temperature deviation of SABER-FY3D is smaller in the low latitude region, larger in the high latitude area, smaller in summer and larger in winter. NRLMSISE00-FY3D temperature deviation is just the opposite, smaller in high latitudes, larger in low latitudes, smaller in winter, and larger in summer. The zero deviation line of the average monthly temperature deviation of the two types is located at a higher height in spring and summer and a lower autumn and winter in both northern and southern hemispheres. In the winter altitude area of 40~60 km, the negative deviation of SABER-FY3D average temperature in the northern hemisphere is more obvious than that in the southern hemisphere.
Study of near-Earth asteroid impact event disposal rules and processes
 doi: 10.11728/cjss2023-0064
Abstract(34) [PDF 614KB](3)
Abstract:
To address the shortcomings of China’s near-Earth asteroid defense research in terms of disposal rules, coordination mechanisms and operational processes, and to respond to meet the increasing demand for asteroid defense and disaster relief, a strategy for conducting asteroid defense simulation exercises on a regular basis is proposed. Firstly, the current status of asteroid defense development at home and abroad is studied, and the gaps in asteroid defense in China are analyzed. Secondly, from the perspective of mechanism establishment and cooperative emergency response, the asteroid defense simulation rehearsals at home and abroad are reviewed and the general disposal rules for near-Earth asteroid impact events are analyzed. Then, based on the current situation at home and abroad, an asteroid defense simulation and rehearsal program is designed, and the organizational structure, emergency response mechanism, and general disposal rules for asteroid defense in China are proposed, and a preliminary exercise scenario is designed to verify the mechanism and rules. Finally, suggestions are given for the future development of asteroid defense in China, which provide a reference for the organization and implementation of near-Earth asteroid defense in China.
 
 
Dynamic characteristics of airship envelope material with concentrated mass
 doi: 10.11728/cjss2023-0008
Abstract(23) [PDF 946KB](2)
Abstract:
Aiming at the design and analysis of stratospheric airship rigid flexible large complex structure system, this paper carried out the simulation analysis of dynamic characteristics of airship envelope material with concentrated mass. The structural parts with high stiffness and relatively concentrated mass are simplified as concentrated mass. The airship envelope is simplified as a biaxially stretched cross envelope material sample. The influences of pretension, quality and concentrated mass of the size on the natural frequency of cross film material sample are analyzed. The results show that the natural frequency of the sample increases with pretension, decreases with quality of the concentrated mass, and increases with the side length of the connection between the concentrated mass and the sample. The fundamental frequency of the sample is independent of the height of the concentrated mass, but the second and third frequency decreases with the height of the concentrated mass. The research results provide a theoretical basis for the overall design and analysis of airship structure and the further dynamic experiments of airship envelope materials with concentrated mass.
Study on evolution mechanism of PCM liquid-bridge phase transition
 doi: 10.11728/cjss2023-0105
Abstract(31) [PDF 1158KB](6)
Abstract:
In order to reveal the flow characteristics and phase transition evolution law of PCM liquid bridge phase transition process under microgravity conditions, the evolution process of solid-liquid interface during PCM liquid bridge phase transition under different working conditions was systematically studied based on the axisymmetric PCM liquid bridge mathematical model. the effects of different high diameter ratios and different temperature differences on the shape of the liquid bridge, the evolution law of solid-liquid interface, the phase transition speed and thermocapillary flow were investigated. The results show that the thermal capillary flow is more intense under the action of large temperature difference, the phase change speed of the phase change material at the outer wall will be faster, and the angle between the phase change interface at the outer wall and the wall surface will be smaller. A large high diameter ratio has the same effect, but also produces more eddy currents, making the final steady-state process more oscillating.
Modeling next 3-day Kp index forecasting with neural networks and exploring the application of explainable AI
 doi: 10.11728/cjss2023-0107
Abstract(65) [PDF 731KB](17)
Abstract:
    The current operational needs of space weather forecasting strongly require accurate predictions of the future 3-day Kp index. Such forecasts involve a multitude of predictors, including physical parameters observed at the Earth-Sun L1 point and historical characteristics of the Kp index. Therefore, previous research primarily relied on statistical or empirical methods for prediction. However, the complex coupling of multiple parameters during geomagnetic storm events has made it challenging to quantify the contributions of various predictors to Kp index forecasting over a 3-day timescale, hindering further improvements in forecast accuracy. This study builds a 3-day Kp index forecasting model based on neural network modeling and utilizes explainable AI algorithm, specifically the integrated gradient algorithm, to quantify the contributions of individual predictor. The research results indicate that the southward interplanetary magnetic field contributes significantly to Kp index prediction, accounting for 37.15% of all factors, making it the primary contributor. Following this, solar wind speed contributes 15.73%, underscoring the model's ability to capture parameters aligned with physical characteristics as the primary predictive factors during training. The contribution of historical characteristics of Kp index (recurrence characteristics) gradually increases with the forecasting horizon and reaches 68.06% at a lead time of 3 days. This substantiates the strong predictive capabilities of the AI model in forecasting geomagnetic storm events induced by high-speed solar wind streams originating from coronal holes. Furthermore, this study conducts contribution analysis on two significant geomagnetic storm events that occurred in 2015 and 2017. It reveals that the predominant predictors contributing to each event differ. This underscores the model's capability to accurately capture the complex coupling of multiple parameters in geomagnetic storm forecasting. In conclusion, this research demonstrates that employing explainable AI algorithms can help quantify the contributions of various predictive factors to Kp index forecasting to some extent. This has the potential to enhance further research and improvements in 3-day Kp index AI forecasting models.
Numerical validation of lunar subsurface dielectric property estimation based on full waveform inversion
 doi: 10.11728/cjss2023-0115
Abstract(55) [PDF 1190KB](6)
Abstract:
Dielectric property is an important parameter that determines the propagation speed of radar wave in materials, which is widely used in stratigraphic division, regolith thickness inversion, radar model construction and water-ice detection. However, continuous impacts may cover the traces of important geological activities and hinder the exploration of lunar geological. The subsurface radar diagram with fine vertical resolution provided by the Chang’E-4 Lunar Penetrating Radar (CE-4 LPR) can deepen our understanding of the dielectric property of lunar subsurface materials. Full waveform inversion (FWI) method can fully utilize the kinematic and dynamic information of radar wave field and invert the dielectric property by constructing an initial dielectric model and continuously updating this model with comparison of the observed radar data. By comparing the simulation results of homogeneous dielectric model and stochastic equivalent media model to the LPR diagram, we selected the stochastic equivalent media model as the real model to simulate the lunar subsurface dielectric profile and valid the dielectric accuracy inversed by FWI method. Our results reported that most error are within 0.2, suggesting FWI method can capture fine-scale dielectric fluctuation and provide 2-D dielectric profile, supporting the regolith thickness estimation and subsurface temperature model.
Remanence model estimation method of geomagnetic navigation carrier based on recursive least square method
 doi: 10.11728/cjss2023-0002
Abstract(75) [PDF 2617KB](42)
Abstract:
Geomagnetic navigation is a method to realize navigation by measuring the vector magnetic field around the earth. It is a passive navigation, which has the advantages of strong anti-interference ability and no cumulative error. One of the difficulties in the application of geomagnetic navigation on moving platform is the influence of platform remanence on geomagnetic measurement, which seriously pollutes the measurement of magnetometer and becomes a key technology in the transformation of geomagnetic navigation to application. In order to realize effective measurement and estimation of remanence of moving platform, a method of differential measurement and estimation of remanence of moving platform based on recursive least square method is proposed. Firstly, based on the analysis of magnetic dipole theory, the method deduces that the value of carrier interference magnetic field is only related to the distance between measuring point and magnetic dipole and the equivalent magnetic moment of magnetic dipole. Based on the above conclusions and the magnetic field distribution characteristics of the magnetic dipole, a remanence difference estimation model of the moving platform based on the built-in magnetometer array is derived, and the difference estimation model is solved by recursive least square method. Finally, a large number of simulation experiments show that platform remanence can be measured and estimated by the built-in array magnetometer, which proves the effectiveness of the proposed method.
Distribution and Characteristics of Martian precipitating H-ENA
 doi: 10.11728/cjss2023-0044
Abstract(42) [PDF 863KB](11)
Abstract:
Energetic Neutral Atom (ENA) is generated by charge exchange between energetic ions and background neutrals. As Martian exosphere extends far above the bow shock, hydrogen ENA (H-ENA) produced by solar wind protons may enter the lower atmosphere directly, depositing mass and energy in the atmosphere. Based on the single-fluid multispecies MHD model and exosphere model, this paper calculates the spatial distribution of the precipitating H-ENA flux at the height of 200km on Mars, evaluates the particle and energy deposition rate of the precipitating H-ENA under different solar wind conditions, analyzes their controlling factors. The results show that the solar wind H-ENA generated upstream of the bow shock is less affected by the crustal fields, and shows a cos(SZA) distribution. As a major mass and energy source, the precipitating H-ENA accounts for 59% and 81% of the total precipitating ENAs. Magnetosheath H-ENAs generated in the magnetosheath is greatly affected by the crustal fields, and their precipitating flux decreases significantly above the strongest magnetic anomalies. The precipitating H-ENA is proportional to the upstream solar wind flux, 2.1~3.5% of which are estimated to be converted into the solar wind H-ENAs.
A Lightweight Automatic Detection Model for Lightning Whistle Waves Based on improved YOLOv5
 doi: 10.11728/cjss2023-0067
Abstract(61) [PDF 2449KB](8)
Abstract:
Lightning whistler wave is a strong electromagnetic whistler wave caused by atmospheric lightning thunderstorm. It shows typical characteristics of electromagnetic spectrum in electromagnetic field observation recorded by LEO electromagnetic satellite, and has important value. The existing reported lightning whistle wave detection models have problems such as high miss detection rate, high computational complexity, and slow deployment on satellite platforms. This project proposes an improved YOLOv5 detection algorithm YOLOv5 Upgraded. To address this issue, the study proposes an improved YOLOv5 detection algorithm called YOLOv5-Upgraded.The model takes into account the vector angle between the predicted edge and the real edge, we propose replacing the CIoU loss function with SIoU to improve the speed of locating the real edge. Additionally, to prevent issues such as gradient disappearance, gradient explosion, and neuron necrosis during network training, we suggest replacing the SiLU activation function with the Mish activation function. The Mish activation function offers better gradient flow, and its smooth function curve allows information to easily penetrate the network.The CA attention mechanism is inserted into the backbone network to help the model identify the Lightning whistler waves more accurately and greatly reduce the missed detection rate. The study is based on the VLF-band data of CSES satellite induction magnetometer (SCM) with 2.4 seconds time window to intercept data, and 1126 time-frequency map data sets are obtained by band-pass filtering and short-time Fourier transform, and then expanded to 7882 images by brightening, darkening, adding pretzel noise, Gaussian noise and other image enhancement operations, of which 7091 are used as training set and 791 are used as test set. Experimentally, the average mean accuracy (mAP) of the improved YOLOv5-based model is 99.09% and the Recall is 96.20%, which are improved by 2.75% and 5.07% compared with the plain YOLOv5s, and 5.89% and 9.62% compared with the time-frequency map-based YOLOv3 model. The size of LSTM based on the speech processing technology Lightning whistler waves recognition model is 82.89MB, while the YOLOv5-Upgraded model is only 13.78MB, saving about 83.38% of memory resources. It is shown that the model greatly reduces the leakage problem of Lightning whistler waves, achieves better results in the test set as well as in the real orbit, and its lightweight features are easy to deploy to satellite devices, which greatly improves the possibility of satellite recognition.
 doi: 10.11728/cjss2023-0057
Abstract(28) [PDF 1211KB](4)
Abstract:
The system design of millimeter wave atmospheric ozone radiometer
 doi: 10.11728/cjss2023-0053
Abstract(32) [PDF 974KB](2)
Abstract:
Stratospheric ozone concentration has an important impact on global climate change and ecological environment. Hyperspectral millimeter wave radiometer with spectral analysis capability is a passive microwave remote sensor used to detect atmospheric trace gases. It can effectively detect the vertical profile of atmospheric ozone and has very important application value in the field of space earth science. In this paper, a new hyperspectral millimeter wave ozone radiometer system for detecting stratospheric ozone absorption lines is developed. The system structure includes RF receiver and digital back-end spectrum analyzer. The RF receiver part uses a superheterodyne structure to obtain a 142.175GHz ± 100MHz bandwidth signal. The digital back-end spectrum analysis part uses a high-performance analog-to-digital converter to sample the input analog signal at 500Msps, 14bit quantization, and the input signal 3dB bandwidth is 200MHz. The signal power spectrum is obtained by high-performance field programmable gate array(FPGA), and the number of detection channels is 16384, and the spectral resolution is 12.2kHz. This paper introduces the design scheme, device selection and test method of the key modules of the radiometer system. By conducting atmospheric detection experiments and comparing the experimental results with the simulation results of atmospheric radiative transfer simulation software (ARTS), the correctness of the system design is verified. It meets the application requirements of stratospheric ozone concentration monitoring, early warning and climate change research.
 doi: 10.11728/cjss2023-0028
Abstract(167) [PDF 377KB](27)
Abstract:
There is an order of magnitude difference in the occurrence of different classes of flares. This makes it difficult for conventional convolutional neural network-based flare prediction models to capture M,X class flare features, which leads to the problem of low accuracy of high level flare prediction. In this paper, we discuss different deep long-tail learning methods to improve the accuracy of flare forecasting by controlling the variables for the long-tail distribution phenomenon in flare forecasting. We try to improve the forecast performance of the model for M,X flares from the perspectives of training set optimization, loss function optimization, and network weight optimization. The experiments on SDO/HMI solar magnetogram data show that the accuracy of M,X class flare prediction is significantly improved by 53.10% and 38.50%, respectively, and the recall is increased by 64% and 52% compared with the baseline model trained by conventional methods. It shows that the treatment of the long-tailed distribution of data is crucial in the flare forecasting problem, and verifies the effectiveness of the deep long-tailed learning method. This method of improving the accuracy of tail class forecasts can be applied not only to the field of flare forecasting, but also can be transferred to the analysis of forecasting other typical events of space weather with long-tailed distribution phenomenon.
QX-1 GNOSMRadio Occultation Data Performance Analysis
 doi: 10.11728/cjss2023-0071
Abstract(53) [PDF 1057KB](19)
Abstract:
  QX-1 GNOS M is a commercial global navigation satellite occultation sounder that is the first to achieve miniaturization and compatibility with the BeiDou, GPS, and Galileo systems in orbit. It was launched into orbit on October 14, 2021 at 18: 51, aboard the QX-1 satellite, and has collected a large amount of occultation data. The composition of QX-1 GNOS M payload is introduced, and the global distribution of the occultation events on August 17, 2022 is statistically analyzed. Based on the QX-1 GNOS M datasets from August 17 to September 3, 2022, the detection penetration depth of the occultation profiles has been inspected.
  Comparing with the NCEP reanalysis data, the QX-1 GNOS M occultation refractivity accuracy has been analyzed, which verified the reliability and consistency of Galileo radio occultation data. The preliminary results indicate that the compatibility with three systems increases the number of occultation events by about 1.5 times compared to GPS alone. This study further demonstrated the consistency of the radio occultation product accuracy of different GNSS systems. The successful operation of the QX-1 GNOS M micro-nano occultation satellite opens the prelude to China's micro-nano occultation constellation network exploration.
A Statistical Analysis of Distributions of Electron Energy Spectra in the Earth's Radiation Belts based on Van Allen Probes Observations
 doi: 10.11728/cjss2023-0070
Abstract(97) [PDF 2927KB](28)
Abstract:
The characteristics of energy spectra distributions of radiation belt electrons can help reveal the dominant physical mechanism behind the dynamics of the radiation belt. In this study, the temporal and spatial distribution characteristics of energy spectra of energetic electrons are statistically analyzed using the measurements from Van Allen probes during 2014-2018. The results show that most of the electron spectra in the radiation belt can be classified into three types: exponential, power-law and reversed spectra. The exponential spectra dominate in the outer radiation belt outside the plasmapause. The power-law spectra usually occur at higher L values and move to lower L values during geomagnetic storms. During quiet geomagnetic activity periods, the power-law energy spectra stay at the high L with longer time and higher proportion. The reversed energy spectra dominate at L>2.5 inside the plasmasphere. As the increase of plasmapause locations, more reversed energy spectra occur while the proportion of the exponential energy spectra decreases. During long-term quiet periods, electron fluxes near the peak of the reversed energy spectra (around 2 MeV) are relatively low to form obvious reversed spectral. The results also show that the peak location of reversed energy spectra is ~2 L inside the plasmapause while the peak location of exponential energy spectra is ~1.5 L outside the plasmapause. Appearances of power-law energy spectra are related to substorm injections of electrons. Stronger magnetic storms produce wider L ranges where reversed energy spectra are replaced by exponential spectra. During quiet times, exponential energy spectra inside the plasmapause are replaced by reversed energy spectra due to pitch angle scattering produced by plasmaspheric hiss waves.
Simulation and experimental validation of charge-driven extreme ultraviolet photoelectric effect
 doi: 10.11728/cjss2023-0038
Abstract(64) [PDF 2507KB](29)
Abstract:
The quality control of inertia sensors is crucial in precision gravity measurement systems. High-energy charged particles in space can deposit in the quality control material made of heavy metals, leading to an accumulation of charge. The charged quality control material will produce stray noise in the measurement of the inertia sensor due to the electromagnetic field inside the sensor, affecting the accuracy of the precision gravity measurement. By utilizing the photoelectric effect on the metal surface with extreme ultraviolet (EUV) light, electrodes of the inertia sensor can be irradiated with EUV light generated by UVLED, and an appropriate electric field can be applied between the electrodes to change the charge amount of the quality control material. This is a non-contact method to eliminate the charge of the quality control material without introducing external forces. In this paper, the EUV charge driving process was theoretically modeled and simulated based on a simplified electrode model of a parallel plate capacitor. Based on this, a set of charge driving verification test systems was designed and built, and experiments were conducted on the effects of light power and bias voltage on charging and discharging rates, as well as AC charge driving. The experiments confirmed that the charge/discharge rate was proportional to the EUV light power and the quantum yield varied with the electric field strength between the plates. The theoretical model for the EUV charge driving was validated by the experimental results. Ultimately, stable control of the discharge rate of the quality control charge at 0.31pC/s-0.76pC/s and the charging rate at -0.05pC/s--0.17pC/s was achieved. This study provides strong support for the development of charge management and control systems by presenting a theoretical model for the distribution of light power on the plates and the charging and discharging rates of the quality control charge.
Present and Enlightenment of the International Space Station External Payloads Mission Planning
 doi: 10.11728/cjss2023-0047
Abstract(127) [PDF 726KB](27)
Abstract:
The external payload platform of the space station supports the deployment of many different types of payloads, which provides opportunities for space scientific research. With the increasing number of external payloads and corresponding missions, and limited by resource constraints, it is necessary to develop scientific and reasonable mission planning to improve the efficiency of external payloads. Aiming at the external multi-payload mission planning method, this paper investigates the present status of external payload mission planning of the International Space Station, and focuses on analyzing its external payload platform, payload type and mission planning method. This paper summarizes the current mission planning strategy, method and future development direction, and provides reference and suggestions for the subsequent external multi-payload system mission planning of the China’s Space Station.
 doi: 10.11728/cjss2023-0040
Abstract(185) [PDF 989KB](44)
Abstract:
The F10.7 index is an important indicator of solar activity. Accurate predictions of the F10.7 index can help prevent and mitigate the effects of solar activity on areas such as radio communications, navigation and satellite communications. Based on the properties of the F10.7 radio flux, the prediction model of F10.7 based on BiLSTM-Attention is proposed for the first time by incorporating an Attention mechanism on the Bidirectional Long Short-Term Memory Network (BiLSTM). The mean absolute error (MAE) on the Canadian DRAO dataset is 5.38, the mean absolute percentage error (MAPE) is controlled to within 5% and the correlation coefficient (R) reaches 0.987. It has superior predictive performance compared to other RNN models. A Conversion Average Calibration (CAC) method is proposed for the first time to preprocess the F10.7 data set observed by the Langfang L&S telescope in China. The processed data has high correlation with the DRAO dataset. Based on this dataset the forecasting effectiveness of the RNN series models is compared and analysed. The experimental results show that both BiLSTM-Attention and BiLSTM models have significant advantages in predicting the F10.7 index and show excellent predictive performance and good stability.
Integratedthermal control system for space platform and fractionated payload
 doi: 10.11728/cjss2023-0041
Abstract(99) [PDF 1436KB](13)
Abstract:
Combined spacecrafts which can implement more complicated targets through fractionated payload or part of the spacecraft from the space platform have been in urgent need with the development of space exploration. Space platform provides carriage service for the fractionated payload or part of the spacecraft before separation. The paper proposed an integrated thermal control system for the space platform and fractionated payload, Thermal simulation proved the rationality and effectiveness of the system, which can be as a reference of such cases.
Research on Ground Simulation Method of Heat Transfer Characteristics for Space High-Temperature Material Experimental Furnace Based on Data-Driven Approach
 doi: 10.11728/cjss2023-0023
Abstract(86) [PDF 1284KB](16)
Abstract:
The temperature stability during the crystal growth process has a significant impact on the morphology and structure of the crystal. In order to improve the quality of crystals, it is necessary to ensure the stability of temperature throughout the crystal growth process. Currently, in China, PID controllers are used to control the crystal growth temperature in space high-temperature material science experimental furnaces. Due to the limited and scarce opportunities for space experiments, the tuning of control parameters needs to be completed on the ground. However, due to the difference in heat transfer between the ground and space environments, there are differences in the heat transfer characteristics of the furnace, and its transfer functions are also different. If the control parameters tuned on the ground are directly applied to space conditions, it will result in a worse temperature control effect. To address this, this paper proposes a data-driven depressurization method that approximates and simulates the heat transfer characteristics of the furnace under microgravity environments on the ground, and provides the pressure values for ground adaptation conditions. This overcomes the problem of the traditional depressurization method being difficult to determine the pressure value for ground adaptation conditions due to lack of prior knowledge.
Research Progress of Lunar In-Situ Water Production Techniques
 doi: 10.11728/cjss2023-0006
Abstract(229) [PDF 1135KB](78)
Abstract:
With the continuous advancement of deep space exploration, lunar exploration will be the first step for mankind to carry out interplanetary exploration and expand living territory. The lunar in-situ resource utilization will be a key technical approach to support manned exploration and long-term survival on the moon surface. Almost all space powers are carrying out continuous research on lunar in-situ water production technology, and China has also listed lunar surface in-situ water production as one of the key technologies for lunar exploration missions. Lunar in-situ water production can be mainly divided into two methods: polar water ice exploration/extraction and hydrogen reduction of lunar regolith. The water ice resources that had been detected are mainly located in the lunar polar region, with uneven distribution and great difficulty in extraction. Many different types of polar water ice exploration and extraction schemes have been put forward, but the actual effect needs to be verified by the lunar in-situ test. Hydrogen reduction of lunar regolith can used for in-situ water production, and its working conditions are not limited by the region, and its application scope is wide. However, there are some remaining technical limitations such as extreme reaction condition requirements and high energy consumption, which implies urgent demand to make breakthroughs in energy conservation and effective ingredient enrichment.
Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
Microgravity and Space Life Science
Space Exploration Technology
Linear Stability Analysis of Thermocapillary Convection in Annular Pools
CHEN Qisheng, HE Meng, HU Kaixin
2016, 36(4): 476-480.   doi: 10.11728/cjss2016.04.476
Abstract(1357) [PDF 946KB](181)
Abstract:
The linear stability of thermocapillary convection in annular pools is studied through the Chebyshev-collocation method. As Pr=6.8, the ratio of outer radius and inner radius is 0.5, and the range of aspect ratio A is from 0.25 to 1.4, numerical results show that the critical mode of the flow are oscillating. The critical Marangoni number, critical wave number and oscillating frequency decreases as A increases. Energy analysis shows that surface tension in the radial and azimuthal directions plays a leading role in the variation of perturbation energy. And the interaction between perturbation flow and the basic flow is small compared to the two former terms. We find out that the work done by the surface tension in the radial direction reaches minimum were analyzed, while the work done by the surface tension in the azimuthal direction and the interaction between the perturbation flow and the basic flow reach maximum, as A=0.8.
Study on Spectrum of Sprite Emissive Using Numerical Simulation
Jiang Fang, Huang Chaoyan, Zhang Hualong, Li Xiaoyin, Wang Yongmei
2015, 35(3): 315-323.   doi: 10.11728/cjss2015.03.315
Abstract(1243) [PDF 1816KB](47)
Abstract:
Sprites are the transient luminous events above very active thunderstorms and are the direct evidence of the energy in troposphere coupled to the upper atmosphere. The emissive spectrum study is the important means to understand the energy injected into upper atmosphere and regional ionization, the electron energy distribution during the whole event. These parameters are useful for the study of sprites' physical mechanism, in addition as a kind of natural atmospheric luminous phenomenon, the emissive spectrum study is useful for providing important information to the research of atmospheric radiation background information. Based on the Boltzmann Equation to calculate the time evolution of the electron energy distribution function in a mixture of partially ionized gases with an applied electric field, the paper calculated the spectral intensity in typical emissive band for sprites. Simulation results show that the emissive intensity is more intensive with more intensive E/N and the emissive spectrum is from far ultraviolet to near infrared.
Study on Geoeffectiveness of Interplanetary Coronal Mass Ejections by Support Vector Machine ormalsize
YE Yudong, FENG Xueshang
2019, 39(3): 295-302.   doi: 10.11728/cjss2019.03.295
Abstract(6168) [PDF 1514KB](2938)
Abstract:
As arriving at the Earth, Interplanetary Coronal Mass Ejections (ICME) will interact with the Earth's magnetosphere and cause geomagnetic storms. The ICME event set is obtained by Richardson and Cane's Near Earth ICME list, and the input features are extracted based on interplanetary solar wind and magnetic data during ICME disturbance. A total of 483 ICME events from 1996 to 2006 are chosen in this study. 13 magnetic and kinetic features are finally selected for the training of the machine learning model. Rank of each feature's Fisher score indicates that the duration of the south-directed interplanetary magnetic field that is larger than 10nT and the increase of solar wind speed at the upstream shock or wave disturbance is closely related to the geoeffectiveness of ICME events, which is consistent with those former statistical results. The trained Radial Basis Function Support Vector Machine (RBF-SVM) can determine whether an ICME event could trigger moderate or stronger geomagnetic storms (Dst ≤ -50nT) effectively with an accuracy of 0.78±0.08. The results show that RBF-SVM can be used as a powerful tool in further analysis, and the better prediction of the geoeffectiveness of ICME will be obtained.
Finite Time Control of Space Robot with Elastic Base and Flexible Arms
HUANG Xiaoqin, CHEN Li
2019, 39(3): 399-406.   doi: 10.11728/cjss2019.03.399
Abstract(3103) [PDF 2123KB](91)
Abstract:
Based on the finite time control, the trajectory tracking and flexible vibration suppression of a free-floating space robot system with two flexible arms and elastic base are discussed. Because of the multiple dynamic coupling relationship between the elastic base and the two flexible arms, the system is a highly nonlinear system. Firstly, the connection between the elastic base and the first arm is regarded as a linear spring, and the dynamic model of the system is derived from the Lagrange equation of the second kind and the assumed mode method. Secondly, by applying the two time-scale assumptions of singular perturbation theory, the system is decomposed into a slow subsystem which represents the rigid motion and a fast subsystem which represents the elastic base and two arms vibration. For the slow subsystem, a finite-time controller based on the nominal model is designed to realize the rigid desired trajectory tracking. Due to the finite time convergence property of the integral sliding mode surface, it has faster convergence speed and stronger robustness than the traditional asymptotic convergence control method. For the fast subsystem, the linear quadratic optimal control method is adopted to suppress the vibration of the elastic base and the two flexible arms simultaneously. Lyapunov theory is used to prove that the proposed control algorithm can enable the tracking error converging to the origin within a finite time. Finally, the simulations verify the effectiveness of the control method.
Design of VHF System Spaceborne SVOMormalsize
LIU Yang, WU Hao, YU Xianyong, LI Zongde, DAI Yuanyuan
2019, 39(3): 373-380.   doi: 10.11728/cjss2019.03.373
Abstract(3185) [PDF 3359KB](52)
Abstract:
The on-board VHF system is an important part of the SVOM satellite. It provides a quasi-real-time VHF-band information access channel for the location information and the important data of the scientific target which is detected by payloads. In this paper, the design of VHF system on-board SVOM is introduced. The equipment design, software design and modulation algorithm design are described in detail. SVOM VHF system is the first application of 4CPFSK modulation in VHF band for spaceborne data transmission in China. Test results show that the implementation of the VHF system can meet the application requirements of the satellites and provides a solution for the real-time transmission of important data of space science satellites.
Solar Wind Parameters and Auroral Hemispheric Power of Magnetic Storm during ICME
LI Xiangyu, NIU Chao, XU Buyun, KANG Zhiqian, LIU Daizhi
2019, 39(3): 310-315.   doi: 10.11728/cjss2019.03.310
Abstract(3140) [PDF 3071KB](99)
Abstract:
Based on three types of ICME-driven magnetic storms, including fierceness magnetic storm (SA type), strong magnetic storm (SB type) and delayed main phase storm (SC type) from 1995 to 2004, temporal superposition of the solar wind speed, the electric field EK-L, the interplanetary magnetic field and the auroral hemispheric power at the 1AU are conducted, and compared with the -vBz coupling function and the Newell coupling function respectively. The results show that there is a relative quiet period of the solar wind, auroral hemispheric power, interplanetary magnetic field and magnetic layer in the early stage of ICME arrival. However, the background solar wind speed, the southward component of the interplanetary magnetic field and the auroral hemispheric power of the SA magnetic storm are higher than those of the other two magnetic storm types. It indicates that the large coronal mass ejection has an effect on the interplanetary magnetic field, the background solar wind, and HP before the ICME arrives. After the rapid start of the magnetic storm, the low slope, delayed peak of the EK-L electric field of SC type magnetic storm and the northward component enhancement of the interplanetary magnetic field are the manifestations of the main phase delay of the magnetic storm.
Model and Impact Risk Assessment of Meteoroid for Marsormalsize
LI Hao, KONG Xiangsen, ZHAO Chuan
2019, 39(3): 283-294.   doi: 10.11728/cjss2019.03.283
Abstract(3235) [PDF 3678KB](44)
Abstract:
A Meteoroid is a small rocky or metallic body in the space. In the solar system, most meteoroids are fragments from comets or asteroids. In the space between Earth and Mars, the speed of meteoroid ranges from 24.13km·-1 to 42.2km·-1. The high speed meteoroid may cause catastrophic damage to Mars probes. In this paper, the meteoroid environment models for the flight from Earth to Mars and the flight in the near-Mars orbits are established respectively. The meteoroid environment models are established based on the zodiacal light observations by the space probes Helios I and Ⅱ, and the observed orbital parameters of comets. The assessment method of meteoroid impact risk for the Mars orbiter mission is also established using the finite element method. A Mars probe with relative anomalous shape is proposed, and the meteoroid impact risk of this assumed Mars probe is predicted for demonstration purpose.
Transport Time for the Geomagnetic Storm Caused by CME
MENG Chen, LU Jianyong, WANG Ming, GU Chunli, JI Haisheng
2019, 39(3): 303-309.   doi: 10.11728/cjss2019.03.303
Abstract(3361) [PDF 1659KB](119)
Abstract:
The transport time is defined as the interval time between the occurrence of CME and the maximum value of the geomagnetic storm. In view of the 89 CME-Dst events collected from 1997 to 2015, the impact of CME speed, energy, and flare type on the transport time is analyzed. Using the non-linear fitting and the nonlinear regression of the Support Vector Machine (SVM), the Curve Fitting (CF) model and the Support Vector Machine (SVM) model for the CME transport time are built. In these models, 62 CME-Dst events during 1997-2006 are used as model input, and the remaining 27 CME-Dst events are used to test the model prediction. The results show that the prediction accuracies both of CF model and SVM model reach at about 85.2%, and the average absolute error of CF model is 13.77h while the SVM model is 13.88h. Comparing with the ECA model (its prediction accuracy is 77.8%, and the average absolute error is 14.55h), the accuracy of these two models is higher and the error is smaller than that of the ECA model. Therefore, CF model and SVM model can predict accurately the geomagnetic storm explosion with 1~5 days in advance.
Prediction of High-energy Electron Flux of Geosynchronous Orbit Based on Empirical Mode Decomposition
QIAN Yedong, ZHANG Hua, YANG Jianwei, WU Yewen
2019, 39(3): 316-325.   doi: 10.11728/cjss2019.03.316
Abstract(3458) [PDF 2941KB](111)
Abstract:
During the recovery of a magnetic storm, the relativistic electrons with MeV energy diffuse from the outer radiation belt to geosynchronous orbit. The electrons which energy are larger than 2MeV could penetrate the surface of satellites and accumulate inside them. Such an electron flux effect could cause satellites to be unable to function properly or to fail completely. Relativistic electrons change very rapidly during the magnetic storm and are very non-stationary. These effects are reduced by empirical mode decomposition method. Data in 2008-2009 are used as the training set, and data in 2010-2013 are used as the testing set. The result shows that the average prediction efficiency of the testing set is 0.81. The solar activity is complex in 2013, and the prediction efficiency is up to 0.81. The prediction efficiency of electron flux has been greatly improved by using empirical decomposition method.
Principle and Accuracy Problems of Gravitational Redshift Experiments in Space
ZHANG Yuanzhong
2019, 39(3): 349-353.   doi: 10.11728/cjss2019.03.349
Abstract(3724) [PDF 1177KB](75)
Abstract:
In this paper, the problems about the principle and accuracy in the experiments of space gravitational redshift are analyzed. Firstly, according to Einstein Equivalent Principle (inertial force is equivalent to gravity), the main part of Earth's gravity inside the spacecraft is cancelled out by inertial force, so that the microgravity inside the spacecraft is much smaller than the gravity at its orbit. For this reason, the gravitational potential of the space borne clock should be taken as an effective gravitational potential corresponding to the microgravity. However, in Ref.[4] (GP-A experiment) and Ref.[5] (Radio astron satellite program), the gravitational potential of the clock is simply taken as the gravitational potential at the orbit. Secondly, testing the relativistic redshift requires a comparison between theoretical prediction and experimental measurement. The accuracy of this test is determined by the larger error. Therefore, if improving just the experimental precision but not the accuracy of the Earth Gravitational Model, then the test accuracy cannot be improved.
Method of Temperature Control and Its Validation for Atomic Clock Cabin on Navigation Satellite
LIN Shifeng, LI Kai, JIANG Guizhong, WU Jian, MA Errui
2019, 39(3): 381-387.   doi: 10.11728/cjss2019.03.381
Abstract(3045) [PDF 2788KB](115)
Abstract:
Atomic clock, as an important part of the navigation satellite, provides high-accuracy and high-stability time frequency source for the satellite. For the continuity and stability of atomic clock operation in orbit, the satellite thermal control system should provide a suitable temperature environment for it. In this paper the thermal control design and the control algorithm of atomic clock are introduced, and the results of thermal simulation and tests based on the atomic clock thermal control for the navigation satellite are provided. Temperature data in orbit show that the thermal design of cabin for atomic clock is suitable. Thermal simulation results and the tests are effective. In addition, the temperature of atomic clocks in orbit meets the requirement and is nearly one order of magnitude better than that of the indicator.
Orbit Determination for Geostationary Earth Orbit Targets Based on the CCD Drift-scan Photoelectric Telescope at One Single Stationormalsize
YU Yong, LUO Hao, MAO Yindun, ZHAO Xiaofen, TANG Zhenghong
2019, 39(3): 365-372.   doi: 10.11728/cjss2019.03.365
Abstract(2680) [PDF 2733KB](66)
Abstract:
As a passive measurement method, the ground-based photoelectric observation is not limited by the equipment on the satellite and can be used to measure most of Geostationary Earth Orbit (GEO) targets above the station. The ground-based photoelectric observation has the advantages of low operating cost, strong intuition and high measurement precision, hence it can play an important role in monitoring the GEO targets. In order to evaluate the actual monitoring ability for GEO targets based on the photoelectric telescope at one single station, observation experiments of 3 Beidou GEO satellites are carried out by 1.56-meter telescope with CCD drift-scan photoelectric technology of Shanghai Astronomical Observatory. The external precisions are estimated by the precise ephemeris of the satellites. The results show that the accuracy of the celestial positioning of the GEO satellites is better than 0.3" in both azimuth and elevation. In the case of single observation pass, although the accuracy of orbit prediction is low, the orbit determination accuracy during observation arc is better than 100m. The effect of orbit improvement based on multi-pass of observations is obvious. In the absence of orbit control, the orbit determination accuracy is better than 50m, and the prediction precision of extrapolating to 4-day is about the order of hundreds of meters. In addition, the accuracy of the orbit prediction of the GEO target in the case of different observation time span is quantitatively evaluated, which can provide the reference for the practical application of the CCD drift-scan photoelectric telescope at one single station.
Life Prediction and Analysis of Momentum Wheel Based on Wiener Process Degradation Modelingormalsize
XU Jingbo, TAN Xueqian, WU Zhen, SUN Danfeng, JIANG Ningxiang, SUN Dan
2019, 39(3): 388-398.   doi: 10.11728/cjss2019.03.388
Abstract(3177) [PDF 1863KB](102)
Abstract:
Momentum wheel as a key actuator for satellites, its reliability and life span directly affect the success or failure of satellite missions in orbit. For the life prediction and analysis of momentum wheel products, due to the limited number of samples, long test cycle and high cost, it is impossible to obtain enough life sample data. Therefore, combined with engineering experience and existing ground life test data, the Wiener process degradation model is used to model the reliability of the momentum wheel product, and its life expectancy is estimated and analyzed. The results show that this model provides an effective method for predicting the life of a momentum wheel and is suitable for life prediction and analysis of high reliability, long life products.
A Model for Real-time Calculation of the Atmospheric Neutronormalsize
CHEN Shanqiang, LIU Siqing, CHEN Dong, LIN Ruilin, SHI Liqin, CAO Yong
2019, 39(3): 342-348.   doi: 10.11728/cjss2019.03.342
Abstract(3134) [PDF 4015KB](56)
Abstract:
In order to evaluate the global distribution of atmospheric neutron at 0~100km altitude for real time, the propagation of cosmic rays in the geomagnetic field and the atmosphere is analyzed. By using the TSY05 and MAGNETOCOSMICS model, the real-time calculation of global geomagnetic cut-off rigidities with 1h resolution is realized. The spherical shell geometry model is established at intervals of 1km using NLRMSISE-00 model, and the spectrum distribution of secondary particles generated by different particles is calculated by the Monte Carlo simulation techniques, namely, the Geant4 toolkit, then an atmospheric neutron database is created. Compared with EXPACS model, the validity and reliability of the database are verified. Based on the observed or predicted space environment parameters, the energy spectra of the cosmic ray and the solar proton event in the synchronous orbit are calculated, and the effective vertical cut-off rigidities in function of latitude and longitude at the altitude of 100km. The atmospheric neutron and effective dose are calculated by using linear interpolation per hour.
SOLAR ACTIVITY,SEA TEMPERATURE IN THE KUROSHIO REGION AND THE FLOOD AND DROUGHT IN THE MIDDLE REACH OF THE YANGTZE RIVER
Ruan Xue-qin, Ma Fu-hui
1995, 15(4): 326-332.   doi: 10.11728/cjss1995.04.326
Abstract(2283) [PDF 560KB](54)
Abstract:
The relationship among solar activity,the sea temperature in the Kuroshio region and the flood and drought in the Middle Reach of the Yangtze River (MRYR)is investigated by using 30 years'data of solar activity,the sea temperature in the Kuroshio region and the rainfall in the MRYR. Results show that the rainfall in the MRYRis obviously controlled by the interannual and seasonal variations of solar activity and the sea temperature in the Kuroshio region.The solar 10.7cm radiation flux is taken as the index of solar activity and the interannual fluctuation curve of the difference of F10.7 between winter and summer oscillates with a period of about 11 years.The flood years(or drought years)frequently occurred when the positive part (or negative part and odd point) of the curve appeared 3 years ago and the last year lay in the peak (or valley,or near zero point)of the seasonal variation curve of the sea temperature in the Kuroshio region.According to these features, the solar activity data in the previous two years and the sea temperature data in the Kuroshio region before this spring can be used to analyze the trend of flood or drought in the MRYRin the coming summer.
Analysis of Stratospheric Gravity Wave Parameters Based on COSMIC Observationsormalsize
WANG Yizhou, HUANG Yingying, LI Huijun, LI Chongyin
2019, 39(3): 326-341.   doi: 10.11728/cjss2019.03.326
Abstract(3139) [PDF 10967KB](93)
Abstract:
Using the temperature profiles between 30°N and 40°N latitude observed by COSMIC satellites from 29 December 2006 to 3 January 2008, the disturbances and potential energy (Ep) of Gravity Waves (GWs) in lower stratosphere are calculated by vertical running windows method, double-filter method and single-filter method, respectively. The altitude and longitude distributions, and multi-time scale variations of these parameters are obtained. The spatial characteristics of background temperature and horizontal wind fields are analyzed to investigate the possible origins of GWs. The disturbances and potential energy (Ep) of GWs in lower stratosphere obtained by the above three methods are compared. The results are as follows. The errors of GW perturbations calculated by vertical running windows method are relatively large, because it can only remove the disturbances with large vertical scales, while can not remove small vertical scales in derived GW disturbances. The double-filter can well suppress both large-scale background and small-scale disturbances in temperature profiles. GW disturbances obtained by a single-filter does not include large vertical scale background, but still contain some small vertical scale disturbances. The double-filter method cannot obtain altitude variations of Ep, while the single-filter method can give altitude variations of monthly averaged Ep. The relationships between GWs' parameters (including disturbances and Ep) and background temperature and horizontal wind fields are revealed.
Global Space Weather Roadmap and Its Enlightenment to China
LIU Siqing, LUO Bingxian
2019, 39(3): 275-282.   doi: 10.11728/cjss2019.03.275
Abstract(3356) [PDF 1571KB](115)
Abstract:
With the development of technology, space weather has an increasingly impact on global technology infrastructure such as power systems, communication and navigation systems and aerospace assets. Humans need to strengthen their understanding of space weather events, improve space weather forecasting capabilities, and optimize infrastructure designs to mitigate the impact of space weather on society. Based on these requirements, the Committee on Space Research (COSPAR) of the International Council for Science (ICSU) and the International Living With a Star (ILWS) Steering Committee jointly established an expert group to study and develop a global road map for 2015-2025 on space weather. This paper introduces and interprets the roadmap and discusses the implications of the roadmap for the development of space weather in China.
IDENTIFICATION OF THE DISCONTINUITIES AT THE MAGNETOPAUSE
Zhou Guo-cheng(Chow Gou-chon)
1981, 1(1): 41-46.   doi: 10.11728/cjss1981.01.041
Abstract(2067) [PDF 499KB](52)
Abstract:
In this paper we have studied the possibility to identify different types of the magnetopause discontinuities by means of the characteristics of the discontinuities of the magnetic fields, teh bulk flow velocities and the thermaldynamic parameters.This method itself is independent of the normal directions on the magnetopause.The analysis shows that this method may be used to identify several types of the discontinuities which may occur at the magnetopause.
Demonstration and Analysis of LEO Real-time Kinematic Precise Orbit Determination with Priori Orbit Constraint ormalsize
SHI Yishuai, HAO Jinming, JIAO Wenhai, DONG Ming, JIAO Bo, LIU Weiping
2019, 39(3): 354-364.   doi: 10.11728/cjss2019.03.354
Abstract(3043) [PDF 5059KB](65)
Abstract:
Real-Time Precise Orbit Determination (RTPOD) of Low-Earth-Orbit (LEO) satellites can greatly expand their ability to perform complex scientific missions, such as real-time environment monitoring, maneuver control and satellite autonomous navigation. In this paper, the model of real-time kinematic precise orbit determination is introduced. We present a conception that the LEO Priori Orbit Constraint (POC) is used in the process of RTPOD for the sake of improving the accuracy, convergence speed and stability. The broadcast ephemeris, predicted part of ultra-rapid ephemeris and real-time precise ephemeris are adopted respectively to propose 6 different RTPOD solutions, which are then demonstrated and analyzed using the observations from Swarm A/B/C satellites during 7 days. The results show that the accuracy is improved in turn by using broadcast ephemeris, IGU and IGC ephemeris. Moreover, adding POC can further enhance the result while using the same ephemeris. The IGC+POC solution using the priori orbit with a 1m standard deviation reaches an accuracy of 6.12cm, 5.55cm and 4.98cm in the radial, along and cross component, respectively, which is comparable to the post-processing kinematic POD. Analyses based on different priori orbits indicate that the ideal priori orbit should appear less noise and long-term systematic biases, and short-term systematic biases show little influence on constraint results. Furthermore, adding POC can remarkably speed up the convergence. The convergence of IGC solution needs about 31min on average, whereas the average convergence time after adding POC with a 1m standard deviation is about only 4min, which is beneficial to the fast re-convergence after the occurrences of cycle slip, loss of lock and communication link interruption, and is of great significance in practical application scenarios.
Optimal control for state-keeping stage of tethered satellite with random perturbation
Wang Changqing, Zhang Malin, Wang Wei, Li Aijun, Y Zabolotnov
2014, 34(6): 881-886.   doi: 10.11728/cjss2014.06.881
Abstract(1278) [PDF 633KB](57)
Abstract:
The dynamic equations of a Tethered Satellite System (TSS) with elastic tether were established. This model was linearized at the equilibrium position, and the influence of random perturbation on TSS was considered. In order to fulfill the station-keep control of the TSS along orbits, by integrating Kalman filter with the optimal state feedback control, a control scheme based on the 2nd Young Engineers' Satellite (YES2) project was proposed. Finally, simulation analyses based on the models with considering elasticity and neglecting elasticity were made respectively. Simulation results show that the system under proposed law has good anti-ja mming performance. Besides, the tether tension changes smoothly and its amplitude is small, so that the TSS has superior reliability and security. And with the decrease of stiffness, the tether longitudinal vibration increases, which could provide ideas for selecting the appropriate tether material.
Analysis on Application of Real-Time Ethernet in Spacecraft
Qiu Aihua, Zhang Tao, Gu Yidong
2015, 35(3): 368-380.   doi: 10.11728/cjss2015.03.368
Abstract(1213) [PDF 2338KB](76)
Abstract:
The main purpose to use Ethernet in spacecraft is to take advantage of its flexibility to meet the requirement of communication access convenience, simultaneously take into account that Ethernet has high bandwidth and data rates, and expect that it has both real-time and deterministic in control field. Looking for some real time network is the priority of the spacecraft using Ethernet. The deterministic scheduling mechanism of communication and transmission characteristics of real-time Ethernet has become a main determination of whether the Ethernet can meet the demand of spacecraft network traffic characteristics. According to the analysis of data communication characteristics in spacecraft, and comparison of real-time Ethernet communication scheduling strategy, the real-time Ethernet applied in spacecraft should has time synchronization, strong real-time, deterministic, high-bandwidth, containing multiple data types, dual redundant channels, meanwhile it is compatible with standard Ethernet.
Whistler Wave and Hall Effect in Magnetic Reconnection
QIU Qi, JIN Shuping
2008, 28(2): 114-122.   doi: 10.11728/cjss2008.02.114
Abstract(2760) [PDF 4723KB](50)
Abstract:
The effects of Hall current on the reconnection dynamics and wave behavior are numerically studied in this report. The notable reductions in the openness of outflow region and the reconnection rate are shown as Hall effect weakens. The time series of the out-of-plane magnetic field By and the velocity components vx, vz in the (x, z) plane at the given points are transferred into the power spectra by the Fast Fourier Transformation (FFT) for the cases with various intensive Hall terms. Using the Minimum Variance Analysis (MVA) on E, the propagation directions and the polarized features of waves are determined. It can be found that there exists the whistler wave with the typical features near the magnetic separatrices in the case of the stronger Hall effect and the wave signature weakens substantially as the intensity of Hall effect is reduced. These results indicate that Hall effect has an important influence on the reconnection dynamics and plays a crucial role in generating the whistler-mode wave and fast reconnection rate. Besides, there is a positive coherency between the amplitude of whistler wave and the field-aligned current Jp in the plane near the magnetic separatrices in the case with the strong Hall term. It demonstrates the closed linkage between the whistler wave and Hall effect on the other hand.
2400 Years and track cycles of the sun's orbital motion
Liu Fugang, Zheng Yi, Wang Jian, Luo Jinming, Bao Kunshan
2015, 35(4): 381-392.   doi: 10.11728/cjss2014.04.381
Abstract(1785) [PDF 5318KB](42)
Abstract:
Through Fourier transferring of data from the planetary synodic index, it is found that the year, 10-year, 100-year, 1000-year, 10000-year and 100000-year scales of cycles have 10n multiple relationship. More interestingly, if we set the most significant period (4.96488a) on the year scale as the unit time step and put it into the equation of planetary synodic index, 2400 years cycle would be determined stably. On this basis, 2400 years cycle can be also assembled to form 100000 years and 400000~410000 years cycles of the Sun's orbital motion. This is helpful to unveil the relationship between the Sun's orbital motion and solar activity, and is significant to discuss the mechanism of climatic variation on the thousand years and orbital scales.
Polynomial Solutions of the Ion Velocity Distributions and the Calculation of Incoherent Scatter Spectra in the High-latitude Auroral Ionosphere
XUE Kun, XU Zhengwen, WU Jian, ZHANG Yabin
2015, 35(4): 424-437.   doi: 10.11728/cjss2015.04.424
Abstract(1394) [PDF 927KB](142)
Abstract:
In order to describe accurately ion velocity distribution in the auroral ionosphere, the relaxation collision model and the Maxwell molecule collision model is used to describe ion-neutral collisions of Boltzmann equation respectively. The expressions of the ion velocity distribution for 13-moment approximation based on the Maxwell and for 16-moment approximation based on the bi-Maxwell can be obtained by solving the transport equations of the Maxwell molecule collision model and the relaxation collision model respectively. According to Sheffield's theories, the incoherent scatter spectra are calculated using the ion velocity distribution of 13-moment approximation and 16-moment approximation for the relaxation collision model and the Maxwell molecule collision model respectively. Finally, the comparison of results of the incoherent scatter spectra between Maxwell molecule collision model and relaxation collision model are given. It is found that, the Maxwell molecule collision model is better than the relaxation collision model to describe the interaction between ion and neutral component in the ionosphere E layer. The 16-moment approximation is better than 13-moment approximation to describe the ion temperature anisotropy due to increased electric field.
The Curvature Radiation from Cosmic Monopole
Li Xiao-qing, Li Zhong-yuan
1985, 5(3): 161-167.   doi: 10.11728/cjss1985.03.161
Abstract(1908) [PDF 393KB](49)
Abstract:
The curvature radiation resulting from cosmic monopole is investigated in detail. It is shown that there are suppressed effects for cosmic plasma on the curvature radiation of monopole.
Strategic Priority Program on Space Science
Wu Ji, Sun Lilin
2014, 34(5): 505-515.   doi: 10.11728/cjss2014.05.505
Abstract(1229) [PDF 13448KB](48)
Abstract:
In 1957, the launch of the first artificial satellite ushered in a new era for modern space science.The past 50 years' developments in China's space science have witnessed many major missions, and substantial progress has been achieved in space science study, exploration technology as well as experiment technology. Strategic Priority Program on Space Science was officially started in 2011. Through both self-developed space science missions and those with international cooperation,it is expected that the innovative breakthroughs will be realized, leapfrog development of related high-tech will be achieved to establish the important strategic status of space science in national development. To sum up, the implementation of the Strategic Priority Program on Space Science will definitely promote the rapid development of China's space science endeavor, making contributions to China's development and the progress of human civilization.
LIDAR OBSERVATIONS OF THE MESOSPHERIC Na LAYER OVER WUHAN: SEASONAL AND NOCTURNAL VARIATIONS
MAO Fei, YI Fan
2003, 23(3): 197-204.  
Abstract(2349) [PDF 752KB](66)
Abstract:
Based on the lidar observations between March 2001 and October 2002, the characteristics of background Na layer over Wuhan (30.5°N, 114.4°E) are presented and compared with other reported lidar measurements, especially with that of Ur-bana (40°N, 88°W). The sodium abundance in Wuhan reaches a maximum value in November which is approximately 2.5 times larger than that in April. In November and May, the layer centroid height reaches its minimum and its maximum in April, September and December. The yearly averaged rms width is 4.47km. There is a variation trend in the parameters of Na layer. Especially, the layer rms width shows a semiannual variation trend. The sodium layer abundance generally increases through the night. After rapidly ascending from sunset, the layer centroid height climbs up slowly between 2000 LT and 0500 LT, then descend swiftly. The sodium layer rms width shows about 1.3km variation during the night. At first the layer rms width diminishes, after arriving at a minimum at 0035 LT, it increases steadily with time.
Statistical Properties of Solar Proton Events during Solar Cycle 23 and 24
BAI Tienan, LE Guiming, ZHAO Haofeng
2017, 37(6): 649-658.   doi: 10.11728/cjss2017.06.649
Abstract(1246) [PDF 1047KB](64)
Abstract:
There were totally 128 Solar Proton Events (SPEs) from 1997 to 2016. Their peak flux ranges are from 10pfu to 99pfu, 100 to 999pfu, 1000 to 2999pfu and greater than 3000pfu, and the percentage is 55.15%, 27.94%, 9.56% and 7.35% respectively. The results show that SPEs with different peak flux have different asymmetry. The SPEs with peak flux ranged from 1000pfu to 2999pfu have the largest asymmetry, while those with peak flux greater than 3000pfu have smallest asymmetry. In Solar Cycle 23, the SPEs mainly occurred during the period from the first peak to the second peak and after the second peak of the smoothed monthly mean sunspot numbers. In Solar Cycle 24, the SPEs mainly occurred during the period before maximum of smoothed monthly mean sunspot numbers.
Simplified Calculation Method of Geomagnetic Field Model ormalsize
ZHANG Tao, GAO Dong, ZHENG Jianhua
2018, 38(1): 88-93.   doi: 10.11728/cjss2018.01.088
Abstract(1916) [PDF 1338KB](57)
Abstract:
To realize the application of geomagnetic navigation on the low orbit satellite, the complexity, enormous calculation, poor real time ability of traditional Gaussian spherical harmonica function should be solved before being used to calculate the geomagnetic vector. A geomagnetic field approximation function, Geomagnetic Field Approximation Functions (GFAF), is proposed to replace the spherical harmonic function. Dipole model under a pseudo-centers is utilized to replace the main geomagnetic model in GFAF method. And the coefficient of pseudo-center of different latitude-longitude grid is obtained by polynomial fit method. Finally, the geomagnetic field vector of any position can be achieved using different interpolation algorithm. A simulation test is carried out under the condition that the increment of latitude and longitude is 0.5° and the orbital height is from 300 to 500km. The results show that the navigation accuracy of GFAF method is the same to that of geomagnetic field model. However, GFAF method effectively decreases the cost of computing and and improves the calculation efficiency.
Research Advances of Solar Corona and Interplanetary Physics in China:2012-2014
Zhao Xinhua, Wang Yuming, Yan Yihua, Chen Yao, Cheng Xin, He Jiansen, Qin Gang
2014, 34(5): 565-604.   doi: 10.11728/cjss2014.05.565
Abstract(1226) [PDF 432KB](42)
Abstract:
Solar transients and their related interplanetary counterparts have severe effects on the space environments of the Earth. Therefore, the research of solar corona and interplanetary physics has become the focus of study for both solar and space scientists. Considerable progress has been achieved in these aspects by the solar and space physics community of China during 2012-2014, which will be given in this report. The brief report summarizes the research advances of solar corona and interplanetary physics into the following parts: solar wind origin and turbulence, coronal waves and seismology, solar eruptions, solar energetic particle and galactic cosmic ray, magnetic reconnection, Magnetohydrodynamic (MHD) models and their applications, waves and structures in solar wind, propagation of ICMEs/shocks and their arrival time predictions. These research achievements have been achieved by Chinese solar and space scientists independently or via international collaborations.
Science Researches of Chinese Manned Space Flight
Gu Yidong, Gao Ming, Zhao Guangheng, Liu Yingchun, Jin Zhaojun
2014, 34(5): 518-524.   doi: 10.11728/cjss2014.05.518
Abstract(1800) [PDF 6392KB](54)
Abstract:
With the complete success of the 2nd stage of Chinese Manned Space Program (CMSP), several science researches have been performed on Tiangong-1 experimental spacelab, which was docked with three Shenzhou spaceships one after another. The China's real spacelab, Tiangong-2 will be launched in 2015, docked with a Shenzhou spaceship soon. After six months, it will be docked with the first Chinese cargo ship (Tianzhou-1). More space science researches, involving with space biology, fluid physics, fundamental physics, materials science, Earth science, astronomy and space environmental science, will be operated on Tiangong-2 spacelab, and crewed and cargo spaceships. Furthermore, the considerable large-scale space utilization of Shina's Space Station is planned. The research fields include yet not limited to space medicine and physiology, space life science and biotechnology, fluid physics and combustion in microgravity, space material science, and fundamental physics in microgravity, space astronomy, Earth science, space physics and space environment utilization, technology demonstration.
Quantum Science Satellite
Pan Jianwei
2014, 34(5): 547-549.   doi: 10.11728/cjss2014.05.547
Abstract(2937) [PDF 1081KB](165)
Abstract:
Quantum Science Satellite is one of the first five space science missions, slated for launch in the framework of Chinese Academy of Sciences (CAS) Strategic Priority Research Program on space science. The project aims to establish a space platform with long-distance satellite and ground quantum channel, and carry out a series of tests about fundamental quantum principles and protocols in space-based large scale. The satellite will be launched at Jiuquan and on orbit for 2 years. The orbit will be circular and Sun-synchronous with an altitude of 600km. It crosses the descending node at 00:00LT. The satellite is under early prototype development currently.
Kinetic Magnetic Turbulence Associated with Flux Transfer Events Observed by THEMIS Satellite ormalsize
ZHOU Zhaodi, ZHANG Hui, NI Binbin, ZHANG Xiaojia, ZHU Changbo, FU Song
2018, 38(2): 169-177.   doi: 10.11728/cjss2018.02.169
Abstract(1101) [PDF 1110KB](71)
Abstract:
Intense magnetic fluctuations are recorded in the magnetosphere near the magnetopause when Flux Transfer Events (FTE) are passed by the THEMIS satellites. The power spectra of these fluctuations obtained by Fast Fourier Transform (FFT) show that the Power Spectra Density (PSD) peaks around the disturbance frequency of FTE (about 0.1Hz), and decreases from the proton gyrofrequency (about 1Hz) to 64Hz following a power law of P0f-α. These fluctuations are interpreted as magnetic turbulences in the kinetic regime in the Low Latitude Boundary Layer (LLBL). The results show that both the PSD and the slopes of the power spectra α decrease when the observing satellite position is more and more away from the magnetopause or the FTE location in the LLBL. However, α and the PSD are independent from the azimuthal position of FTE or local time of the low latitude magnetopause. All these observations suggest that the moving FTEs are the source for these magnetic fluctuations. Large scale perturbations on the magnetopause, e.g. FTEs and the associated magnetic turbulences, provide a hint which may reveal the interaction between the magnetosheath and the magnetosphere in a kinetic scale. Whether the magnetic turbulences can provide enough viscosity for the forming of the flow vortices on the magnetospheric side of FTEs or not need to be further confirmed.
Fuzzy Robust Sliding Mode Control and Flexible Vibration Active Suppression of Flexible-joint Space Robot Based on Flexibility Compensation
Xie Limin, Chen Li
2013, 33(6): 683-689.   doi: 10.11728/cjss2013.06.683
Abstract(1138) [PDF 577KB](25)
Abstract:
For free-floating flexible-joint space robot system with uncertain parameters, the dynamics modeling, motion controller design and flexible vibration active suppression are developed. Dynamic equations of the system are established by the system's linear and angular momentum conservation and Lagrange equation. In order to overcome the limitations of that the traditional singular perturbation method only applies to the system with weak joint flexibility, a joint flexibility compensator is designed to improve the flexible-joint's stiffness of space robot system equivalently. On the above basis, the system is decomposed into a slow subsystem and a fast subsystem by singular perturbation method, and the controllers of the subsystems are designed. The slow subsystem's fuzzy robust sliding mode controller can compensate the uncertain parameters, decrease the rotation angle transmission errors caused by the flexible-joint, and realize the asymptotic tracking of the system desired trajectory. The fast subsystem controller can suppress the flexible vibration caused by flexible-joint actively. The simulation experimental results prove the efficiency of the hybrid controller.
Thermal Control Design and Simulation Calculation of the Alpha Particle X-ray Spectrometer
Zhang Jiayu, Wang Huanyu, Zhang Chengmo, Yang Jiawei, Liang Xiaohua, Gao Min, Wang Jinzhou, Cui Xingzhu, Peng Wenxi
2013, 33(6): 672-677.   doi: 10.11728/cjss2013.06.672
Abstract(1481) [PDF 1294KB](69)
Abstract:
The APXS (Alpha Particle X-ray Spectrometer) is installed on the outside of the Lunar Rover, so that the lunar rocks and soil can be studied by the mobility of the Rover and flexibility of the robotic arm. Because of being exposed outside the rover, APXS will have great impact by the complex outer heat flux. In view of this, a reasonable thermal design is necessary for APXS to ensure that the APXS detector and electronic devices operate within the temperature range of its allowance. In this paper, the thermal control designs of APXS and the thermal simulation calculation results based on its thermal control designs are summarized. And the calculation results have been validated by corresponding thermal balance tests.
Gyroresonance between Fast Magnetosonic Waves and Particles in a Multi-ion Space Plasma
XIAO Hui, ZHOU Qinghua
2018, 38(3): 332-341.   doi: 10.11728/cjss2018.03.332
Abstract(1913) [PDF 4081KB](39)
Abstract:
Fast Magnetosonic (MS) waves are right-hand polarized waves. They propagate both inside and outside the plasmasphere, and the wave vectors are almost perpendicular to the ambient magnetic field. Fast MS waves can lead to local electron acceleration, scattering of outer radiation belt energetic electrons, and scattering of energetic protons etc. Using the fully and high-density approximated dispersion relations, the dispersion curve of fast MS with different wave normal angle is analyzed, and the minimum resonant energy between MS waves and ions (H+, He+, and O+) are calculated. The results show that, as the wave normal angle is relatively small, the minimum resonant energy obtained by the high-density approximated and fully dispersion relation is quite close to each other in a high density and weak magnetic field space plasma. Remarkable error occurs when the high-density approximated dispersion relation is used in the low and medium density space plasma or when the wave normal angle is greater than 88°. Therefore, the fully dispersion relation must be used in these cases.
Study on the Survivability of Space Tethers Due to Debris Collisionsormalsize
YU Ziyuan, LI Aijun, YANG Shu, WANG Changqing
2018, 38(4): 560-566.   doi: 10.11728/cjss2018.04.560
Abstract(1094) [PDF 833KB](112)
Abstract:
The structures and dimensional parameters of space tether significantly affect their survivability against space debris collisions in complex space environment. This work addresses the probability analysis for double tethers and tape tethers severed by debris based on tether-debris collision model and Poisson distribution. The influence of debris on the survivability of space tethers is also studied. A double tether is a pair of parallel strings connected at a certain distance, and tape tethers can be treated as a specific type of single tethers with rectangular cross-sections. The probability of single tethers severed by space debris is modeled, and the survivability functions for double tethers and tape tethers are also formulated. Moreover, the survivability of tethers with different structures and dimensional parameters is calculated based on a cumulative debris flux model. The results show that double tethers and tape tethers are of higher survivability compared with single tethers.
Characteristics of Multi-GNSS Global Gonospheric Godeling and Gnalysis of the Accuracy
Zhao Wenjiao, Wang Hu, Dang Yamin, Bai Guixia
2015, 35(3): 306-314.   doi: 10.11728/cjss2015.03.306
Abstract(1187) [PDF 14054KB](44)
Abstract:
The model of ionospheric delay correction is established by only GPS and by fusing BDS, GPS and GLONASS with observations of pseudo distance smoothed by carrier phase and spherical harmonics. And some experiments of the global ionospheric inversion have been done. The variations process of ionospheric is fused daily in January, 2014 to obtain monthly comprehensive differential code bias product and did some analysis on the accuracy of the products. The fusion of the three systems not only increases the number of satellites observation but also improves the geometric distribution of the puncture point. The analysis result shows that the accuracy of inversion of global ionospheric of three system fusions is better than GPS system alone, about 5 to 10 increase in TECU. The Precision of monthly comprehensive differential code bias product of GPS is better than GLONASS, while the BDS stability is poor.
Fuzzy Neural Networks Sliding Mode Control and Active Vibration Suppression for Free-floating Space Flexible Manipulator
WANG Zongyuan, CHEN Li
2013, 33(5): 569-576.   doi: 10.11728/cjss2013.05.569
Abstract(2028) [PDF 741KB](62)
Abstract:
This paper discusses the trajectory tracking and vibration suppression of free-floating flexible space manipulator with uncertain system parameters. The conception of virtual control force is used to design a virtual desired trajectory which reflects both flexible vibration and rigid motion. Then, in order to steadily track the trajectories of the base's attitude and the joint angle, the adaptive non-singular terminal sliding mode controller is proposed to track the desired trajectory. The controller integrates the advantages of terminal sliding mode technique, Fuzzy Wavelet Neural Network (FWNN) with good function approximation characteristic and robust control technology to process approximate error. In addition, adaptive algorithm is adopted for fuzzy wavelet neural network to adaptively adjust its all network weights and parameters, so the controller has strong robustness. Simulation results are given to illustrate the effectiveness of the proposed control scheme.
Multi-body Dynamics of Repeated Fold-unfold and Lock-unlock Solar Array
Hu Ming, Kong Fei, Chen Wenhua, Li Wenjuan, Han Yadi, Wang Qingjiu
2014, 34(4): 489-496.   doi: 10.11728/cjss2014.04.489
Abstract(1452) [PDF 1495KB](155)
Abstract:
This paper presents the dynamic characteristics of repeated fold-unfold and lock-unlock solar array, which is in a topological tree configuration. According to the first modal stiffness analysis, assumptions about solar array multi-body system are proposed. Deduced from Jourdain variation principle, dynamic model of solar array flexible multi-body system is built. Furthermore, the forward-inverse mixed dynamic model is established through forward recursive formulation and motion law of solar array hinges. In order to study the impact of flexible structures on solar array deployment, the motion parameters of solar array panels, such as rotation angle, angular velocity and angular acceleration, are obtained from numerical simulation, which is based on the structure and physical parameters of repeated fold-unfold and lock-unlock solar array prototype. The results can well predict dynamic behaviors of solar array during its deploying process. In conclusion, this study has laid a foundation for subsequent engineering applications of repeated fold-unfold and lock-unlock solar array.
Spacecraft attitude disturbance optimization of space robot under multi-position restraint
Guo Chuangqiang, Ni Fenglei, Liu Hong
2015, 35(2): 230-236.   doi: 10.11728/cjss2015.02.230
Abstract(1198) [PDF 1692KB](107)
Abstract:
Optimization design of the path of the space manipulator tip is an economic and efficiency way to reduce the attitude disturbance on the basement arising from the motion of manipulator. However, research on the motion trajectory optimization for space robot under the condition of multi-position restraint in the Cartesian space is rare. In this paper, the motion trajectory was parameterized on the basis of revised cubic spline. Disturbance on the basement arising from the motion of manipulator was expressed by the objective function about the interpolating point of the spline and the migration time between two adjacent restrained positions. The global optimization of the objective function was realized using genetic algorithm. Simulation results indicated that the presented approach can effectively reduce the influence of disturbance on the attitude of basement, which was caused by the motion of manipulator. The designed trace in joint space is twice continuously differentiable.
Impact Dynamics of Flexible Space Manipulator Capturing a Satellite, Stabilization Control and Flexible Vibration Linear Quadratic Optimal Suppression
Dong Qiuhuang, Chen Li
2014, 34(3): 367-376.   doi: 10.11728/cjss2014.03.367
Abstract(1105) [PDF 685KB](55)
Abstract:
The impact dynamics of space manipulator system capturing a satellite, and control of post-impact unstable system were discussed. The dynamics model of space manipulator system was derived by the second Lagrange equation. At the impact moment when the space manipulator capturing a satellite, the impact effect for the space manipulator was calculated by momentum impulse method. For stabilizing the post-impact unstable space manipulator and satellite combination system, the linear feedback and linear quadratic optimal composite control algorithm was proposed for the space manipulator stabilization control and flexible link vibration suppression, and there was no need for the position control of the free-floating base under the proposed control algorithm employed, which would save the fuel consumption of free-floating base thruster. Finally, numerical examples are proposed to simulate the impact effect for space manipulator motion state which is caused by the impact, and the effectiveness of above control algorithm is verified.
AN OPTIMIZED METHOD TO CONTROL THE MOTION PLANNING OF SPACE MANIPULATORS BASE GENETIC ALGORITHM
GE Xinsheng, ZHANG Qizhi, LIU Yanzhu
2000, 20(2): 185-191.   doi: 10.11728/cjss2000.02.185
Abstract(2259) [PDF 382KB](17)
Abstract:
The problem of nonholonomic motion planning of space manipulator system isdiscussed in this paper. The problem of nonholonomic motion planulng of spacemanipulator is transformed into the optimized colltrol of nonlinear system by usingthe nonholonomic characters of the system. The genetic algorithm is introducedto solve the optimized control problem. Based on genetic algorithm for optimizedcontrol of nonholonomic motion planning of space manipulator is proposed. Theeffectiveness of the method is proved by the numerical simulation examples.
Motion simulation and function test on repeated fold-unfold mechanism of fan-shaped solar array
HU Ming, LI Wenjuan, CHEN Wenhua, TIAN Fangfei, ZHANG Yang
2016, 36(1): 92-98.   doi: 10.11728/cjss2016.01.092
Abstract(1352) [PDF 1797KB](86)
Abstract:
The traditional folding solar array with large size and big mass, using single deployment and locking mechanism, can cause flutter during the spacecraft attitude adjustment or orbital transfer, and hence a fan-shaped solar array with repeated fold-unfold and lock-unlock mechanism scheme was designed. A virtual prototype model is established based on ProE/Adams co-simulation, and the motion parameter changing rule of the pivot panel at different motor rotational speeds is obtained. The deployment function verification test is carried out using the prototype. By comparing the simulation result with the test data, it can be known that the mechanism can be fully deployed and locked in time when the motor speed is changed in prescriptive range, and can be deployed and locked repeatedly. The simulation result is highly consistent with the test data, which shows that the design can meet the requirements.
Time Delay Estimation of Flexible Space Robot Robust H Control and Vibration Suppression
YE Bingneng, CHEN Li
2016, 36(2): 237-244.   doi: 10.11728/cjss2016.02.237
Abstract(912) [PDF 918KB](51)
Abstract:
This paper discusses the trajectory tracking and vibration suppression of free-floating flexible space robot with uncertain system parameters, which combines the advantages of time delay estimation control and robust H control. Time-delayed estimation is used to achieve unknown dynamics of space robot system online and to perform a compensation during the tracking control. L2 gain control is employed to achieve L2 interference suppression of time-delay estimation error, which could further improve the robustness of the system. At the same time, theoretical analysis proves that the introduction of L2 gain control can suppress the influence of time delay estimation error on the system to satisfy the robust H performance, and ensures all signals in the closed-loop system to be bounded. In addition, the virtual control force is proposed to transform the original control scheme, which can achieve both tracking the desired trajectory and suppressing the flexible vibration control target through only one control input. Simulation results and comparison chart are given to illustrate the effectiveness of the proposed control scheme and the active vibration suppression of flexible.
Ion-scale Structures in Flux Ropes Observed by MMS at the Magnetopause
LIU Yang, PU Zuyin, XIE Lun, GUO Ruilong, WANG Xiaogang, XIAO Chijie, SHI Quanqi, DUNLOP M, BOGDANOVA Y V, MOORE T E, RUSSELL C T, LINDQVIST P A, TORBERT R B, POLLOCK C, ZHAO Cong
2018, 38(2): 147-168.   doi: 10.11728/cjss2018.02.147
Abstract(1193) [PDF 3653KB](113)
Abstract:
In this paper the structures with scale of ion inertial length (di) in flux ropes at the magnetopause are studied based on MMS measurements. The results show that currents ( j m) of di scale are found to exist in many flux ropes with different scales, which flow in the -M direction in magnetopause local coordinates (i.e., in the same direction of the Chapman-Ferraro current at the magnetopause) and are carried by electrons' motion in the +M direction ( v em). Within the current structures, magnetosheath and magnetospheric plasma populations are mixed; the magnetic field has open topology; ions are non-magnetized, while electrons are frozen-in with the magnetic field lines; the N-component of electric field ( E n), which is Hall electric field in nature, substantially enhances (up to about 20mV·m-1), accompanying with notable fluctuations. Detailed analysis shows that the current, separation of electrons' motion from ions and the Hall electric field are closely related to each other, and obey the general Ohm's Law. In addition, we have also analyzed the MMS measurements of magnetic reconnection events at the magnetopause. It is found that structures similar to those in flux ropes are also present inside the reconnection region in many cases. Their scales are of di length. The directions (magnitudes) of the Hall electric field E N, current filament j M and electron velocity v eM are as same as (close to) those in flux ropes. On the bases of above observations and making use of the classical flux rope models, how the di-scale structures in flux ropes are formed is studied. It is suggested that they are likely to originate from the corresponding structures in the reconnection region at the magnetopause which play an essential role in the formation process of di-scale flux ropes.
Thermal Design and Simulation of a Space Phase Change Heat Exchanger
MA Caixin, SHENG Qiang, TONG Tiefeng
2018, 38(3): 409-417.   doi: 10.11728/cjss2018.03.409
Abstract(1505) [PDF 3773KB](136)
Abstract:
Phase Change Material (PCM) is widely used in energy storage due to its huge latent heat. To overcome its drawback of poor thermal conductivity, a Phase Change Heat Exchangers (PCHE) which combine the advantage of heat exchanger and PCM is designed. It can be used cooling high density of heat flow rate surface in aero-space. Based on the phase change computing methods-Enthalpy method for solidification and melting model, the numerical simulation of a kind of plate PCHE, which used water and paraffin as cooling medium and phase-change material, is studied. The transient temperature distribution, solid-liquid phase interface changes and melting time are obtained under different gravity conditions. The results show the performances of PCHE satisfy the design request. comparing the results under different gravity conditions, Heat Transfer Enhancement Method (HTEM) is used by add fins and metal or ceramic foams to improve the efficiency of the PCHE under microgravity. It is valuable to the design and experiment research of space PCHE.
High-precision Space-Borne Accelerometer and its Applications
Bai Yanzheng, Tian Wei, Zhou Zebing, Wu Shuchao, Tu Haibo
2010, 30(6): 601-606.   doi: 10.11728/cjss2010.06.601
Abstract(2795) [PDF 595KB](53)
Abstract:
High precision accelerometers are not only used to measure the non-gravitational forces such as thermal radiation pressure, solar radiation pressure and atmospheric drag, but also used to improve the microgravity level of the spacecraft as an inertial reference, namely to achieve the spacecraft's drag-free control. The basic operation principle of inertial sensor or accelerometer is introduced. The principles of several high-precision accelerometers are described, such as MEMS accelerometers based on the capacitive sensor, MEMS tunneling accelerometers, the superconducting accelerometer, the electrostatic accelerometer and inertial sensors with optical position detection and feedback control. The developmental trend and applications in the fields of the geoscience and fundamental physics of high-precision space-borne accelerometers are discussed. The main development trend is: high-precision and miniaturization MEMS accelerometers, weak stiffness and high-precision satellite-borne accelerometers and cold atom inertial sensors.
Dark Matter Particle Explorer:The First Chinese Cosmic Ray and Hard γ-ray Detector in Space
Chang Jin
2014, 34(5): 550-557.   doi: 10.11728/cjss2014.05.550
Abstract(2790) [PDF 5663KB](86)
Abstract:
The Dark Matter Particle Explorer (DAMPE) mission is one of the five scientific space science missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Science (CAS) approved in 2011. The main scientific objective of DAMPE is to detect electrons and photons in the range of 5GeV-10TeV with unprecedented energy resolution (1.5% at 100GeV) in order to identify possible Dark Matter (DM) signatures. It will also measure the flux of nuclei up to above 500TeV with excellent energy resolution (40% at 800GeV), which will bring new insights to the origin and propagation high energy cosmic rays. With its excellent photon detection capability, the DAMPE mission is well placed for new discoveries in high energy-ray astronomy as well.
Finite-time Control of Satellites Formation[-1.5mm] Based on Terminal Sliding Mode
HUANG Yong, LI Xiaojiang, WANG Zhiheng, LI Zhaoming
2014, 34(1): 109-115.   doi: 10.11728/cjss2014.01.109
Abstract(1517) [PDF 2116KB](62)
Abstract:
Aiming at the relative control problem of reference satellite maneuver-considered formation flying, a finite-time control method based on terminal sliding mode (TSM) is given. Based on the dynamic model of formation satellites relative motion, a finite-time terminal sliding controller is designed, and it is proven that the system state error can converge in finite time under the controller. Lastly, the formation reconfiguration and the formation keeping considering reference satellite maneuver are simulated and analyzed with the control method. The results show that the finite-time control method based on terminal sliding mode has higher formation control precision as well as faster error convergence speed compared with the traditional linear sliding mode.
Relationship of Halo CME and Solar Proton Events ormalsize
WANG Cong, CUI Yanmei, AO Xianzhi, LUO Bingxian, WANG Jingjing, LIU Siqing
2018, 38(1): 9-18.   doi: 10.11728/cjss2018.01.009
Abstract(1370) [PDF 7542KB](129)
Abstract:
Coronal Mass Ejections (CME) are an important source of Solar Proton Events (SPE). Their speeds and source region locations have significant effects on SPE productions. In this paper, all halo CME in recent five years are statistically analyzed. The results show that fast halo CME with small angle distances are more likely to produce SPE, especially those halo CME with the speed greater than 1200km…-1 and the angle distance less than 60°. Three fast halo CME without SPE are elaborately studied. The results show that CME's main body moving direction and the variations of interplanetary magnetic fields also have important impacts on SPE emerging. Consequently, in daily operational space environment forecasts, an accurate SPE forecast must take various factors into account, such as CME burst speed, source region location, CME main body ejection direction, interplanetary environment, and so on.
L2 Back-stepping Control Based on Disturbance Observer for Space Robot under Dead-zone Effect
DAI Qiaolian, CHEN Li
2017, 37(4): 499-506.   doi: 10.11728/cjss2017.04.499
Abstract(994) [PDF 859KB](46)
Abstract:
The trajectory tracking control problem of space robot system with uncontrolled base is discussed. Considering the existence of uncertain parameter and unknown dead-zone in the space robot, an L2 back-stepping control scheme based on the disturbance observer is proposed. Firstly, the dynamic model of system in inertia space is established by the combination of the second Lagrange method and Jacobi matrix. Then, the disturbance observer is used to observe and compensate the model error, and the observer error is eliminated by the method of L2 disturbance suppression. Meanwhile, a fuzzy compensator is used to compensate the bad effect caused by dead-zone. The control scheme doesn't need to know the accurate inertia parameters and linearly parameterize the dynamic model. Moreover, it is not necessary to estimate the upper bound of system uncertainties and the dead-zone parameters, which simplifies the system control. A planar space robot with two links is simulated to verify the feasibility of the control scheme.
Statistical Study of Axial Orientations of Flux Transfer Events at the Magnetopauseormalsize
LI Zhaoyu, CHEN Tao
2018, 38(1): 19-28.   doi: 10.11728/cjss2018.01.019
Abstract(1114) [PDF 2367KB](64)
Abstract:
Flux Transfer Events (FTE) are related to magnetic reconnection. The typical characteristic of FTE is bipolar variation of the field component normal to the local magnetopause. There still exist different views about FTE global topology on the magnetopause. In different models, the FTE structures are either reconnected flux tubes, or magnetic flux ropes formed by multiple X-line reconnection or sheared magnetic loops formed by single X-line reconnection. To infer the global configuration of FTE, a statistical study of axial orientations of 505 FTE observed by Cluster during one dayside magnetopause crossing season is performed. The result shows that most FTE have north-south-orientated axes roughly aligned with the local magnetospheric flux tubes at both the low-and middle-latitude flanks. However, most FTE have dawn-dusk-orientated axes which are more consistent with the single or multiple X-line orientations at high latitude, especially near the cusp. These statistical features will improve our understanding about the global topology of FTE.
Relationship between Dynamic Pressure Pulse and Geomagnetic Sudden Commencement
LI Yuxin, XIE Yanqiong
2017, 37(6): 659-666.   doi: 10.11728/cjss2017.06.659
Abstract(1066) [PDF 1265KB](77)
Abstract:
A deep understanding of the relationship between geomagnetic SC (Sudden Commencement) and DPP (Dynamic Pressure Pulse) is important for comprehensively understanding the response characteristics of geomagnetic field to interplanetary disturbance and improving the ability of SC prediction. In this paper, 363 SC events observed between 1994 and 2011 are the objectives. Firstly, whether there are corresponding DPP events associated with the SC events or not are determined by using automatic DPP recognition algorithm. Secondly, the characteristics of the DPP events and the SC events as well as their relationship statistically are analyzed. The results are as follows. 91% of the SC events are associated with the DPP events, and 53% of the SC events are associated with the shocks. The DPP events and the shocks are observed by WIND satellite. This result indicates that DPP is the main cause of SC. Most of the DPP events (70%) that cause the SC events are associated with large scale solar wind structures, such as Interplanetary Coronal Mass Ejections (ICME), Corotating Interaction Region (CIR) and complex projections aused by ICME and/or CIR. And the averaged dynamic pressure amplitude change of the DPP events is 3.9nPa. Strong DPP events account for 42% of all the events. There is an obvious relationship between the amplitude of the SC events and the absolute dynamic pressure change as well as the difference of the square root of the dynamic pressure of the DPP events, and the correlation coefficients are 0.79 and 0.82, respectively. The correlations between them are much stronger when the interplanetary magnetic field is southward. Although the duration, speed and amplitude of DPP have a certain influence on the duration of SC respectively, there is no obvious relationship between them. These results contribute to the prediction of SC based on DPP parameters.
Analysis of Condensation Heat Transfer in Curved Triangle Microchannel under Microgravity
LEI Yuchuan, CHEN Zhenqian
2018, 38(3): 368-372.   doi: 10.11728/cjss2018.03.368
Abstract(1092) [PDF 2249KB](43)
Abstract:
Numerical simulations of condensation heat transfer in triangle microchannels are presented. The model is established on the Volume of Fluid (VOF) approach and the user-defined routines which includes heat transfer at the vapor-liquid interface and latent heat. The predictive accuracy of the numerical model is assessed by comparing the heat transfer coefficient with the available empirical correlations in the literature. The influence of gravity and surface tension on the liquid-vapor interface distribution and heat transfer performance are analyzed. No obvious effect of the gravity is observed in the liquid-vapor interface distribution and the average cross sectional heat transfer coefficient. Surface tension, which plays a dominate role during the condensation in non-circular microchannels, leading to reduction of the condensate film thickness at the sides of the channel and accumulation of the condensate at the corners of the channel, giving rise to smaller thermal resistance and better heat transfer performance.
Tailward Expansion of the Plasma Sheet during a Substorm Using THEMIS Observations
REN Nian, SHEN Chao, MA Yonghui
2018, 38(3): 315-331.   doi: 10.11728/cjss2018.03.315
Abstract(1134) [PDF 8631KB](101)
Abstract:
A moderately intense substorm from 10:40UT to 12:10UT on 13 March 2008 observed by THEMIS probes is examined to analyze the global evolution of the substorm in the magnetotail. During this substorm, five THEMIS probes are arranged along the x-axis in the vicinity of the midnight, from the radical distance of about 8.7 to 13.2Re. Magnetic field dipolarization and plasma sheet expansions are all observed by different probes after the substorm onset. The average velocity of the plasma sheet expansions is about 140km·s-1. Two types of dipolarization are detected in this substorm. One type is dipolarization front which is associated with the Bursty Bulk Flow (BBF). The other type is global dipolarization which is associated with plasma sheet expansions.The occurrence of Pi2 pulsation can be observed at low, medium and high latitudes 7 minutes later from the substrom onset. The amplitude of Pi2 pulsation gradually increases with the increase of latitude. The ion bulk velocity in the substorm event is mainly caused by the ion drift velocity, and the measured electric field is the induced electric field generated by the change of the local magnetic flux.
Deflection of Magnetopause in the Distant Magnetotail
SHANG Wensai, LÜ Jianyong, WANG Ming, NI Sulan
2018, 38(3): 307-314.   doi: 10.11728/cjss2018.03.307
Abstract(1150) [PDF 4043KB](80)
Abstract:
The responses of the magnetopause in the distant magnetotail to the interplanetary and solar wind conditions, especially to the variation of the solar wind velocity, are studied by WIND and ARTEMIS data. It is found that the properties of sustaining dense high-speed flow were observed by P2 satellite in the magnetosphere on 13 September 2011, which suggests that the satellite passed through the magnetopause and entered the magnetosheath region. The data are analyzed using the minimum variable method. The results show that the normal of the magnetopause is along the direction of the solar wind velocity. According to the similar triangular theorem, it can be deduced that the deflection scale of the magnetopause is about 10Re and 6Re in y and z direction respectively. And the relative position of the P1 and P2 satellites also confirmed this opinion. The analyses suggest that the magnetopause location and shape in this event are mainly affected by the solar wind speed in the distant magnetotail. The result can provide observational evidence for establishing the magnetopause model which includes the effects of the solar wind vy and vz.
Progress of Strategic Priority Program on Space Science
WU Ji, WANG Chi
2018, 38(5): 585-590.   doi: 10.11728/cjss2018.05.585
Abstract(884) [PDF 3440KB](63)
Abstract:
The Strategic Priority Program on Space Science in 2011-2017 (hereafter referred to as SPP I), which officially went ahead in 2011, marks that a new chapter of Chinese space endeavor has been opened. The 4 satellites, Wukong/DAMPE, SJ-10, Mozi/QUESS and Insight/HXMT, has been achieving promising scientific results since their launch, e.g., Wukong directly detected a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons. To enable the sustainable development of China's space science endeavor, the Strategic Priority Program Ⅱ on Space Science (hereafter referred to as SPP Ⅱ) was officially approved in late 2017. SPP Ⅱ includes 4 satellites-EP, ASO-S, SMILE and GECAM, Intensive Study of Future Space Science Missions, Advanced Research of Space Science Missions and Payloads, Space Science Mission Concept Research, and Data Analysis Research. Dedicated to exploring the unknown, the program is aiming to address scientific questions such as the origin and evolution of the universe and life, search for extraterrestrial life, and the impact of the Sun and the solar system on Earth and human development. Chinese space science community is committed to contributing to the progress of human civilization.
Numerical Computation and Analysis on Radiation Field of the Plasma Column
ZHAO Guowei, CHEN Cheng, XU Yuemin
2005, 25(2): 93-98.  
Abstract(2573) [PDF 1746KB](86)
Abstract:
There are many ways to excite the plasma, surface waves can be used to excite the plasma from a single end. One of them is by means of capacitively coupled low-pressure Radio-frequency (RF) discharge, plasma surfaces can be suspended in free space to serve as antenna elements. The surface wave driven plasma antenna produces sufficiently low noise so as to be useful for broadcast communications. When frequencies well below the plasma frequency, the plasma surface wave also propagates near the speed of Light just as on a metal-dielectric interface. According to opproach of radiation pattern of metal, the radiation patterns of travelling wave and standing wave transmitting in a column plasma in simple conditions are calculated. When relevant parameters like plasma density are changed, radiation pattern also changes correspondingly. Compared with metal, there are similar results. Using wave vector from dispersion relation of the plasma surface wave for an ideal column plasma, radiation pattern will change greaterly compared with radiation pattern in metal. Radiation pattern of plasma column can be controlled by changing plasma parameters, so utilizing plasma to transmitting the signal, there are certain reference meanings.
Effect of Substrate and Flow Rate on Hydroxyapatite Growthormalsize
DAI Guoliang, LAN Ding, CHEN Jialu
2018, 38(4): 539-545.   doi: 10.11728/cjss2018.04.539
Abstract(794) [PDF 8371KB](56)
Abstract:
Hydroxyapatite (HAP) has excellent biocompatibility and bioactivity. Synthetic HAP can be widely used as medical and eco-friendly materials. In order to know valuable information of study and development of bone tissue engineering, the influence on HAP crystals growth by the changed of fluid field and the chosen of substrates are studied. The composites materials are used as substrates, which are made of Polydimethylsiloxane (PDMS)/HAP, PDMS/bioglass, and pure bioglass, respectively, and the effect of different substrates on HAP growth are analyzed. The results show that HAP crystals growth rates are different on different substrates when the flow rate is zero. HAP crystals growth rate is highest on PDMS/HAP substrate. However, it is lowest on pure bioglass substrate. Moreover, the influence of different flow rates of HAP growth solution (Simulated Body Fluid, SBF) by a homemade flow rate adjustment apparatus is studied. Three different flow rates, 10ml/min, 15ml/min, and 30ml/min, are used in this study. Under SBF flow conditions, the sizes of HAP crystals increased and the amount of amorphous precipitate decreased.
Construction of Regional Point Mass Model in Polar Regions
FENG Jinkai, WANG Qingbin, HUANG Jiaxi, ZHANG Chao, FAN Diao
2018, 38(3): 418-426.   doi: 10.11728/cjss2018.03.418
Abstract(854) [PDF 4597KB](50)
Abstract:
In the traditional polar coordinate system, the latitude and longitude grids will undergo serious deformation in the polar regions. This deformation will cause the design matrix of point-mass model equation unsolvable, and the spherical harmonic method is singular near the two polar points. In this paper, the singularity problem in the calculation of disturbing gravity and the instability problem during the construction of point mass model in polar regions is studied. The singularity elimination algorithm is introduced in spherical harmonic method and the construction of point mass model based on pole transform is proposed. Numerical experiment results show that the singularity elimination algorithm can effectively solve the singularity problem near the poles, and the structure of point mass model based on the pole transform method is stable and the model can achieve the same accuracy compared with the traditional one, which provides a new way for disturbing gravity fast calculation of polar region aircraft.
Chang'E-1 lunar mission: an overview and primary science results
Ouyang Ziyuan, Li Chunlai, Zou Yongliao, Zhang Hongbo, Lu Chang, Liu Jianzhong, Liu Jianjun, Zuo Wei, Su Yan, Wen Weibin, Bian Wei, Zhao Baochang, Wang Jianyu, Yang Jianfeng, Chang Jin, Wang Huanyu, Zhang Xiaohui, Wang Shijin, Wang Min, Ren Xin, Mu Lingli, Kong Deqing, Wang Xiaoqian, Wang Fang, Geng Liang, Zhang Zhoubin, Zheng Lei, Zhu Xinying, Zheng Yongchun, Li Junduo, Zou Xiaoduan, Xu Chun, Shi Shuobiao, Gao Yifei, Gao Guannan
2010, 30(5): 392-403.   doi: 10.11728/cjss2010.05.392
Abstract(3825) [PDF 2183KB](116)
Abstract:
Chang'E-1 is the first lunar mission in China, which was successfully launched on Oct. 24th, 2007. It was guided to crash on the Moon on March 1, 2009, at 52.36ºE, 1.50ºS, in the north of Mare Fecunditatis. The total mission lasted 495 days, exceeding the designed life-span about four months. 1.37 Terabytes raw data was received from Chang'E-1. It was then processed into 4 Terabytes science data at different levels. A series of science results have been achieved by analyzing and applicating these data, especially "global image of the Moon of China's first lunar exploration mission''. Four scientific goals of Chang'E-1 have been achieved. It provides abundant materials for the research of lunar sciences and cosmochemistry. Meanwhile these results will serve for China's future lunar missions.
A New Method of Predicting the Ionospheric F2 Layer in the Asia Oceania Region
Cao Hongyan, Sun Xianru
2009, 29(5): 502-507.   doi: 10.11728/cjss2009.05.502
Abstract(2460) [PDF 515KB](66)
Abstract:
The new method of predicting the ionospheric F2 layer in the Asia Oceania region is based on cross-correlation theory of ionospheric parameters and the twelve-month running mean of sunsport number (R12). The R12 is substituted for the ionospheric prediction index Ic produced from f0F2 of Chongqing, and the B coefficients interpolated by three different R12 data are not used, which can reduce the error caused by converting R12 into Ic. Lots of data at several sounding stations have been prudently selected and suplemented based on the old predicting method, and the $ B$ coefficients needn't be computed any more, which can avoid interpolation error resulting from the intermediate link. A comparison of several predicting results shows that the new edition is much more accurate.
An Introduction to Magnetosphere-Ionosphere-Thermosphere Coupling Small Satellite Constellation
LIU Yong, WANG Chi, XU Jiyao, LI Xiaoyu, CAI Jinrong, KONG Linggao, HUANG Jia, KLECKER Berndt, LEI Jiuhou, ZONG Qiugang, OCTAV Marghitu
2015, 35(6): 653-663.   doi: 10.11728/cjss2015.06.653
Abstract(2035) [PDF 2168KB](103)
Abstract:
A future Chinese mission is introduced to study the coupling between magnetosphere, ionosphere and thermosphere, i.e. the Magnetosphere-Ionosphere-Thermosphere Coupling Small Satellite Constellation (MIT). The scientific objective of the mission is to focus on the outflow ions from the ionosphere to the magnetosphere. The constellation is planning to be composed of four small satellites; each small satellite has its own orbit and crosses the polar region at nearly the same time but at different altitude. The payloads onboard include particle detectors, electromagnetic payloads, auroral imagers and neutral atom imagers. With these payloads, the mission will be able to investigate acceleration mechanism of the upflow ions at different altitudes. Currently the orbits have been determined and prototypes of some have also been completed. Competition for next phase selection is scheduled in late 2015.
Recent development and preliminary results of Chinese Meridian Project
WANG Chi, REN Liwen
2013, 33(1): 1-5.   doi: 10.11728/cjss2013.01.001
Abstract(2768) [PDF 662KB](85)
Abstract:
The Meridian Project is a ground-based network program to monitor solar-terrestrial space environment, which consists of a chain of 15 ground-based observatories located roughly along 120°E longitude and 30°N latitude. The Meridian project started in 2008, and its construction was completed by 2011. The integration and test phase of the Meridian Project conducted in 2011 demonstrated its observation capabilities as expected. The project will be in full operation in 2012. This report gives an overview of the recent development and preliminary results of the Meridian Project since 2010.
Application of Contact Graph Routing in Satellite Delay Tolerant Networks
ZHU Laitao, LI Yong, ZHANG Junxiang, WU Jing, TAI Xiao, ZHOU Jianguo
2015, 35(1): 116-125.   doi: 10.11728/cjss2015.01.116
Abstract(1495) [PDF 1577KB](39)
Abstract:
Satellite networks have many inherent advantages over terrestrial networks and have become an important part of the global network infrastructure. Routing aimed at satellite networks has become a hot and challenging research topic. Satellite networks, which are special kind of Delay Tolerant Networks (DTN), can also adopt the routing solutions of DTN. Among the many routing proposals, Contact Graph Routing (CGR) is an excellent candidate, since it is designed particularly for use in highly deterministic space networks. The applicability of CGR in satellite networks is evaluated by utilizing the space oriented DTN gateway model based on OPNET(Optimized Network Engineering Tool). Link failures are solved with neighbor discovery mechanism and route recomputation. Earth observation scenario is used in the simulations to investigate CGR’s performance. The results show that the CGR performances are better in terms of effectively utilizing satellite networks resources to calculate continuous route path and alternative route can be successfully calculated under link failures by utilizing fault tolerance scheme.
Study on Langmuir Wave Activities Within the Magnetic Cloud Boundary Layers
Zuo Pingbing, Zhu Chunming, Wei Fengsi, Feng Xueshang, Li Huijun
2009, 29(3): 262-267.   doi: 10.11728/cjss2009.03.262
Abstract(3684) [PDF 805KB](38)
Abstract:
Two particular types of Langmuir wave activities are found within the Magnetic Cloud Boundary Layers (MCBL): Langmuir wave enhancements in entire region of MCBL compared with the adjacent magnetic cloud body and sheath region for majority MCBL and the rapid Langmuir wave burst phenomena associated with broad-band Doppler shifted ion-coustic wave activities for a few MCBL. On 3 Oct., 2000, WIND detected a typical MCBL inside which rapid Langmuir waves burst was observed. The Langmuir waves burst was right corresponded to the magnetic field minimum within the MCBL. The analysis based on high resolution electron distribution function data indicates that the bump-on-tail instability, resulting from the electron beam with beam velocity vb about7×10^3 km/s, is responsible for the rapid Langmuir waves burst.
Ionosphere response to recurrent geomagnetic activity during 2008 and 2009
Liu Xiaoju, Chen Yanhong, Gong Jiancun
2014, 34(1): 29-37.   doi: 10.11728/cjss2014.01.029
Abstract(1447) [PDF 4882KB](97)
Abstract:
GPS TEC data are used to analyze ionospheric response to recurrent geomagnetic activity in 2008 and 2009. Periodic analysis indicates that the significant periodicities of 9 and 13.5 days exist in in global mean Total Electron Content (TEC), ap index and solar wind speed but not in solar F10.7 index. This shows that the short period variations in TEC are mainly related to recurrent geomagnetic activity caused by solar high-speed stream. The local time and latitudinal analysis indicates that the positive and negative perturbations always occur at high-latitude of northern and southern hemisphere at nighttime. At middle to low latitudes, there is mainly positive perturbation at night. The amplitude of the nighttime disturbance in high latitude is larger than middle to low latitudes at night. The daytime TEC response at middle to low latitude is generally in-phase with ap's perturbation. There is a time delay between TEC disturbance and ap variations at high-latitude of southern hemisphere. The amplitude of 9-day, 13.5-day periodicities in 2008 are larger than those in 2009.
Space-Based TTC Method of Lower Orbit Satellite
YANG Tianshe, Dong Xiaoshe, XI Zheng, LI Jisheng, HUANG Yongxuan
2007, 27(3): 245-249.   doi: 10.11728/cjss2007.03.245
Abstract(2289) [PDF 2239KB](64)
Abstract:
Currently, TTC (Tracking, Telemetry and Command) for satellites of our country is mainly executed by Ground-Based TTC network. With the increment of requirement for different kinds of purposes, the numbers of satellites in lower orbits increase rapidly. It is very difficult to meet the requirements of the satellites only based on ground-based TTC network. To seek a new, effective and economical mode to TTC lower orbit satellites is absolutely necessary for our country and to apply space-based TTC technology is an appropriate way to solve ground-based equipment shortages. Based on analysis of Tracking and Data Relay Satellite System (TDRSS) of NASA (National Aeronautics and Space Administration of the United States), a new mode, space-ground-based TTC Mode (SGBM) for lower orbit satellites, is proposed. In this paper, the operating principle of space-ground-based TTC mode is discussed, the simulation system used to simulate space-ground-based TTC mode is designed, and the key technologies need to be solved when using space-ground-based TTC mode is analyzed. The different functions of space-ground-based TTC mode are verified based on the developed simulation system. The simulation results show that the proposed satellite TTC mode is feasible and reliable, and the requirement of lower orbit satellite can be met by using the mode.
Overview of the Solar Polar Orbit Telescope Project for Space Weather Mission
XIONG Ming, LIU Ying, LIU Hao, LI Baoquan, ZHENG Jianhua, ZHANG Cheng, XIA Lidong, ZHANG Hongxin, RAO Wei, CHEN Changya, SUN Weiying, WU Xia, DENG Yuanyong, HE Han, JIANG Bo, WANG Yuming, WANG Chuanbing, SHEN Chenglong, ZHANG Haiying, ZHANG Shenyi, YANG Xuan, SANG Peng, WU Ji
2016, 36(3): 245-266.   doi: 10.11728/cjss2016.03.245
Abstract(1278) [PDF 4166KB](91)
Abstract:
The Solar Polar ORbit Telescope (SPORT) project for space weather mission has been under intensive scientific and engineering background studies since it was incorporated into the Chinese Space Science Strategic Pioneer Project in 2011.SPORT is designed to carry a suite of remote-sensing and in-situ instruments to observe Coronal Mass Ejections (CMEs),energetic particles,solar high-latitude magnetism,and the fast solar wind from a polar orbit around the Sun. The first extended view of the polar regions of the Sun and the ecliptic enabled by SPORT will provide a unique opportunity to study CME propagation through the inner heliosphere,and the solar high-latitude magnetism giving rise to eruptions and the fast solar wind.Coordinated observations between SPORT and other spaceborne/ground-based facilities within the International Living With a Star (ILWS) framework can significantly enhance scientific output.SPORT is now competing for official selection and implementation during China's 13th Five-Year Plan period of 2016-2020.
Transition Process of Supercritical Thermocapillary Convection in a Shallow Annular Pool for Low Prandtl Number Fluids
ZHANG Li, LI Yourong, LIU Lina, WU Chunmei
2018, 38(3): 373-379.   doi: 10.11728/cjss2018.03.373
Abstract(927) [PDF 4436KB](90)
Abstract:
In order to understand the transition process of thermocapillary convection of low Prandtl number (Pr) fluids, a series of three-dimensional numerical simulations on thermocapillary convection of Pr=0.011 fluid in a shallow annular pool are performed. Results indicate that the flow is axisymmetric steady flow at a small Marangoni number. When Marangoni number exceeds a critical value, the flow destabilizes and bifurcates to the hydrothermal wave. In this case, the wave number decreases and the fundamental frequency increases with the increase of Marangoni number. When Marangoni number continue increasing, the hydrothermal waves are enhanced and bifurcated to the radial waves. During this transition, there exists a sharp drop of the wave number. Finally, the noise on frequency spectrum increases and behaves in multi-frequencies. Therefore, the bifurcation route of thermocapillary convection is from axisymmetric steady flow, hydrothermal wave, radial waves with one frequency to three-dimensional oscillatory flow with multi-frequencies.
FY-3 Meteorological Satellites and the Applications
Tang Yunqiu, Zhang Jiashen, Wang Jingsong
2014, 34(5): 703-709.   doi: 10.11728/cjss2014.05.703
Abstract(1309) [PDF 9491KB](56)
Abstract:
FY-3 is the second generation polar-orbiting meteorological satellite of China. The first satellite named FY-3A of this series was launched on 27 May 2008. The first operational satellite named FY-3C of this series was launched on 23 September, 2013. The new generation satellites are to provide three-dimensional, quantitative, multi-spectral global remote sensing data under all weather conditions, which will greatly help the operational numerical weather prediction, global climate change research, climate diagnostics and prediction, and natural disaster monitoring. They will also provide help for many other fields such as agriculture, forestry, oceanography and hydrology. With the abovementioned capability, the FY-3 satellites can make valuable contributions to improving weather forecasts, global natural-disaster and environmental monitoring.
Statistical Analysis of Space Weather Effectson Satellites Anomalies
ZHANG Xiaofang, LIU Songtao, WU Yaoping
2015, 35(4): 461-472.   doi: 10.11728/cjss2015.04.461
Abstract(1567) [PDF 1655KB](86)
Abstract:
Based on a large database of satellite anomalies containing 2384 anomalies from NGDC (USA) and 263 malfunctions from 19 satellites of China (CHN), and with a large set of hourly space weather condition parameters data over the period of 1963-2012, this paper quantifies statistically space weather conditions which may induce different spacecraft anomalies including Single Event Upset (SEU), Electrostatic Discharge (ESD) induced by surface charging, and Electron Caused Electromagnetic Pulse (ECEMP) resulting from internal, deep dielectric charging. The results are as follows. (1) Most anomalies of SEU, ECEMP occurred on quiet space conditions, whereas geomagnetic storms tended to happen during the 3 days (72h) before or after satellite anomalies started, and the most probable time for anomalies was on the third day (48~72h) after the minimum Dst (Dstmin). (2) Geomagnetic activities and high-energy electrons showed apparent effects on anomalies of ESD. Occurrence probabilities of ESD and ECEMP clearly increased in equinoxes (March, September), and such seasonal characteristic was consistent with that in occurrence probabilities of magnetic storms and Relativistic Electrons Flux Enhancement Events (REFEE). For 93.6% anomalies of ESD, geomagnetic storms tended to happen during 72h before, after ESD started, and the most probable occurring time was 0~48h before Dstmin or 0~24h after Dstmin. 54.9% anomalies occurred on geomagnetic conditions of Dst <-30nT, and intensities of storms seemingly influenced ESD little. 40.6% anomalies occurred at the time when the hourly >2MeV electron flux is above 10^3pfu (1pfu =1cm-2·s-1·sr-1). For 81.9% anomalies of ESD, the hourly maximum of high-energy electron flux, during 72h before or after ESD started, was above 10^3pfu, and the most probable time interval was 48~72h before electron flux maximum, when 33.3% anomalies occurred. (3) High-energy electrons showed apparent effects on SEU of GEO from CHN database, 42.5% of anomalies occurring on conditions of electron flux ≥ 103pfu. For those anomalies, the hourly maximum of > 2MeV electron flux exceeded 103pfu during 72h before or after which started. The anomaly occurrence probabilities at the time of 48~72h before and 48~72h after electron flux maximum, were comparative, being about 23.0%. (4) Solar Proton Event (SPE) showed more influence on SEU of GEO. SPEs seemed no regular seasonal variations based on data during 1975-2013, while occurrence probabilities of SEUs showed little seasonal dependence. For 22.0% SEUs of GEO from CHN database, SPEs occurred during 72h before or after anomalies started, and SEUs might occur at any time of the 72h before or after the maximum of >10MeV proton flux.
Study of Slitless Imaging Technique of Solar Extreme Ultraviolet Spectrometer
SHENG Fangliang, PENG Jilong
2016, 36(6): 925-931.   doi: 10.11728/cjss2016.06.925
Abstract(1137) [PDF 1360KB](74)
Abstract:
Solar imaging spectrometer in the extreme ultraviolet band is an important kind of instrument for solar observation. But traditional solar imaging spectrometer cannot observe the Sun in a large field of view simultaneously. Slitless imaging spectrometer allows imaging spectroscopy with high spatial and temporal resolution. Slitless imaging technique is a revolutionary technique for solar research in the extreme ultraviolet band. In this paper, a reconstruction algorithm is studied which has been used in a slitless imaging spectrometer, but it is found that there is a systematic error in the reconstruction result. A new optical design is proposed to solve this problem. By reconstructing the simulated data, the effectiveness of this design is proved. The reconstruction of new design shows better measurement accuracy in Doppler velocity. It will provide more accurate data for space weather studies.
Magnetospheric Physics in China:2012-2014
Cao Jinbin, Yang Junying
2014, 34(5): 605-647.   doi: 10.11728/cjss2014.05.605
Abstract(1361) [PDF 458KB](29)
Abstract:
In the past two years, many progresses have been made in magnetospheric physics by using the data of Double Star Program, Cluster, THEMIS and RBSP missions, or by computer simulations. This paper briefly reviews these works based on papers selected from the 126 publications from March 2012 to March 2014. The subjects cover various sub-branches of magnetospheric physics, including geomagnetic storm, magnetospheric substorm and magnetic reconnection.
ANALYSIS OF THE CHARACTERISTICS OF THE TRANSFER TRAJECTORY OF LUNAR EXPLORER
ZHOU Wenyan, YANG Weilian
2004, 24(5): 354-359.  
Abstract(2035) [PDF 466KB](35)
Abstract:
The characteristics of a trans-lunar trajectory affected by some parameters such as the height of perigee, trans-time and inclination of transfer trajectory is analyzed in this article. Assuming a lunar explorer is injected into the transfer trajectory from a circle earth parking orbit on 025000, 08/27/2004 and approaches perilune of 200km high forming a polar lunar orbit. Two velocity impulse at perigee and perilune are calculated. The results show that the inclination of transfer trajectory has little effect on the velocity impulse of perigee, but remarkable on the velocity impulse of perilune. A transfer trajectory with certain inclination should be chosen to the least fuel consume. The total velocity impulse will decrease with the trans-time increases. When the trans-time is longer than 90 h, the total velocity impulse varies little. But the trans-time of 120h is chosen to ensure that the spacecraft be observed at perilune. The fuel can be saved by increasing the injecting height, but the capability of launch vehicle should be considered simultaneously to decide the height.
Phase Bias Estimation and Calibration of Meteor Radar System
CHEN Xiaobo, WAN Weixing, NING Baiqi
2007, 27(5): 420-424.   doi: 10.11728/cjss2007.05.420
Abstract(2374) [PDF 1675KB](79)
Abstract:
A new method was developed to estimate the radar system phase bias and calibrate the radar system. Using the data collected by this radar, the phase differences of the meteor echo between each receiver pairs are estimated, by taking account of the receiver pairs geometries the linear equation matrix is formed, the phase bias between each receiver pairs in the least-squares sense is solved, and finally the location of meteor echoes after calibration is found. Compared with the conventional method, this method can use the history data to find the system phase bias, without the need for additional hardware. It can routinely use for off-line to correct data collected using the bias estimated before. The data of Wuhan Meteor Radar (WHMR) between April 2004 to June 2004 is used as an example, the bias of the radar system is estimated and the data is used after calibration to calculate the location of the meteor echoes. The data calibrated using this method show a more consistent height distribution in terms of number of echoes with the same meridian.
Design and deploying characteristics analysis on two-stage helical repeated fold-unfold and lock-unlock solar wing
Hu Ming, Yuan Weidong, Chen Wenhua, Kong Fei, Qian Ping, Chen Changzu
2013, 33(1): 108-114.   doi: 10.11728/cjss2013.01.108
Abstract(2163) [PDF 598KB](72)
Abstract:
Two-stage helical repeated fold-unfold and lock-unlock solar wing is designed. Its function analysis is conducted. Firstly, its working principle is analyzed. Based on the requirement of two-stage helical repeated fold-unfold and lock-unlock solar wing, technological parameters and specific structural parameters are determined. The fold-unfold and lock-unlock solar wing unfolding characteristic is analyzed. According to the transitive relation analysis of repeated fold-unfold and lock-unlock solar wing, the analysis modeling on its deploying kinetic characteristics, including forward kinematics and inverse kinematics, are derived. Simulation results show that plane degree and synchronization degree of the solar wing can meet the requirements of specifications, which lays the theoretical foundation to further research the fold-unfold and lock-unlock solar wing in the future.
The Demand, Status and Perspective of COTS Components in Space Application
JIANG Xiujie, SUN Huixian, WANG Zhihua, ZHANG Li
2005, 25(1): 76-80.  
Abstract(1866) [PDF 1685KB](26)
Abstract:
With the rush development of the microelectronics technology and the increasing boost of the high-performance need in space mission,present space-level radiation-hardened components and technology cannot meet the high-performance need of spacecraft.That makes it possible to use Commercial-Off-The-Shelf(COTS) components with high-performance in space application.The space requirements to COTS products is summarized in this paper.The advantages of using COTS parts are the increased functionality,the speed of the instrument,less power consuming and lower cost compared to the space-level components.However,not all COTS parts are suitable for utilization in space applications.Most of them are designed to operate in the ordinary earth environment and are not intended to withstand the radiation environments of space.The radiation in space can cause permanent damage in some types of electronic components.This paper also points out the problems and risks associated with the use of COTS parts in spacecraft,and presents the current status and perspective of COTS components in space application.
Analysis and Results from ISR Observations of Lower Ionosphere
MA Xin, CHEN Gang, ZHONG Dingkun, ZHAO Zhengyu
2015, 35(4): 438-444.   doi: 10.11728/cjss2015.04.438
Abstract(1441) [PDF 3703KB](193)
Abstract:
The D and E regions lie in the lower ionosphere region of 60~110km height. This region is influenced by solar radiation, cosmic noise radiation, atmospheric electrodynamics and many factors, and there exists a variety of incredible variation characteristics. Even in the magnetically quiet day, atmospheric electrodynamics can make a significant effect on this region except solar radiation. In the D region, there exists radio waves strong absorption, which can influence the transmission of high frequency radio waves. Electron and ion density can be obtained from the Incoherent Scatter Radar (ISR) Arecibo, located at Puerto Rico. ISR data can be used to study the movement characteristics of the lower ionosphere in mid-latitude, and get the electron density curves changing with time and height, which present obvious diurnal changing phenomenon. The spectrum of the data is analyzed to probe diurnal effects of electron density changes. Besides the electron density height profiles have been drawn, and observe obvious plasma descending from the base of F-layer to E region. The layer structure characteristics of the lower ionosphere and electron density changing show that there exists different degree of disturbance. By analyzing the influencing factors it is concluded that the atmospheric tides and the acoustic gravity waves can cause disturbance to lower ionosphere, which is coupled with the atmosphere in certain degree.
Preparation of Cu-Pb Alloy in Ground Simulating Microgravity Condition and Research of Microstructure and Friction Performance of the Alloy Samples
WANG Xiaoyong, DA Dao'an
2008, 28(1): 6-11.   doi: 10.11728/cjss2008.01.006
Abstract(2304) [PDF 3060KB](48)
Abstract:
With electro-magnetic simulating equipment established on the ground Cu-Pb binary immiscible alloy are produced successfully,and microstructure and friction performance of the alloy samples are analyzed and tested.The analyzed results of microstructure show the alloy specimens produced on electro-magnetic simulating microgravity condition overcome severe phase separation due to gravity,the minority phase of simulating samples are well distributed in matrix,the lower contents of the minority phase is,the smaller size of dispersive phase is and the better it are distributed;test results of friction performance show friction performance of simulating samples is evidently better than the matrix metal,friction factor become small and wear properties rapidly reduce first and slowly increase later with increase of the minority phase contents.Simultaneously the test results are analyzed and discussed briefly.
System Design for the Event Horizon Imaging Experiment Using the PECMEO Concept
KUDRIASHOV Volodymyr, MARTIN-NEIRA Manuel, BARAT Itziar, MARTIN IGLESIAS Pertonilo, DAGANZO-EUSEBIO Elena, ALAGHA Nader, VALENTA Vaclav
2019, 39(2): 250-266.   doi: 10.11728/cjss2019.02.250
Abstract(1423) [PDF 894KB](45)
Abstract:
The concept for space interferometry from Polar or Equatorial Circular Medium Earth Orbits (the PECMEO concept) is a promising way to acquire the image of the “shadow” of the event horizon of Sagittarius A* with an angular resolution of circa 5 microarcseconds. The concept is intended to decrease the size of the main reflector of the instrument to about 3 m using a precise orbit reconstruction based on Global Navigation Satellite System (GNSS) navigation, inter-satellite range and range-rate measurements, and data from the Attitude and Orbit Determination System (AODS). The paper provides the current progress on the definition of the subsystems required for the concept on the basis of simulations, radio regulations, and available technology. The paper proposes the requirement for the localization of the phase centre of the main reflector. The paper provides information about the visibility of GNSS satellites and the needed accuracies of the AODS. The paper proposes the frequency plan for the instrument and its Inter-Satellite Links (ISLs). The concepts for measurement of range and range rate using ISLs (as well as for the data exchange at these ISLs) are presented. The block diagram of the interferometer is described and its sensitivity is estimated. The link budget for both ISLs is given as well as their critical components. The calculated measurement quality factors are given. The paper shows the expected performance of the sub-systems of the interferometer. The requirements for the localization of the main reflectors and the information about the availability of the GNSS satellites are based on the simulations results. The frequency plan is obtained according to the PECMEO concept and taking into account the radio regulations. The existing technology defines the accuracies of the AODS as well as the link budgets and the measurement accuracies for both ISLs and the sensitivity of the instrument. The paper provides input information for the development of the orbit reconstruction filter and the whole PECMEO system.
Design for Fuzzy Variable Structure Controller of Hybrid Position and Force Control for Dual-arm Coordinated Space Robot Systems
Chen Zhihuang, Chen Li
2011, 31(2): 260-268.   doi: 10.11728/cjss2011.02.260
Abstract(2518) [PDF 717KB](26)
Abstract:
A kind of nonlinear dynamics model of free-floating dual-arm space robot system is based on Lagrange method, and the dynamics model of object is presented based on Newton-Euler method. Based on the results and closed kinematic chain constraints, the dynamics model of synthetical system is obtained, and the control problems for object to track the desired trajectory in workspace and adjustment of interactive forces due to the interaction between the object and the end-effectors are discussed. Because of the high complexity of structure and the uncertainty of parameter of such systems, the scheme of variable structure global sliding-mode control with better robustness to uncertainty and disturbance is proposed to track the desired trajectory of object, and the corresponded scheme of internal forces control is proposed synchronously. Therefore, the object position and internal forces can be regulated simultaneously. A fuzzy controller is designed to reduce shiver due to the inherent defect of sliding-mode control and ensure rapid response. The fuzzy controller can tune the sliding-mode control law parameters automatically according to the relationship between the system state and switch surface. The effect of the controllers is testified by computer simulation.
Predicting whether an interplanetary shock will encounter the Earth by using solar and interplanetary parameters
Xie Yanqiong, Zhang Ying, Du Dan
2014, 34(1): 11-23.   doi: 10.11728/cjss2014.01.011
Abstract(1202) [PDF 854KB](51)
Abstract:
Predicting whether an Interplanetary (IP) shock driven by solar eruptions will encounter the Earth is the prerequisite and foundation to predict its arrival time at the Earth and the geoeffectiveness. Using 542 IP shock events associated with solar eruptions during 1997—2006, the influence of intensity, location, initial shock speed, duration of solar eruptions and Solar Energetic Particles (SEP) flux upon the propagation of IP shocks is investigated statistically, and then key physical parameters mentioned above that obviously influence the IP shock's arrival at the Earth are chosen. Finally, an Earth-directed and Earth-away Shock Prediction Model (EdEaSPM) based on not only solar parameters but also SEP parameters is built. The results of historical prediction show that the success rate of EdEaSPM model is about 66%, which is significantly higher than that of the other prevailing models, STOA, ISPM and HAFv2. The False Alarm Ratio (FAR) of EdEaSPM is less than 50% and the situation that FAR is too high is improved. For the ratio of number of events with shock forecast to that with shock detection, bias, although the value of Bias of all of the models is greater than 1, the Bias of EdEaSPM is the smallest and most close to 1. For the other forecast skill scores, TSS, HSS and GSS, the EdEaSPM performs better than HAFv2 model. In addition, prediction test of 6 IP shock events between Jan. and Oct. 2012 shows that the forecast results are consistent with observations. The EdEaSPM model can forecast whether an IP shock will encounter the Earth about 1 to 3 days in advance, and its accuracy is comparable to that of the other prevailing models. In particular, the success rate and false alarm ratio are improved significantly.
Scientific Progress in China’s Lunar Exploration Program
Xu Lin, Ouyang Ziyuan
2014, 34(5): 525-534.   doi: 10.11728/cjss2014.05.525
Abstract(1813) [PDF 7409KB](103)
Abstract:
Chang'E-1, the first lunar mission in China, was successfully launched on October 24, 2007, which opened the prelude of China's Lunar Exploration Program. Later on, the Chang'E-2 and Chang'E-3 satellites were successfully launched in 2010 and 2013, respectively. In order to achieve the science objectives, various payloads boarded the spacecraft. The scientific data from these instruments were received by Beijing and Kunming ground stations simultaneously. Up to now, about 5.628 Terabytes of raw data were received totally. A series of research results has been achieved. This paper presents a brief introduction to the main scientific results and latest progress from Chang'E-3 mission.
Application of ERA5 Reanalysis to the Construction of Initial Conditions for WACCM Simulations
WANG Yegui, JING Wenqi, CUI Yuanyuan, CAI Qifa, LAN Weiren, FANG Hanxian, WENG Libin, NIU Jun
2018, 38(4): 460-468.   doi: 10.11728/cjss2018.04.460
Abstract(967) [PDF 3465KB](41)
Abstract:
This study uses ECMWF fifth-generation reanalysis, ERA5, which extends to the mesopause, to construct the Initial Conditions (IC) for WACCM (Whole Atmosphere Community Climate Model) simulations. Because the biases between ERA5 and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature data are within ±5 K below the lower mesosphere, ERA5 reanalysis is used to construct IC in the lower atmosphere. Four experiments are performed to simulate a Stratospheric Sudden Warming (SSW) event from 5 to 15 February 2016. The simulation using the WACCM default climatic IC cannot represent the sharp meteorological variation during SSW. In contrast, the 0~4 d forecast results driven by ERA5-constructed IC is consistent with ERA5 reanalysis below the middle mesosphere. Comparing with WACCM climatology ICs scheme, the ICs constructing method based on ERA5 reanalysis can obtain 67%, 40%, 22%, 4% and 6% reduction of temperature forecast RMSE at 10 hPa, 1 hPa, 0.1 hPa, 0.01 hPa and 0.001 hPa respectively. However, such improvement is not shown in the lower thermosphere.
Investigations of low latitude E region field-aligned irregularities with Hainan VHF radar
Shang Sheping, Shi Jiankui, Yan Jingye, Yang Guotao, Wang Xiao, Yan Chunxiao, Wang Jihong, Wu Qiongzhi, Nan Fang
2014, 34(1): 53-62.   doi: 10.11728/cjss2014.01.053
Abstract(1294) [PDF 5275KB](42)
Abstract:
Using the continuous observation data of Hainan VHF radar (19.5°N, 109.1°E; dip latitude 8.1°N) on July 15—22, 2011, the characteristics of 3m scale Field-Aligned ionospheric Irregularities (FAI) in Eastern Asia low latitude are analyzed. The main results show the E region FAI echoes almost occur everyday during the whole observation period. They can occur both in day and night and have different complicated structures. According to their occurrence time and structure, the E region FAI echoes can be classified into the following three cases. First is the lower continuous echoes, which mainly occur from the later afternoon to pre-midnight (17:30LT—23:00LT) with evident enhanced echo intensity and negative (downward/southward) Doppler velocities. The second is the upper descend layer structures, which mainly appear from nearly midnight to pre-sunrise (23:00LT°05:00LT) with more enhanced echo intensity and both positive and negative Doppler velocities, where the positive Doppler velocities (upward/northward) dominate in the upper E region echoes. The third is the daytime continuous echoes, which mainly occur from morning to nearly noontime (07:00LT—11:30LT) with reduced echo intensity and both positive and negative Doppler velocities. These low latitude E region echoes mainly are type-I!I, which is similar to that of the Equatorial Electrojet (EEJ) and mid-latitude regions, but their temporal behavior is evidently different from that of the latter two latitudes and also has some differences with that of the other low latitudes.
Research of Ambiguity Solution in CEI-based Orbit Determination
LI Xiaojie, DU Lan, HUANG Jin
2011, 31(5): 659-665.   doi: 10.11728/cjss2011.05.659
Abstract(2449) [PDF 485KB](33)
Abstract:
Connected-Element Interferometry (CEI) was a passive angular tracking method with the merits of high phase precision, flexible network distribution and nearly real-time processing due to short length of baselines. Firstly, feasibility of ambiguity solution in CEI-based orbit determination for GEO was analyzed. Integer ambiguity must be primarily solved in the orbit determination for TDRS because of its low initial orbit precision. It could be calculated by the high precise range measurement if the master control station could obtain range measurement, while the method of parameter estimation by fixing integer ambiguity was used without high precise range measurement. The simulation results indicated that this method was effective when the systematic error was less than 1.0m. The orbit determination precision for the satellite belt between 80°E and 140°E was gained, when the systematic error was 0.1m, along-track positional error component of the 110°E satellite reached 25 m, while 82m and 34m respectively for the 80°E satellite and 140°E satellite.
Adaptive control based on saturated velocity filter for space-based manipulator system with bounded control torques
Xie Limin, Chen Li
2013, 33(2): 213-218.   doi: 10.11728/cjss2013.02.213
Abstract(2016) [PDF 470KB](41)
Abstract:
The intelligent control problem of space-based manipulator system with bounded control torques and uncertain parameters is studied. According to the system's momentum conservation and Lagrange's equation, the system's dynamics equation is established. An adaptive control based on saturated velocity filter for space-based manipulator system with bounded control torques and uncertain payload parameters is developed. The proposed control scheme overcomes the influence of the uncertain parameters on the control accuracy by using adaptive controller; limits the control torques by using hyperbolic functions, which lets the control more realistic. And in the control process, it doesn't need to measure and feed back the system's velocity signal by using the velocity filter, which makes the control simpler. The simulation validates the effectiveness of the proposed control scheme.
A Review on the Acquisition and Analysis Methods of Spectral Characteristics of Space Debris
JIN Xiaolong, TANG Yijun, SUI Chenghua
2014, 34(1): 95-103.   doi: 10.11728/cjss2014.01.095
Abstract(1319) [PDF 1988KB](119)
Abstract:
The reflectance spectrum of space debris is the interactive result of the space debris material and the solar spectrum, which can reflect the material nature of space debris and provide the basis for studying the optical properties of space debris. In this paper, we preprocess the observed space debris images, extract debris spectral curves, correct spectral data of atmospheric turbulence and then compare the actually observed reflectance spectra of space debris with the known space material reflectance spectra. The optical properties differences between them, such as peak, slope, shape, narrow band characteristics, absorption lines in the continuous reflectance spectrum curve and imaging differences, color indices, characteristic temperature in multiband can be analyzed. Then the space debris can be distinguished from others by its surface materials finally.
Robust Control Based on Velocity Filter of Free-floating Dual-arm Space Robot System in Inertial Space
LIN Chengjin, CHEN Li
2012, 32(5): 757-764.   doi: 10.11728/cjss2012.05.757
Abstract(2389) [PDF 558KB](46)
Abstract:
The robust control scheme based on velocity filter of free-floating dual-arm space robot system with uncertain payload parameters was studied. Through the Lagrangian approach, the dynamic equation of the free-floating space robot was modeled as under-actuated system. With the augmentation approach, it was demonstrated that the dynamic equations and the augmented generalized Jacobi matrix of the system can be linearly dependent on a group of inertial parameters, respectively. Based on the results, a robust controller based on velocity filter was developed for dual-arm space robot system with uncertain payload parameters to track the desired trajectories in inertial space. Ascribe to the pseudo-velocity signal acquired through the velocity filter, the proposed control scheme with only accurate positions of the joints and the end-effectors feedback avoid measuring the velocity and acceleration of the end-effectors. And it can avoid the control chatter effectively at the same time. The effect of the controller is testified by computer simulation.
Comparison and analysis of the thermospheric density between TIEGCM and CHAMP during a severe geomagnetic storm
Wu Yuan, Li Jiawei, Zhang Xiaoxin, Wang Wenbin, ZHOU Lü, Li Chuanqi
2014, 34(1): 81-88.   doi: 10.11728/cjss2014.01.081
Abstract(1373) [PDF 2101KB](65)
Abstract:
The thermospheric densities at the altitude of 410km during the geomagnetic storm on Nov. 20—21, 2003 are calculated by NCAR-TIEGCM model, and the results are compared and analyzed with the observational data from CHAMP/STAR. The results show that the model can exactly represent the distribution and variation of the density during geomagnetic storm, and the model results have a good consistency with the CHAMP data in trends and orders. But some differences do exist in detailed structure and magnitude. The model underestimated the increases of the density during geomagnetic storm with the values of 100%~125%, instead of the 250%~400% observed by CHAMP. The deviations between the model and CHAMP at high latitude are bigger than those of low latitude, and dayside bigger than nightside. It is also found that the density disturbance during geomagnetic storm presents day-night asymmetry and Southern-Northern hemisphere asymmetry. The model can exactly represent the propagation of the density disturbance from high latitude to low latitude, and the time delay in response of the density to geomagnetic storm.
Tracking Control for Coordinated Motion of Space Manipulator in Joint Space Based on Fuzzy Wavelet Neural Network
HUANG Dengfeng, CHEN Li
2011, 31(6): 821-828.   doi: 10.11728/cjss2011.06.821
Abstract(2296) [PDF 606KB](18)
Abstract:
The trajectory tracking control for coordinated motion of free-floating space manipulator system with an attitude controlled base is discussed. According to the geometrical relationship and law of conservation of momentum, the dynamic equations of space manipulator system are constituted through Lagrange equation of the second kind. Based on the above, a fuzzy wavelet neural network scheme is designed to control the base attitude and the joint angle of manipulator to track desired trajectories synchronously in joint space on condition that system parameters are unknown. The control scheme needs neither linearly parameterize the dynamic equations of the system, nor know any system parameters. Further more, its network weights are learning online based on errors by back propagation algorithm so the self-learning and self-adapting ability of fuzzy neural network is enhanced and meantime the offline training time is saved. Numerical simulations are presented to verify the feasibility and effectiveness of the proposed control scheme.
Some Investigations on the Ionosphere during 2012-2014 in China
Liu Libo, Chen Yiding, Le Huijun, Liu Jing, Wan Weixing
2014, 34(5): 648-668.   doi: 10.11728/cjss2014.05.648
Abstract(1095) [PDF 2012KB](28)
Abstract:
In this national biannual report, we will outline some recent progresses in ionospheric studies conducted by Chinese scientists since 2012. The mentioned aspects include: the solar activity control of the ionosphere; couplings between the ionosphere, lower atmosphere and plasmasphere; ionospheric climatology and disturbances; ionospheric irregularities and scintillation; models, data assimilation and simulations; unusual phenomena of the ionosphere; possible seismic signatures presented in ionospheric observations, and some methodology progresses. These progresses will enhance our ability to observe the ionosphere, provide more reasonable understanding about the states of the ionosphere and underlying fundamental processes, and stimulate ionospheric modeling, forecasting and related applications.
2012-2014 China’s Earth Observation and Earth Science Development
Guo Huadong, Ma Jianwen, Xiao Han, Lu Feng, Liang Dong, Bi Haiyun, Wang Fangjian
2014, 34(5): 721-732.   doi: 10.11728/cjss2014.05.721
Abstract(1068) [PDF 155KB](30)
Abstract:
Human beings are now facing global and regional sustainable development challenges. In China, Earth observation data play a fundamental role in Earth system science research. The support given by Earth observation data is required by many studies, including those on Earth's limited natural resources, the rapid development of economic and social needs, global change, extreme events, food security, water resources, sustainable economic and urban development, and emergency response. Application operation systems in many ministries and departments in China have entered a stage of sustainable development, and the State Key Project of High-Resolution Earth Observation Systems has been progressing since 2006. Earth observation technology in China has entered a period of rapid development.
Analysis of flywheel disturbance and measuring technology
Wang Quanwu, Hu Gang
2009, 29(1): 39-44.   doi: 10.11728/cjss2009.01.039
Abstract(3298) [PDF 723KB](27)
Abstract:
Flywheel has been identified as one of the main disturbance sources that affect the precision of attitude control system of spacecraft. In this paper, the main sources of vibration disturbances from flywheels were analyzed. The disturbance measuring technology used by some research centers were introduced and reviewed, which included NASA Goddard Space Flight Center, Tsukuba Space Center of the National Space Development Agency of Japan and MIT Space Systems Laboratory. This paper is helpful for establishing flywheel disturbance measuring system.
THE STRUCTURE OF THE MERIDIAN SOLAR WIND AND ITS EFFECT ON THE PROPAGATION OF CORONALMASS EJECTIONS
Guo Wei-ping, Wang Jing-fang, Yao Yong-qiao, Liang Bai-xian
1991, 11(3): 168-175.   doi: 10.11728/cjss1991.03.168
Abstract(1827) [PDF 535KB](65)
Abstract:
Acombined scheme is developed to solve the ideal MHDequations. Keeping certain precision, this model has ensured stability and small computing capacity. Atwo-dimensional hemlet-streamer solution of the meridian solar wind near the sun is obtained. Using this solution as initial state, the effect of the hemlet-streamer configuration on the propagation of coronal mass ejections is investigated. It is found that the configuration deflects the ejected mass toward equator. This effect can explain some observational results satisfactorily.
A Spatial Redundant Robotic Manipulator’s Chaotic Self-motion
GE Xinfeng, YIN Zhifeng
2012, 32(6): 897-902.   doi: 10.11728/cjss2012.06.897
Abstract(2395) [PDF 515KB](81)
Abstract:
The model and kinematics equations of a floating redundant spatial robotic manipulator are established. The Jacobian matrices are analyzed, and the inverse kinematics is obtained. Chaotic motions which existed in the floating spatial redundant robotic manipulator's self-motions are proved by simulation. At last, a spatial 3R redundant robotic manipulator is taken as an example, and the links' self-motion has been studied when the end-effector tracking a plane path repeatedly in its workspace for PD controlling by analysis of direct observation, time history method, phase diagram method, and poincare mapping method. Results show that there exist chaotic motions in the self-motion of the floating spatial redundant robotic manipulator when solving the floating redundant robotic manipulator's inverse kinematics based on pseudo-inverse Jacobian matrix.
Statistical Analysis of Space Debris's Parameters Based on the Incoherent Scattering Radar
DAI Li, ong, DING Zonghua, ZHAO Zhenwei, XU Zhengwen
2015, 35(4): 495-501.   doi: 10.11728/cjss2015.04.495
Abstract(1286) [PDF 6225KB](55)
Abstract:
The ISR (Incoherent Scatter Radar) raw sampling data (time duration about 7 hours) is processed by Matching Filter (MF) method and totally 394 space debris are detected. Parameters including the height, radial velocity, Radar Cross-Section (RCS), effective diameter and radial velocity etc. are estimated, and statistical analysis about these parameters is made. The results show that the mean flux per hour through the radar beam is 60; the signal to noise ratio of space debris echo is above 10, which shows that the space debris is a strong target for ISR; the orbital height mainly is in two zones (600~1100km and 1400~1600km); the RCS is about 10-5~10-2m2 and the effective diameter is about 3~10cm; the radial velocity is about -1.5~1.5km·s-1; the radial acceleration is about 20~90m·s-2. These results show the good perspective for ISR in the monitoring and forecasting of space debris.
Relationship between interplanetary magnetic field clock angle and magnetosphere open magnetic flux
Xia Zhiyang, Wang Chi, Peng Zhong, Lu Quanming
2014, 34(1): 24-28.   doi: 10.11728/cjss2014.01.024
Abstract(1373) [PDF 469KB](68)
Abstract:
The open magnetic flux (Fpc) is a key parameter to study magnetospheric dynamical process, which is closely related to magnetic reconnections in the dayside magnetopause and magnetotail. The dayside reconnection rate controls the amount of the open magnetic flux, which is affected by various solar wind parameters, among which the clock angle θc of the interplanetary magnetic field (IMF) is an important factor that influence the dayside reconnection rate. Using global MHD simulations, we analyze the relationship between θc and Fpc. The results show that the open flux Fpc increases as the clock angle θc approaches 180°(due southward), and the open flux Fpc is proportional to sin3/2 (θc/2). This reflects the physical connection between them, since θc describes the magnitude of the shear between IMF and terrestrial magnetic field, and affects the dayside reconnection rate, thus controlling the open flux Fpc.
Development for detecting upper atmospheric wind and temperature from satellite
Wang Yongmei, Fu Liping, Du Shusong, Wang Yingjian
2009, 29(1): 1-6.   doi: 10.11728/cjss2009.01.001
Abstract(5319) [PDF 610KB](42)
Abstract:
Upper atmospheric wind and temperature are important basic parameters. Its global high-precision measurement has broad prospects for various applications, so the strong demand to explore them is growing the interferometric spectrometer is characterized with multi-channel, high-throughput and high spectral resolution, it becomes the optimum choice for detecting upper atmospheric wind and temperature. The current successful application of the interferometric spectrometer has two kinds, Fabry-Perot interferometer and wide angle Michelson interferometer. The paper mainly reviews the interferometric spectrometers used in the upper atmosphere wind and temperature field exploration, analysis and compares the feasibility of several interferometers measurement of wind and temperature and their respective advantages and disadvantages. These work lays a foundation for our future on-board detection in China.
Coordinated Motion Control and Vibration Suppression of Rigid-Flexible Space Robot Based on Neural Network
CHEN Zhiyong, CHEN Li
2012, 32(1): 147-153.   doi: 10.11728/cjss2012.01.147
Abstract(2147) [PDF 572KB](60)
Abstract:
The joint motion control and vibration suppression problems of rigid-flexible space robot with an attitude controlled base were discussed. With Lagrangian method and singular perturbation theory, the singular perturbation model of the system was derived. To guarantee the accurate coordinated motion control of the base attitude and the arm's joints under the effects of unknown system parameters, the compensation control strategy based on Radial Basis Function (RBF) neural network was proposed for the slow subsystem. Simultaneously, the linear quadratic optimal controller was given for the fast subsystem to suppress the elastic vibration of the system. Simulation results demonstrate that the presented control scheme can effectively compensate for the influence of unknown system parameters, and control the system to track the desired trajectory and suppress the elastic vibration preferably.
The Experimental Satellite on Electromagnetism Monitoring
Shen Xuhui
2014, 34(5): 558-562.   doi: 10.11728/cjss2014.05.558
Abstract(1132) [PDF 253KB](60)
Abstract:
The Experimental Satellite on Electromagnetism Monitoring (ESEM) was proposed in 2003 and proved in 2013 after 10-years' scientific demonstration. The ESEM mission was proposed to be the first satellite of space-based geophysical fields observation system in China with a lot of application prospects in earthquake science, geophysics, space sciences and so on. And coincide with the mission objectives, the satellite decides to use the Circular Sun Synchronous Orbit with an altitude of 507km and descending node time at 14:00LT. The payload assemble includes 8 instruments, Search-Coil Magnetometer, Electric Field Detector, High precision Magnetometer, GNSS occupation Receiver, Plasma Analyzer, Langmuir Probe, Energetic Particle Detector, and Three-frequency Transmitter. According to the planned schedule, the satellite is due to be launched in 2016-2017 and will be onboard operated for 5 years.
Ocean Observation from Haiyang Satellites:2012-2014
Jiang Xingwei, Lin Mingsen
2014, 34(5): 710-720.   doi: 10.11728/cjss2014.05.710
Abstract(1304) [PDF 13852KB](40)
Abstract:
During 2012 and 2014, China has two Haiyang (which means ocean in Chinese, referred to as HY) satellites operating normally in space which are HY-1B and HY-2A. HY-1B is an ocean color environment satellite which was launched in April 2007 to observe global ocean color and sea surface temperature, and HY-2A is an ocean dynamic environment satellite which was launched in August 2011 to obtain global marine dynamic environment parameters including sea surface height, significant wave height, ocean wind vectors, etc. Ocean observation data provided by HY-1B and HY-2A have been widely used by both domestic and international users in extensive areas such as ocean environment protection, ocean disaster prevention and reduction, marine environment forecast, ocean resource development and management, ocean investigations and scientific researches, etc.
A MODIFIED TAIL-SUSPENSION MODEL FOR SIMULATING LONG-TERM WEIGHTLESSNESS
Chen Jie, Ma Jin, Ding Zhao-ping, Zhang Li-fang
1993, 13(2): 159-162.   doi: 10.11728/cjss1993.02.159
Abstract(3013) [PDF 329KB](37)
Abstract:
The rat tail-suspension model may be more acceptable for simulating weightlessness than other animal models in the view of its less stressful situation. However, there are problems of injury to the skin and development of abscesses and ischemic necrosis of the tail. Inorder to minimize this traumatic nature of the technique and make longer the suspension period, modifications are made to the Morey-Holton and Wronski's tail-suspension method. The main points are as following: (1) Apart from tincture of Benzoin, tincture of resin is spracyed on the tails, which help to unsmooth the tail surface and firm the attachment of the adhesive tape stripes. (2) The taping places on the tail are changed regularly every 7 days. For this reason, the tail surface is divided into four sides and only two opposite ones (upper and below or left and right) are applied with tape stripes, leaving the other two unattached for the later taping place replacement. (3) The traction force acting on the tail is mainly carried by the tape stripes attached longitudinally with the tail rather than those twining around the tail. These modifications effectively protected the tail from ischemic injures caused by the surrounding tape stripes either by the force acting on the tail or the constriction of the tail as the rat grows. The skin injuries by the irritation or tearing of the tape strips rarely happened and could recovery soon after the taping place replacement. The modified tail-suspension is well tolerated by five groups of male SDstrain rats (10 animals per group)for 90 to 120 days, as evidenced by normal feeding, normal grooming behavier and a continued weight gain kept close to or almost same as that of pair-fed control groups hroughout the suspension period. So it may be a useful model for simulating the effects of long-term weightlessness.
2018, 38(1): 6-6.  
Abstract(1585) [PDF 339KB](97)
Abstract:
Study on the Autonomous Celestial Navigation of Near Space Vehicles With Hypersonic Speed Based on Non-Keplerian Orbits
LI Hailin, WU Dewei
2012, 32(6): 874-880.   doi: 10.11728/cjss2012.06.874
Abstract(2488) [PDF 526KB](40)
Abstract:
In allusion to the problem that the aircraft autonomous celestial navigation is not suitable for the near space vehicles with hypersonic speed, an approach of the autonomous celestial navigation of near space vehicles with hypersonic speed based on non-Keplerian orbits is studied. Mechanism of the autonomous celestial navigation based on non-Keplerian is analyzed, and the dynamic equations are developed by analyzing the strength of near space vehicles with hypersonic speed. The space motion equation is educed using the vector derivatives rules. States model based on non-Keplerian orbits and measurement model using the concept of stellar horizon atmospheric refraction are designed, and the Kalman filter simulation is adopted. Results show that the autonomous celestial navigation of near space vehicles with hypersonic speed based on non-Keplerian orbits can meet the requirement of high precision for position and velocity, which is important for further research on the near space vehicles with hypersonic speed.
THE INFLUENCE OF SOLAR FLARE ON THE TEMPERATURE OF THE MIDDLE ATMOSPHERE
Yu Hai-ren, Ma Rui-ping
1995, 15(1): 73-76.   doi: 10.11728/cjss1995.01.073
Abstract(2109) [PDF 271KB](66)
Abstract:
Using the NIMBUS-7 SAMS GRID-T data,the variations of the middle atmosphere temperature induced by solar flare events classed larger than 3.5 during 1979-1982 is discussed. The results show that the temperature of the upper mesosphere is obviously decreased and that, of the lower mesosphere is obviously increased,while the stratospheric temperature does not varies obviously,within sevaral days around the Ha flare bursts day.
Recent Advances in Chinese Meridian Project
Wang Chi
2014, 34(5): 535-543.   doi: 10.11728/cjss2014.05.535
Abstract(1270) [PDF 7143KB](46)
Abstract:
To develop an understanding of near-Earth space's response to solar activities and the coupling among different layers in geospace, China has initiated a ground base program to monitor China's geospace environment called the Meridian Space Weather Monitoring Project (Chinese Meridian Project). The effort consists of a chain of 15 ground-based observatories located roughly along 120°E longitude and 30°N latitude. Each observatory is equipped with multiple instruments to measure key parameters such as the baseline and time-varying geomagnetic field, as well as the middle and upper atmosphere and ionosphere from about 20 to 1000 kilometers. This project started collecting data in 2012. We will give a brief introduction to the Chinese Meridian Project, and present recent scientific results mainly in ionospheric and atmospheric studies.
Advances of Microgravity Sciences
Kang Qi, Long Mian, Zhang Yuanzhong, Duan Li, Zhao Jianfu, Xu Shenhua, Wang Shangfeng
2014, 34(5): 733-739.   doi: 10.11728/cjss2014.05.733
Abstract(891) [PDF 105KB](45)
Abstract:
Advances of microgravity sciences in China are introduced. The research works include ground-based study and space experiments. In the recent years, the main means still are theoretical analysis, numerical simulation, ground-based experiment, and short-time microgravity experiments of drop tower. Besides, many space experiment projects are arranged. SJ-10 recoverable satellite will carry out 19 scientific experiment projects. Nine of them are for microgravity Sciences. The other ways for space microgravity experiment are with the help of Chinese Shenzhou spacecraft, Chinese Tiangong space laboratory, and Chinese space station in the near future. The Chinese space station will become main platform of Chinese microgravity sciences experiment in space.
Main Science Results from Chinese Meridian Project(2014—2015)
WANG Chi
2016, 36(5): 620-625.   doi: 10.11728/cjss2016.05.620
Abstract(1200) [PDF 122KB](56)
Abstract:
The Chinese Meridian Space Weather Monitoring Project (Meridian Project for short) is a ground-based geospace monitoring chain in China. It consists of a chain of 15 ground-based observatories located roughly along 120°E longitude and 30°N latitude. Each observatory is equipped with multiple instruments to measure key parameters such as the baseline and time-varying geomagnetic field, the middle and upper atmosphere and ionosphere from about 20 to 1000km. This project started collecting data in 2012. Here a brief overview of the Chinese Meridian Project is given, and most recent science results mainly in the ionospheric and atmospheric studies are presented.
Scientific Objectives and Payloads of Chinese First Mars Exploration
JIA Yingzhuo, FAN Yu, ZOU Yongliao
2018, 38(5): 650-655.   doi: 10.11728/cjss2018.05.650
Abstract(1300) [PDF 556KB](92)
Abstract:
China plans to implement the first Mars exploration mission in 2020. It will conduct global and comprehensive exploration of Mars and high precision and fine resolution detection of key areas on Mars through orbiting, landing and roving. The scientific objectives include studying the Martian morphology and geological structure characteristics, studying the soil characteristics and the water-ice distribution on the Martian surface, studying the material composition on the Martian surface, studying the atmosphere ionosphere and surface climate and environmental characteristics of Mars, studying the physical field and internal structure of Mars and the Martian magnetic field characteristics. The mission equips 12 scientific payloads to achieve these scientific objectives. This paper mainly introduces the scientific objectives, exploration task, and scientific payloads.
Impact of Martian Atmosphere Model Parameters on Aerodynamic Characteristics of Mars Science Laboratory
Lü Junming, Miao Wenbo, Cheng Xiaoli, Wang Qiang
2014, 34(4): 377-383.   doi: 10.11728/cjss2014.04.377
Abstract(1503) [PDF 2554KB](123)
Abstract:
The difference between Martian atmosphere and Earth atmosphere results in the different flow field and property around the entry vehicles, and the possible change of aerodynamic characteristic on account of chemical non-equilibrium will differ from that in Earth re-entry process. The differences between Martian and Earth atmosphere include species, density and temperature. Three-dimensional Navier-Stokes equations coupling real gas model are solved by a parallel code to analyze the change of aerodynamic characteristic of Mars Science Laboratory (MSL) introduced by CO2 effect as well as the uncertainty of density and temperature in hypersonic entry phase of Entry-Descending-Landing procedure when MSL entering the Martian atmosphere. The results show that the computational data of Viking based on current Martian atmosphere model and numerical methods has a good agreement with both the flight data and LAURA results. Gas species in the model, which are mainly CO2 for Mars, have a great influence on the drag and pitching moment coefficients compared to the air model of Earth, so CO2 correction should be considered while the aerodynamic data is derived from air. Increase of the density in atmosphere model enhances chemical non-equilibrium effect, but produces no distinctness for aerodynamic characteristic; increase of the temperature improves chemical non-equilibrium effect greatly, and has a small influence on aerodynamic characteristic.
SEU-tolerant System Design of SRAM FPGA Based on Scrubbing in Aerospace
MA Yin, AN Junshe, WANG Lianguo, SUN Wei
2012, 32(2): 270-276.   doi: 10.11728/cjss2012.02.270
Abstract(3139) [PDF 573KB](59)
Abstract:
Aerospace and extra-terrestrial applications on SRAM FPGA are sensitive to SEU which might result in information loss or functional interruption. In this paper, a detailed introduction to TMR and Scrubbing, which are the significant techniques of this design, was given; then, a highly reliable fault-tolerant system based on TMR, Scrubbing and Reload rules was implemented. An anti-fuse FPGA periodically scrubbed the configuration bitstream of SRAM FPGA in milliseconds level, and both FPGAs implemented triple module design redundancy. This fault-olerant design has been adopted in an actual spacecraft electronic system, which can make reference to the design of highly reliable electronic systems.
A Brief Review of Interplanetary Investigations in China from 2014 to 2016
ZHAO Xinhua, ZHANG Min, WANG Yuming, HE Jiansen, KONG Xiangliang
2016, 36(5): 639-671.   doi: 10.11728/cjss2016.05.639
Abstract(967) [PDF 355KB](38)
Abstract:
Great progress has been made in the research of solar corona and interplanetary physics by the Chinese scientists during the past two years (2014-2016). Nearly 100 papers were published in this area. In this report, we will give a brief review to these progresses. The investigations include:solar corona, solar wind and turbulence, superhalo electron and energetic particle in the inner heliosphere, solar flares and radio bursts, Coronal Mass Ejections (CMEs) and their interplanetary counterparts, Magnetohydrodynamic (MHD) numerical modeling, CME/shock arrival time prediction, magnetic reconnection, solar variability and its impact on climate. These achievements help us to better understand the evolution of solar activities, solar eruptions, their propagations in the heliosphere, and potential geoeffectiveness. They were achieved by the Chinese solar and space scientists independently or via international collaborations.
Comprehension and non-contact measurement of surface tension under microgravity
Dou Lei, Li Jianqiang, Yuan Zhangfu
2009, 29(1): 150-153.   doi: 10.11728/cjss2009.01.150
Abstract(4564) [PDF 582KB](51)
Abstract:
Surface tension is one of the most important physical chemistry parameters in material field. Many interface phenomena under microgravity attract scientists and need farther study. Sessile drop method is the main way to measure surface tension of melts, which works well on the earth. However, it is difficult to be used under microgravity environment. The paper expresses new cognition about measurement after thinking of the theory of surface tension, and discusses the difficulty of using sessile drop method under microgravity environment. This paper introduces levitation method to measure the surface tension, especially the electromagnetic levitation method, which avoids the error brought by vessel contacting. Under microgravity environment, the electromagnetic levitation method can improve the measurement precision.
Thermoluminescence Study on Bo County Meteorite
Wang Kui-ren, Liu Jing-fa, Yang Hai-tao
1987, 7(1): 73-77.   doi: 10.11728/cjss1987.01.073
Abstract(2141) [PDF 357KB](50)
Abstract:
In this paper the results of thermoluminecence (TL) study on Bo County meteorite are reported. Temperature gradient in the meteorite, produced by heating during its atmospheric passage, is 34.2°C/mm in head, 24.8°C/mm in side. The temperature profiles of the meteorite is closed to the Barwell meteorite, and more reasonably consistent with the steady-state solution to the heat conductivity equation in a case of the ablation rate of 0.10 cm/sec. According to the TLcurve of the meteorite the parameter Ln (LT/HT) is 1.30. So the meteorite belong to type A.
Study of the Lower Thermospheric Neutral Wind at Chinese Arctic Yellow River Station During Auroral Substorms
Xiong Bo, Zhang Yange, Ai Yong, Zhang Hong, Liu Jue
2013, 33(6): 629-636.   doi: 10.11728/cjss2013.06.629
Abstract(1535) [PDF 5097KB](50)
Abstract:
Auroral substorm is a basic energy input, coupling and dissipation process. Complex auroral substorm effects are not to be neglected for the thermospheric neutral wind effects, and has important significance on its in-depth study. A self-developed all-sky Fabry-Perot Interferometer (FPI) has been deployed by Chinese Arctic Yellow River Station (78.92°N, 11.93°E) at Ny-Alesund, Svalbard in November 2010, and formal observation has been carried out, which obtained FPI measured data for the first time in domestic. This paper briefly introduces the observations during winter in 2012. Two auroral substorm events on November 12-14, 2012 and December 9-11, 2012 were selected for data processing, and wind fields corresponded to 5 interference rings were calculated. The comparison and analysis between wind field and geomagnetic activity variations during the periods of auroral substorms indicated that the dramatic change of wind speed may be caused by a violent disturbance of geomagnetic activity. Contrastive analyses between auroral images by an all sky camera and FPI interference fringes corresponding line of sight wind field during November 13, 2012, 00:00UT-02:00UT and December 10, 2012, 05:00UT-07:30UT suggest that the enhanced direction is perpendicular to the aurora arc, and it weakens in the direction paralleled with the arc.
China’s Deep-space Exploration to 2030
Zou Yongliao, Li Wei, Ouyang Ziyuan
2014, 34(5): 516-517.   doi: 10.11728/cjss2014.05.516
Abstract(2940) [PDF 61KB](123)
Abstract:
Focusing on the key scientific questions of deep space exploration which include the origin and evolution of the solar system and its planets, disastrous impact on the Earth by the solar activities and small bodies, extraterrestrial life, this paper put forward a propose about the roadmap and scientific objectives of China's Deep-space Exploration before 2030.
Microgravity Material Research in China:2012-2014
Wang Yuren, Dai Guoliang, Wang Jing, Feng Shaobo, Luo Xinghong, Zhou Yanfei, Chen Lidong, Yu Yude
2014, 34(5): 757-764.   doi: 10.11728/cjss2014.05.757
Abstract(1116) [PDF 1493KB](44)
Abstract:
During 2012-2014, the main research activities from microgravity material research were focused on, which include study of microgravityeffects on collagen fibrillogenesis and HAP crystallization, microgravity experiments using drop tube, and research of thermoelectric materials for space. This paper summarizes all these activities.
Fengyun satellites: achievements and future
Wang Jingsong, Zhang Jiashen, Tang Yunqiu
2010, 30(5): 468-473.   doi: 10.11728/cjss2010.05.468
Abstract(2786) [PDF 490KB](84)
Abstract:
Chinese meteorological satellite, Fengyun (FY) Satellite, has a polar-orbiting series and a geostationary series. Up to now, 5 polar-orbiting (FY-1A/B/C/D and FY-3A) and 5 geostationary (FY-2A/B/C/D/E) satellites were launched. FY data has been being intensively applied not only to meteorological monitoring and prediction but also to many other fields regarding ecology, environment, disaster, space weather and so and. The FY data sharing system, FengyunCast, is now one of the three components of global meteorological satellite information dissemination system, GEONETCast. The first satellite of the new generation polar-orbiting series, FY-3A, was launched on 27 May, 2008, demonstrating the FY polar-orbiting satellite and its application completed a great leap to realize three-dimensional observations and quantitative application. The first of the next generation geostationary series (FY-4) is planned to launch in 2014.
Flux and Spectra of Primary Cosmic Rays at Yangbajing With the AMS-01 Experiment
Zhu Fengrong, Ran Zheng, Xu Lijun, Gao Linchao, Liang Hanxiao, Shi Yali, Jia Huanyu
2013, 33(6): 604-607.   doi: 10.11728/cjss2013.06.604
Abstract(1131) [PDF 498KB](54)
Abstract:
Based on AMS-01 experiment, the integral fluxes and the energy spectra are investigated for the estimation of background cosmic ray radiation. Using the data from AMS-01 experiment in the Sun quiet phase of June 1998, the integral fluxes of primary protons for the kinetic energy ranges of 0.44~4.31GeV, 4.31~12.38GeV, 12.38~199.06GeV near the Earth at geomagnetic latitude of Yangbajing are achieved respectively. And the integral fluxes of primary for the kinetic energy ranges of 6.92~14.45GV and 14.45~229.9GV are also obtained. Correspondingly, the energy spectra functions for the protons and helium are then fitted for this 5 energy ranges, separately. The integral fluxes for the same energy range above is consistent by the two methods of approximate calculation of integral and the integral of function curves.
THE ORBITAL PERFORMANCE ANALYSIS FOR SPACE EXPLORING SATELLITE WITH HIGH ECCENTRICITY
SHE Mingsheng
1998, 18(4): 348-355.   doi: 10.11728/cjss1998.04.348
Abstract(2345) [PDF 474KB](57)
Abstract:
The exploring satellite which operates on the high eccentricity orbit has many orbital characteristics. In this paper, SJ-4 satellite is taken as an example to discuss some features in satellite designed general operation, and the emphasis is put on the main characteristics of orbit design, and shows the data and figures which stand for orbital calculation, window, satellite's launching illumination and tracking conditions. It is pointed out that the accuracy of orbit design and initial attitude selection of the SJ-4 satellite has verified by the telemetric data in two months operation.
Designing and Implementing of the Payload Self-exploration
LIANG Yaoming, MA Miao, WANG Lianguo, SHEN Weihua, ZHU Yan
2016, 36(2): 209-214.   doi: 10.11728/cjss2016.02.209
Abstract(1454) [PDF 849KB](82)
Abstract:
The payload of the satellite has different working modes. In order to obtain the optimum working state, it needs to be switched constantly between each mode. When switching, many working state parameters need to be configured, such as, 28 Front Electronic Ends (FEE), neutron acquisition and processing circuit, the trigger system circuit, high voltage powers and payload data management system. To improve the switch flexibility of payload exploration mode and lower the complexity of parameter configuration during switching, the management project is studied for payload self-exploration of the satellite by analyzing the working modes of this explorer. The designing method is based on event-driven which are combined by programming-experts on the ground and perform-units on the satellite. Software realization result is given out for the payload self-exploration. Meanwhile, the reliability and security measures are studied. The test results show that the function is implemented. It can be used on the satellite to explore space anytime and anywhere. It reduces the dependency on the remote control center.
Design of a 1553B IP core based on ASIC technology
Zhou Li, An Junshe, Xie Yan, Li Xianqiang, Cao Song
2014, 34(1): 127-136.   doi: 10.11728/cjss2014.01.127
Abstract(1882) [PDF 721KB](44)
Abstract:
It is a problem to miniaturize space avionics when we use traditional 1553B bus interface chips. To solve this problem, design of an ASIC chip for spacecraft integrated avionics is proposed. The design of a 1553B IP core with independent intellectual property in this chip is described in detail. The 1553B IP core includes the bus controller module, the remote terminal module, the Manchester decode and encode module, the shared RAM, the RAM arbitration module, the AXI bus slave interface module, the channel select module and the timer module. Each module is introduced. The top-down designing method is used and the program is described by Verilog hardware description language. The 1553B IP core design is tested and verified by the functional simulation, the ASIC system simulation and FPGA test. DDC's 1553B test board is used to test the IP core. The test results indicate that the 1553B IP core design is reasonable. The design of 1553B IP core has good performance in reliability, portability, real-time and less resource occupancy.
Orbit Design for Responsive Space Using Multiple-objective Evolutionary Computation
FU Xiaofeng, WU Meiping, ZHANG Jing
2012, 32(2): 238-244.   doi: 10.11728/cjss2012.02.238
Abstract(2072) [PDF 217KB](59)
Abstract:
Responsive orbits have exhibited advantages in emergencies for their excellent responsiveness and coverage to targets. Generally, there are several conflicting metrics to trade in the orbit design for responsive space. A special multiple-objective genetic algorithm, namely the Nondominated Sorting Genetic Algorithm Ⅱ (NSGAⅡ), is used to design responsive orbits. This algorithm has considered the conflicting metrics of orbits to achieve the optimal solution, including the orbital elements and launch programs of responsive vehicles. Low-Earth fast access orbits and low-Earth repeat coverage orbits, two subtypes of responsive orbits, can be designed using NSGAⅡ under given metric tradeoffs, number of vehicles, and launch mode. By selecting the optimal solution from the obtained Pareto fronts, a designer can process the metric tradeoffs conveniently in orbit design. Recurring to the flexibility of the algorithm, the NSGAⅡ promotes the responsive orbit design further.
Chang’E-3 Lunar Rover’s Scientific Payloads
Dai Shuwu, Wu Ji, Sun Huixian, Zhang Baoming, Yang Jianfeng, Fang Guangyou, Wang Jianyu, Wang Huanyu, An Junshe
2014, 34(3): 332-340.   doi: 10.11728/cjss2014.03.332
Abstract(1578) [PDF 1987KB](111)
Abstract:
Four scientific instruments are selected as the payloads for Chinese Chang'E-3 Lunar rover, including panoramic cameras, lunar radar, IR acousto-optic spectrometer, X-ray spectrometer. Panoramic cameras are to acquire the stereo optical image of lunar surface topography around the lunar rover. Lunar radar explores the lunar regolith thickness and structure. IR acousto-optic spectrometer obtains the IR spectrum and image of lunar surface, which can be used to analyze the lunar surface's mineral composition and distribution. X-ray spectrometer analyzes the content of the lunar surface rock to get the rock elements composition. In this paper, Chang'E-3 Lunar rover's scientific exploration objectives, the scientific payload's components and system design are mainly introduced. Each payload's design and main technical index are also described in detail.
Ballistic coefficient estimation of satellite in low Earth orbit and atmosphere model error analysis
Qi Yalong, Li Huijun, Xiang Jie, Man Haijun
2014, 34(1): 89-94.   doi: 10.11728/cjss2014.01.089
Abstract(1431) [PDF 587KB](54)
Abstract:
An inversion method is introduced to study the variations of the ballistic coefficient for orbital satellites with different geometrical characteristic. Using satellite tracking data and NRLMSISE00 empirical model of the atmosphere, ballistic coefficients B of the selected satellites are compiled out with this new method. The "true" values of B (Bt) were computed by averaging the 31 years of B values obtained for each satellite. These true B values were validated by comparing the Bt values of two spheres and by comparing the Bt values obtained for a pair of satellites having very similar size, shape and mass. The estimated ballistic coefficients B' variations for a number of selected satellites were then averaged over each year, and compared with solar indices. Some interesting results are found. Firstly, there does not appear to be a bias in the Bt values computed using the 31 years' time period. Secondly, the large similarity between the time series of B ratios is apparent and solar activity related variations in the thermosphere increase in amplitude with increasing height, as do the errors in the NRLMSISE00 model. Thirdly, the anti-correlations of B' variations with the F10.7 variations were found in short periods. Finally, the NRLMSISE00 model has failed to produce the low thermospheric density during the 2008 solar minimum. The variations in B' point out that the scaling factor is required to correctly predict the true densities from empirical atmosphere models, especially in solar maxima and minima. It is also shown that changes in B ratios during some major geomagnetic storms cannot be explained by atmosphere model.
Empirical reconstruction of flux transfer events at the magnetopause
LI Zhaoyu, CHEN Tao
2017, 37(6): 675-689.   doi: 10.11728/cjss2017.06.675
Abstract(1053) [PDF 4698KB](105)
Abstract:
Flux Transfer Events (FTEs) observed at the Earth's magnetopause are generally believed to be products of transient and patchy magnetic reconnection processes, serving as linkage channels between solar wind and Earth's magnetosphere and therefore playing a crucial role in the exchange of mass, momentum, and energy between these two regions. Magnetic field reconstruction techniques are useful for better understanding FTE's formation and evolution and its interaction with surrounding environment. Traditional techniques such as Grad-Shafranov reconstruction and FTE model fitting methods, however, are confined to specific physical conditions. A new multi-point method applicable to two-dimensional FTEs in various physical condition is devised based on plane linear interpolation. The applications to two FTEs observed by THEMIS and Cluster show that the method can quickly and efficiently reconstruct the spatial distribution of the magnetic field structure, and will help to infer the magnetic field line configurations, understand the temporal variation of measured data and analyze the spatial distribution characteristic of plasma parameters relative to the magnetic field.
THE NONLINEAR PROPAGATION OF GRAVITY WAVE PACKETS IN COMPRESSIBLE ATMOSPHERE
ZHANG Shaodong, YI Fan
1998, 18(1): 39-51.   doi: 10.11728/cjss1998.01.039
Abstract(1973) [PDF 610KB](71)
Abstract:
In this paper, numerical simulation of nonlinear propagation of gravity wave packets with Gaussian distribution in isothermal and compressible atmosphere is presented by using 2-dimentional FICE scheme. The numerical analysis show that though there exists nonlinear reaction, during the propagation process, the phases of waves move downward, the wave packets and the wave-associated energy propagate upward. Wave-associated disturb velocities increase exponentially with the height and the reaction between the waves and the background leads to the enhancement of the mean flow. These agree well with the linear gravity wave theory. The propagation trace of gravity wave packets is consistent with the prediction of linear ray theory, but the average horizontal group velocity and vertical group velocity are obviously smaller than the results given from the linear ray theory. It indicates that the nonlinear process of gravity waves can change the propagation velocities of wave- associated energy. The simulation results show quantitatively that the effect of nonlinearity on propagation of gravity wave packets for the first time, it indicates that the definitions of dynamics of gravity waves given by the linear theory are reasonable.
Polarimetric mode of full polarization interferometric radiometer
Yang Xiaocheng, Yan Jingye, Wu Ji
2014, 34(2): 226-234.   doi: 10.11728/cjss2014.02.226
Abstract(1411) [PDF 1137KB](50)
Abstract:
Demonstrator of Full Polarization Interferometric Radiometer (FPIR) is a one dimensional microwave interferometric radiometer with high resolution, light weight and low power consumption at X-band. The theory of polarimetry is analyzed to deduce the polarimetric visibility function in FPIR. To obtain the full polarimetric information, two kinds of different antenna arrays are designed in the FPIR system. Corresponding optimal polarization switching sequence for each sparse antenna array is also designed. The minimum degradation in sensitivity is achieved and sensitivities of the horizontal, vertical, and complex cross brightness temperatures are the same in the polarimetric mode of FPIR with the polarization switching sequence.
Long-term Ionospheric Characteristics over Urumchi
ZHAO Haisheng, WU Zhensen, XU Zhengwen, WU Jian, ZHANG Yabin, XU Bin, XUE Kun
2014, 34(4): 398-405.   doi: 10.11728/cjss2014.04.398
Abstract(1325) [PDF 5503KB](70)
Abstract:
There are important effects on the electron equipments for the variations of ionosphere, such as it can induce shortwave communications quality decline indeed interrupted, navigation signal scintilla and error increase, space craft orbit change, surface charging up and proton event etc. In a word, it is important to study ionospheric characteristic and its impaction on electronic equipments. Based on Urumchi ionospheric vertical sounders and its more than fifty years data, the daily variations, seasonal changes and long-term trends of the ionosphere over Urumchi were studied. Some meaningful conclusions are given at the end of the paper.
Space Brain Science Research
Mei Lei
1984, 4(4): 324-330.   doi: 10.11728/cjss1984.04.324
Abstract(2489) [PDF 553KB](54)
Abstract:
In this paper, the author put his emphasis to the importance of brain science research in space flight based, on the flight experinces and laboratory investigationsdur-ing the past twenty years. The theories and techniques developed in author's laboratory for astronaut brain function research are briefly summerized. The viewpoints on brain evolution in the gravitational field, the principle of frontalization of brain function and the problem of extraterrestrial intelligence are also stressed. Finally, a space brain science research program is suggested.
Method for determining the critical frequency and propagation factor at the path midpoint from maximum usable frequency and its propagation delay based on oblique sounder
Wang Jian, Ji Shengyun, Wang Hongfa, Lu Dongming, Wang Xianyi
2014, 34(2): 160-167.   doi: 10.11728/cjss2014.02.160
Abstract(1395) [PDF 643KB](42)
Abstract:
Accurately determining critical frequency and propagation factor of ionosphere was important to frequency forecast and management of short-wave communication. Oblique sounder provide a valid method for real-time observation of it. A new practicable method was presented for determining f0F2 and M(3000)F2 at the path midpoint from the oblique sounding data, which was based on simple oblique ray theory and only rely on maximum observation frequency and its propagation delay. The inversion from oblique sounding data on the Changchun-Jingyang and Xinxiang-Chifeng path, were compared with the vertical sounding data in Beijing during October 2009. According to analysis, the stability, accuracy and practicability of the new method are validated. The results show that the root-mean-square error of the new inverse method is 0.48MHz, and the relative root-mean-square error is 10.50%. It is obvious that the new inverse method is better than Smith's method and reference ionosphere of China. Moreover, the method is simple and easy to use. It provides the basis for frequency forecast and management of short-wave communication, and help to know ionospheric variational characteristics.
NUMERICAL MODELING OF THE IONOSPHERIC VARIATIONS OVER THE GREAT WALL STATION, ANTARCTICA
Zhu Minghua, Cao Chong, Wu Jian
1997, 17(4): 337-342.   doi: 10.11728/cjss1997.04.337
Abstract(1810) [PDF 413KB](82)
Abstract:
The diurnal variations of the ionosphere over the deat Wall Station reveal theWeddell Sea Anomaly in the summer. In this paper, the diumal variations of f0F2 andhm are simulared by using a one-dimensional and hme-dependent theorehcal model.We studied the effects of the neutral wind and O+ flux on f0F2 and hm and concludedthat one reason why simulated f0F2 are greater than measurements is the upperboundary values are overeshmated by IRI. In the last part of the paper, a method forobtaining the actual f0F2 and hm is presented.
THE STUDY ON IMPROVEMENT OF "BEIDOU" DOUBLE-STAR NAVIGATION SYSTEM AND IT’S ALGORITHM
LIN Xueyuan, LIU Jianye
2003, 23(2): 149-154.  
Abstract(1994) [PDF 1330KB](42)
Abstract:
“Beidou” Double-star positioning system is one kind of positioning system for local area (RDSS). In this paper, the disadvantage of double-star navigation system is discussed and a new idea is put forward. The idea is to set an inactive regional navigation system made up of the barometer and the existing two working satellites and the third (spare satellite). The algorithm expression for this navigation idea is presented. The simulation results show that this method for navigation is feasible and can fulfill the media-accuracy navigation positioning, so to offer a new way to develop a relatively simple satellite navigation system.
Numerical Simulation of Oblique Ionospheric Heating Effects in Nanjing Districtormalsize
GUO Zhe, FANG Hanxian, HE Yingming, YANG Ding, MA Jie, JING Wenqi, WANG Shiqi
2017, 37(5): 531-537.   doi: 10.11728/cjss2017.05.531
Abstract(1624) [PDF 2062KB](31)
Abstract:

Compared with vertical heating, oblique ionospheric heating has advantages of higher flexibility, wider effect range and more practicable operability. In this paper, based on the energy conservation equation and continuity equation of electron, the physical model is built for lower ionosphere heated by oblique radio wave by considering Ohm absorption in the non-deviated section, and oblique heating in low ionosphere over Nanjing district is simulated using the background parameters obtained by IRI-2007 and NRLMSISE-00 models. The results show that heating effect increases when incident elevation angle and effective radiated power increase. The rising amplitude of electronic temperature and density decreases when the frequency of radio wave increases. The perturbation amplitudes of electron temperature and density caused by X mode are bigger than those caused by O mode, and X mode can make electron temperature and electron density reach a steady state more quickly than O mode. Within a certain range, the radio wave with smaller incident elevation angle, lower frequency and larger effective power can make electron density reach a steady state more quickly, and the latter two can also accelerate the process of electron temperature to reach stability. The time that electron temperature to reach stability varies singlet with elevation angle of incident electromagnetic wave, and will be a maximum as the elevation angle is 62°.

Prototype System Used for Flame Structure Display and Temperature Measurement Technology in Microgravity Combustion Experiment
WANG Jing, SUN Zhibin, DAI Bin, DAI Guoliang, KONG Liming, WANG Baorui
2015, 35(3): 336-342.   doi: 10.11728/cjss2015.03.336
Abstract(1036) [PDF 5777KB](38)
Abstract:
The facility for combustion experiments in space is lightweight, small sized and multi-functional. In this paper, a prototype system used for flame structure display and temperature measurement is presented, which combined the schlieren method, rainbow schlieren deflection method and differential interference method. It is also lightweight and small sized. As for the prototype system, the flame structure display function was checked by schlieren method in microgravity drop tower, and the temperature measurement function was checked by rainbow schlieren deflection and differential interference method under normal gravity condition. Results show that the resolution of flame structure was not less than 1mm, and temperature field measurement was accurate with relative error smaller than 2%. Such prototype system is important to the promotion of space combustion science experiment technology and will be beneficial to the future combustion experiments in space.
Solar Variation and Global Climate Change
ZHANG Liang, WANG Chi, FU Suiyan
2011, 31(5): 549-566.   doi: 10.11728/cjss2011.05.549
Abstract(2540) [PDF 1416KB](66)
Abstract:
The Sun continually radiates electromagnetic wave and particles to Earth, and the solar radiation is the main energy resource for the Earth’s climate system. The response of climate system to the solar variation is very complex, including radiative process, dynamic process and microphysics process. This paper reviews the measurements from satellites and reconstruction results by other proxies of the solar irradiance variation, enumerates some climate observational evidence in the fields of paleoclimate, temperature, atmospheric circulations and clouds affected by the solar activity. The three main possible mechanisms by which the solar variation may influence the global climate include: the variability of total solar irradiance could change the earth surface temperature, and thus change the atmospheric circulation via the ocean-atmosphere couple; the solar ultra violet radiations modulate the stratospheric temperature and wind field by heating ozone, and the stratosphere response could then affect the lower troposphere by stratosphere troposphere coupling; the solar modulates galactic cosmic ray through interplanetary magnetic field, and galactic cosmic ray may change the cloud cover via ionizing the atmosphere, which could further change the earth’s energy budget.
Study on Assessment Method of Reliability of Spaceflight Electronic Device
SUN Peng, ZHAO Yang, DONG Haiping
2012, 32(2): 265-259.   doi: 10.11728/cjss2012.02.265
Abstract(2506) [PDF 400KB](32)
Abstract:
A Bayesian reliability assessment method for spaceflight electronic device is put forward. The method combines the reliability information of the whole system and its subsystems. At first, the maximum entropy method is used to syncretize reliability information of subsystems; then the calculation formulas of moments of system reliability are deduced from reliability moments of subsystems and inheritance factor is determined and mixed Beta distribution is built; finally, the posterior distribution is used to assess system reliability. With the new method, the reliability of a spaceflight electronic device is evaluated to reach 0.9991 under the confidence level 0.70 with 240 whole system tests which is one-fifth of system tests needed by the classical method. It is feasible to use the new method to assess reliability of spaceflight electronic device.
Chang’E-3 Lander’s scientific payloads
Jia Yingzhuo, Dai Shuwu, Wu Ji, Sun Huixian, Liu Enhai, Wei Jianyan, Chen Bo, Huang Changning, Chen Xiaomin
2014, 34(2): 219-225.   doi: 10.11728/cjss2014.02.219
Abstract(2528) [PDF 2769KB](109)
Abstract:
Four kinds of scientific instruments are chosen as the payloads on Chinese Chang'E-3 Lander, including topography camera, lunar astronomical optical telescope, extreme ultraviolet imager and descending camera. Topography camera is to acquire the optical image of lunar surface topography around the landing area, and observe the rover moving process on the lunar surface. Lunar astronomical optical telescope operates in the near ultraviolet spectrum, which can observe the brightness variations of various stars. Extreme ultraviolet imager works on the wavelength of 30.4nm, and the observation target is the resonance scattering between Earth's plasma He+ layer and 30.4nm solar radiation. Descending camera is to acquire the lunar optical image in the landing region during descending. In this paper, Chang'E-3 Lander's scientific exploration missions, as well as the payloads' system design are introduced. Each payload's design and main technical specifications are also described in detail.
Magnetospheric Boundary Layer Structure and Dynamics as Seen From Cluster and Double Star Measurements
Y V Bogdanova, C J Owen, M W Dunlop, M G G T Taylor, A N Fazakerley
2013, 33(6): 577-603.   doi: 10.11728/cjss2013.06.577
Abstract(1151) [PDF 1784KB](42)
Abstract:
In this review, we discuss the structure and dynamics of the magnetospheric Low-Latitude Boundary Layer (LLBL) based on recent results from multi-satellite missions Cluster and Double Star. This boundary layer, adjacent to the magnetopause on the magnetospheric side, usually consists of a mixture of plasma of magnetospheric and magnetosheath origins, and plays an important role in the transfer of mass and energy from the solar wind into the magnetosphere and subsequent magnetospheric dynamics. During southward Interplanetary Magnetic Field (IMF) conditions, this boundary layer is generally considered to be formed as a result of the reconnection process between the IMF and magnetospheric magnetic field lines at the dayside magnetopause, and the structure and plasma properties inside the LLBL can be understood in terms of the time history since the reconnection process. During northward IMF conditions, the LLBL is usually thicker, and has more complex structure and topology. Recent observations confirm that the LLBL observed at the dayside can be formed by single lobe reconnection, dual lobe reconnection, or by sequential dual lobe reconnection, as well as partially by localized cross-field diffusion. The LLBL magnetic topology and plasma signatures inside the different sub-layers formed by these processes are discussed in this review. The role of the Kelvin-Helmholtz instability in the formation of the LLBL at the flank magnetopause is also discussed. Overall, we conclude that the LLBL observed at the flanks can be formed by the combination of processes, (dual) lobe reconnection and plasma mixing due to non-linear Kelvin-Helmholtz waves.
SPACE CRYSTAL GROWTH OF PROTEINS WITH DOMESTIC FACILITY
Bi Ru-chang
1996, 16(3): 208-215.   doi: 10.11728/cjss1996.03.208
Abstract(2108) [PDF 581KB](66)
Abstract:
The cytstal growth of proteins and other biomacromolecules is an important study in space science'Using tube-like vapour diffusion apparatus made in China,two missions of protein crystallization have been carried out on Chinese re-entry satellites.52% and 80% of 48 samples prepared by 10 different kinds of proteins yielded crystals in the two space experiments respectively,and among them,a few of the proteins preduced better-quality Crystals.The results of the two missions show that the microgravity environment in space benefits improvement of protein crystal growth, and in the case with good enough optimized crystallization conditions,the space-grown protein crystals have larger size,better morphology and higher intend order than the Earth-grown crystals of the same protein.The effect of microgravity on protein crystal growth and its exploitation are also discussed in the paper.
A METHOD OF CELESTIAL AUTONOMOUS ORBIT DETERMINATION AND ATTITUDE DETERMINATION FOR SATELLITE
LI Linlin, SUN Huixian
2003, 23(2): 127-134.  
Abstract(2048) [PDF 1610KB](16)
Abstract:
An autonomous real-time orbit determination for satellite flying around the Earth by the extended Kalman filtering is proposed in this paper. The observables are as follows, Satellite-Sun direction vector measured by Sun sensor, Satellite-Earth direction vector and Satellite-Moon direction vector measured by ultraviolet sensor, and the geocentric distance measured by radar altitude. Moreover, the satellite attitude to the Earth is determined. The simulation results show that orbit determination precision is better than 200m. By simulation experiments of autonomous orbit determination, the effects of sample period, orbit inclination, orbit eccentricity and orbit height on orbit determination precision are analyzed and compared. The changing law is submitted, which can improve satellite autonomous orbit determination precision.
Research on ground system for space science satellite of microgravity experiments
Li Xuzhi, Liu Yurong, Wang Hongfei, Hei Baoqin
2009, 29(1): 93-97.   doi: 10.11728/cjss2009.01.093
Abstract(4322) [PDF 559KB](37)
Abstract:
Relative to other space missions, space microgravity experiments have such charachteristics as dispersed users, real-time or near real-time process control requirement in experiments, a variety of processing requirements for space scientific data, etc. A framework assumption of ground system platform is proposed, according to the characteristics of space scientific experiments and the requirements for its ground support system, considering some finished ground support systems for space scientific experiments such as Shijian-8 satellite, Double Star and Shenzhou spacecrafts and the requirements of space scientific experiments in the future. This system platform supports status monitoring and control of space scientific experiments, telescience experiments and customizing standard data product. It can meet the need of multi-task in space scientific experiments with commonality and extensibility.
Algorithm of astronomy autonomous navigation based on multi-sensors and the analysis of observability
Pan Xiaogang, Jiao Yuanyuan, Zhou Haiyin
2014, 34(1): 116-126.   doi: 10.11728/cjss2014.01.116
Abstract(922) [PDF 3915KB](29)
Abstract:
The technology of autonomous navigation is an inevitable trend in the development of spacecraft in the future. Based on the integrative platform of multi-sensors composed of sun sensor, moon sensor and the infrared Earth sensor, the observation model of multi-sensors were proposed. In order to construct the autonomous navigation system, the observability of navigation system was analyzed. Then the algorithm of astronomy autonomous navigation was built up based on two modes. One is based on the original astronomy multi-sensors data. The other is based on the analytical single position data calculated by the original astronomy multi-sensors data. Simulation results showed that the navigation precision of the mode based on original astronomy multi-sensors data was higher than that of the mode based on analytical single position data. And the navigation error was approximately within 200m when the observation data contains no system error. The precision of navigation with constant observation error is equal with that of the navigation with only random observation error when the system error estimation method is used.
Removing Solar Radiation Based on the Empirical Mode Decomposition Method for Seismo-Ionospheric Anomaly Before the M9.0 Tohoku Earthquake
HU Yanli, XU Tong, WU Jian
2013, 33(5): 518-524.   doi: 10.11728/cjss2013.05.518
Abstract(2200) [PDF 2583KB](24)
Abstract:
The ionospheric effect from solar activity can be seen as the background in the process of detecting the ionospheric precursor prior to strong earthquakes. The ionospheric variation induced by the forthcoming earthquake can be covered by the strong solar background during the period of high solar activity. The issue of how to remove the ionospheric effect from solar radiation is of outstanding significance. In this paper, a method of Empirical Mode Decomposition (EMD) is used to eliminate the solar background. As a case study, the global ionospheric map TEC before the M9.0 Tohoku earthquake on 11 March 2011 is analyzed. After the effect of solar radiation is removed using the EMD method, the precursor of the imminent earthquake is more obvious. The ionospheric anomaly had a local character and only appeared close to the earthquake epicenter while the useful signals were covered by the solar radiation background with traditional method, which implies that the EMD method is effective in eliminating solar radiation background.
Alfvén Waves in the Solar Wind
L. YANG, J. K. CHAO
2013, 33(4): 353-373.   doi: 10.11728/cjss2013.04.353
Abstract(3241) [PDF 251KB](102)
Abstract:
Alfvén waves are found to be ubiquitous in the solar wind. Recent progress in observational studies of the waves is reviewed to formulate a microscopic picture for the Alfvénic fluctuations. The main aspects of the observational properties of these waves, including the wave intervals, propagation, evolution, origin and generation, are presented. Then Alfvén wave heating and acceleration of the solar wind plasma are briefly introduced. The relation of the waves to rotational and tangential discontinuities, magnetic decreases, and other relatively large-scale structures such as flux tubes/ropes, magnetic clouds and interplanetary coronal mass ejections in the solar wind is particularly investigated. Finally, some remaining open questions are also indicated due to their fundamental importance of understanding of the physical nature of Alfvén waves and the role of the waves in heating and accelerating the solar wind.
The Interplanetary Causes of the Anormalous SSC Events
LI Changxing, HUANG Zhaohui, WANG Chi
2007, 27(3): 182-191.   doi: 10.11728/cjss2007.03.182
Abstract(2870) [PDF 4375KB](40)
Abstract:
SSC is a result of the interrelation between strong solar wind dynamic pressure or interplanetary shock and the geomagnetosphere. Generally, the rise time of SSC varies from 4 minutes to 10 minutes. So, we refer to the SSC of the rise time which is more than 15 minutes as anomalous SSC event. We identified 5 anomalous SSC events from the geomagnetic index SYM-H data since the observation beginning of the geomagnetic field. Using the multipoint observations of the solar wind from the Wind, ACE, IMP 8, Goes and Geotail, the interplanetary causes of those anomalous SSC events were analyzed. It is found that: (1) all of 5 anomalous SSC events are accompanied with strong interplanetary disturbances, among which there are 4 events corresponding with the forward fast interplanetary shocks, and 3 events corresponding with multi-step solar wind dynamic pressure changes and 1 event corresponding with a sudden direction change and large amplitude variation in interplanetary electric field. (2) the rise time of those resulted from interplanetary shocks desponds on the orientation of the interplanetary shock, i.e., the bigger the angle between the interplanetary shock normal and the Sun-Earth line, the shorter the rise time, and the contribution of the orientation of the interplanetary shock is more remarkable than its speed. (3) There is no explicit relation between the rise time of the anomalous SSC events and the interplanetary field direction.
Monitoring of Ionospheric Anomaly Using COSMIC Occultation Measurementsormalsize
WANG Hu, LIU Zhiqiang, BAI Guixia, DANG Yamin
2014, 34(1): 46-52.   doi: 10.11728/cjss2014.01.046
Abstract(1098) [PDF 3049KB](60)
Abstract:
The paper introduces the method of electron density inversion using COSMIC occultation data, and advantages of the inversion method are analyzed using practical calculation. Meanwhile, electron density profiles obtained from ISR (Incoherent Scattering Radar) are compared and analyzed with those from COSMIC occultation. Finally, electron density profiles over the SHAO (IGS station) which is located in Yangtze river region, are reversed using COSMIC occultation measurements during the total solar eclipse and the solar storm, and are compared with electron density profiles during the quite day. Ionospheric anomaly caused by the total solar eclipse and the solar storm are analyzed. The advantages of the inversion method from COSMIC occultation data have been found by using inversion method to monitor the ionosphere anomaly.
Status of the Hard X-ray Modulation Telescope Project
LU Fangjun
2014, 34(5): 544-546.   doi: 10.11728/cjss2014.05.544
Abstract(1082) [PDF 3826KB](68)
Abstract:
The Hard X-ray Modulation Telescope (HXMT) is China's first astronomical satellite. It will perform a broad band (1-250keV) scan survey and do pointed observations of X-ray sources to study their spectra and multi-wavelength temporal properties. The pre-flight models of the satellites have been finished, and the flight models are in production. The expected launch date of HXMT is in late 2015.
Phenomena of Geomagnetic and Ionospheric Anomalies and Their Relation to Earthquakes
DING Jianhai, SUO Yucheng, YU Surong
2005, 25(6): 536-542.   doi: 10.11728/cjss2005.06.536
Abstract(2704) [PDF 2025KB](65)
Abstract:
On the basis of data from the geomagnetic network and ionospheric observatories in China, the geomagnetic low point displacement, diurnal variation anomalies of geomagnetic field and ionospheric f0F2 (critical frequency of F2 layer) anomaly phenomena before large earthquakes have been summarized. Anomaly distribution and characteristics of geomagnetic variation field and ionospheric f0F2 before Mani MS 7.5 earthquake on Nov.8, 1997, and Kunlunshan MS 8.1 earthquake on Nov. 14, 2001, have been comparatively studied. The result shows that the temporal spatial characteristics of short term and imminent anomalies of geomagnetic field and ionosphere are consistent. The obvious anomalies of diurnal variation of geomagnetic field near epicentral area and ionospheric f0F2 at Lhasa observation are found. The geomagnetic low point displacements appeared about one month before the two great earthquakes, the boundary lines of sudden change passed through the epicentral area.
MODIFIED DESIGN AND STRUCTURALANALYSIS FOR ADJUSTMENT MECHANISM OF THE IMAGING LENS’S FOCAL LENGTH OF A SPACE SOLAR TELESCOPE
YUE Jianru, GUAN Fuling, YANG Yulong
2003, 23(2): 155-160.  
Abstract(2456) [PDF 1414KB](146)
Abstract:
Based on the previous work, a modified model of adjustment mechanism of the imaging lens’s focal length of a space solar telescope is designed. Analysis on the environment and contact ifluence of the modified model are also presented in the paper. The design principle is illustrated in the article. The movement of the image lens is controlled by the step motor and screw. According to the result of the contact analysis, the modified mechanism is workable.
Orbit requirements for detecting the upflow ion source region
Liu Yong, Wang Chi, Xu Jiyao, Li Xiaoyu
2014, 34(1): 104-108.   doi: 10.11728/cjss2014.01.104
Abstract(1053) [PDF 712KB](53)
Abstract:
Polar upflow ions from ionosphere to magnetosphere are crucial for space weather modeling. The origin and the acceleration of the upflow ions are the main scientific objectives for the Magnetosphere-Ionosphere-Thermosphere Coupling Constellation Mission. The constellation is composed of two magnetosphere satellites and two ionosphere/thermosphere satellites to monitor the polar region at different altitude jointly. The in-situ measurement on the source region of the upflow ions is vital for investigating the magnetosphere/ionosphere coupling, and it is also the requirement for designing orbit of the ionosphere/thermosphere satellite. We compared the circular and elliptical orbits based on the observations of other missions, and then choose the orbit of ionosphere/thermosphere satellites to be elliptical.
Comparison between Diviner Data and CELMS Data
Ran Zhen, Wang Zhenzhan, Li Yun
2014, 34(3): 249-261.   doi: 10.11728/cjss2014.03.249
Abstract(1350) [PDF 3248KB](59)
Abstract:
With a selected spot (45.1°-45.5°N, 33.1°-33.5° W) in Sinus Iridum, the measurements by Chang'E Lunar Microwave Sounder (CELMS) at five different lunar local time are analyzed. Then the lunar microwave brightness temperatures at four different frequencies of CELMS are simulated based on the microwave radiative transfer model. Grounded on the analyses for CELMS2 measurement as well as the simulated brightness temperatures in matched longitude, latitude and solar elevation angle, it is suggested that these two kinds of brightness temperature have a high correlation coefficient which can tend to 96%. Therefore, the stability of measurements of CELMS2 is verified.
Sporadic E morphology of East Asia
Zhao Haisheng, Xu Zhengwen, Wu Zhensen, Wu Jian
2014, 34(1): 38-45.   doi: 10.11728/cjss2014.01.038
Abstract(1060) [PDF 7870KB](54)
Abstract:
Sporadic E (Es) is the irregular structure of ionosphere occurred in the layer E sporadically, and the highest electron density can exceed the background by more than 100 times. In East Asia, the Es is of frequent occurrence, and the Es morphological characteristics research in this region has the uniqueness and typicality, which is of great significance to explore the cause and reveal the essence of Es. Based on more than fifty years' data from Chinese ionospheric vertical sounders, and combining with the Japanese vertical sounders data, the strength characteristics, spatial distribution characteristics, daily variations, seasonal changes and long-term trends of the Es over East Asia were studied, and conclusions are obtained.
Comparison of the Thermospheric Densities Between GRACE/CHAMP Satellites Data and NRLMSISE-00 Model
Chen Xuxing, Hu Xiong, Xiao Cunying, Wang Xijing
2013, 33(5): 509-517.   doi: 10.11728/cjss2013.05.509
Abstract(2542) [PDF 2413KB](59)
Abstract:
NRLMSISE-00 model is widely used in orbit determination and prediction of low-Earth orbit satellites. In order to calibrate the atmospheric density of NRLMSISE-00, the density errors of the model were analyzed by comparing with the observations from GRACE and CHAMP satellites. The density of the model was generally larger than that observed by GRACE and CHAMP satellites, especially under low solar activity. The density of the model showed higher accuracy at high latitude and its error varied with latitude and longitude. At the same location on the same orbit, density error of the model varied with local time and reached its maximum at 02:00LT and 15:00LT while reached its minimum at about 10:00LT and 20:00LT relatively. The 10.7cm solar radio flux (F10.7 index) showed high correlation with the density errors. The density of the model showed low accuracy during the solar minimum while good accuracy during the solar maximum. The model density showed better result at CHAMP satellite orbit with lower altitude comparing to the GRACE orbit. The error has less correlation with ap index during relatively quiet period of geomagnetic field (ap< 27).
The Research on GDOP of PL-Aided Beidou Positioning System
WANG Wei, LIU Zongyu, XIE Rongrong
2005, 25(1): 57-62.  
Abstract(2236) [PDF 1709KB](89)
Abstract:
The Beidou Positioning and Navigation System in the stand-alone mode cannot accomplish real-time 3-D passive positioning due to the limited number of constellation,but when aided by Pseudolites,through which the number and geometry of constellation is improved,it is capable of realizing high-precision passive positioning.Pseudo-satellites,also called pseudolites(PLs),which are the transmitters of navigation satellite-like signals,have the similar principle and function as spaceborne satellites,hence can provide the additional ranging source and thereby improving the geometry and increasing the accuracy,integrity,availability and reliability of the positioning results.And by simple,software only modifications,an existing satellite receiver can acquire PL signals and derive pseudoranges or carrier-phase measurements to be used in a navigation algorithm.As well known,such performances as accuracy of satellite-based positioning system are heavily dependent on the number and geometric distribution of satellites being tracked,and GDOP is a right measure of the geometry of the constellation.Therefore in the paper,the impacts of various locations and geometries of PLs on the accuracy of the augmented system are comprehensively investigated based on GDOP,and the conclusions obtained are the useful references for configuring PLs rationally as to improve further the performances of the system.
Choice of CCD optical remote sensor parameter
Jin Guang, Zhong Xing
2009, 29(1): 135-139.   doi: 10.11728/cjss2009.01.135
Abstract(3466) [PDF 605KB](56)
Abstract:
Image quality is the ultimate target for evaluating an optical remote sensing system. This paper introduces the concept and physical intension of resolution, and educes the concept of optical cutoff frequency and image smearing from the diffraction resolution of diffraction-limited incoherent imaging. To evaluate the image quality of sampling imaging system, the IQF (Image Quality Factor) λF/P is used to perform the sampling extension of CCD. This paper discusses the relation between optical remote sensor and SNR (signal to noise ratio) of the image. Taking advantage of image simulation function of ZEMAX software, the image of a space-based remote sensor with 9 m focal length and F number being 18 optical system is analyzed. The pixel size of the CCD is chosen to be 8.75μm and 13μm . The simulation result validates the influence of λF/P and SNR on image resolution. This result will instruct the choice of CCD optical remote sensor parameter.
Derivation of TEC and GPS hardware delay based on dual-frequency GPS observations
Wang Xiaolan, Ma Guanyi
2014, 34(2): 168-179.   doi: 10.11728/cjss2014.02.168
Abstract(1521) [PDF 1085KB](57)
Abstract:
The ground-based GPS receivers and hence networks enable studies of the ionosphere on a large regional or global scale by measuring the ionospheric TEC from dual-frequency GPS observations. However, originated in the hardware delay of the GPS satellite and receivers, a systematic bias affects the accuracy of the TEC derivation greatly. For accurate estimation of TEC, satellite and receiver instrumental biases should be removed from TEC measurements properly. This paper gives a comprehensive review of the algorithms on TEC and GPS hardware delays derivations. Starting from ionospheric radio wave propagation, the paper describes how the TEC is related with hardware delays. Then the TEC derivation methods are analyzed, evaluated and categorized into 3 main types. Finally, some suggestions are provided for further research on derivation of TEC and hardware delay.
Study of Ionospheric TEC Horizontal Gradient by Means of GPS Observations
Huang Wengeng, Chen Yanhong, Shen Hua, Zhuang Chunbo
2009, 29(2): 183-187.   doi: 10.11728/cjss2009.02.183
Abstract(5186) [PDF 596KB](63)
Abstract:
Dual-frequency GPS receiver can automatically correct time delay error caused by ionospheric Total Electron Content (TEC). But it cannot eliminate signal scintillation error caused by ionospheric irregularities. Even for differential GPS systems, ionospheric error is one of major sources in GPS positioning, for example, error from ionospheric TEC gradient, which will affect accuracy and degrade performance of GPS application system. In this paper, the magnitude of ionospheric TEC horizontal gradient is studied by means of GPS observations. The vertical TEC, and its horizontal gradient and ROTI index over NTUS station, which located in equatorial anomaly region, are derived from GPS observation provided by IGS network. It is found that, between post-sunset and around midnight, the ionospheric TEC has great fluctuation, and intense radio waves scintillation, which is represented by big ROTI index, takes place during this periods. Furthermore, the steep TEC horizontal gradient and its fast variation with respect to time appear. By comparison, the ROTI index, ionospheric TEC horizontal gradient and vertical TEC correlate very well with each other, and their variations characteristics result from density irregularities produced by plasma instability in ionosphere. It is suggested that when scintillation events are investigated, ionospheric TEC gradient is also one of considerable parameters.
A Simulation of the Mid- and Low-latitude Ionospheric Electric Fields
YU Tao, MAO Tian, XIA Chunliang, WAN Weixing
2014, 34(3): 287-295.   doi: 10.11728/cjss2014.03.287
Abstract(1006) [PDF 615KB](30)
Abstract:
A theoretical model of ionospheric electric fields at mid- and low-latitudes is developed. In the geomagnetic dipolar coordinate system, the ionospheric dynamo equations were solved, and the ionospheric electric potential and electric field were derived respectively. Major parameters for the model inputs, such as the neutral winds, the densities and temperatures of electron, ions and neutrals, are obtained from empirical models. The global ionospheric electrical potential and field at mid- and low-latitudes derived from our model are largely in agreement with the results presented by other authors and the empirical model. Using our model, it is found that the diurnal component of the HWM93 wind mainly contributed to the formation of the vertical electric field, while the semidiurnal component mainly contributed to the zonal electric field. Finally, by adjustment of the input F region winds and conductivities, most discrepancies between our model and the empirical one can be eliminated, and it is proved that the F region dynamo is the most significant contribution to the electric fields.
Recent Progresses on Ionospheric Climatology Investigations
LIU Libo, WAN Weixing, CHEN Yiding, LE Huijun, ZHAO Biqiang
2012, 32(5): 665-680.   doi: 10.11728/cjss2012.05.665
Abstract(2543) [PDF 590KB](120)
Abstract:
The ionosphere varies over multiple time scales, which are classified into two categories: the climatology and weather variations. In this national report, we give a brief summary of recent progresses in ionospheric climatology with focus on (1) the seasonal variations, (2) solar cycle effects, and (3) empirical modeling of the ionosphere. The seasonal variations of the ionosphere have been explored in many works to give a more detailed picture with regional and global features at various altitudes by analyzing the observation data from various sources and models. Moreover, a series of studies reported the response of the ionosphere to solar cycle variations, which revealed some novel and detailed features of solar activity dependence of ionospheric parameters at different altitudes. These investigations have improved our understanding on the states of the ionosphere and underlying fundamental processes, provided clues to future studies on ionospheric weather, and guided ionospheric modeling, forecasting and related applications.
Solar Wind Electrons Reflected by the Lunar Crustal Magnetic Field
Feng Yongyong, Xu Ronglan, Zhao Hua
2009, 29(2): 161-165.   doi: 10.11728/cjss2009.02.161
Abstract(4777) [PDF 567KB](38)
Abstract:
In this paper, the solar wind electrons which are moving toward the moon surface are traced to study the reflection of these electrons due to the crustal magnetic field of the moon. The magnetic field in the solar wind Bsw is supposed to be perpendicular with the moon surface, and the crustal magnetic field is supposed as a small dipole field with a moment Mcb, where Mcb are parallel, anti-parallel, and ±90° correspond to the direction of the Bsw. The calculation shows that the reflection number of the electrons varied with the angle between Mcb and Bsw. When Mcb is parallel with Bsw, the number of the reflected particles is the largest. The number decreases when the angle between Mcb and Bsw increases. These results are expected to provide some important information for the remote measuring of the lunar crustal magnetic field by using electron reflectometry technique.
Advances in Researches on the Middle and Upper Atmosphere in 2010-2012
CHEN Zeyu, CHEN Hongbin, LIU Xiao, HU Xiong, BIAN Jianchun, CHEN Wen, ZHANG Shaodong, XUE Xianghui
2012, 32(5): 681-692.   doi: 10.11728/cjss2012.05.681
Abstract(2494) [PDF 155KB](63)
Abstract:
This article summarizes the researches on the middle and upper atmosphere by Chinese scientists in 2010?2012. The focuses are placed on the advances in construction of ground-based remote sensing facilities, the mean state and long-term changes in the middle atmosphere circulation, the prevailing dynamical processes, and the coupling of the middle atmospheric layers.
Statistical analysis of solar wind velocity from ACE and STEREO-B satellites
Song Dan, Xue Bingsen, Cheng Guosheng
2014, 34(1): 1-10.   doi: 10.11728/cjss2014.01.001
Abstract(1512) [PDF 7054KB](78)
Abstract:
The wavelet analysis method was used to discuss the 27-day periodicities characteristic of the solar wind speed detected by ACE and STEREO-B satellites from the year of 2008 to 2011. Using the method of unary linear regression, the linear equation of solar wind speed is calculated. From the analysis and calculation results detected by ACE and STEREO-B, it is shown that the solar wind speed in 8~16d and 16~32d frequency domain is significant. The solar wind speed detected by the two satellites presents significant 27-day periodicities in parts of the same frequency domain. And it presents better correlation in the year when solar activity is low. As an application example, solar wind data detected by STEREO-B is applied to predict the solar wind speed of ACE from 1 to 17 in October, 2012. The results show that the trend of predicted values and measured values are consistent, although the CME has a certain influence on the predicted values. Through this research, the relationship of solar wind speed detected by ACE and STEREO-B satellites was preliminarily studied, and the solar wind speed was detected by STEREO-B a few days before it came to the Earth. This work laid the foundation to establish the medium-term forecast models for the non-recurrent geomagnetic storms.
Research on electrostatic deformation of space membrane mirror
Liu Chunyu, Jin Guang
2009, 29(1): 68-72.   doi: 10.11728/cjss2009.01.068
Abstract(3239) [PDF 566KB](65)
Abstract:
Aerospace Relay Mirror System (ARMS) as a new conceptional weapon used in reflection of High Energy Laser (HEL) in space is studied. It extends the attacking range of Ground Based Laser (GBL) weapons enormously. Relevant researches have been carried out for many years. The structure and operating theory of the entire system consists of ground-based high energy laser weapon and space-based relay mirror. The main work of this study was focused on the analysis of relay mirror energy character to deduce the relationship among the attacking range of weapon and diameter of ARMS and target irradiance. Calculation examples are also given. The result further proves the strong points and feasibility of ARMS in principles. It is summarized that more importance should be attached to ARMS development. The results given in this paper can be the reference of actual ARMS system to some extends.
Contour Constraint Based Geomagnetic Matching Method
LIU Ying, WU Meiping, HU Xiaoping, XIE Hongwei
2007, 27(6): 505-511.   doi: 10.11728/cjss2007.06.505
Abstract(2438) [PDF 1912KB](54)
Abstract:
Geomagnetism Aided Navigation (GAN) is a new branch of the integrated navigation technique. Navigation principle and the development of the GAN system are introduced in the paper. The emphasis is laid on the research of the matching method. Geomagnetic matching is the technique that uses a geomagnetic map to determine the location of the vehicle. The obtained position information can be used to limit error accumulation of the Inertial Navigation System (INS). An improved correlation matching method based on the contour constraint is proposed. Map contour is used to confine the searching process, changing the uncertainty field to an uncertainty line, which efficiently reduces the computation burden of the system and eliminates the initial position error of INS. A nearest point principle (NPP) is applied in the precision matching part. The NPP technique can bind the error of INS accumulated during the matching process. The simulation results show that the proposed method can greatly improve the efficiency and precision of the whole GAN system. The accuracy of the matching method is less than the unit cell size of the map. In addition, the proposed method is, to some extend, adaptive to the heading error of the INS.
Analysis on Ionospheric Perturbations before Yushu Earthquake
ZHANG Xuemin, LIU Jing, ZHAO Biqiang, XU Tong, SHEN Xuhui, YAO Lu
2014, 34(6): 822-829.   doi: 10.11728/cjss2014.06.822
Abstract(1412) [PDF 3347KB](67)
Abstract:
In this paper, the ionospheric perturbations in three parameters have been analyzed around Yushu earthquake, including f0F2 from ionosonde, GPS TEC, and in-situ plasma parameters by satellite. Their temporal and spatial relationship with this event were studied, and the results showed synchronous disturbances in multi-parameters on 13 April, just one day before the Yushu earthquake. The f0F2 abnormally increased 40% relative to its sliding median of 5 days before, and its anomalous center moved from southeast to southwest. GPS TEC with abnormal amplitude of 15TECU (1TECU=1016m-2) concentrated in a longitudinal scale of 15° over the south of the epicenter, and similar anomalies were found at its conjugate areas. While the in-situ observation of oxygen ion density Ni(O+) from DEMETER reached its maximum on April 13 for the four months from January to April in 2010, with the anomalies deviating to the equatorial areas but limited in the longitude scale of 30°-50°. Su mming up the anomalous characteristics in these three parameters, whatever the local feature in space, or the close relevance in time, both exhibited possible relationship with the Yushu earthquake. Combined with other observations, the seismo-ionospheric coupling mechanism was discussed during the preparation process of Yushu earthquake.
Space Life Science of China in 2013
Lei Runhong, Zhou Guangming, Ma Hong, Zhuang Fengyuan, Deng Yulin
2014, 34(5): 747-756.   doi: 10.11728/cjss2014.05.747
Abstract(1119) [PDF 148KB](62)
Abstract:
In the past two years, space life science research in China is characterized by a wide area of basic researches for providing foundation for the future China Space Station. The effect of microgravity and radiation was further studied from physiology phenomena to the level of bio-molecule mechanisms. Chinese space life science is maturing in a new era of comprehensive development. Here, we review and summarize researches on space life sciences which were contributed by Chinese scientists.
A new GNSS signal carrier tracking algorithm for ionospheric TEC monitoring
Liu Wenxue, Yuan Hong, Wei Dongyan, Xu Ying
2014, 34(1): 63-72.   doi: 10.11728/cjss2014.01.063
Abstract(1339) [PDF 1570KB](50)
Abstract:
Currently, GNSS (Global Navigation Satellite System) is widely used in ionospheric TEC monitoring. The traditional method of GNSS monitoring ionospheric TEC is based on the original output measurements of navigation receiver, and then we obtain the ionospheric TEC information through the data conversion. The signal processing algorithm is also the navigation receiver algorithm which is used for navigating. The purpose of this work is to design a new GNSS dual-frequency signals tracking algorithm for the GNSS ionospheric TEC monitoring application, which is called sum-diff joint tracking algorithm. Compared with the traditional method, the algorithm is directly tracking the ionospheric TEC changes, and can improve the sensitivity of dual-frequency tracking and the TEC observation precision, so that it can improve the performance of GNSS monitoring ionospheric TEC.
Structural Analysis About a New Solar Sail
ZHENG Jinjin, SHENG Zhaoyu, ZHOU Hongjun, HUANG Wenhao, SHENG Lianguan
2009, 29(2): 249-256.   doi: 10.11728/cjss2009.02.249
Abstract(3130) [PDF 378KB](34)
Abstract:
The article presents a structural analysis of a new space probe-solar sail. It was deployed successfully on ground. The loads for an outer space mission was introduced and expressed with equation. As a special state, the largest load around earth was used to analyze the model by the finite element method. Some results about strain and stress was obtained after setting some initial parameters. Compared to the results in the literature, the results presented here are significant.
Electrodynamic coupling in the solar wind-magnetosphere-ionosphere system
Hu Youqiu, Wang Chi
2010, 30(4): 321-332.   doi: 10.11728/cjss2010.04.321
Abstract(2534) [PDF 321KB](46)
Abstract:
This paper presents a brief summary of our recent work based on global MHD simulations of the Solar wind-Magnetosphere-Ionosphere (SMI) system with emphasis on the electrodynamic coupling in the system. The main conclusions obtained are summarized as follows. (1) As a main dynamo of the SMI system, the bow shock contributes to both region 1 Field-Aligned Current (FAC) and cross-tail current. Under strong interplanetary driving conditions and moderate Alfven Mach numbers, the bow shock's contribution may exceed more than fifty percent of the total of either region 1 or cross-tail currents. (2) In terms of more than 100 simulation runs with due southward Interplanetary Magnetic Field (IMF), we have found a combined parameter f = EswPswMA-1/2 (Esw, Psw, and MA are the solar wind electric field, ram pressure, and Alfven Mach number, respectively): both the ionospheric transpolar potential and the magnetopause reconnection voltage vary linearly with f for small f, but saturate for large f. (3) The reconnection voltage is approximately fitted by sin3/2θIMF/2, where θIMF is the IMF clock angle. The ionospheric transpolar potential, the voltage along the polar cap boundary, and the electric fields along the merging line however defined they may be, respond differently to θIMF, so it is not justified to take them as substitutes for the reconnection voltage.
RELAXATION PROCESS OF IONIZATION IN FLARING REGION
Chen Gui-fu, Huang Yong-nian
1989, 9(3): 175-179.   doi: 10.11728/cjss1989.03.175
Abstract(1639) [PDF 359KB](21)
Abstract:
This paper presents a model describing the changes of ion charges and their relaxation process in solar flare phenomena based on the fact of low temperature magnetic loops emerging before solar flare bursts and prompt heation of plasma in impulsive phase of solar flares. Numerical calculations of charge state distributions and mean ionic charges of element C, N, Oare obtained and the results are coincident with the observations.
ORBITAL DESIGN OF VERTICAL HITTING MOON PROBE
XI Xiaoning, ZHU Wenyao
1998, 18(2): 161-167.   doi: 10.11728/cjss1998.02.161
Abstract(1945) [PDF 289KB](42)
Abstract:
In this paper, the problem of orbital design of vertical hitting moon probe is discussed. The probe starts from a near-earth circular parking orbit and accelerates in the velocity direction of the parking orbit then enters the landing moon orbit and finally hits the moon with free flight, Firstly,in the constraint conditions of the parking orbit,energy limit,and the landing moon point using theories of two-body and double two-boby, not only the approximate initial values of the orbit are given,but also the characteristics of it are illustrated. Then, based on a dynamic model of general restricted four-boby, three point boundary values are searched and the high accuracy orbit of the probe is gained.
Fuzzy Adaptive Compensator Control for Free-floating Space Manipulator With Unknown Payload Parameters to Track Desired Trajectory in Joint Space
Liang Jie, Chen Li
2009, 29(3): 338-345.   doi: 10.11728/cjss2009.03.338
Abstract(4427) [PDF 761KB](48)
Abstract:
In this paper, when the case of the attitude of base controlled and its location uncontrolled, we discuss the control for free-floating space manipulator to track desired trajectory in joint space. Combined the relationship of the linear conversation of the system and the Lagrange approach, the full-controlled dynamic equation of free-floating space manipulator are established. Base on above results proposed, aiming at the case of free-floating space manipulator system with uncertain payload parameters, a composite scheme of a computed torque controller plus a fuzzy compensator is proposed to track desired trajectories in joint space. Namely, it will transfer the impact of system's unknown parameters to computed torque controller through fuzzy adaptive compensation system controller, to
ensure the whole closed-loop control system's asymptotic stability with the existence of unknown parameters. The mentioned control scheme can effectively control two joint of space manipulator to stably track the desired trajectory in joint space. It has obvious advantages that with needless feedback and measured the position, velocity, acceleration, attitude angle velocity and attitude angle acceleration of the floating base. At the same time, no requirements for the dynamic equations of the system are linearly dependent on inertial parameters. A two space-based manipulator system is simulated to verify the proposed control scheme.
Exploring the Dynamic X-ray Universe: Scientific Opportunities for the Einstein Probe Mission
YUAN Weimin, OSBORNE Julian P, ZHANG Chen, WILLINGALE Richard
2016, 36(2): 117-138.   doi: 10.11728/cjss2016.02.117
Abstract(2115) [PDF 11002KB](64)
Abstract:
Time-domain astrophysics will enter a golden era towards the end of this decade with the advent of major facilities across the electromagnetic spectrum and in the multi-messenger realms of gravitational wave and neutrino. In the soft X-ray regime, the novel micro-pore lobster-eye optics provides a promising technology to realise, for the first time, focusing X-ray optics for wide-angle monitors to achieve a good combination of sensitivity and wide field of view. In this context Einstein Probe, a soft X-ray all-sky monitor mission, was proposed and selected as a candidate mission of priority in the space science programme of the Chinese Academy of Sciences. This paper reviews the most important science developments and key questions in this field towards 2020 and beyond, and how to achieve them technologically. It also introduces the Einstein Probe mission, including its key science goals and mission definition, as well as some of the key technological issues.
Space Solar Physics in 2012?2014
Gan Weiqun
2014, 34(5): 563-564.   doi: 10.11728/cjss2014.05.563
Abstract(1203) [PDF 67KB](49)
Abstract:
The main activities of Chinese space solar physics in 2012-2014 include: to continue studying the mid and long-term (2016-2030) plan of Chinese space solar physics; to arrange a group of pre-study projects of space solar physics; to initiate and continue a few solar mission-level projects. This paper summarizes all these activities briefly.
YingHuo-1——Martian Space Environment Exploration Orbiter
ZHAO Hua
2008, 28(5): 395-401.   doi: 10.11728/cjss2008.05.395
Abstract(2622) [PDF 297KB](34)
Abstract:
This paper gives a brief introduction of YingHuo-1 (YH-1), a Chinese Martian Space Environment Exploration Orbiter. YH-1 is a micro-satellite developed by Chinese Aerospace Industry,and will be launched together with Russian spacecraft, Phobos-Grunt, to orbit Mars in September,2009. Four payloads are selected for the mission, plasma package, including of electron analyzer, ion energy and mass analyzer; sat-sat occultation receiver; flux-gate magnetometer; and optical monitor.YH-1 mission focus on the investigation of the characteristics and its evolution of the Martian space Environment, and identifying major plasma processes, which provide channels for Martian volatiles escaping.
Adjust to the balance of three-DOF air-bearing test-platform and the research of disturber torque
Yang Xiubin, Jin Guang, Xu Kai
2009, 29(1): 34-38.   doi: 10.11728/cjss2009.01.034
Abstract(4160) [PDF 539KB](74)
Abstract:
Three-DOF air-bearing test-platform is the key test base of simulating the satellite attitude motion for simulating the satellite emulation effective, so as to simulate the torque-free environment in the space. 3-DOF air-bearing test-platform disturber moment is analysed. When there is a shift between the gravity center and the rotary center, the static unbalance appears. While a shift exits between main inertia axes and rotary axis, the dynamic unbalance appears. In addition, the principal and procedure of balancing a 3-DOF air-bearing test-platform and the technology of manual and automatic balancing it are discussed. The equations of kinetics are derived. At last a lot of methods are used to measure the static unbalance moment and disturber moment in order to supply satellites' attitude motion with a model of availability, precisions and efficiency.
A method of in-orbit calibration of fluxgate magnetometer based on the measurement of absolute scalar magnetometer
Zhang Zhenqi, Li Lei, Zhou Bin, Zhang Yiteng
2014, 34(2): 235-241.   doi: 10.11728/cjss2014.02.235
Abstract(1620) [PDF 838KB](43)
Abstract:
High precision measurement of the magnetic field is required for in-orbit magnetic field monitoring and mapping. Due to the restrictions of processing technology and installation, the three axes of fluxgate magnetometer cannot be strictly orthogonal and the offsets in three directions are unknown in actual measurement. To solve this problem, it is necessary to determine the alignment and offset of the fluxgate magnetometer in-orbit instead of on the ground. According to the method of calibrating with scalar magnetometer, a method for calibrating the alignment, sensitivity, and offset by an improved least square calibration algorithm is proposed. Results show that considering the noise of detector itself, the error of fluxgate magnetometer can be reduced from about 100nT to less than 0.2nT. This calibration algorithm offers a feasible way of in-orbit high-precision measurements.
Design Of Optical And Mechanical Structure For Lunar Simulator Based On Variable Shape And Adjustable Radiance
LIU Shi, ZHANG Guoyu, SUN Gaofei, WANG Lingyun, GAO Yujuni
2015, 35(5): 647-652.   doi: 10.11728/cjss2015.05.647
Abstract(943) [PDF 2765KB](38)
Abstract:
To simulate the different lunar phases and ensure continuous adjustability of the radiant brightness, a new broad spectrum light and frosted glass were applied and designed in the optical system for lunar simulator with the shapes and radiance being able to be adjusted. According to the engineering demand and index requirements of the optical system, three major design aspects are addressed, including the high reliability and maintainability for broad-spectrum light, heat dissipation in lunar simulator for long working hours, and bearing of the main frame under different working conditions. By designing a reasonable machine structure, and through the structure itself with the matrix arrangement of 48 axial flow fans, an effectively cooling air duct is established. Deformation and temperature were calculated by the finite element software ANSYS. The results showed that the displacement deformation reached 0.33mm and stress deformation reached 0.02MPa at the temperature of 20℃; when the main frame was in the temperature field between 20℃ and 65℃, the maximum displacement deformation reached 13.30mm and maximum stress deformation is 97.90MPa, and the amount of this deformation is very small in considering of the mechanical structure dimensions and weight of the lunar simulator.
Correlations between solar activity and thermospheric density
Niu Jun, Fang Hanxian, Weng Libin
2014, 34(1): 73-80.   doi: 10.11728/cjss2014.01.073
Abstract(1246) [PDF 3616KB](42)
Abstract:
The periodic characteristics of solar F10.7 index and the thermospheric density at 250km, 400km and 550km altitude have been investigated. The results show that the thermospheric density correlates well with the solar activities, and both of them have significant period of 27 days and 11 years. Besides, the thermospheric density also has 7~11 days' period, semiannual and annual variations. The response of thermospheric density lags the solar activity for three days. No matter what the level of geomagnetic activity is, the correlation between solar activity and thermospheric density at 400km is larger than 250km, minimum at 550km. The relationships between the neutral density and solar activity show linear, saturation and amplification features. The thermospheric density in higher altitude is more sensitive to the solar activities.
Development of Operational Space Weather Prediction Models
Gong Jiancun, Liu Siqing, Shi Liqin, Luo Bingxian, Chen Yanhong, Huang Wengeng, Cao Jinbin, Xie Lun, Lei Jiuhou, Tang Wei-wei
2014, 34(5): 688-702.   doi: 10.11728/cjss2014.05.688
Abstract(1169) [PDF 7634KB](53)
Abstract:
In this report, we summarize the needs of space weather models, and recommend that developing operational prediction models, rather than transitioning from research to operation, is a more feasible and critical way for space weather services in the near future. Operational models for solar wind speed, geomagnetic indices, magnetopause, plasma sheet energetic electrons, inner boundary of ion plasma sheet, energetic electrons in outer radiation belt, and thermospheric density at low Earth orbit, have been developed and will be introduced briefly here. Their applications made a big progress in space weather services during the past two years in China.
AN APPROACH TO STUDY THE DAY-TO-DAY VARIATIONS OF IONOSPHERIC TEC DIRECTLY BY GPS TIME-DELAY SIGNALS
XIAO Zuo, ZHANG Donghe
2000, 20(2): 97-102.   doi: 10.11728/cjss2000.02.097
Abstract(1901) [PDF 559KB](21)
Abstract:
In this paper, an approach was presented to deduce the diurnal variation ofionospheric TEC through only the measured data of time-delay (pseudo-range) ofGPS signals without using any phase information. Thus the procedure to studyTEC day-tcaday vaxiations is greatly simpllfied. In this method, satellite clock biascan be removed self consistently in the calculations while the receiver clock erroris corrected by using the average night values from IRI model- In this way someabsolute error due to receiver clock may still exist, but this does not infiuence thestudy of day-to-day vaxiations. The calculated vertical TEC is the average of verticalprojections of all the line-of sight TEC from differellt satellites in a conical angleof 60 degrees around the local vertical direction. An example of three consecutivedays' TEC variation was given, which shows the validity of the method suggestedin this paper. Finally it is pointed out that in the case of large zenith angle ofsatellite, ionospheric irregularities may contribute certain amoullt to the multi-patheffect.
THE THEORV OF GPS-BASED GEOMETRIC ORBIT DETERMINATION FOR LOW-EARTH SATELLITES
HU Guorong, OU Jikun
2000, 20(1): 32-39.   doi: 10.11728/cjss2000.01.032
Abstract(1671) [PDF 632KB](18)
Abstract:
Methods of single frequency carrier phase-based relative orbit determination(OD) and kinematic network OD for low-earth satellite are developed. From theresults calculated using L1 data collected by GPS/DR onboard Topex/Poseidon,we can draw following conclusions: (a) the accuracy of single frequency carrierphase-based relative OD may attain the order of a few decimeters; (b) the accuracyof relative OD depends on the data quality of ground tracking stations; (c) theaccuracy of kinematic network OD is equavalent to a weighting among relative ODsof different ground tracking stations and can improve the reliability and precisionof OD due to its redundant condition and good geometric configuration.
Design of dynamic star simulator based on LCOS optical splicing technology
Liu Shi, Zhang Guoyu, Sun Gaofei, Wang Lingyun
2013, 33(2): 200-206.   doi: 10.11728/cjss2013.02.200
Abstract(2438) [PDF 632KB](46)
Abstract:
The technical scheme of a dynamic star simulator based on the LCOS optical splicing technology is proposed in order to meet the demands of a star sensor in spacecraft engineering. Optical system parameters of the simulator are calculated by the specification of a LCOS. The two LCOS optical splicing principle and scheme are introduced in detail, method of the dynamic star map realization is given, and its error is analyzed. The simulating results indicate that field of view is of 10.2° × 10.2°, star magnitude simulated is of 2~6.5, the single star field angle is less than 20", and the star diagonal distance error is less than 22". The experimental result can satisfy the system requirements of big field of view, wide magnitude range and update rate, etc.
Design of three-axis stable robust adaptive attitude control of microsatellites
Zhang Liu, Wang Shaoju, Jin Guang
2009, 29(1): 29-33.   doi: 10.11728/cjss2009.01.029
Abstract(4495) [PDF 508KB](53)
Abstract:
The attitude control problem of certain microsatellites with uncertainty structure and unknown but constant external interference is studied in this paper. Based on Lyapunov method and utilizing the input-output property of Euler-Lagrange systems, a robust adaptive controller without dynamics decoupling is presented. Computer simulation shows that this control algorithm possesses good control performance and robustness.
Comparison of f0F2 between observation and the prediction based on IRI-2012 over Guangzhou
Wan Dehuan, Huang Jiang, Deng Baichang, Xu Jie, Kong Debao, Lin Guoguo
2015, 35(2): 166-177.   doi: 10.11728/cjss2015.02.166
Abstract(1234) [PDF 4011KB](45)
Abstract:
Monthly mean values of f0F2 parameter, with an hour time interval resolution for diurnal variation, obtained at Guangzhou (23.2°N, 113.3°E) station are used to investigate the variations and comparisons with the International Reference Ionosphere (IRI-2012) model predictions. The results show that generally, IRI-2012 predictions follow well with the diurnal and seasonal variation patterns of the observed values of f0F2, and the predictions with CCIR coefficients is better than URSI. However, there are systematic deviation between observed values and IRI predictions with either CCIR or URSI coefficients. Generally IRI model greatly underestimates the values of f0F2 from about noon to sunrise of the next day, especially at 20:00LT, and slightly overestimates them from sunrise to about noon. The deviation will increase at the time when the nighttime enhancement occurred, especially in spring and autumn. This means that the predictions can not follow well with variation of the observed values of f0F2.
Dynamics and Control of Displaced Orbits for Solar Sail Spacecraft
QIAN Hang, ZHENG Jianhua, YU Xizheng, GAO Dong
2013, 33(4): 458-464.   doi: 10.11728/cjss2013.04.458
Abstract(2573) [PDF 619KB](75)
Abstract:
Based on the linear dynamics model and nonlinear dynamics model, the sun-centred displaced orbits keeping control problem is studied. Firstly, the solar sail dynamics model in cylindrical coordinate form is derived and orbit controllability of the state equation by linearizing the model along the nominal orbit is investigated. Then, by choosing the control weighted matrix R reasonably, a control law for the linear model is designed using the Linear-Quadratic Regulation (LQR) approach. The numerical simulations which are obtained by taking the control law into the nonlinear model indicate that the designed controller which has asymptotic stability and high control accuracy is capable.
China’s Space Astronomy and Solar Physics in 2011-2012
ZHANG Shuangnan, YAN Yihua, GAN Weiqun
2012, 32(5): 605-617.   doi: 10.11728/cjss2012.05.605
Abstract(2636) [PDF 159KB](91)
Abstract:
In the first part of this paper, we describe briefly the mid and long-term plan of Chinese space astronomy, its preliminary study program, the current status of satellite missions undertaken, and the current status of astronomy experiments in China’s manned space flight program. In the second part, the recent research progress made in the fields of solar physics is summarized briefly, including solar vector magnetic field, solar flares, CME and filaments, solar radio and nonthermal processes, EUV waves, MHD waves and coronal waves, solar model and helioseismology, solar wind and behavior of solar cycle.
Overview of Scientific Objectives of China-Russia Joint Mars Exploration Program YH-1
Wu Ji, Zhu Guangwu, Zhao Hua, Wang Chi, Li Lei, Sun Yueqiang, Guo Wei, Huang Chengli
2009, 29(5): 449-455.   doi: 10.11728/cjss2009.05.449
Abstract(3263) [PDF 688KB](84)
Abstract:
Mars has been one of the most interesting planets in the solar system for human beings due to its orbit characteristics and its geology, and the main attraction is the possibility to find life on it. Since the 1990s, many exploration missions have been sent to Mars. From the beginning of this century, many space power countries have announced their manned Mars program strategy. China was the fifth country in the world to launch its artificial satellite on its own, and the third country to have the ability to carry out independent manned space program. However, China is not a power at all in deep space exploration. To catch up, China and Russia have signed an agreement on a joint Mars exploration program by sending a Chinese microsatellite Yinghuo-1 (YH-1) with Russian's Phobos-Grunt mission. Once YH-1 is in orbit, it will not only carry out its own exploration mission but also conduct joint measurement with Russian Phobos-Grunt spacecraft. In this paper, the scientific background is reviewed, the scientific objectives of YH-1 are given, and the scientific payloads and operation considerations are also briefly described.
Preliminary Scientific Results of Chang E-1 Lunar Orbiter:Based on Payloads Detection Data in the First Phase
OUYANG Ziyuan, JIANG Jingshan, LI Chunlai, SUN Huixian, ZOU Yongliao, LIU Jianzhong, LIU Jianjun, ZHAO Baochang, REN Xin, YANG Jianfeng, ZHANG Wenxi, WANG Jianyu, MOU Lingli, CHANG Jin, ZHANG Liyan, WANG Huanyu, LI Yongquan, ZHANG Xiaohui, ZHENG Yongchun, WANG Shijin, BIAN Wei
2008, 28(5): 361-369.   doi: 10.11728/cjss2008.05.361
Abstract(2519) [PDF 3447KB](65)
Abstract:
Chang'E-1 lunar Orbiter was launched by Long March 3A rocket from Xichang Satellite Launch Center at 18:05 BT (Beijing Time) Oct. 24, 2007. It is the first step of its ambitious three-stage moon program, a new milestone in the Chinese space exploration history. The primary science objectives of Chang'E-1 lunar orbiter are to obtain three-Dimension (3D) stereo images of the lunar surface, to analyze the distribution and abundance of elements on the surface, to investigate the thickness of lunar soil, evaluate helium-3 resources and other characteristics, and to detect the space environment around the moon. To achieve the above four mission objectives, eight sets of scientific instruments are chosen as the payloads of the lunar orbiter, including a CCD stereo camera (CCD), a Sagnac-based interferometer spectrometer (IIM), a Laser Altimeter (LAM), a Microwave Radiometer (MRM), a Gamma-Ray Spectrometer (GRS), an X-ray spectrometer (XRS), a High-Energy Particle Detector (HPD), and two Solar Wind Ion Detectors (SWID). The detected data of the payloads show that all payloads work well. This paper introduces the status of payloads in the first phase and preliminary scientific results.
Latest Scientific Results of China's Lunar Exploration Program
XU Lin, ZOU Yongliao, QIN Lang
2018, 38(5): 598-603.   doi: 10.11728/cjss2018.05.598
Abstract(1018) [PDF 2297KB](53)
Abstract:
Through the implementation of China's Lunar Exploration Program (CLEP), a large amount of data has been acquired. This paper will present the latest scientific results based on these data involving the composition, topography, space environment, subsurface structure of the Moon, and asteroid exploration and moon-based observations, etc.
Application of combinatorial materials approach for fast screening of Zn-Al alloy films
Liu Qian, Chen Wei, Liu Qingfeng, Gui Linhua, Zhu Lihui, Wang Li
2009, 29(1): 10-16.   doi: 10.11728/cjss2009.01.010
Abstract(4289) [PDF 800KB](64)
Abstract:
A combinatorial method was used to deposit a Zn-Al material library on a low carbon steel substrate by ion beam sputtering. As-deposited film samples were annealed at varied heat treatment conditions to promote the diffusion between the elements for a through-thickness homogenous sample. XRD and EDS analyses were carried out for composition and structure, AFM and TEM images were obtained for morphology observation. Nanoindentation tests were conducted to investigate the mechanical behaviour of samples. Electrochemical corrosion properties of the Zn-Al material library were evaluated by a modified tape test. A relationship among composition-structural phase-property of Zn-Al alloy films was set up by the fast screening method. Results show that the Zn-Al film with a composition of about 30 at % Zn has either the best anti-corrosion property, or better mechanical property.
Review of the Development of Robotic Manipulator for International Space Station
Zhang Kaifeng, Zhou Hui, Wen Qingping, Sang Ruipeng
2010, 30(6): 612-619.   doi: 10.11728/cjss2010.06.612
Abstract(2679) [PDF 760KB](67)
Abstract:
In extreme environment of the space, most of Extra-Vehicular Activity (EVA) has to depend on the aid of robotic manipulator. As a main part of International Space Station (ISS), robotic manipulator is playing a crucial role in the on-orbit assembly, external maintenance and the operations of ISS, and it therefore allays the working time and frequency of astronauts EVA. This paper reviews the development of the robotic manipulator based on ISS member countries' research, including shuttle remote manipulator, space station remote manipulator, European robotic arm, Japanese experiment module remote manipulator and German manipulator. It is expected that the concerning research will provide some references for the design of Chinese robotic manipulator.
Ionospheric Weather Disturbance Indices Based on Spectral Whitening
ZHAO Yuxin, MAO Tian, CHEN Zhou, WANG Jingsong
2017, 37(3): 270-276.   doi: 10.11728/cjss2017.03.270
Abstract(1048) [PDF 4240KB](46)
Abstract:
A Spectral Whitening Method (SWM) is introduced and applied in the study of ionospheric weather disturbances to calculate Js, Jr and Jp indices on the basis of Total Electron Content (TEC) data provided by IGS. These indices can reflect the disturbances of ionospheric weather of single station, latitude circle (integral along longitude) and the whole planet separately. During a geomagnetic storm in March 2015, all three indices well reflect the ionospheric disturbances. The correlation coefficient between Jp and Dst indices reaches -0.72, and the 2D images of ionospheric disturbances can be well captured by Js map. The correlation coefficient between Jp index and Dst index, from 2011 to 2014, reaches -0.67 if Jp is greater than or equal to 2, and the correlation coefficient can reach -0.87 if Jp is greater than or equal to 3. By analyzing the frequencies of different levels of geomagnetic storms under different threshold values of Jp index, the results suggest that Jp index, as a possible characterization parameter of ionospheric weather condition, can well reflect planetary ionospheric disturbances during geomagnetic storms.
Characters of the Pc3-4 Magnetic Pulsations at Middle and Low Latitudes: Preliminary Geomagnetic Results From Chinese Meridian Project
Zhang Qingmei, Wang Chi, Li Hui, Li Chuanqi
2013, 33(6): 608-616.   doi: 10.11728/cjss2013.06.608
Abstract(1090) [PDF 3183KB](55)
Abstract:
The characters of the Pc3-4 magnetic pulsations and their relationships to interplanetary conditions were studies during the periods of both the magnetic quite (March 20 to 27, 2011) and storm (September 25 to October 1, 2011), using ground-based geomagnetic field measurements from the new-developed Chinese Meridian Project. Preliminary results show there exist significant dawn-dusk asymmetric distribution of the Pc3-4 pulsations in the middle-low latitudes (1.3<L < 2.3), with Pc3-4 pulsations activity are observed mainly in the pre-noon sector, during both time periods. They are closely related to the interplanetary conditions, with high-speed solar wind and solar wind dynamic pressure pulsation leading to enhancement of the Pc3-4. However, Pc3-4 pulsations activity is not observed near the equatorial low latitudes (L <1.3) due to latitudinal effect.
Research of Spectrum Correction Method Based on All Phase FFT for Induction Magnetometer
REN Haiyan, ZENG Li, LIU Xu, WEI Dong, WANG Yan, CHEN Yu
2016, 36(3): 366-372.   doi: 10.11728/cjss2016.03.366
Abstract(999) [PDF 1383KB](76)
Abstract:
Induction magnetometer,based on Faraday's law,is used to measure the magnetic field changes with low frequency in space.It usually has the function of on-orbit FFT spectrum analysis, which can obtain the information of magnetic field fluctuation directly,such as frequency and amplitude.However,when using FFT to process the truncated signal,non-complete period sampling will cause spectrum leakage and fence effect.Namely the spectrum information will generate deviations, which affects the accuracy of real-time monitoring of magnetic field changes.Compared with traditional FFT,the all-phase FFT with phase invariability can effectively prevent spectrum leakage.In this paper,an all-phase time-shift phase difference method (apFFT/apFFT) is used to correct the aveform data of a satellite induction magnetometer.Simulation and experimental results indicate that this method can improve the measurement accuracy.This study also provides a method about on-orbit spectrum analysis for the next generation of spaceborne induction magnetometer.
RESEARCH ON THE INTELLIGENT DIAGNOSISFOR SPACECRAFT BASED ON FAULT TREE ANDNEURAL NETWORK
JI Changwei, RONG Jili, HUANG Wenhu
1999, 19(2): 160-166.   doi: 10.11728/cjss1999.02.160
Abstract(2025) [PDF 464KB](65)
Abstract:
Fault diagnostic system is of great importance in monitoring and controllingspacecraft in the ground control center. The bottleneck problem of knowledge acquisition for spacecraft fault diagnosis is solved by using fault tree knowledge. Thepaper presents a fault diagnostic method based on fault tree and neural networkmodel. Based on the hierarchical model of fault tree, knowledge representationmethod based on frame and generalized rule is presented, and the relevant certainand possible reasoning strategies are described. Learning diagnosis based on neuralnetwork model is used to confirm and verify the results from the possible reasoning. By using Borland C++ under Windows, a fault diagnostic prototype systemis developed, and the validity is also demonstrated by diagnosing a satellite powersystem fault imitation bench.
TLE Prediction Accuracy Improvement and its Application in Collision Warning
Liu Wei, Wang Ronglan, Liu Siqing, Shi Liqin, Gong Jiancun
2014, 34(4): 449-459.   doi: 10.11728/cjss2014.04.449
Abstract(1209) [PDF 5017KB](81)
Abstract:
Two Line Elements (TLE) is the only publicly available and most complete data sets of Earth orbit objects. The prediction accuracy with SGP4/SDP4 is limited. The TLE+SGP4/SDP4 prediction error sources and improvement method with historical TLE data were analyzed. A pseudo-observation data generation method was introduced. The fitting period of TLE data and the value of Δt used in generating pseudo-observation are dependent on the orbital altitude. An effective area-to-mass ratio (A/M) determination method was obtained. GPS satellites prediction error in case of η estimated or not are also tested. The improved prediction accuracy is prominent in the application of US and Russian satellites collide event. Objects were selected and their orbit were predicted with an improved TLE-numerical method. The statistical results show that the TLE prediction accuracy is greatly improved. The application of the improved TLE and possible problems were also discussed.
Simulation Of Induced Step-Transient Magnetic Field With A Lunar Homogeneous Model
ZHANG Xiangyu, ZHAO Hua
2015, 35(5): 525-532.   doi: 10.11728/cjss2015.05.525
Abstract(824) [PDF 5427KB](41)
Abstract:
With a homogeneous model of the Moon, the induced magnetic field caused by step-transient disturbation of interplanetary magnetic field is simulated by the electromagnetic induction theory. As the range of conductivity assigned, the variation from step to calm of both the vectors and magnitudes can be obtained with a fixed permeability μ0. Then the magnetic characteristic transient response function, the field components and total field at 3 different points selected in a longitude line can all be given in different conductivities by numerical inverse Laplace transformation. The calculation provides a reasonable result that components perpendicular to the external step-transient field will disappear in a long-enough time, whereas the parallel component will become unity with it. When the external field step varies, the maximum field value which can be detected in the vicinity of the equator and the polar region are 13.65nT and 2.71nT, respectively. The processes of parallel component change are remarkably different in low latitude and polar region. This phenomenon reflects that magnetometers in different sites of lunar surface may lead to different field curves.
Central and Northern China TEC Map Using the Kriging Method
MAO Tian, WAN Weixing, SUN Lingfeng
2007, 27(4): 279-285.   doi: 10.11728/cjss2007.04.279
Abstract(2895) [PDF 2246KB](77)
Abstract:
In this paper the Kriging method was introduced to map Central and Northern China (30°N-55°N, 70°E-140°E) Total Electron Content (TEC) Map (CNC TEC Map). Firstly, three popular ionosphere models (Klobuchar model, IRI and JPL GIM) were compared with grid TEC. Then CNC TEC Map using Kriging method with constant drift, linear drift and quadratic drift were compared with each other. Then TEC map derived from nearest neighbor method, polynomial regression method (order=5) and Kriging method with different temporal resolution of 5 minutes, 30 minutes and 120 minutes were compared. The result revealed that even in the mid-latitude area, these popular ionosphere models showed great differences from observation; that the results of the Kriging algorithms were similar which led us go use ordinary Kriging method, i.e. Kriging method with constant drift; and that the Kriging method was begger than other methods, especially when temporal resolution was high.
Nonholonomic Motion Planning of Space Robots with Prismatic Joint for Obstacle Avoidance via Hierarchical Lyapunov Methods
GUO Yishen, CHEN Li
2005, 25(2): 154-160.  
Abstract(1977) [PDF 2577KB](81)
Abstract:
Based on hierarchical Lyapunov methods, the motion planning of free-flying space robots with prismatic joint for obstacle avoidance is discussed. First, with the momentum conversation and the Jacobian matrix, the system state equations and the control output equations for control design are established. And then the primary and secondary Lyapunov functions are selected. The primary function insures the movement of the endeffector from the start point to the end point. The secondary ascertains obstacle avoidance of the endeffector. Combined the primary and secondary functions, the endeffector implements the specific movement and realizes obstacle avoidance. A planar space robot with prismatic joint is simulated to verify the proposed methods.
Select for material science processing experiment furnaces on space station
Xi Risheng
2009, 29(1): 154-158.   doi: 10.11728/cjss2009.01.154
Abstract(3235) [PDF 693KB](24)
Abstract:
It is summarized in the paper that material science processing experiment furnaces on International Space Station (ISS) prepared by some country. Some features are presented as follows: highly integrated synthesis experiment ability such as preparing materials, measuring, analyzing and managing, higher precision, stability and long lifetime; modularization, standardization and assembled, applying telescience experiment technology. Since 1998, to meet the requirement for China space station in the future, a few kinds of telescience processing furnaces in space and teleoperation prototype furnaces have being developed, which can be used during unmanned long flight and with robotic sample replacement. Proposal is given for design and development aiming at that the function is specialized, the structure is modularized and the interface is standardized. It is also proposed that the future furnace should be able for quick reconfiguration through technical integration.
A Method of Satellite Calibration for Radar’s System Error Based on Least-square Estimation
Zhong Xia, Zhang Jianwei, Yu Hao
2013, 33(5): 554-560.   doi: 10.11728/cjss2013.05.554
Abstract(2143) [PDF 2473KB](36)
Abstract:
It is important to calibrate the system errors of precise-measurement radar for the aim of ensuring its measurement precision. The satellite calibration method for radar system error is a new method by measuring optical tracking satellites. In this paper, the key algorithm of satellite calibration method based on least-square estimation is analyzed and deduced. Then, the satellite calibration system is designed. Finally, the algorithm is simulated, according to the value of radar system error parameter obtained with traditional calibration method, and the simulation results are analyzed. It shows that the satellite calibration technique based on least-square estimation method is effective.
Observations of energetic particles in the upstream of a quasi-parallel collisionless shock
Zhang Weina, Wu Mingyu, Lu Quanming, Shan Lican, Hao Yufei, Gao Xinliang, Wang Shui
2014, 34(2): 137-142.   doi: 10.11728/cjss2014.02.137
Abstract(1253) [PDF 539KB](49)
Abstract:
With the Cluster observations of a quasi-parallel shock on 16 March 2005, relationship between the upstream low-frequency waves and the energetic ions (about several keV) has been studied. The observation results show that there are full of waves in the upstream of the shock which can interact with the upstream plasma. The differential energy flux of energetic ions in the upstream is dependent on the magnetic field strength of these waves. The energetic ion energy flux is higher in the regions with a weaker magnetic field. The possible explanation is that the ions can be trapped by the nonlinear upstream waves. Then the energetic ions were accelerated by the electric field every time when they bounced in these nonlinear waves. Our observation results are consistent with the recent hybrid simulation results.
Relationship Between Solar Proton Events and the Associated Solar Flares
LE Guiming, WANG Hongyan, BAI Tienan
2018, 38(4): 437-443.   doi: 10.11728/cjss2018.04.437
Abstract(1272) [PDF 454KB](129)
Abstract:
The Correlation Coefficients (CC) between the time integral of solar Soft X-Ray (SXR) flux and the intensities of Solar Proton Events (SPE) in 0°W-39°W, 40°W-70°W and 71°W-90°W longitudinal areas have been calculated. The results show that the CC has its largest value. The property of CC is consistent with the concept that the largest flux of flare-accelerated particles can only be observed in the longitudinal area well magnetic connected with the observer. The results suggest that solar flares contribute to the production of SPE, namely that E ≥ 10MeV protons may be accelerated by the concurrent flares at the early phases of SPE.
Auxiliary Trellis Based Viterbi Decoding Algorithm Research of 4D-8PSK-TCM
HUANG Yu, a, XIONG Weiming, SUN Huixian
2008, 28(6): 578-583.   doi: 10.11728/cjss2008.06.578
Abstract(3322) [PDF 916KB](74)
Abstract:
Four-Dimensional 8PSK Trellis-Coded Modulation (4D-8PSK-TCM) is recommended as an efficient coded modulation standard for the Earth Exploration Satellite Service (EESS) 8025-8400 MHz band by the Consultative Committee for Space Data System (CCSDS). The advantage of 4D-8PSK-TCM is that coding gains can be achieved without expanding the bandwidth relative to the un-coded signal set. In this paper, the 4D-8PSK-TCM system with the modulation efficiency of 2.5 bit/symbol and its Viterbi decoding are presented and the Viterbi decoding algorithm is implemented on Matlab Simulink. During the algorithm implementation, an auxiliary trellis is introduced to reduce greatly the number of computations of metrics of each path. In this way, there are only 64 comparisons to compute the metrics in comparing with the 2032 comparisons required in a directly computing approach.
Analysis of the Major Parameters in Solar Active Regions Based on PCA Method
SHEN Lin, DUN Jinping, ZHANG Xiaoxin, JIANG Yong
2014, 34(6): 765-772.   doi: 10.11728/cjss2014.06.765
Abstract(1002) [PDF 922KB](31)
Abstract:
Solar active region has close relationship with solar flares and solar proton events. In order to better understand the complicated relations between them as well as to build a concrete foundation for the forecasting of solar flares and solar proton events, the Principal Component Analysis (PCA) method is adopted to analyze the main parameters of solar active regions during 2007-2010. The parameters selected include sunspot magnetic classification, McIntosh classification, sunspot group area, 10.7 cm radio flux, flare index, the position of proton flares and soft X-ray flare intensity. A total of 81 principal component scores are obtained and compared with the solar proton event peak flow and annual average sunspot, 10.7 cm radio flux annual average, and it is found that the similarity is very high. The statistic results show that the principal component scores can represent the strength of solar activity to some extent.
Comparison of diurnal, seasonal and solar cycle variations of high-latitude, mid-latitude and low-latitude ionosphere
K G Ratovsky, J K Shi, A V Oinats, E B romanova
2014, 34(2): 143-153.   doi: 10.11728/cjss2014.02.143
Abstract(1220) [PDF 482KB](36)
Abstract:
Comparison of regular (diurnal, seasonal and solar cycle) variations of high-latitude,mid-latitude and low-latitude ionospheric characteristics has been provided on basis of local empirical models of the peak electron density and the peak height. The local empirical models were derived from the hand-scaled ionogram data recorded by DPS-4 digisondes located at Norilsk (69°N, 88°E), Irkutsk (52°N, 104°E) and Hainan (19°N, 109°E) for a 6-year period from December, 2002 to December, 2008. The technique used to build the local empirical model is described. The primary focus is diurnal-seasonal behavior under low solar activity and its change with increasing solar activity. Both common and specific features of the high-latitude (Norilsk), mid-latitude (Irkutsk) and low-latitude (Hainan) regular variations were revealed using their local empirical models.
Study on pool boiling heat transfer in microgravity
Zhao Jianfu, Hu Wenrui
2009, 29(1): 145-149.   doi: 10.11728/cjss2009.01.145
Abstract(3359) [PDF 613KB](20)
Abstract:
Two experiments on pool boiling in microgravity have been conducted aboard the Chinese recoverable satellites. Ground-based experiments have also been performed both in normal gravity and in short-term microgravity in the Drop Tower Beijing. A thin platinum wire and a plain plate were used as heaters, respectively. Steady boiling of R113 on the wire was studied with a temperature-controlled heating method, while quasi-steady boiling of FC-72 on the plate was investigated with an exponentially increasing heating voltage. In the first case, slight enhancement of heat transfer is observed in microgravity, while diminution is evident for high heat flux in the second one. Lateral motions of bubbles on the heaters are observed before their departure in microgravity. The surface oscillation of the merged bubbles due to lateral coalescence between adjacent bubbles drives it to detach from the heaters. It's also discussed about the Marangoni effect on the bubble behavior.
Discussion on SFODB Application for Spacecraft Data Management
Qiu Aihua, Zhang Tao
2013, 33(6): 664-671.   doi: 10.11728/cjss2013.06.664
Abstract(1237) [PDF 1153KB](52)
Abstract:
SFODB is used to solve the data exchange for payload of high data rates in spacecraft and transmit mass detector data, which is proposed by the United States Department of Defense. It is a high-speed aerospace data bus based on commercial Asynchronous Transfer Mode (ATM). In its physical layer, the fiber link connects many FBIU units and single CFBIU unit to compose a ring network. The distance between each node cannot exceed 100m, and the data rate ranges from 200Mbit·s-1 to 1Gbit·s-1. The data bus has very high real-time performance and reliability, and its network size as well as the performance is better than others. This paper introduces the characteristics and latest development status as well as the technical approach of SFODB up to now. It is suggested that an spacecraft internal data bus should be designed as the backbone data network architecture based on SFODB, such as for the satellites and other spacecrafts. The network can complete spacecraft internal reliable data transmission with hierarchical classification for payload. Finally, we give some guidance for research and application of SFODB in the future, some highly reliable design concepts about internal bus in spacecraft may refer SFODB.
Research on the Reliability of FPGA Configuration in Space-based Systems
Wang Wenhua, Han Shuangli, Zhang Yu, Li Guoning, Li Xine, Ren Jianyue
2011, 31(1): 106-111.   doi: 10.11728/cjss2011.01.106
Abstract(2702) [PDF 704KB](81)
Abstract:
Designers of space-based systems face unique challenges to insure each unit against failure. FPGA are used gradually in the aerospace field since it is invented with abundant I/O pins and flexible design margin. Many manufactures have been improving those space-qualified FPGA devices to adapt the aerospace high-radiation environments. FPGA devices based on SRAMs have to load configuration data from external PROMs on power-up before the logic is activated. However, not each batch or each device can be configured successfully with zero-failure. This paper explores every possible factor such as environment temperature, signal integrality, configuration rate and so on. Aiming at Xilinx FPGA devices, this paper provides a series of safeguard solutions for higher reliability of configuration. It has significant reference value in aerospace application fields for its feasibility and reliability.
Relationship between X-class Flares and Geomagnetic Effects
ZHU Yiting, ZONG Weiguo, PEI Shixin
2015, 35(4): 415-423.   doi: 10.11728/cjss2015.04.415
Abstract(978) [PDF 3448KB](71)
Abstract:
A statistical study has been conducted on all the geomagnetic storms caused by Coron Mass Ejection (CMEs) which are associated with flares from January 2010 to December 2012. The following results are obtained. The initial locations of CMEs mentioned above are distributed from 45°E to 45°W in solar longitude, accounting 78.95% of the total. Besides, the CMEs located in the west hemisphere are more likely to cause geomagnetic effects. X-class flares are more likely to be geo-effective, while flares in other classes have much lower probability. Geomagnetic storms will be observed in two or three days after 60% of X-class flares eruption. Therefore, more attention should been paid on X-class flares. By analyzing all the X-class flares erupted during this period, it is found that for the X-class flares located from 45°E to 45°W in solar longitude, if there is no disturbance on the solar surface (EUV wave) during eruption, the probability of the occurrence of geomagnetic storms after the flares will be very small. Therefore, a new method for geomagnetic storm forecasting by analyzing the Sun surface observations has been proposed.
One Analysis on the Rocket Detection of Polar Mesosphere Summer Echoes
Li Hailong, Wu Jian, Huang Jiying, Wang Maoyan
2009, 29(4): 397-401.   doi: 10.11728/cjss2009.04.397
Abstract(2895) [PDF 523KB](178)
Abstract:
Polar Mesosphere Summer Echoes (PMSE) are very strong radar echoes from altitudes near the polar summer mesopause. ECT-02 is carried out when PMSE in polar mesopause was occured. Based on the experiment results of ECT-02, the electron number densities and dust charge number densities are deduced in the paper. The data will provide a good basis to study various features of PMSE. By analyzing the data, one can find that dusty plasma in polar summer mesopause is weakly ionized and weakly coupled. The variable disturbance of electron density is used to explain the generation mechanism of PMSE. The stronger disturbance of the electron density corresponds to the stronger radar echoes, and when the disturbance becomes small, the radar echoes become weak, even disappear.
Comparison Of Ionospheric Total Electron Content Over North America And East Asia With Eof Analysis
Yao Xin, Zhao Biqiang, Liu Libo, Wan Weixing
2015, 35(5): 556-565.   doi: 10.11728/cjss2015.05.556
Abstract(1340) [PDF 6969KB](79)
Abstract:
In the present work, variations of ionospheric Total Electron Content (TEC) are investigated and compared with applying Empirical Orthogonal Functions (EOF) on the dataset from the Global Ionospheric Maps (GIMs) which are produced by Jet Propulsion Laboratory (JPL) over two concerned areas: the North America (30°N-50°N, 140°W-50°W) and East Asia (42.5°N-57.5°N, 65°E-140°E). The first three EOF components attribute about 99.57% and 99.79% to the total variations separately, and spatial-temporal features manifested by each EOF components are similar for the two areas: the first order EOF component for both areas represents semiannual variation which is strongly modulated by the solar activity; the second order component exhibits pronounced east-west longitude difference to the zero valued geomagnetic declination line, and these east-west longitude differences are coincidently consistent with plasma drift velocity caused by thermospheric zonal wind; the third order component demonstrates latitudinal variations possibly influenced by plasma drift velocity caused by thermospheric meridional wind. Results of the this paper are useful for understanding the physics mechanism of the ionospheric variations.
Calculation Method for Geoelectric Field in Mid- and Low-latitude Area Based on Sparse Geomagnetic Data
Wu Weili, Liu Lianguang
2013, 33(6): 617-623.   doi: 10.11728/cjss2013.06.617
Abstract(1052) [PDF 2624KB](48)
Abstract:
Mastering spatial and temporal distribution of geoelectric field is the premise of researching and preventing adverse effect on technology systems due to geomagnetic induced current. This paper presents a model for geoelectric field on the basis of sparse geomagnetic observation data in China. Firstly, the model of equal Spherical Elementary Currents System (SECS) is used to represent ionospheric current. Then, the hybrid algorithm of SECS and Complex Image Method (CIM) is proposed to calculate the geoelectric field and the magnetic field due to geomagnetic disturbance. The method provided can be used to calculate the fields at any time, any place during magnetic storms. To test and validate the approach put forward, the observation geomagnetic data at Umq, KSH, GRM and JYG were applied, the induced fields in northwest area were calculated, and the errors between the measurement and calculation were analyzed as well. The results of geoelectric field are consistent with that of the plane wave method, which verifies the algorithm proposed. The results can be directly used to calculate the geomagnetically induced currents flowing in power system, which is of great significance in the hazards assessment of power systems.
Applications of Surface Plasmon Resonance Biosensor in Life Science and Space Medicine
WANG Chunyan, LI Yinghui, XIONG Jianghui, TAN Yingjun, NIE Jielin, LIU Xueyong
2005, 25(3): 208-211.  
Abstract(2160) [PDF 1266KB](66)
Abstract:
The use of Surface Plasmon Resonance (SPR) biosensors in analyzing biomolecular interactions is increasing significantly in recent years, since it has various advantages including real-time measurement of biomolecular interactions without labeling, high-throughput analysis of multiple proteins and the simple optical system for the device. Applications in life science include clinical assay, disease diagnosis, drug screening and so on. In this technique, one of the interacting partners is immobilized on a sensor chip and the binding of the other is followed by the increase in refractive index caused by the mass of bound species. Developments of related theories and technologies have accelerated performance of SPR biosensor greatly. For its high sensitivity, facility, expeditiousness and stable ability in weightlessness, SPR biosensor has a strong potential for on-line analyzing biochemical markers in astronauts' body fluids which are highly related to some kinds of diseases, and this is a practical method used as the health early alarm and medical care system for astronauts. This article is focused on the principle and advantages of SPR-based biosensor and its applications in life science. The future uses in space medicine are also discussed.
Development of space environment research and service in China
Gong Jiancun, Liu Siqing, Shi Liqin, Hu Xiong, Lin Kexin
2010, 30(5): 464-467.   doi: 10.11728/cjss2010.05.464
Abstract(2458) [PDF 137KB](48)
Abstract:
During the past two years, space environment has achieved great development in space environment monitoring, model research, system developing and space environment service in China. In this paper, we mainly introduce space environment safety support for Shenzhou-7 manned spacecraft, two typical space environment operation platforms, and the advance of Re-locatable Atmospheric Observatory (RAO). At the last part of this paper, the Sub-committee on Space Environment(SSE) which was set up in 2009 under the Technical Committee on Space Technology and Operation of Standardization Administration of China is briefly introduced.
Research on Positioning of High Earth Orbital Satellite Using GNSS
Qin Honglei, Liang Minmin
2008, 28(4): 316-325.   doi: 10.11728/cjss2008.04.316
Abstract(2990) [PDF 4171KB](146)
Abstract:
The GNSS as a navigation and positioning method has global, all-weather, real time and high precision characteristics. Using it on the high earth orbital satellites in positioning can provide precise orbit and attitude determination, overcome the disadvantage of complex equipment and high cost which using ground measurement and control system to positioning, make it possible to autonomous navigation . New and exciting opportunities become possible if satellites are able to autonomously determine their own orbit. For example, precise onboard orbit determination opens the door to satellites flying in formation. However, receivers in low Earth orbit have virtually the same view of the navigation satellite constellation as receivers on the ground. But satellites orbiting at geostationary altitudes and higher have a severely limited view of the main beams of the GNSS satellites. The main beams are either directed away from these high-altitude satellites or they blocked to a large extent by the Earth. So, using much weaker signals is a fundamental requirement for a high orbital altitude GNSS receiver, but it is certainly not the only challenge. Other unique characteristic of this application must also be considered. On the one hand, dynamic characteristics will be more different at high Earth orbit. High dynamic situation makes it difficult to use weaker signals. On the other hand, Position Dilution of Precision (PDOP) figures are much more higher at geostationary and higher altitudes because visible navigation satellites are concentrated in a much smaller region with respect to the spacecraft antenna. Spacecraft navigation receiver must be designed to withstand a variety of extreme environmental conditions. In this paper, positioning of high earth orbital satellites using GNSS is researched. The visibility of navigation satellites, dynamic characteristics, Geometric dilution of precision are analyzed using single GNSS and integrated GNSS. Through simulation and analyzing, it is verified that using GNSS can realize the positioning of HEO satellite and obtain enough positioning precision requirement.
A THEORETICAL LOW LATITUDE IONOSPHRIC MODEL
TU Jiannan, LIU Libo, BAO Zongti
1997, 17(3): 212-219.   doi: 10.11728/cjss1997.03.212
Abstract(1940) [PDF 742KB](36)
Abstract:
A theoretical low-latitud ionospheric model is presented. The continuity andmomentum equations of O+, H+ are solved, using operator splitting difference schemeon the fixed grid points distributed along the magnehc fields. Molecular ion densitiesof N2+, O2+, NO+ are calculated under the assumption of photochemical equilibrium.The modeling results fairly reproduced the gross features of daily development ofequatorial anomaly observed in East Asia under equinochal, solar maximum conditions.It is also shown that HWM90 model estimates much too large nighttime windvelocities at low latituds in East Asia, and the vertical drift velocity in East Asiamay be smaller than that in American region.
Research of lunar tectonic features: Primary results from Chang'E-1 lunar CCD image
Wang Jie, Zeng Zuoxun, Yue Zongyu, Hu Ye
2011, 31(4): 482-491.   doi: 10.11728/cjss2011.04.482
Abstract(3150) [PDF 1208KB](53)
Abstract:
The Moon retains the information of initial period, because its geological activity was ceased 3.1billion years ago. This information is very important for us to recognize the formation and evolution of the Moon, the earth and even the solar system. On the basis of initial study and Chang'E-1 CCD images, the geological, topographic and geomorphologic features of the main tectonic patterns on the Moon are introduced. The two important kinds of structures on the moon are circular tectonics and linear tectonics. Circular tectonics are the annular appearances on remote sensing images displayed through architecture and color, which are the most striking features of lunar images. This article studies the formation of Mons Rümker, Hainzel Crater, King Crater and the fracture at the bottom of Humboldt Crater, and then, analyzes the difference in lunar crater both near and far side, the South and North Pole. Linear tectonics refer to those structures extended as linear on lunar surface, which can reflect the global or territorial stress condition and stress field of the lithosphere and tectonic forms on the planets. This article also studies the echelon structure nearby the Cauchy Crater, step scarp of Mare Humorum, regional fault nearby the Hippocrateson Crater, fault structures along Apennine Mountains, crater chain at the bottom of Davy Crater, Rima Hyginus and Vallis Alpes. The result shows that the Chang'E-1 CCD images have sharp details and rich information which are clear enough to research the lunar tectonic features.
Research Of Viscous Fluid Damping Isolator Used In Space Telescope
CHEN Tao, XU Zhenbang, WU Qingwen, CHEN Liheng
2015, 35(5): 618-625.   doi: 10.11728/cjss2015.05.618
Abstract(1229) [PDF 3091KB](80)
Abstract:
In order to suppress infrared telescope astronomy disturbance caused by the satellite payload, it is needed to design vibration reduction device for the telescope. Therefor a viscous fluid damper used in space is designed, which could be sealed reliably and adapted to the space environment well. Firstly, a damping calculation model based on the theory of fluid mechanics is built. Then, the structure of the damper is designed, and parameters of the spring sheet which was a core component belonging to the damper, are optimized. A set of prototype was manufactured, and a finite element model of the vibration isolation system was created to get the system's first two models. Finally, the simulation results are compared with the experimental results. According to the analysis results, it can be seen that the damper's stiffness characteristics and damping characteristics can meet the design requirement. The theory analysis results coincide with the experimental results, which proves that the finite element model is precise and the prototype has guidance value in engineering design.
Analysis of the Characteristics of the Stratospheric Quasi-zero Wind Layer Over China
XIAO Cunying, HU Xiong, Gong Jiancun, LIU Jia
2008, 28(3): 230-235.   doi: 10.11728/cjss2008.03.230
Abstract(2616) [PDF 3688KB](116)
Abstract:
The characteristics of the stratospheric quasi-zero wind layer and its seasonal and geographic variation features over China are obtained by using the ERA-40 reanalyzed wind data which are provided by ECMWF. Results show that quasi-zero wind layer generally exists at the height range of 18--25 km and some variation of the height of the zero wind line would happen when the time or location change. According to the latitudinal variation of the quasi-zero wind layer, the atmosphere over China could be divided into three parts to discuss its features: low-latitude area (5ºN~20ºN), transition area (20ºN~32.5ºN), middle- and high-latitude area (32.5ºN~55ºN). The quasi-zero wind layer may exist in winter and at the beginning of spring in low-latitude area. In middle-and high-latitude area, the quasi-zero wind layer may be found at the end of spring and in summer. The quasi-zero wind layer in transition area relates to the equatorial quasi-biennial oscillation (QBO). During the easterly phase of QBO, the characteristics of the transition area are similar to that of the middle-latitude area, while during the westerly phase of QBO, its characteristics are similar to that of the low-latitude area. The quasi-zero wind layer varies little with the longitude. The longitudinal variation of the height of zero wind line may not exceed 2 km. However, this variation is relatively larger in the transition area.
Numerical Modeling of Ion Contributions in Ionospheric Sporadic-E Layerormalsize
ZHANG Yabin, WU Jian, XU Zhengwen, XU Bin, XU Tong, LIU Yao, HU Yanli, WANG Zhange
2018, 38(4): 452-459.   doi: 10.11728/cjss2018.04.452
Abstract(1311) [PDF 2714KB](146)
Abstract:
The ionospheric kinetic numerical model is expressed as the solution to the temporal evolution of the electron density profile. The ion continuity and the momentum equations, the solar ionization, star ionization, coronal ionization, interstellar background ionization and meteor ion flow are all considered. The main kinetic process and photochemical process of Es layer are analyzed synthetically. The effects of neutral component collision, electric field, metal ion and molecular ion on the ion distribution are also included. In the paper, a one-dimensional time-dependent model of the ionospheric Es has been developed on the basis of the wind shear theory. The ion production rate and the distribution of the vertical ion velocity in height and time are simulated by the model. The variations of ion density profile in 24 hours are also obtained. According to the observation results of winds by coherent scattering radar in Kunming station, the time and space dependent of electron density of Es (Ne) is acquired by the model. Then the f0Es are given by the conversion of Ne, and the retrieval results are in good agreement with the contemporaneous ionosonde data in Kunming.
Fault detection for in-orbit satellites using an adaptive prediction model
Li Weizheng, Meng Qiao
2014, 34(2): 201-207.   doi: 10.11728/cjss2014.02.201
Abstract(1437) [PDF 949KB](77)
Abstract:
Faults are unavoidable for in-orbit satellites. They are able to be detected by carefully analyzing the telemetry data from these satellites. It is obvious that a good performance of anomaly detection algorithm is very important. This paper presents a new approach which takes the advantage of the similarity of preceding telemetry data to detect current anomaly. Because of its adaptive checking criteria, it can find some faults that cannot be found by some traditional methods. Most of important thing of this algorithm is that no prior knowledge about any particular satellite is needed except telemetry data themselves. In order to prove its availability, we use this new approach to process telemetry data from a China on-orbit satellite in 2012 and a fault is detected instantaneously.
Analysis of Seed Development of Arabidopsis Plants Under a 3D Clinostat Rotated Condition
XU Guoxin, ZHANG Yue, WEI Xiaojing, ZHENG Huiqiong
2012, 32(2): 230-237.   doi: 10.11728/cjss2012.02.230
Abstract(2653) [PDF 1366KB](86)
Abstract:
Gravitropism is an important physiological response and an essential mechanism for plants to maintain the normal growth and development on earth. In the life cycle of higher plants, seed development is a key process, but whether gravity can affect the development of seeds has not been confirmed. In this study, the development of siliques and seeds of Arabidopsis under the 3D clinostat rotated condition was analyzed to examine whether seed development including formation of embryos and the activities of metabolism is affected by the altered gravity condition. Our results showed that in the 3D clinostat rotated treated Arabidopsis plants, the morphology of siliques showed an irregular curvature, and the cell division and elongation of suspensor were inhibited. The content of soluble carbohydrates and starch in the young and mature seeds obviously increased, while the content of salt soluble protein decreased. In addition, developing seeds at globular stage are most sensitive to the 3D clinostat rotated treatment with the inhibition of cell division and elongation of the suspensors. Suspensors are important for the transportation of nutrients into embryos and abnormal development of suspensor under the clinostat rotation condition might cause seed abortion.
Study of High Precision and Continuous Ionosphere Model Determination
Fan Guoqing, Wang Wei, Xi Xiaoning, Wei Lidong
2009, 29(2): 188-194.   doi: 10.11728/cjss2009.02.188
Abstract(4056) [PDF 756KB](25)
Abstract:
This paper presents a new idea to determine polynomial ionosphere model with the circumstance that lacking of real observation data in special region. Besides real observation data, grid data calculated by global ionosphere model has been used as a background. The weight of two kinds of data has been discussed, and then mathematical model has been established. Secondly, the model continuity between two segments have been discussed, and then a smoothing method to calculate ionosphere delay has been studied, which uses two groups of time weighting neighbored model coefficients. Finally, the availability of the model was proved by mathematic experimentation.
Interplanetary Physics in Mainland China
ZHAO Xinhua, ZHANG Min, WANG Yuming, HE Jiansen, NING Hao, QIN Gang
2018, 38(5): 665-693.   doi: 10.11728/cjss2018.05.665
Abstract(724) [PDF 348KB](28)
Abstract:
During the past two years (2016-2018), great achievements have been made in the Chinese research of interplanetary physics, with nearly 100 papers published in the academic journals. The achievements are including but not limited to the following topics:solar corona; solar wind and turbulence; filament/prominence and jets; solar flare; radio bursts; particle acceleration at coronal shocks; magnetic flux ropes; instability; instrument; Coronal Mass Ejections (CMEs) and their interplanetary counterparts; Magnetohydrodynamic (MHD) numerical modeling; solar energetic particles and cosmic rays. The progress further improves our understanding of the eruptions of solar activities, their evolutions and propagations in the heliosphere, and final geoeffects on our Earth. These results were achieved by the Chinese solar and space scientists independently or via international collaborations. This paper will give a brief review of these achievements.
PREDICTION OF MAJOR STORMS BY USING NEURAL NETWORKS
ZHOU Xiaoyan, PAN Xinping, YANG Yiping
1998, 18(3): 228-234.   doi: 10.11728/cjss1998.03.228
Abstract(2062) [PDF 467KB](61)
Abstract:
Good prediction results for geomagnetic indices have been obtained with the use of artificial intelligent(AI)technique,especially by the neural networks.While a common Problem is how to increase the advance time of the prediction.It is true that the earlier of the prediction, the less possibility to predict the detail of an impending event.Therefore threshold prediction should be also a very helpful and useful method for early time prediction when forecasting the occurrence of the events which bring disaster on the cormmunication,power transmission and satellite life etc. Threshold prediction means the predicted events are over a threshold,such as-120nT. In this paper BP model of neural networks is used to predict the major storms 4 hours ahead, with the minimum of Dst less than-120nT. The inputs are 13 solar wind parameters and geomagnetic AE and Dst.The ought is I for major storms or 0 for non major storms. The results show that the threshold prediction by neural networks can give accurate prediction for major storm occurrence.
THE INFLUENCE OF SOLAR MASS-LOSS ON PLANETARY ORBITS
Yu Li-zhong, Zheng Xue-tang, Li Lin-sen
1994, 14(1): 70-75.   doi: 10.11728/cjss1994.01.070
Abstract(1915) [PDF 355KB](65)
Abstract:
Using Gylder-Meshcherckii equation and Eddington-Jeans law, the influence of solar mass-loss on planetary orbits is discussed in this paper. It is shown that solar mass-loss will cause the first-order secular and periodic terms in the semimajor axis a, the first-order periodic and secon-order mixed terms in the eccentricity, and the first-order periodic, second-order secular and mixed terms in the argument of perihelion of planetary orbits. The secular variation of the semimajor axis of planetary orbits should influence the stability of solar system.
Study of small rocket-borne SF6 active releaser
Cai Minghui, Feng Ying, Wu Fengshi, Huang Wengeng, Li Hongwei, Yang Tao, Han Jianwei
2014, 34(2): 214-218.   doi: 10.11728/cjss2014.02.214
Abstract(1262) [PDF 543KB](57)
Abstract:
Chemical release at ionospheric altitudes is one of the most important ways to carry out active experiments for investigation of ionosphere features. A new rocket-borne SF6 releaser is studied. This releaser has many advantages such as small size, light weight, low requirements for the launch platform, and when the device weight is 6kg, 2kg SF6 can be released. By means of simulation, the diffusion process of neutral gas and relevant chemical reactions in ionosphere are calculated, and the effect of SF6 releases is investigated.Results showed that the designs scheme of the SF6 releaser is feasible and consistent with domestic rocket-borne platform and conditions in China, hence has high application value.
The Suppression of Triangle Size Effect in Spaced Antenna Wind Measurements
SHU Weiping, ZHAO Zhengyu
2006, 26(4): 257-263.   doi: 10.11728/cjss2006.04.257
Abstract(2435) [PDF 377KB](81)
Abstract:
There is the Triangle Size Effect (TSE) in wind measurements with Spaced Antenna (SA) method due to electronic noise and ground clutters etc. Another possible cause (non-stationary of atmosphere) of TSE and the mechanism of its effect to wind measurements was discussed in this paper. The work also presents Increment's Cumulant Approach (ICA) to eliminate the nontationary of atmosphere and ground clutter based on the analysis of the causes of TSE; the analytical expression of one dimension mean velocity can also be obtained by the special case of Increment's Cumulant Approach (the 2nd order zero-lags ICA). In addition the high order (k ≥ 3) cumulant of increment are proposed to suppress Gaussian noise. The comparisons between FCA and ICA with non-stationary and ground clutter by numerical simulations show that the measurement errors of ICA are much less than those of FCA by comparing mean horizontal velocities (output of simulations) and input velocities of mode.
Soot Formation in Laminar Diffusion Flame under Microgravityormalsize
YUAN Hongliang, KONG Wenjun
2018, 38(4): 517-523.   doi: 10.11728/cjss2018.04.517
Abstract(1364) [PDF 2750KB](149)
Abstract:
The soot formation in a coflow ethylene/air laminar flame at 1g/0g (normal gravity and zero gravity) has been studied using particular fuel oxidation and PAH mechanism. The nucleation process is regarded as the dimerization of two large PAH, and HACA mechanism is used to describe the surface growth process. The collision of soot and PAH is mainly taken into account for the condensation process in soot surface. The initial nucleation, soot surface growth, condensation and oxidation are simulated with a discrete sectional aerosol model to capture the different size soot with different mass. The calculating results show that the peak temperature of the flame at 0g decrease by 230K, whereas the peak soot volume fraction is nearly twice larger than that of the 1g condition. This paper also studied the distribution of precursors (C2H2 and PAH), nucleation rate, surface growth rate, and condensation rate under microgravity. It is indicated that the condensation is the major process of soot formation in the centerline of flame for both 1g and 0g conditions, and it plays a more important role under microgravity. The average diameter of soot is lager due to long residence time under microgravity.
Feature of the Martian Magnetic Field Structure
ZHANG Yiteng, LI Lei
2009, 29(3): 257-261.   doi: 10.11728/cjss2009.03.257
Abstract(3786) [PDF 603KB](58)
Abstract:
Based on a single-fluid MHD model, this paper has studied the global magnetic field structure in the near-Mars space, and investigated the influence of the Martian crustal magnetic fields on the magnetic field structure. Mars bow shock, Magnetic Pileup Region are produced when the solar wind flows over Mars. The interplanetary magnetic field lines are curved and `draping' around the planet. The majority of magnetic field lines bypass over two poles, leaving `V shaped' structure in the wake behind Mars. Near the surface of Mars, the local crustal magnetic fields also have noticeable influence on the magnetic field structure. The crustal magnetic fields at different positions, with different intensities form the dissimilar magnetic filed structure and mini-magnetospheres when interacting with the solar wind. The towed mini-magnetosphere and the mini-magnetosphere with open magnetic lines are illustrated in the paper. The local crustal magnetic fields change the morphology of the magnetic field, and accordingly may play an important role in determining the plasma distribution.
Numerical Simulation of Flow Velocity and Silver Ion Concentration Distribution in Sterilization Moduleormalsize
LI Peng, TAN Xu, MA Yong, YU Haibin, XIE Wen, LI Leilei
2018, 38(4): 546-552.   doi: 10.11728/cjss2018.04.546
Abstract(1346) [PDF 2159KB](231)
Abstract:
Future manned spacecraft needs to provide a long-term working environment, in which sterile water is the guarantee of life and health. The sterilization module is installed at the end of the water treatment system to release the specified concentration of silver ions to the purified water, playing a role of sterilization and long-term preservation of the water. According to the exchange basin using standard k-ε model standard wall function, the calculating model of flow field and concentration field of silver ions have been set up for the 600mL·min-1 flow condition as the water flows through the wall. The sterilization module electrode alternating exchanges with 30s period, and draws the concentration change. For meeting the actual conditions, the model is solved by iterative method. By analyzing the production rate of silver ion velocity, the highest concentration of silver ions locates at the anode surface near the cathode. Anode-cathode converting repeatedly can effectively reduce the silver ion concentration near the electrode surface. That is, the conversion has transmission effect to the decreasing of silver ion concentration, and can be carried out repeatedly. There is no AgOH precipitation, and then the process parameters can be determined and the engineering design can be guided. Finally, according to the simulation results, the optimization suggest of the sterilization module is given.
A Method of Calibrating Thermosphere Density Based on Temperature Parameters
LI Xie, TANG Geshi, LI Zheng, LI Cuilan, LIU Shushi
2014, 34(6): 830-836.   doi: 10.11728/cjss2014.06.830
Abstract(1644) [PDF 2766KB](57)
Abstract:
Thermosphere atmospheric drag is the significant factor affecting most space operations of low Earth orbiter, especially, an inherent 15% formal error of empirical models has become the cumber to improve orbit calculations accuracy. Among the empirical models used in aerospace engineering, JACCHIA71 model, which has relative explicit physical bac kground and less parameters, is selected as a basic model. The temperature Tc and Tx, namely nighttime minimum of the global exospheric temperature and inflection point temperature, are chosen as the estimated parameters during the differential correction. The condition equation of density with respect to these two temperatures is established, and the least square solutions are given as well. The model accuracy improvement is almost enhanced by over an order of magnitude after calibration using CHAMP data. Orbit prediction accuracy of TG01 with the position bias of 2 km is also improved to 1.3 km through temperature corrections using in-site detecting data. All of these case studies validates the effectiveness of the calibration algorithm.
Space Life Science of China
MA Hong, REN Hao, LI Xiaoqiong, YANG Chunhua, CHEN Yu, WANG Rui, YING Zhang, WANG Changyong, ZHOU Jin, LI Hong, JIANG Xiaoxia, ZHANG Fengzhi, HAO Tong, ZHU Huimin, DONG Xiaohui, ZHENG Huiqiong, WANG Lihua, SUN Weining, TONG Guanghui, ZHENG Weibo, ZHANG Tao, LONG Mian, LIU Hong, ZHUANG Fengyuan, DENG Yulin
2018, 38(5): 820-828.   doi: 10.11728/cjss2018.05.820
Abstract(1273) [PDF 1323KB](66)
Abstract:
With the human space exploration activities, space life science is an emerging interdiscipline, which covers a wide range of researches. Based on our country's manned space station and recoverable satellite science experimental platform, the development of space life science research is very important to acquire new knowledge or new technological innovation, to give further services to the human space exploration activities, to improve the national economic and social development. Both ground-based and flight applied studies were continuously performed in the previous 2 years. Here, we review and summarize the researches on space life sciences contributed by Chinese scientists.
ROBUST VARIABLE STRUCTURE CONTROL FOR SPACE MANIPULATOR SYSTEM WITH UNCERTAIN PARAMETERS
CHEN Li, LIU Yanzhu, WU Wenlong
1998, 18(2): 174-179.   doi: 10.11728/cjss1998.02.174
Abstract(1876) [PDF 259KB](39)
Abstract:
In this paper, the control scheme is discussed for a free-floating space manipulatror,based on the augmented statefeedback control model. The scheme of robust variable structure control is proposed for a free-floating space manipulator,whose load parameters is uncertain, to track the desired trajectory of workspace. It is demonstrated by the simulation that the control scheme is efficient.
Abnormal Echoes in Lower Stratosphere Observed by Wuhan MST Radar during a Cold front Event
PAN Zhenhao, ZHOU Xiaoming, CHEN Gang, YAN Chunxiao, CHEN Feilong, WANG Ying
2018, 38(4): 492-501.   doi: 10.11728/cjss2018.04.492
Abstract(1445) [PDF 3209KB](167)
Abstract:
Wuhan Mesosphere-Stratosphere-Troposphere (MST) radar is a radio atmosphere detection radar deployed by the Chinese Meridian Project. As the frequency is in VHF band, the echoes are sensitive in all their aspects. Such echo characteristics are much more obvious in the Upper Troposphere and Lower Stratosphere (UTLS), which provides a practical approach to investigate the atmosphere dynamics. Observations of echo characteristic during a cold front are obtained by Wuhan MST radar in mid-latitude in April 2016. The experiment results show that the typical feature of the echo aspect sensitivity is significantly changed compared with that of normal days. Reasons of the echo anomaly are studied by analyzing echo characteristics variations, wind field spatial distributions, turbulence generation mechanisms and Inertia Gravity Waves (IGWs) effects. The result demonstrates that the dissipating (or even breaking) of upward IGWs coming from convection system might feed the long-time persistence of Kelvin-Helmholtz (K-H) instability, which further tilts the horizontal reflection layer and results in the intense turbulence and the echo enhancement.
Analysis Of High Energy Electron Environment Properties On The Middle Earth Orbit
Yang Xiaochao, Zhu Guangwu, Fu Yang, Sun Yueqiang, Liang Jinbao, Jing Tao, Chang Zheng, Shi Chunyan
2015, 35(5): 581-587.   doi: 10.11728/cjss2015.05.581
Abstract(1225) [PDF 5470KB](33)
Abstract:
By utilizing data obtained on Chinese satellite in the middle Earth orbit from solar activity descending phase to solar activity ascending phase, the properties of high energy electron environment in the middle Earth orbit are analyzed, such as spatial distribution, flux intensity, temporal variations, and response to geomagnetic storms. The investigating results indicate that the spatial distribution of high energy electron in the middle Earth orbit is stable; the fluxes of electrons decrease with energy increasing; the high energy electron environment is a dynamical system which disturbs evidently on different timescales; the evolvement of this system is stimulated by geomagnetic storms, but the correlation between the evolvement and the storms is nonlinear.
Influence of impurity on surface morphology and growth kinetics of a lysozyme crystal
Dai Guoliang, Liu Xingyu, Wang Sujing, Kang Qi, Hu Wenrui
2009, 29(1): 17-22.   doi: 10.11728/cjss2009.01.017
Abstract(5002) [PDF 627KB](31)
Abstract:
The influences of impurity on surface morphology and growth kinetics of tetragonal lysozyme crystals were studied. There was a significant difference in morphology of 2D islands on a {110} face when the impurities existed. Impurities significantly decreased the normal growth rates of both the {110} and {101} face. F-lysozyme decreased the normal growth rate of both the {110} face and {101} face. The values of kinetic coefficient of the steps, surface free energy, and ledge free energy of the step edge were determined.
Numerical Simulation of Stratospheric Gravity Waves Induced by a Rainstorm
SUN Rui, YAO Zhigang, HAN Zhigang, ZHAO Zengliang, CUI Xindong, YAN Wei
2018, 38(4): 469-481.   doi: 10.11728/cjss2018.04.469
Abstract(1275) [PDF 12947KB](196)
Abstract:
In order to analyze the characteristics of the deep convection-induced stratospheric gravity waves in Chinese continental region, a stratospheric gravity wave process, which is observed by the satellite Aqua/AIRS and accompanied with the heavy rainstorm process on July 25th, 2011 in Rushan, is simulated using the mesoscale numerical WRF (Weather Research and Forcasting) model. The analysis of the vertical velocity field and the temperature disturbance field of the mode output show that the structure of the torrential wave in the stratosphere is mainly concentrated in the east of the precipitation cloud system, and the horizontal influence range is more than 1000km. With the increase of the height, the structure of the torrential wave tends to close, and the wave energy is also significantly enhanced. The results of power spectrum analysis based on Fast Fourier Transform (FFT) show that the stratospheric gravity wave induced by the storm at 35km has the horizontal wavelength of about 1000km and the vertical wavelength of 5~10km. Finally, the parameterized forcing in gravity wave uploading process is quantifiably reflected by analyzing the vertical transport of momentum flux reflects.
Height Profile Inversion of the Ionospheric Movement from the Observed Parameters of HF Radio Echoes
Wan Wei-xing, Li Jun
1987, 7(2): 85-94.   doi: 10.11728/cjss1987.02.085
Abstract(1773) [PDF 627KB](60)
Abstract:
Under the condition of an unstable, inhomogeneous and anisotropic ionosphere, some relations among the dynamic parameters of the ionosphere and the observables of HFradio echoes reflected from the ionosphere are derived from the general ray equations. On the basis of these relations, a method is proposed to invert the height profile of the electron density, N(Z), and the height profile of the normal velocity, V(Z) of the constant electron density surface from the observed Dopplionogram, gonionogram, ionogram and rangionogram. Furthermore, comparing the possible combination of the radio wave obserables which are necessary and sufficient for the determination of the height profiles of V(Z) and N(Z), the authors suggest a new operation mode of ionosonde to observe the large scale ionospheric disturbances such as the gravity waves from a single station. This may be the theoretical basis for data analysis and instrumental improvement of modern ionosonde.
Recoverable satellites and space science experiments in China
Li Chunhua, Ni Runli
2009, 29(1): 124-129.   doi: 10.11728/cjss2009.01.124
Abstract(3949) [PDF 646KB](62)
Abstract:
Twenty-three recoverable satellites have been successfully launched in China since 1975. A number of microgravity experiments were successfully performed by utilizing the piggyback capability of the satellite apart from the main task during the previous flights. An overview of the recoverable satellite development in China is given in the present paper. Main characteristics of the Chinese recoverable satellites and the scientific experiments completed onboard the satellites are discussed. The environment condition and the interface between the working payload and satellite during different design and manufacture phase are also briefly described. Future trend of platform technology and the applications are presented.
Theories and Simulations in Substorm Research: A Review
R. A. Wolf
2011, 31(2): 125-149.   doi: 10.11728/cjss2011.02.125
Abstract(2477) [PDF 1177KB](56)
Abstract:
Both theory and simulation have played important roles in defining and illuminating the key mechanisms involved in substorms. Basic theories of magnetic reconnection and of interchange and ballooning instabilities were developed more than 50 years ago, and these plasma physical concepts have been central in discussions of substorm physics. A vast amount of research on reconnection, including both theoretical and computational studies, has helped provide a picture of how reconnection operates in the collisionless environment of the magnetosphere. Still, however, we do not fully understand how key microscale processes and large-scale dynamics work together to determine the location and rate of reconnection. While in the last twenty years, it has become clear that interchange processes are important for transporting plasma through the plasma sheet in the form of bursty bulk flows and substorm expansions, we still have not reached the point where simulations are able to realistically and defensibly represent all of the important aspects of the phenomenon. More than two decades ago it was suggested that the ballooning instability, the basic theory for which dates from the 1950s, may play an important role in substorms. Now the majority of experts agree that regions of the plasma sheet are often linearly unstable to ideal-MHD ballooning. However, it is also clear that kinetic effects introduce important modifications to the MHD stability criterion. It is still uncertain whether ballooning plays a leading role in substorms or has just a minor part. Among the different types of simulations that have been applied to the substorm problem, global MHD codes are unique in that, in a sense, they represent the entire global substorm phenomenon, including coupling to the solar wind and ionosphere, and the important mechanisms of reconnection, interchange, and ballooning. However, they have not yet progressed to the point where they can accurately represent the whole phenomenon, because grid-resolution problems limit the accuracy with which they can solve the equations of ideal MHD and the coupling to the ionosphere, and they cannot accurately represent small-scale processes that violate ideal MHD.
THE CHARACTERISTICS OF WINDS AT HEIGHT OF 20-80km IN THE CHINESE AREA
MA Ruiping, LIAO Huaizhe
1999, 19(4): 334-341.   doi: 10.11728/cjss1999.04.334
Abstract(3048) [PDF 556KB](89)
Abstract:
Some characteristics of winds at height of 20-80 km in the Chinese area areobtained using the Nimbus-7 SAMS temperature data from 1979 to 1981 by thegeostrophic balance thermal wind equations. It is shown that the winds from satellite are coincident roughly with the winds from Chinese rocket measurements andthe derivation of winds with the satellite temperature data is effective in obtainingclimate characteristics of winds at height of 20--80 km in Chinese area. These results show the difference between the zonal mean winds above China with the zonalmean wind of CIRA-1986 is obvious. The longitudinal difference of the winds atheight 20--80km over China is also evident. The effect on the middle atmospherewinds by topography of this area can not be disregarded. The meridional wind andvariations of winds over China is discussed.
An Improved Double r-iteration IOD Method for GEO UCTs Based on SBSS System
TANG Yi, ZHONG Wenan, LI Shuang, SHOU Junming
2014, 34(6): 867-871.   doi: 10.11728/cjss2014.06.867
Abstract(1535) [PDF 399KB](113)
Abstract:
The purpose of initial orbit determination, especially in the case of angles-only data for observation, is to obtain an initial estimate that is close enough to the true orbit to enable subsequent precision orbit determination processing to be successful. However, the classical angles-only initial orbit determination methods cannot deal with the observation data whose Earth-central angle is larger than 360°. In this paper, an improved double r-iteration initial orbit determination method to deal with the above case is presented to monitor geosynchronous Earth orbit objects for a spacebased surveillance system. Simulation results indicate that the improved double r-iteration method is feasible, and the accuracy of the obtained initial orbit meets the requirements of re-acquiring the object.
Accuracy Analysis of Satellites Velocity with BDS Broadcast Ephemeris Based on Position Observationsormalsize
CHANG Zhiqiao, HU Xiaogong, SHI Xin, LI Jin, MA Yongbo, DONG Wenli, SHAO Jia'ni
2018, 38(4): 553-559.   doi: 10.11728/cjss2018.04.553
Abstract(1721) [PDF 1141KB](154)
Abstract:
Using broadcast ephemeris to calculate the velocity vector of navigation satellites is a necessary condition for GNSS real-time velocity determination. In this paper, the accuracy of velocity vector calculated by Beidou broadcasting ephemeris only with position observations is analyzed, and the calculation formula of velocity vector with Beidou 18-element model is deduced. Based on one year data of 13 Beidou satellites in orbit, the accuracy of velocity vector calculated by broadcasting ephemeris is obtained. The results show that the maximal velocity error calculated by the 18-element model is in the order of 10-4-1. At the same fitting period, the velocity accuracy of GEO and IGSO satellites is higher than that of MEO. By analyzing position residual sequence, the conclusion is drawn that the velocity accuracy computed by broadcast ephemeris is very high because of little position residual with smooth change trend. The analysis and calculation results in this paper verify the effectiveness of fitting BDS broadcast ephemeris only using position observations.
EVOLUTIONARY RELATION BETWEEN METEORITES, METEOROIDS AND ASTEROIDS OR COMETS
Hu Zhong-wei, Xuan Jia-yu
1982, 2(2): 111-117.   doi: 10.11728/cjss1982.02.111
Abstract(2565) [PDF 718KB](19)
Abstract:
In this paper,the evolutionary relation between meteorites,meteonoids and asteroids or comets is discussed in our viewpoint on the origin of asteroids and comets.Both asteroids and comets are the'halffinished product' of the planets evolved from the primitive nebula,i.e.surviving planetesimals.They show differences in their evolutions,in their orbital characters and their physics-chemical properties only because they form in different places,under different environmental conditions.When volatile-rich comets moved into inner portion of the solar system,they could easily disintegrate into a great number of meteoroids.The surviving planetesimals in the asteroid region could be broken into fragments by collision.Those fragments and crumbs could turn into smaller asteroids or meteoroids.In fact,there is no strict limits between smaller asteroids and bigger meteoroids.Some fragments of planetesimals in the asteroid region would evolve into meteoroids and enter into the atmosphere of the earth,they could then ablaze out as meteors.Cosmic dust,which failed into the solar system from interstellar space,could also become meteoroids
Payload Data Transmission Link Design for the Satellite with Attitude of Inertial Space Orientation
Xiong Weiming, Cheng Xin, Ye Yunshang, Yao Ye
2014, 34(4): 483-488.   doi: 10.11728/cjss2014.04.483
Abstract(1930) [PDF 3157KB](184)
Abstract:
Satellites whose attitude is inertial space orientation cannot keep the transmitting antenna beam accurately pointing to the ground stations when the data transmitting device in the satellite is working. As a result, a new technical challenge of transmitting the payload data from the satellite to the ground stations in a high speed is brought forward. In this paper, a method using the transmitting antenna whose beam has proper width and pointing direction to resolve the problem is dedicated. For this aim, by simulating the satellite orbit with STK software, variation of the relative attitude of such satellites to the ground stations, as well as comparison on the data transmission time from the satellite to the ground stations at different beam width of the transmitting antenna, are researched. The key research is to develop an antenna whose gain is 0dBi in 140° angle of beam, and the link is designed to ensure a sufficient margin at the transmission rate of 85Mbit·s-1. As a result, under the constraint of space avionics miniaturization (10kg of mass, 80W of power consumption), the miniaturized antenna with wide beam and the solid-state power amplifier are designed to solve the problem of payload data transmission of satellites whose attitude is inertial space orientation.
Characteristics of Wind and Planetary Waves Based on FPI over Kelan of Chinaormalsize
ZHANG Yiyao, SHENG Zheng, SHI Hanqing, JIANG Yu, YANG Pinglü, CAO Yu
2018, 38(4): 482-491.   doi: 10.11728/cjss2018.04.482
Abstract(1137) [PDF 5057KB](155)
Abstract:
The horizontal wind data observed by Fabry-Perot Interferometer (FPI) over Kelan, China, has been used to investigate the characteristics of wind and planetary waves at altitudes of 87, 97 and 250km. Firstly, the midnight winds have been compared with those from HWM07. The results are as follows. At 87 and 97km, the AO (Annual Oscillation) and SAO (Semiannual Oscillation) phases of zonal wind of FPI tend to consist with those from HWM07, while the phases of FPI meridional wind lag behind. Both the zonal and meridional FPI amplitudes are smaller. It shows large discrepancies between FPI and HWM07 winds, which reveals that the improvement of HWM07 model needs to further consider the influence of solar activity and interplanetary magnetic field. Secondly, the Lomb-Scargle analysis and the least squares harmonic fitting method have been used to derive the amplitudes of planetary waves at the three altitudes. At 87 and 97km, the 16-day waves are prominent at autumn, winter and spring during 2013-2014, while the 6.5-day waves tend to dominant spring and autumn. Both of the two planetary waves have weak amplitudes around mesopause. The amplitudes are stronger in meridional wind than zonal at 250km. Three typical planetary wave period bands of meridional wind show that the strongest amplitudes persist from May to October. This is consist with the results of ionospheric f0F2 oscillations.
Effect of Solar Wind Speed on the Middle and High Atmosphere Circulation of Meteorological to Climatological Scale
Huang Jing, Zhou Limin, Xiao Ziniu, Chen Tao
2013, 33(6): 637-644.   doi: 10.11728/cjss2013.06.637
Abstract(1205) [PDF 1146KB](26)
Abstract:
The relation between the solar wind speed and the winter northern hemisphere circulation, characterized as Arctic Oscillation (AO), was investigated with the superposed epoch analysis method and the correlation analysis method on the day-to-day and seasonal time scale. The results showed that on day-to-day time scale, the decease of solar wind speed associated with the dip of AO could be significantly detected, which implied that there exist the linkage chain from solar wind speed to the tropospheric circulation mediated by relativistic electron. This process could be explained by the correlation of "space particle-global circuit-cloud microphysics". On seasonal scale, the winter mean of solar wind speed in past 48 winters took significant correlation with the AO index. To understand the linkage between Sun and the climate, we should collect all the detailed physical environment information from Sun to low atmosphere in the future.
Investigation of Ionospheric Scintillations over South China
ZUO Xiaomin, HUANG Jiang, XIA Chunliang, XU Jie
2014, 34(6): 802-808.   doi: 10.11728/cjss2014.06.802
Abstract(1353) [PDF 3342KB](34)
Abstract:
Data recorded by GPS ionospheric scintillation monitors in Guangzhou (23.17°N, 113.34°E) and Maoming (21.45°N, 111.31°E) stations, which are situated near the northern crest of the equatorial ionosphere anormaly, has been used to study the day-to-day, month-to-month, local time and spatial variation characteristics of ionospheric amplitude scintillation during the period from July 2011 to June 2012. The results show that different intensity of amplitude scintillations has co mmon temporal variation characteristics. The scintillation activities with S4>0.4 and S4>0.6 mostly occur from 20:00LT to 24:00LT in spring and autumn. Spatially, scintillations distribute throughout the large region with the latitude from 18° to 27° and the longitude from 109° to 118° for Guangzhou and the latitude from 17° to 26° and the longitude from 107° to 116° for Maoming in the fall of 2011. However, scintillations mainly appear in a small area overhead in the spring of 2012 of both stations.
STORM-TIME JOULE HEATING OF AURORAL THERMOSPHERE AND IONIZATION DEPLETION IN THE F-REGION ──EISCAT RADAR OBSERVATION
MA Shuying, LIU Huixin, XU Jisheng
1999, 19(1): 34-41.   doi: 10.11728/cjss1999.01.034
Abstract(2164) [PDF 516KB](48)
Abstract:
With the help of EISCAT radar data, auroral ionospheric electromagnetic parameters, such as convection electric field, conductivity tensor, and Joule heating rates etc. are calculated and analyzed for an intense magnetic storm (min.Dst<=-150nT) occurring in summer of a high solar activity year. An investigationis emphatically made on the relationship between the thermospheric Joule heatingin the E-region and frictional heating of ions in the F-region with the ionizationdepletion in the F-region. It is found that at the sector of eastward auroral electrojet in the afternoon, a maximum depletion of 70% in electron density occurs ataltitudes of 300-325 km, its occurrence lags just 5-10 minutes after the integatedJoule heating reaches to its mamximun of about 92 mW/m2 in the E-region and ionfrictional heating in the F-region, to its maximum, too.
Recent Advances in Observation and Research of the Chinese Meridian Project
WANG Chi
2018, 38(5): 640-649.   doi: 10.11728/cjss2018.05.640
Abstract(868) [PDF 165KB](34)
Abstract:
The Chinese Meridian Space Weather Monitoring Project (Meridian Project) is a ground-based geospace monitoring chain in China. It consists of 15 ground-based observation stations located roughly along 120°E longitude and 30°N latitude. In recent two years, using data from the Meridian Project, significant progress has been made in space weather and space physics research. These advances are mainly in four aspects:regional characteristics of space environment above China or along 120°E meridian line, coupling between space spheres at different heights and different physical processes, space weather disturbance and its propagation along the meridian chain, and space weather effects on ground technical facilities.
Research on Meridian Project Sounding Rocket Boom Deploying Technology
Yang Xuan, Yang Hua, Sun Jian, Zou Xiangrong, Ma Xin, Zhou Wei
2013, 33(6): 678-682.   doi: 10.11728/cjss2013.06.678
Abstract(927) [PDF 1197KB](38)
Abstract:
Based on the needs of Meridian Project of sounding rockets' electronic and electric field probe, a sleeve-type of boom deployment mechanism was designed. Structure scheme design, mechanical simulation analysis, single mechanical property test, the whole rocket matching mechanical test as well as the flight test validation of both electronic boom and the electric field boom showed that the boom technical scheme is reasonable and feasible, and the boom overall configuration, layout design and structure design can meet the requirements of technical index for scientific exploration. According to the scientific exploration mission needs and space restrictions of the installation on the sounding rocket, a wide range of innovative design and development are carried out in the structure style, deployment and motion mode, locking and fixed mechanism of the boom deployment mechanism, as well as its installation on the rocket and release, etc.
Dynamic Properties of the Two-phase Loop Thermal Control System for Space Application
MO Dongchuan, LÜShushen, HE Zhenhui
2012, 32(5): 739-749.   doi: 10.11728/cjss2012.05.739
Abstract(2412) [PDF 926KB](69)
Abstract:
Loop heat pipe with flat evaporator (Flat Loop Heat Pipe, FLHP) driven by capillary force and mechanical pumped two-phase loop (Tracker Thermal Control System, TTCS) are typical two-phase loop thermal control systems. The working principles of both FLHP and TTCS are discussed in this paper, and samples are tested. Also, dynamic models are built by both SINDA/FLUINT and Matlab/Simulink. The results show that both the FLHP and TTCS may have start-up problem, that the FLHP may have larger temperature oscillation, while the TTCS are more stable, that gravity has obvious effect on the FLHP performance, yet has no obvious effect on the TTCS performance, and that the FLHP with bi-transport loops has a better performance than that with single-transport loop, and the two radiators of the TTCS has the ability of self-adjust in mass flow rate and heat transfer. To choose a two-phase thermal control system, some items should be considered, such as the characteristic of the heat source, the life requirement, the temperature requirement, as well as the system size and mass, etc. Development of the two techniques may be cross-reference and complementary in future.
Application of FPGA in space electronics device
Yan Lei, Wang Qiang, Fang Liang, Gu Hongjing, Li Nan
2009, 29(1): 54-58.   doi: 10.11728/cjss2009.01.054
Abstract(3337) [PDF 604KB](51)
Abstract:
This paper introduces several mainstream programmable logic devices used in space electronics equipment. In consideration of particular characteristics of space environment, special approaches should be used when using FPGA in space. Functional Triple Modular Redundancy (FTMR) approach in FPGA design has been introduced to protect design from the SEU (Single Event Upset) induced by radiation. Examples of FTRM are given to demonstrate the effects of this approach.
Selection of Suitable Internal Control Genes in Microalgae Under Radiation Condition
Cai Wenkai, Hu Jinlu, Li Shuangshuang, Shan Ge, Wang Gaohong
2013, 33(6): 651-658.   doi: 10.11728/cjss2013.06.651
Abstract(1222) [PDF 1420KB](62)
Abstract:
As a major component of space radiation, ultraviolet radiation can extensively destruct terrestrial plants and aquatic. Real-time PCR technique has been widely used to detect the level of target mRNA expression when cell or tissues exposed to various types environmental stress. Choosing an appropriate internal control gene is important to accurately analyze the level of target gene transcription with real-time PCR technique. Therefore, our experiment tries to choose the most appropriate and stability reference gene from six traditional internal control genes, i.e., 18S rRNA, GAPDH, β-actin, β-tubulin, EF1-α and UBC in the Chlamydomonas reinhardtii under radiation conditions. The results showed that C. reinhardtii 18S rRNA gene expression is the most unstable through GeNorm analysis, but β-actin and GAPDH gene were finally selected as a pair of suitable internal control genes in expression analysis, with which more accurate experimental results can be obtained.
Introduction to the Payloads and the Initial Observation Results of Chang'E-1
SUN Huixian, WU Ji, DAI Shuwu, ZHAO Baochang, SHU Rong, CHANG Jin, WANG Huanyu, ZHANG Xiaohui, REN Qiongying, CHEN Xiaomin, OUYANG Ziyuan, ZOU Yongliao
2008, 28(5): 374-384.   doi: 10.11728/cjss2008.05.374
Abstract(2039) [PDF 718KB](56)
Abstract:
Chang'E-1, the orbiter circling the moon 200km above the moon surface, is the first Chinese Lunar exploration satellite. The satellite was successfully launched on 24th October 2007.There are 8 kinds of scientific payloads onboard, including the stereo camera, the laser altimeter, the Sagnac-based interferometer image spectrometer, the Gamma ray spectrometer, the X-ray spectrometer, the microwave radiometer, the high energy particle detector, the solar wind plasma detector and a supporting payload data management system. Chang'E-1 opened her eyes to look at the moon and took the first batch of lunar pictures after her stereo camera was switched on in 20th November 2007.Henceforth all the instruments are successfully switched on one by one. After a period of parameter adjustment and initial check out, all scientific instruments are now in their normal operating phase.In this paper, the payloads and the initial observation results are introduced.
Practical Analysis and Improvement of Klobuchar Model
Zhao Wei, Zhang Chengyi
2013, 33(6): 624-628.   doi: 10.11728/cjss2013.06.624
Abstract(1729) [PDF 482KB](85)
Abstract:
Ionosphere delay error is an unneglectable error source in the propagation of radio signal. The GPS authorized users utilize dual-frequency observations of dual-frequency receivers to determine the ionosphere delay in real time, so the measured results have a high precision. Compared to authorized users, most general users use the ionosphere model to correct the delay error when they utilize single-frequency receivers. Relative to dual-frequency observations, the correction effect by ionosphere model is not ideal. In this paper, dual-frequency observations are used to verify the Klobuchar model which chosen by GPS broadcast ephemeris has a widespread application in single-frequency receivers. Ten days' data of WUHN Observation Station has been picked up to analyze Klobuchar model, and the obtained results were consistent with previous researching results. Also, a new improvement method is proposed based on previous analysis. Since the variability of ionosphere has a close relationship with the Sun's activity intensity, and the sunspot relative number is a symbol reflecting the Sun's activity intensity, the new improvement method is realized by means of sunspot relative number to modify Klobuchar model. This improved method has been proved with a large scale promotion in the correction effect through experimental data. Relative to original model, the correction rate greater than 50% has upgraded from about 60% to 85% above, and that greater than 80% upgraded from 10% to 40% above. In practical application, users of single-frequency receivers can refer to this improvement method to correct Klobuchar model.
Cold-dense Plasma Sheet and Its Impact on the Spatial Distributions of the Magnetotail Plasma Sheet ormalsize
BAI Shichen, SHI Quanqi, TIAN Anmin, ZHANG Shuai
2018, 38(4): 444-451.   doi: 10.11728/cjss2018.04.444
Abstract(1131) [PDF 2121KB](130)
Abstract:
Plasma sheet plays an important role in the coupling of solar wind and Earth magnetosphere, and the Cold-Dense Plasma Sheet (CDPS) is an important evidence of solar wind entry during the geomagnetic quiet time. However, there are handful statistical analyses using in situ observations to investigate the 2D profile of ion number density, temperature of plasma sheet and the CDPS occurrence rate in the xy plane of GSM coordinate. The Geotail data from 1996 to 2016 are used to fill that blank. The 2D profile of ion density, temperature of plasma sheet and the CDPS occurrence rate are plotted. A dawn-dusk asymmetry is seen in the 2D profile of ion density and in the cold-dense plasma sheet occurrence, but not seen in the 2D profile of ion temperature. The dawn-dusk asymmetry of ion density is more clear during the geomagnetic quiet time than that during the geomagnetic active time. Furthermore, the possible affect caused by the CDPS on the 2D profile of ion number density and temperature of the plasma sheet are investigated.
Analysis On The Distribution Of Geomagnetic Storm Number
LIU Yumei, CHEN Chun, SUN Shuji, BAN Panpan
2015, 35(5): 533-540.   doi: 10.11728/cjss2015.05.533
Abstract(1039) [PDF 977KB](33)
Abstract:
A geomagnetic storm is a global disturbance in Earth's magnetic field, which is caused by various solar phenomenon. Dst index is the most widely used index which denotes the intensity of magnetic storm activity. The distributions of moderate geomagnetic storms (-100<Dst≤ -50nT) and intense geomagnetic storms (Dst≤ -100nT) and their causes in 1957-2008 are identified. Moreover, annual average number of geomagnetic storm in ascending phase, maximum phase, declining phase, and minimum phase of solar activity was analyzed according to different kinds of geomagnetic storms. It is found that the total number of geomagnetic storm in maximum phase year is greater than that in minimum phase year of the same solar activity, and there is close relation between the average number of Sun spots per year and the total number of geomagnetic storm. A dominant dual-peak distribution usually exists in the solar cycle variability of intense geomagnetic storm, but a dual-peak distribution of moderate geomagnetic storm exists and a trinal-peak distribution appears in intense geomagnetic storm. The presence of the extra peak might be attributing to a typical year compared to other rising phase years. On the other hand, another possibility is that 1999 could be an unusual year, with a low rate of intense magnetic storm. The magnetic storms mainly happen in equinox, and the number of magnetic storm is obviously changed with the increased Dst index.
STUDIES OF IONOSPHERIC SCINTILLATION FOR C BAND SIGNALS FROM TV SATELLITE
Zhu Tai-ping
1995, 15(2): 137-142.   doi: 10.11728/cjss1995.02.137
Abstract(2279) [PDF 2573KB](80)
Abstract:
In this paper,results of ionospheric scintillation deduced from satellite TVsignals are presented,as well as properties of the TV signals.These experimental resulsts show that it is Fpossible to study ionospheric scintillation of C band signals using received TVsignals by a general TVreceiver with an additional processingcircuit.
Orbit Determination of Satellite on the Middle-High Earth Orbit Based on GPS
LIU Haiying, WANG Huinan
2005, 25(4): 293-297.  
Abstract(2030) [PDF 1433KB](55)
Abstract:
The using of GPS (Global Positioning System) in space orbit solution is dicussed, especially in the application of HEO (Highly Eccentric Orbit) and GEO (Geodetic Earth Orbit). Aiming at the disadvantage factors of the shortage of visible emitter and weak GPS signal in the HEO and GEO, an efficient algorithm is developed for the acquisition of weak GPS C/A signals. The signals with very low signal-to-noise ratios can be successfully acquired. The capture ability of GPS receive is greatly enhanced that can capture the signal with SNR of 25 dB using the method introduced in this paper. At the same time an original technique based on pseudo-acceleration measurement to compute the fix solution with the spaceborne receiver is presented. The pseudo-acceleration measurements can be computed by pseudorange difference, and the relation between the position and the acceleration can be obtained by Newton's law. When only two transmitters are visible in HEO or only one transmitters is visible in GEO, the state of the receiver (position, velocity, clock bias, and drift) can be obtained. A simulation illustrates that the error is within 100 m in the orbit of 4000 km high and within 2 km in the height of 36 000 km. The simulation result shows that the method in this paper is effective.
Effects of interfacial reaction on tensile strength of carbon fibre reinforced magnesium composites
Li Kun, Pei Zhiliang, Gong Jun, Shi Nanlin, Sun Chao
2009, 29(1): 7-9.   doi: 10.11728/cjss2009.01.007
Abstract(4189) [PDF 562KB](77)
Abstract:
Carbon fibre reinforced magnesium-based composites were fabricated by gas press infiltration method. Three kinds of magnesium alloys matrixes were employed. The fractographes of the composites were characterized by SEM, and the interfacial areas of C/Mg were characterized by TEM. The results showed that the reactions in the interfacial areas were affected by the content of Aluminum in the matrix. As the increasing content of Aluminum, the reactions became more intensive. Also, the interfacial bonding strength and microstructure were seriously influenced by the reactions. A weak-bonding interface was found in the C/c.p.Mg composite, however, the strong-bonding interfaces were found in both Cf/AZ31 and Cf/AZ91 composites.
A COMPARISON OF THE INTERNATIONAL REFERENCE IONOSPHERE(IRI-90)WITH THE ELECTRON DENSITY PROFILE OF THE IONOSPHERE OBSERVED IN CHINA
Luo Fa-geng, Dai Kai-liang, Quan Kun-hai, Liu Rui-yuan
1994, 14(4): 305-311.   doi: 10.11728/cjss1994.04.305
Abstract(2380) [PDF 376KB](28)
Abstract:
Asystematic comparison is made between the electron density profiles observed at four of the Chinese ionospheric stations during high solar activity periods and the International Reference ionosphere IRI-90.It is indicated that the bottomside values of IRI-90 are generally greater than measured ones. In detail, the IRI-90 predicted electron content values are more close to the measured ones in daytime than in nighttime, and more close at mid latitudes than at low latitudes.
Decomposing Algorithm of Laser Altimeter Waveforms
YANG Geng, HUANG Chunming
2005, 25(2): 125-131.  
Abstract(2161) [PDF 2247KB](61)
Abstract:
A method to extract the basic information from laser altimeter return waveforms is developed, by which decompose a laser altimeter return waveform into a series of Gaussian components and obtain the number of the Gaussian components and the position, half-width and amplitude of each Gaussian component. From these basic parameters, the topographic information as the elevations and distributions, the surface slope and roughness, and the albedos of distinct reflecting surfaces within the laser footprint can be further induced. Firstly, the initial values of the number of Gaussian components and the position, half-wide of each component are estimated from the number and positions of the waveform's inflection points. Secondly the linear least-squares method are used to calculate the initial amplitudes of each Gaussian component. At last the waveform is fitted with the chosen and ranked Gaussians by Levenberg-Marquardt method, achieving basic optimized parameters of Gaussians. Three types of simulated return waveforms of the laser altimeter from scalariform terrain, woodland and slope surface have been fitted by this decomposing algorithm, the original waveforms are successfully approximated by the fitted ones and the optimized parameters of simulated return waveforms are satisfied. And the results prove that the decomposing algorithm of laser altimeter waveforms obtains a higher precision, it will have a good effect on the analysis of laser altimeter return waveforms.
Two Upstream Splitting Schemes for Generalized Lagrange Multiplier Magnetohydrodynamics
ZHANG Jingke, LI Huichao
2017, 37(1): 8-18.   doi: 10.11728/cjss2017.01.008
Abstract(1577) [PDF 11420KB](73)
Abstract:
To develop a high performance MHD numerical simulation method is an important factor in research of numerical prediction of space weather. The upwind flux splitting scheme based on finite volume method has good ability to capture discontinuities. Steger-Warming and AUSM (Advection Upstream Splitting Method) schemes are two outstanding upwind flux splitting scheme, which are classified as FVS (Flux Vector Splitting) method. In this paper, these two schemes are applied to solve the Extended Generalized Lagrange Multiplier Magnetohydrodynamics (EGLM-MHD) equation with Galilean invariance. Results obtained from Orszag-Tang vortex and three-dimensional blastwave problem indicate that those two schemes are both robust and accurate. Particularly, AUSM scheme is superior to Steger-Warming scheme in divergence error control and computational speed.
Ground dynamics simulation and experiment of solar array
Guo Qiwei, Gou Yongjie, He Gang, Tang Guoan
2009, 29(1): 59-63.   doi: 10.11728/cjss2009.01.059
Abstract(4031) [PDF 578KB](26)
Abstract:
The research of Shijian-7 (SJ-7) solar array deployment on the ground was carried out using three methods, such as dynamic pressure simple formula, 3D-FLUENT simulation and generalized additive inertia method. For the first time the real-time coupling calculation was realized between multibody system dynamics and aerodynamics, and which is successfully applied on the research of the solar array. The results of the three different methods validate each other and get better precision than previous method. At the same time the simulation results are in accordance with the experiment results. The foregoing methods are applied on other solar array type which is being researched at present.
Study of Covariance Calculation in Space Objects Collision Warning
Yan Ruidong, Wang Ronglan, Liu Siqing, Liu Wei, Gong Jiancun
2014, 34(4): 441-448.   doi: 10.11728/cjss2014.04.441
Abstract(1443) [PDF 2064KB](136)
Abstract:
Collision probability is an important criterion in collision warning of space objects. The accuracy of forecast covariance calculation directly affects the accuracy of the collision probability calculation. In the paper we compute two forms of statistical forecast covariance. One is to use precision numerical forecast model and the satellite precision orbit data to forecast for a specified time period, and make statistical calculation of forecast covariance of different time period as 1~ 7 days. The other is to use SGP4/SDP4 forecasting model and TLE data to forecast, and make the statistical calculation of forecast covariance of the forecast time period as 1~ 7 days. Then the forecast accuracy through two methods with the data elements affected by orbit change and without orbit change is analyzed. Taking the 2012 risk conjunction of the satellite as example, the collision warning accuracy affected by the covariance accuracy is analyzed. This covariance calculation can provide reference for actual collision warning works.
Magnetopause Location and Shape Under Extreme Solar Wind Conditions
DING Kai, HUANG Zhaohui, WANG Chi, LIU Huilian
2012, 32(2): 161-169.   doi: 10.11728/cjss2012.02.161
Abstract(2928) [PDF 989KB](34)
Abstract:
Based on the 3D global MHD numerical simulation data under extreme solar wind conditions, a dynamic 3D asymmetric magnetopause model under extreme solar wind conditions is developed. This magnetopause model parameters are fitted by the Levenberg-Marquart method and this magnetopause model has the ability to describe the saturation effects of the solar wind dynamic pressure Bd on the flaring of the magnetopause, the saturation effects of the interplanetary magnetic field (IMF) Bz on the subsolar standoff distance, the magnetopause indentation in the cusp region, the magnetopause asymmetry and the movement of magnetopause indentation center. On the basis of this model under extreme solar wind conditions, the subsolar point decreases with increasing Bd and increasing Bd causes the decrease of the magnetopause size but almost keeps the magnetopause shapes self-similar; with increasing southward (IMF) Bz, the subsolar point decreases slightly, the flaring of the magnetopause decreases and magnetopause indentation center moves towards lowlatitude. Through analysis of the solar storm on August 1, 2010, it is found that this magnetopause model can describe the global magnetopause location and shape under extreme solar wind conditions.
Close Approach of Walker Constellation Without Orbital Maneuver
WANG Wei, HUANG Wende, FU Xiaofeng, Zhang Jing
2005, 25(6): 547-551.   doi: 10.11728/cjss2005.06.547
Abstract(2373) [PDF 1255KB](60)
Abstract:
A spacecraft that have been launched into orbit can fast close approach multiple non- coplane satellites of Walker Constellation without orbital maneuver by orbital design, since Walker Constellation has several special characteristics in construction, such as symmetry. To approach without orbital maneuver, the height of the spacecraft must be as same as that of the Constellation. Aimed at Walker Constellation, this paper presents a search method and a substitution method that on the base of the characteristic of Constellation. For a given Walker Constellation, both method can get a series of orbits with different orbit inclination. Typical orbits derived from the two methods are given. Each orbit can fast (in half of orbit period) close approach (zero distance for Walker) multiple (2 or more) non-coplane satellites of Walker Constellation.
Study on the transmission properties of plasma sheath based on transfer matrix method
Sun Xin, Liu Yanan, Liu Yimin, Wang Xianyi, Wang Jian
2014, 34(2): 194-200.   doi: 10.11728/cjss2014.02.194
Abstract(1245) [PDF 1633KB](124)
Abstract:
Due to compression and pyrogenation by shock wave, plasma sheath is formed around the surface of vehicle when hypersonic aerocrafts fly in near space. Plasma sheath can absorb and reflect electromagnetic wave radiated by the antenna on the vehicle. In order to analyze transmission property of plasma sheath, transfer matrix method is introduced. Based on the typical vehicle model and fundamentals of computational fluid dynamic, the Navier-Stokes equations are solved and electron density distribution in the plasma sheath is obtained. On the basis of propagation theory of electromagnetic wave and correlative characteristics of plasma sheath, the attenuation coefficient of electromagnetic wave in plasma sheath is diagnosed. On the other hand, propagation characteristics of electromagnetic signals which mainly include refection and transmission coefficients are analyzed. Analysis results show that good agreement is achieved among numerical results of transfer matrix method, theory analysis results and simulation results of FDTD (Finite Difference Time Domain). It is proved that the proposed method dramatically decreases computation complexity and is suitable for any kind of electron density distribution and thickness of plasma sheath.
Ionospheric Electro-magnetic Disturbances Prior to Yutian 7.2 Earthquake in Xinjiang
Zhang Xuemin, Qian Jiadong, Ouyang Xinyan, Cai Jin'an, Liu Jing, Shen Xuhui, Zhao Shufan
2009, 29(2): 213-221.   doi: 10.11728/cjss2009.02.213
Abstract(3825) [PDF 1070KB](44)
Abstract:
Based on the observing data of electro-magnetic field and other plasma parameters on DEMETER satellite of France, the anomalous variations in ion temperature Ti, ion density Ni, Very Low Frequency (VLF) magnetic spectral values and so on were analyzed before Yutian 7.2 earthquake in Xinjiang. The analysis on Ti shows that the abrupt abnormal signals above epicentral area occur frequently in a much wider space, so they are with lower reliability as seismic precursors. Using revisited orbit method to compare the shapes of the density of H+, it is found that all curves in a year are with consistent shape, but the peak amplitude in summer and autumn is 1 times of that in spring and winter. Compared the curves of Ni in 2008 with those in 2007 and 2006, apparent increases were exhibited at peak value regions in one month prior to Yutian earthquake with the amplitude rising to more than a magnitude relative to the other two years since February, and it continued to the earthquake occurrence. As for the magnetic spectrum data, orbits were selected in the distance of 2000\,km and single frequency (400 Hz) values were extracted and arranged to a time series according to their record date and common latitude scale (0~60°N). The results show that during 2 days before the earthquake, the spectrum values at 400 Hz increased approximately by an order of magnitude, reflecting an obvious electro-magnetic emission occurred in ionosphere before the earthquake. It is illustrated after processing the three components of ELF electric and magnetic field on March 20 by vector analysis that, some left-rotated polarization electro-magnetic signals existing at the observing period reflect that the variation of ion density in ionosphere was accompanied by the emission of ELF electro-magnetic signals. Summing up, the variation process of these ionospheric parameters is consistent to the coupling mechanism of earthquake preparation and ionosphere at present.
Energy Budget in the Coupling Processes of the Solar Wind, Magnetosphere and Ionosphere
Xu Wenyao
2011, 31(1): 1-14.   doi: 10.11728/cjss2011.01.001
Abstract(2651) [PDF 843KB](75)
Abstract:
On the basis of the principle of energy conservation, this paper reviews the aspects on energy input and dissipation in the coupling processes of the Solar wind, Magnetosphere and Ionosphere (SMI coupling). We focus on the following 9 principle issues: (1) solar wind energy input, (2) magnetosphere response to solar wind energy injection, (3) ring current dissipation, (4) Joule heating in the polar ionosphere, (5) auroral particle precipitation, (6) energy dissipation and storage in the magnetotail, and energy returning from the magnetosphere to solar wind, (7) energy accumulation and dissipation during quiet periods, (8) energy partitioning in different sinks, (9) the criterions and methods for assessing energy function.
Bi-Directional Approach for Motion Planning of Dual-Arm Space Robot Systems
GUO Yishen, CHEN Li
2005, 25(6): 565-568.   doi: 10.11728/cjss2005.06.565
Abstract(2029) [PDF 1265KB](66)
Abstract:
Based on the bi-directional approach, the paper discusses the motion planning of freeflying dual-arm space robot systems. With the linear and angular momentum conversation, the state equation is established for the system control design. And then applying the Lyapunov method to the state equation, the control input equation of the manipulator joint angles controlling the vehicle attitude and the manipulator joint angles is obtained. Because no continuous trajectory from the start point to the end point in the state space can complete the desired task, the synthesized trajectory is gained to accomplish the desired task through the bi-directional approach. The advantage of the approach is to decrease the fuel consumption for controlling the vehicle attitude and prolong the available life-span of space robot systems. A planar dual-arm space robot system is simulated to verify the proposed approach.
Studies on the Design and Analysis of Regional Navigation Constellations
SHUAI Ping, QU Guangji, CHEN Zhonggui
2006, 26(4): 268-276.   doi: 10.11728/cjss2006.04.268
Abstract(2243) [PDF 3379KB](24)
Abstract:
The navigation constellation design is involved in the optimization issues of many parameters. The goal of constellation design is to search a set of parameters and generate a navigation constellation using them. It is required that not only the optimal performance for the constellation needs to be the hest, but the cost of developing and maintaining the navigation satellite system is also low. Firstly, the indexes of evaluating constellation performance, algorithms of computing constellation availability and parameters of designing constellation are described in detail in this paper. There are three primary performance indexes examined, including the continued coverage, space distribution and redundancy. Secondly, as the navigation constellation design is a multi-objective optimization issue, the semi-analysis approach is presented simply in term of the practical engineering requirement. Only considering the central earth gravity, an ideal constellation can be designed from the aspect of geometry. The constellation parameters can be obtained synthetically and optimally in the case of meeting the constellation performance indexes. Therefore, four constellation schemes are generated optimally by using the approach. Finally, by analyzing the performance indexes and positioning simulation results respectively based on four schemes, it can be shown preliminarily that the semi-analysis approach and constellation schemes are feasible and rational.
Servo-control analysis of electrostatically suspended accelerometer
Xue Datong
2009, 29(1): 102-106.   doi: 10.11728/cjss2009.01.102
Abstract(3152) [PDF 502KB](49)
Abstract:
According to the principle of general relativity, in this paper the reference frame is chosen as the satellites, which levitate freely in the orbit under ideal circumstance, The movement of the test mass and the electrode cage of the electrostatically suspended accelerometer are discussed and the dynamics equation of test mass motion, inside the electrode cage is obtained. It is beared out, that the visible lacunan is in the similar expression offered by references [1],
[2]. The servo-control circuitry of the electrostatically suspended accelerometer is analyzed and the expressions of the electric damp coefficient, the closed loop natural angular frequency (i.e. the basic angular frequency of the accelerometer), the angular frequency dominated by the uncontrolled stiffness, such as the electrostatic negative stiffness, the acceleration from electrostatically suspending and the relatively displacement of the test mass etc are presented. It is put forward that the gain of the servo-control circuitry must be sufficient to provide the appropriate closed loop natural angular frequency. The expressions of the acceleration noise caused by the position noise are offered. It is proved, that the relatively displacement of the test mass is nearly naught in the frequency bandwidth of the suspension, when the gain of the servo-control circuitry is sufficient.
Experimental Study of Frequency Spectrum Characteristics in Spacecraft Dielectric Discharging
Quan Ronghui, Zhang Zhenlong, Han Jianwei
2013, 33(6): 659-663.   doi: 10.11728/cjss2013.06.659
Abstract(1199) [PDF 979KB](65)
Abstract:
Deep dielectric charging and discharging effect is one of the key factors threatening the spacecraft safety. Besides the dielectric and its grounding configuration, deep dielectric discharging is also affected by the electron environment in space. The space dielectrics such as FR4, Teflon and Polyimide were tested in a simulated space radiation environment on ground, and their discharging currents and electrical field pulses were recorded. By analyzing frequency spectrum characteristics of the discharging transients and the effect of dielectric temperature, electron energy and electron beam intensity, a peak frequency in discharging current was discovered. The result shows that the peak frequency varies with the dielectric thickness and electron energy, while no obvious change was observed at different beam intensities or temperatures.
National Report on Space Medicine Progress in 2010-2012
LI Yinghui, LIU Zhaoxia, DING Bai, LIU Yue, ZHANG Xiaoyou, BAI Yanqiang, CHEN Shanguang
2012, 32(5): 693-703.   doi: 10.11728/cjss2012.05.693
Abstract(2418) [PDF 136KB](65)
Abstract:
Accompanying the flourishing developments of China’s manned spaceflight, space medicine has achieved great development during the past two years in China. In this paper, scientific research of space medicine and its application in China during 2010?2012 have been briefly introduced.
Structure Design of Multifunctional Supporting Bench in the Microgravity Combustion Science Experimental System ormalsize
SHANG Lan, WANG Baorui, LIU Chuang, KONG Wenjun
2018, 38(4): 524-529.   doi: 10.11728/cjss2018.04.524
Abstract(1055) [PDF 2540KB](121)
Abstract:
The microgravity Combustion Science Rack (CSR) in a manned space station can provide extended duration microgravity environment for combustion study. It thus has significant value for the development of combustion theories and models and the breakthrough of aerospace propulsion technology. In the CSR, the Multifunctional Supporting Bench (MSB) is a crucial structure because it is used to fix a variety of parts and units such as the combustion measuring devices, the combustor and the experimental control modules and so on. The MSB must have enough stiffness and installation space in view of the constraints of size and mass. In this paper, a split-body structure is designed to make the MSB smoothly pass through the hatch. According to the finite element method, structural optimization design as well as modal analysis is employed to satisfy the stiffness requirement without overweight.
Transformation of Photon Time of Arrival in XNAV
Fei Baojun, Sun Weijin, Pan Gaotian, Ji Chengxiang
2010, 30(1): 85-90.   doi: 10.11728/cjss2010.01.085
Abstract(2562) [PDF 456KB](94)
Abstract:
The navigating method for XNAV (X-ray pulsar-based Navigation) is similar the one of the Differential GPS (DGPS). In order to position and navigate the spacecraft (or satellite), the two Time of Arrival (TOA) from one X-ray pulsar to both the spacecraft and the solar system barycenter are demanded respectively. The difference between the two TOA is generally called the transformation equation of time. But the existent transformation equation of time is not good enough. In this paper, improvements have been made on some current expressions. The time difference between photon arrival at the observation spacecraft and solar system barycenter in XNAV is presented. It is based on the post-Newtonian approximation spacetime theory in GTR and the neglection of celestial bodies spin of the solar system as well as the effect of eccentric orbit. These considerations are reasonable under the condition that the precision of measure time magnitude is in the order of the nanosecond. The transformation of the proper time from observation spacecraft to BCT (Barycentric Coordinate Time) is also obtained. Based on this relation, a proposal is presented that the frequency of clock at spacecraft can be adjusted in the same way as GPS.
Target based SNR analysis of spaceborne panchromatic TDICCD camera
Zhong Xing, Jin Guang, Zhang Lei
2009, 29(1): 45-49.   doi: 10.11728/cjss2009.01.045
Abstract(4278) [PDF 672KB](58)
Abstract:
TDICCD is a new optoelectronic sensor developed these years, and is widely used in the design and developing of spaceborne camera. This paper analyzes the solar elevation and luminance of target, builds a mathematic model of the radiance transition from the observing target on the ground to the entrance pupil of spaceborne camera. This method can fast induce the SNR of spaceborne panchromatic TDICCD camera for any target, and validate the feassibility of satellite platform design. Taking actual camera for example, the result shows the solar elevation of some target at 20° north latitude is 41.5°~76.7°. The maximal SNR of TDICCD camera whose F number is 15 can be more than 40 dB. This paper is useful for the actual engineering.
Response of the Ionospheric Equivalent Current Systems to Interplanetary Shocks
Zhang Qingmei, Sun Tianran, Zhang Jiaojiao, Li Chuanqi, Wang Chi
2013, 33(5): 486-493.   doi: 10.11728/cjss2013.05.486
Abstract(2272) [PDF 3073KB](108)
Abstract:
Interplanetary (IP) shocks, one of the important causes of the magnetosphere ionosphere disturbances, could affect the geo-magnetic field by changing the current systems in the magnetosphere——ionosphere region. By using a global three dimensional MHD simulation code, we analyze the immediate responses of the Equivalent Current Systems (ECS) in the Earth's ionosphere to the impact of IP shocks. The model results show that after the shock arrival a pair of abnormal Field-Aligned Current (FAC) appears, flowing into and out of the ionosphere on the dusk and dawn side respectively. Also developed in the ionosphere is the two-cell ECS: an anticlockwise circulation in the dawn hemisphere and a clockwise one in the dusk hemisphere. The two ECS vortices shift poleward and tailward after their formation. In the meantime, their intensities increase at first and then decrease to virtually disappear within tens of seconds. At last the ECS pattern reaches a quasi-steady state which is controlled by the interplanetary conditions downstream of the IP shock. The quantitative characteristics of such response processes depend on the intensity of the IP shock: for a stronger shock, the two-cell ECS becomes more intense, and its lifetime is shorter.
Study on the Adaptability of Global Ionoshperic Scintillation Model at Low Latitude in China
Sheng Dongsheng, Zhao Zhenwei, Sun Shuji, Wang Feifei
2014, 34(2): 154-159.   doi: 10.11728/cjss2014.02.154
Abstract(1294) [PDF 1490KB](35)
Abstract:
A forecast of ionospheric scintillations can provide the opportunity for radio communication system to take appropriate action to mitigate the effects and optimize service. The Global Ionospheric Scintillation Model (GISM) by Béniguel was developed to forecast the global ionospheric scintillation condition. To check the prediction accuracy of the model at low latitude in China, this paper compares the model predictions with observed L-band ionospheric scintillation data at three low-latitude stations in China from July 2011 to June 2012. The results show that the model predictions had a good correlation with the statistical characteristics of the scintillation during solar maximum. The predicted beginning time of the scintillation agreed with measurements in general, while the end time was delayed for about an hour. As to the maximum scintillation intensity, the predictions could reproduce the measurements fairly well. Under the same cumulate probability condition, the model had somewhat higher prediction precision for each given scintillation intensity. The predicted percentage of occurrence and intensity of scintillation show gradual decrease versus latitude, which is consistence with measurement.
Observations of Ionospheric Irregularity Zonal Velocity in Hainan
Chen Yanhong, Huang Wengeng, Gong Jiancun, Ma Guanyi, Sun Chuanli, Shen Hua
2008, 28(4): 295-300.   doi: 10.11728/cjss2008.04.295
Abstract(2862) [PDF 1947KB](95)
Abstract:
To investigate the drift velocity of the equatorial ionospheric irregularity in low latitude of China, three single-frequency GPS receivers at Hainan (19.3ºN, 109.1ºE) were operated under the corporation of CSSAR, China and NICT, Japan. Distances between the receivers were 91 m and 104 m respectively. The GPS receivers sampled GPS signal intensity at a rate of 20 Hz. Drift velocities of irregularities were measured using cross-correlation analysis with the time series of the GPS signal intensity observed from March to November of 2007. The results indicate that the ionospheric scintillation mainly occurrs in spring and autumn. The zonal drift velocity is mainly eastward at night. It varis from 50 m/s to 150 m/s, and decreases with time. During the generation phase of plasma bubbles, the drift velocity is relatively scattered, which could be related to the random fluctuations of the plasma irregularities. And at the beginning of the scintillation, the plasma has a large vertical velocity, which can also cause the uncertainty of the zonal drift velocity. The characteristic of the drift velocity is consistent with the observational results in other stations at low latitude region.
Centralized Payload Management System for Dark Matter Particle Explorer Satelliteormalsize
WANG Lianguo, ZHU Yan, SHEN Weihua, LIANG Yaoming, TENG Xuejian, ZHOU Changyi
2018, 38(4): 567-574.   doi: 10.11728/cjss2018.04.567
Abstract(1093) [PDF 2568KB](139)
Abstract:
The Dark Matter Particle Explorer (DAMPE) Satellite consists of 4 detectors. The total number of detector Front End Electronics (FEE) is 28. To satisfy the requirements for supporting large numbers of FEEs and complicated interface, a centralized management strategy is proposed. Telemetry and telecontrol, scientific data and housekeeping data collection, secondary power supply of all the payloads are realized by payload management system. In addition, the payload management system provides mass data storage and high data rate multiplex function. The scientific data and the housekeeping data can be stored separately by the mass data storage, which based on flash memory. When entering the ground receiving station, the stored data can be retrieved and formatted to CCSDS protocol frame, and then the frame is channel-coded and sent to X-band transmitter. The strategy solved several key technologies such as burst and multi-source scientific data collection and storage, onboard autonomous detection management, and distribution of large capacity and low-noise secondary power supplies. The system has undergone onboard assessment and verification. The results indicate that the control and information architectures are suitable, and the autonomous detection management and health management measures are effective.
PREDICTION OF PROTON-INDUCED SINGLE EVENT UPSET
HAN Jianwei, YE Zonghai
1999, 19(3): 266-271.   doi: 10.11728/cjss1999.03.266
Abstract(2165) [PDF 296KB](50)
Abstract:
According to the essentials of proton induced single event upset (SEU) and the characterastics of the high-energy proton in space, the present paper put forward a method for predicting proton-induced SEU. This method is based on the experiments of heavy ions. Using this method, predictions of proton-induced SEUfor several kinds of devices were made. It showed that the predictions agree well with the ground testing and flight observations.
Application of GEANT Program to Design Space Particle Detector and Optimize
ZHANG Shenyi, WANG Shijin
2005, 25(2): 118-124.  
Abstract(2047) [PDF 1981KB](29)
Abstract:
GEANT is an important Monte Carlo program and this program is in principal applied in high energetic physics. As the scale and complexity of high energy physics experiments increase, simulation studies require more and more care and become essential to the design and optimizing of the detectors, development and test of the reconstruction and analysis of programs, also to interpreting the experimental data. It has been found today applications also outside this domain in areas such as medical and biological sciences, radio-protection. With the development of space technique, design of the particle detector is helped by the Monte Carlo simulation too. The principal applications of GEANT in space particle detection are:the transport of particles through a detector for the simulation of detector response; the graphical representation of the setup and of the particle trajectories. GEANT uses the memory manager ZEBRA, it can help us to manage and store the data easily. In this paper, the primary structure and the process of particle transferring in detector is introduced. With GEANT program, many problems in particle detections can be solved, such as the particle's energy deposition in detector, the linear energy transfer in matter.
Simulation of 3D X-ray imaging for space material science experiments
Yu Qiang, Tong Fangyuan, Zhou Binghong
2014, 34(2): 242-248.   doi: 10.11728/cjss2014.02.242
Abstract(1332) [PDF 653KB](70)
Abstract:
Developing X-ray observation facility has been planned in the Chinese space station. Simulating the process of three-dimensional X-ray imaging can offer valuable reference for the facility development. The simulation process can be divided into three steps. Firstly, to use the cone beam X-ray to scan an object, and rotate the object to obtain projection images at enough number of views; Secondly, to reconstruct the scanned object according to the projection images and the geometrical information; Finally, to visualize the reconstruction object. By employing a 3D Shepp-Logan model consisting of 10 interlapped ellipsoids with different linear attenuation coefficients as the object, the processes of projection, back projection and 3D visualization are realized by simulation, and through image reconstruction, the stereo structure of the scanned object can be well displayed.
Results about ocean satellite observation
Jiang Xingwei, Lin Mingsen
2010, 30(5): 474-485.   doi: 10.11728/cjss2010.05.474
Abstract(2318) [PDF 4356KB](28)
Abstract:
They have played more and more important roles in marine pollution monitoring, marine environment and marine disaster monitor and forecasting, marine resource investigation and marine scientific research. In this paper, the author will give a brief review of China's operational and scientific activities in satellites ocean observation during 2008 to 2010. These activities include the application of the HY-1B for red tide and green tide detecting and monitoring, sea ice monitoring, fishery resources assessment at coastal zone and ocean, marine water quality assessment, sea surface temperature monitoring and forecasting, ocean primary productivity and carbon cycle research, and the development in the ocean dynamic environment parameter application technology before launch of HY-2. The achievements we have made in the ocean observation and monitoring during the past 3 years indicate that, the development of the ocean satellite series and the application of the ocean satellite can greatly promote the development of China's three-dimensional marine observation system and earth-observation system from space, accordingly we can improve the ability of acquiring the marine environmental parameter to sustain the marine economy development and the sea defense construction.
An orbital anomaly analysis method based on TLE data
Wang Ronglan, Liu Wei, Liu Siqing, Yan Ruidong, Gong Jiancun
2014, 34(2): 208-213.   doi: 10.11728/cjss2014.02.208
Abstract(1595) [PDF 498KB](138)
Abstract:
Orbital Anomaly of space object is an important problem for satellite operators and users. It is very meaningful to find orbital anomaly timely and quickly. By analyzing orbital anomaly of space objects, the avoidance or collision event can be found and discriminated, further the ability of United States Space Surveillance Network (SSN) can be determined. This paper put forward a simple orbital anomaly analysis method based on TLE data called Semi-major Axis Change Method (SACM). This method is rapid and valid, and can be applied to orbital anomaly analysis of LEO operational satellites and the breakup debris produced in the Cosmos 2251 and Iridium 33 satellite collision. With this method, the discrimination accuracy rate can reach 100 percent. By analyzing the orbit anomaly of American Russian breakup debris with SACM, it is found that US SSN can steadily detect over 90 percent breakup debris.
A Review and Prospect for Developing of Lunar Soil Simulants
ZHENG Yongchun, WANG Shijie, LIU Jianzhong, LI Yongquan, ZOU Yongliao
2005, 25(1): 70-75.  
Abstract(2262) [PDF 2065KB](91)
Abstract:
Lunar soil simulants are geochemical copycats of lunar sample.They have similar chemical composition,mineralogy,particle size distribution,and engineering properties with lunar sample.Simulants of lunar rocks and soils have been developed to satisfy the requirements of a variety of scientific and engineering investigations.They are essential to meet the system requirements for lunar exploration and in support of future human activities on the Moon.Such studies include material handling,construction,excavation,and transportation.The simulants is also appropriate for research on dust control,spacesuit durability,and agriculture.
Five lunar soil simulants,JSC-1,MLS-1,MLS-2,MKS-1,FJS-1 are reviewed in the paper.Their starting materials,preparation,and characterization(chemical composition,mineralogy,particle size distribution,specific gravity,angle of internal friction,and cohesion) are also listed.
China will realize the first lunar exploration before 2007.So it is an essential and pressing task to develop lunar soil simulants series corresponding to average chemical and mineral composition of lunar sample at Apollo and Luna landing sites.The tentative ideas of developing new lunar simuants series based on geologic investigations were brought forward in the end.
Ionospheric Scintillation Monitoring and Preliminary Statistic Analysis Over Hainan Region
SHANG Sheping, SHI Jiankui, GUO Jianshan, LUO Xigui, P. M. Kintner, ZHEN Weimin, WU Shunzhi, ZHANG Manlian, WANG Xiao
2005, 25(1): 23-28.  
Abstract(2896) [PDF 2030KB](90)
Abstract:
To investigate the equatorial ionospheric scintillation morphology and the relevant physical processes,one GPS ionospheric scintillation monitor was installed at CSSAR Hainan station.The monitor is built on Plessey GPS Builder-2 development system with its software modified to log signal strength from up to 11 channels at a high data rate(50 samples/s).It is suits the high time resolution studies of scintillation spectral and temporal characteristics and also can be used to perform the statistic analysis of scintillation signals.The preliminary analysis results of L-band ionospheric scintillations during Jul.-Dec.2003 show that ionospheric scintillations mainly occur near from sunset to midnight,where the onset and end time are evidently more advanced in Nov.-Dec.than in Jul.-Aug.;the occurrence rate and intensity of ionospheric scintillations are evidently more enhanced in Sept.-Nov.than in other months,and reach their peaks in Oct.;there is the strong randomness for the day-to-day variability of ionospheric scintillations,and the scintillation occurrence reaches their peak during the magnetic quiet days from the end of Sept.to the middle of Oct.near autumnal equinox;the increase of solar and geomagnetic activities generally may limit the occurrence of ionospheric scintillations,especially near autumnal equinox.
Preliminary Analysis of Ionospheric Scintillations Over Guangzhou Region of China
Wang Siyu, Wang Jinsong, Yu Tao, Shan Haibin, Zhang Xiaoxin
2010, 30(2): 141-147.   doi: 10.11728/cjss2010.02.141
Abstract(2877) [PDF 783KB](64)
Abstract:
Ionospheric scintillation is a kind of rapid variation resulting from ionospheric irregularities. The scintillations may cause problems such as signal power fading, phase cycle slips, receiver loss of lock, etc., and degrade the quality of satellite navigation systems. Being concerned about these effects, ionospheric scintillations observed at Guangzhou station (23º8' N, 113º17' E) during April to September, 2007 and January to September, 2008 are analyzed in this paper. The results show that there are more ionospheric scintillations over Guangzhou region during geomagnetic quiet and low solar activity periods. The scintillations with S4>0.2 have high and stable occurrence rate in summer, and show no obvious daily variation. Most of them are weak scintillations, i.e., 0.2
CONTROL ON TRANSVERSE VIBRATION OFTETHER BY THE LONGITUDINAL MOTION FORTETHERED SATELLITE
GU Xiaoqin, TAN Zhaoyang
1999, 19(2): 187-191.   doi: 10.11728/cjss1999.02.187
Abstract(1681) [PDF 291KB](54)
Abstract:
The transverse vibration of a tethered satellite is studied. The equation of thevibration is formulated. To suppress the transverse vibration of the tethered satellite, the longitudinal control force is gotten by Pontryagin's method. The controlforce to exert to the tether is produced by D'Alembert force of satellites, and satellites are accelerated by the change of the tether's length, which is controlled by themotor in the satellite. The numerical simulation results are included.
Research of Micro-Space-Debris Detection
YUAN Qingzhi, SUN Yueqiang, WANG Shijin, WANG Jing
2005, 25(3): 212-217.  
Abstract(2319) [PDF 1741KB](30)
Abstract:
The continuing growth of the orbital debris population is now recognized world-wide as an environmental issue which must be better defined and addressed now to preserve near-Earth space for future generation. The distribution of the space debris in the LEO and the threaten of debris to the spacecrafts are introduced. Over the last decades, a number of technologies have been developed by the scientists for detection and measurement of the physical, chemical, and dynamical characteristics of dust and debris including (1) impact-plasma detection utilizing thick and ultra-thin targets; (2) charge induction in wires; (3) impact-induced discharge in a Metal-Oxide-Silicon (MOS) capacitor. In this report, A new methods was introduced, which employed a Polarized PolyVinyliDene Fluoride (PVDF) polymer film and fast electronic pulse techniques. The detector is intended to provide direct observations of space debris and interplanetary dust in the space, returning time resolved impact data, with approximate mass and velocity information. The advantages of ruggedness, no bias requirement, ease of large area sensor construction, and space reliability inherent in the PVDF dust sensors are well suited for a variety of dust and debris studies in space. The output of the fast electronic pulse techniques are used to analyze the mass of debris. Two sensors are placed in a Time-Of-Flight (TOF) telescope, which is used to measure the speed of the debris.
Fast Fitting Algorithm of Non-cooperative Space Object’s TLE Parameters
Liu Guangming, Zhang Zhi, Che Wanfang
2014, 34(3): 319-326.   doi: 10.11728/cjss2014.03.319
Abstract(1209) [PDF 1491KB](51)
Abstract:
Due to the singularity existence in the iterative approximation procedure, a new Two-Line Elements (TLE) sampling fitting method is put forward according to the non-singular transformation of orbital elements. To improve the data-processing efficiency of space-based observation platform to the non-cooperative space target, the TLE fitting algorithm introduces the adaptive forgetting factor recursive least-squares algorithm. Numerical simulations indicate that the method can enhance the iterative rapidity of convergence and the accuracy of forecasting orbit, especially for near-Earth space objects. The fitting method can be applied to the tracking system of space-based observation platform to the near-Earth orbit target.
Research on multi-system software GNSS receiver of micro-satellite
He Xiaojun, Wang Shaoju, Jin Guang
2009, 29(1): 130-134.   doi: 10.11728/cjss2009.01.130
Abstract(3546) [PDF 604KB](55)
Abstract:
This paper reviews the Global Position System (GPS) satellite signal first, and then introduced the Software Define Radio (SDR) into Global Navigation Satellite System (GNSS) receiver. It also presents the development of a new kind of GNSS receiver, which is upgradable, highly flexible and multi-system compatible. In order to apply it on the Micro-Satellite Platform (MSP), the hardware system was made up of Field Programmable Gate Array (FPGA) and Digital Signal Processor (DSP). The software structure is also presented. In the end of the paper, the advantage and disadvantage of the software GNSS receiver applied in MSP are given, and the future of this GNSS receiver is discussed.
Advances in Research and Service of Space Environment in China
SHI Liqin, GONG Jiancun, LIU Siqing, HU Xiong, LIU Jing, HUANG Wengeng
2008, 28(5): 412-423.   doi: 10.11728/cjss2008.05.412
Abstract(1934) [PDF 191KB](68)
Abstract:
This paper presents the recent progress of space environment research and service in China.During the past two years,many models of space environment forecast and analysis methods of space environment effects have been developed for tailored space environment service for Chinese space mission.A new Re-locatable Atmospheric Observatory(RAO)for monitoring atmospheric wind,temperature,density and pressure of the near space from 20 km up to 120 km altitudes is being constructed.In space environment service space environment safety was provided to ensure the safety of CE-1 for its launch and operation in 2007.
Wind Retrieval and Error Analysis of Ground-based Fabry-Perot Interferometer for the Middle and Upper Atmosphere
Wang Houmao, Wang Yongmei, Wang Yingjian, Li Yongzhi
2014, 34(4): 415-425.   doi: 10.11728/cjss2014.04.415
Abstract(1218) [PDF 2310KB](101)
Abstract:
Fabry-Perot Interferometer (FPI) is widely used for the wind observation of the middle and upper atmosphere. The wind retrieval algorithm of ground-based FPI has been studied globally for a few years, but a detailed analysis of retrieval precision factors has not been reported yet. Currently, in China, a few studies of FPI wind retrieval based on simulation data have been carried out. However, the studies did not make a detailed analysis of wind retrieval factors yet, such as the airglow intensity, the number of interference fringes, the fringe center and the focal length. In this paper, wind velocity retrieval of the middle and upper atmosphere is based on the ground-based observation mode (one direction at zenith and four cardinal directions with 45° zenith angle) using FPI facility from the Meridian Space Weather Monitoring Project, which included the pre-processing, the fringe center determination, the fringe radius calculation and the wind velocity retrieval. For validation, the wind parameter of 8 days (May 6-13, 2010) retrieved from observation data using ten fringes were compared with the FPI wind products with an average deviation of 2.7m·s-1 (557.7nm airglow), 5.5m·s-1 (630.0nm airglow) and 7.7m·s-1 (892.0nm airglow) respectively. Furthermore, the detailed analysis of the influencing factors mentioned above was also carried out. The results demonstrate that the stronger airglow intensity is, the higher outer fringe radius calculation precision can be obtained, and more usable fringes can be chosen. Besides, the center determination deviation with ± 2pixel (using 5 interference fringes) and ± 1pixel (using 10 interference fringes) and the focal length deviation with ± 10mm have negligible effects on wind retrieval precision, but can cause large retrieval errors when the deviations exceed the ranges mentioned above.
VHF RADAR OBSERVATIONS OF INERTIAL GRAVITY WAVE CRITICAL LAYERS IN THE POLAR MESOSPHERE
Zhang Shao-dong, Yi Fan, J. Klostermeyer, R. Ruster
1996, 16(3): 227-232.   doi: 10.11728/cjss1996.03.227
Abstract(2025) [PDF 407KB](78)
Abstract:
This paper studies the characteristics of inertial gravity wave critical layers in the mesosphere with mobile SOUSY VHF radar observations at Andφya (69° N,10°E)Norway June 1987.Data analysing shows, near critical layers, inertial gravity waves suddenly decay,wave energy are absorbed by background wind, the horizontal and vertical propagation directions may change repidly through critical layers,that indicates a downward prapogating energy source will be there at critical layer.The observations further show there is a maximum echo intensity at critical layers, strongly suggesting that critical layers play an important role on the generation of radar echo.
Simulation and validation of composite shielding for total ionizing dose
Hu Jianhang, Feng Ying, Han Jianwei, Cai Minghui, Yang Tao
2014, 34(2): 180-185.   doi: 10.11728/cjss2014.02.180
Abstract(1174) [PDF 1002KB](71)
Abstract:
Total ionizing dose effects caused by space radiation environment will be hazards for satellite electronic devices, and radiation shielding with appropriate materials is needed. Different shielding schemes for electron have been simulated with Monte-Carlo method. Three different shielding options, i.e., pure aluminum, pure tantalum and double-layer structure constituted by these two materials, have been compared. The results indicated that, when the shielding thickness is large enough, composite shielding for electron is better than single material shielding. And through experiments using the 90Sr-90Y source for irradiation test, pure material shielding and composite shielding are compared. The results were consistent with those of the simulation. The research conclusions can provide valuable references to optimization design for radiation shielding.
A method for separating O wave and X wave in digital ionosonde
Wang Shun, Chen Ziwei, Zhang Feng, Gong Zhaoqian, Fang Guangyou, Wang Yungang
2014, 34(2): 186-193.   doi: 10.11728/cjss2014.02.186
Abstract(1889) [PDF 1868KB](104)
Abstract:
Separation for O wave and X wave is an important job in ionosphere detection. A new digital method for separating O wave and X wave is presented in this paper, being different from using image recognition technique to separate trace O and trace X in ionograms or electrical method to synthesize circularly polarized signals to separate O wave and X wave from echoes of the ionosphere. A numerical synthesizing method is employed in the new method. By introducing phase shifters of ±90° in digital domain, circularly polarized signals are synthesized digitally within the range of 1~ 30MHz, which eliminates the nonlinearity and expands the bandwidth of the ionosonde compared with DPS-4, and there is no need to switch the analog switches continuously. The new method has been successfully applied to CAS-DIS ionosonde and testing results show that the new digital method is capable of separating O wave and X wave well.
National Report on Space Medicine Progress in 2012-2014
Li Yinghui, Zhang Xiaoyou, Wan Yumin, Ding Bai, Liu Zhaoxia, Ling Shukuan, Bai Yanqiang, Chen Shanguang, Liu Shujuan
2014, 34(5): 740-746.   doi: 10.11728/cjss2014.05.740
Abstract(1011) [PDF 117KB](42)
Abstract:
The application of manned spaceflight makes a great impetus on the development of space medicine. With the deep growth of Chinese manned space, our national space medicine has attained great achievements. In this paper, the basic research of Space Medicine and its application in China during 2012-2014 were briefly reviewed.
Development of the Chinese Meridian Project
Wang Chi
2010, 30(4): 382-384.   doi: 10.11728/cjss2010.04.382
Abstract(2514) [PDF 144KB](65)
Abstract:
The Meridian Project is a ground-based network program to monitor Solar-Terrestrial space environment, which consists of a chain of ground-based observatories with multiple instruments including magnetometers, ionosondes, HF and VHF radars, Lidars, IPS monitors, sounding rockets etc. The chain is mainly located in the neighborhood of 120$^\circ$E meridian, and is thus named the Meridian Project. The Meridian Project has officially been approved and supported by the Chinese government and will be finished by the end of 2010. This report gives an overview of the Meridian Project, and reports the recent development since 2008.
SOME ADVANCES IN SMALL SATELLITE TECHNOLOGY
YU Dejiang
1998, 18(3): 265-270.   doi: 10.11728/cjss1998.03.265
Abstract(1886) [PDF 363KB](54)
Abstract:
Some advances in structure,power supply and operation system of small satellites are reported and reviewed.The emphasis is put on new materials,devices and techniques in the stature,and new conceptions and schemes for the autonomous operation system.
Periodic Variations of Drag Coefficient for the ANDE Spherical Satellites During its Lifetime
QI Yalong, LI Huijun, XIANG Jie, MAN Haijun
2013, 33(5): 525-531.   doi: 10.11728/cjss2013.05.525
Abstract(2285) [PDF 1859KB](64)
Abstract:
A drag coefficient (CD) inversion method is introduced to study the variations of the drag coefficient for orbital satellites with spherical geometry. Drag coefficients of the four micro satellites in the Atmospheric Neutral Density Experiment (ANDE) are compiled out with this new method. The Lomb-Scargle Periodgram (LSP) analysis of the four ANDE satellites' CD series has shown that there are obvious 5, 7, 9, and 27 days' period in those data. Interesting results are found through comparing the LSP analysis with series of the daily solar radio flux at 10.7 cm (F10.7 index), the Ap index, and the daily averaged solar wind speed at 1AU. All series in the same time interval have an obvious period of about 27 days, which has already been explained as the association with the 27 days' solar rotation. The oscillating periods less than 27 days are found in series of CD, Ap and solar wind speed at 1AU, e.g., the 5, 7, 9 days period. However, these short periods disappeared in the time series of F10.7 index. The same periodicities of 5, 7, 9 days in Ap and solar wind are presented at the same time interval during the declining phase of solar cycle 23. While in the ascending phase of solar cycle 24, these short oscillations are not so obvious as that in the declining phase of solar cycle 23. These results provide definite evidence that the CD variations with period of 5, 7 and 9 days are produced by a combination of space weather effects caused by the solar wind and geomagnetic activity.
Cit-Based Correction Algorithm For The Ionospheric Delay In Wide Area Augmentation System
Ou Ming, Zhen Weimin, Yu Xiao, Liu Yiwen, Xu Jisheng
2015, 35(5): 541-548.   doi: 10.11728/cjss2015.05.541
Abstract(1143) [PDF 1265KB](62)
Abstract:
Ionospheric delay is one of the most important error sources in satellite navigation and positioning, many methods were adopted to mitigate the ionospheric delay for high precision navigation applications, such as local area differential GPS, wide area differential GPS, wide area augmentation differential GPS and Wide Area Augmentation System (WAAS). A new algorithm based on Computerized Ionospheric Tomography (CIT) for ionospheric delay correction in WAAS was proposed in this paper. The error of ionospheric delay can be corrected by the orthogonal combination of model-based function and Truncated Singular Value Decomposition (TSVD) for single frequency user in WAAS. The simulation results of 23 wide-area reference stations and 10 user stations in China show that the precision of ionospheric delay correction based on traditional grid-based algorithm and CIT-based algorithm have evident correlation with solar activities, local time and magnetic latitude as well. However, the performance of CIT-based algorithm is much better than that of grid-based algorithm. Both the mean error and standard deviation of CIT-based algorithm are far less than grid-based algorithm.
Weak Solar Scintillation Effects on Deep Space Communication
Zhao Na, Meng Xin, Hu Shengbo
2009, 29(2): 244-248.   doi: 10.11728/cjss2009.02.244
Abstract(3561) [PDF 554KB](79)
Abstract:
Solar scintillation effects can be significant for deep-space telecommunication links at small Sun-Earth-Probe (SEP) angles. Severe scintillation can make the telecommunication link unavailable. The physical characteristics of solar conjunction and scintillation are presented, the Rician channel model is set up, and the Gaussian approaches of communications channel are obtained once Rician factor exceeds 10\,dB in deep space exploration due to weak solar scintillation. At last, we simulated the weak scintillation effects on telemetry signals at both X-band and Ka-band by the model.
Rapid and asymmetric response of the Earth's bow shock: multipoint observations
LIU Bing, DUNLOP M W, CAO Jinbin, LAVRAUD B, LI Liuyuan, YANG Junying
2017, 37(2): 129-139.   doi: 10.11728/cjss2017.02.129
Abstract(926) [PDF 4345KB](39)
Abstract:
We analyze observations of three bow shock crossings which occurred during 2007, using upstream data from STEREO A/B, ACE and WIND, combined with multi-point THEMIS and Cluster data, and TC-1 data located near noon. During the crossing of 7 May 2007, we find that following a rapid reduction in solar wind ram pressure and subsequent pressure pulse seen by ACE and WIND upstream, the bow shock responds asymmetrically from dawn to dusk. Cluster data on the dawn-side suggest the bow shock is significantly flared and responds rapidly to the pulse arrival, while TC-1 at noon, and THEMIS on the dusk-side, are well matched to the model bow shock, but show a delayed response. The crossings observed on 21 May and 2 June show contrasting response matching the model boundary for northward Interplanetary Magnetic Field (IMF). The IMF and solar wind plasma data suggest that the bow shock crossing at dawn-dusk side and subsolar point were mainly caused by large and smaller scale features of the solar wind ram pressure rise rather than the influence of IMF.
Research on Spaceborne FPI Detection of Lower Thermospheric Temperature
Liu Jue, Ai Yong, Zhang Yange, Hu Guoyuan, Xiong Bo, Chen Yao
2013, 33(6): 645-650.   doi: 10.11728/cjss2013.06.645
Abstract(1115) [PDF 2353KB](59)
Abstract:
Research on the atmosphere of 80~350km height is of great interest for understanding global aerodynamics and solar-terrestrial coupling. A Fabry-Perot Interferometer (FPI) is a multiple beam interferometer which makes it possible to obtain information on thermospheric airglow from its interference fringes. Recently, various ground-based instruments have been built in China for observing the upper atmosphere, but technology for the temperature inversion and spaceborne detection is still in the initial stage. Based on the convolution of system MTF and function of emission spectra, this paper discussed the detecting principle of inversion calculation on upper atmospheric wind and temperature. It also expatiated the method of spaceborne FPI detection, and simulated the interference pattern of spaceborne FPI. Finally, the feasibility of developing China's spaceborne detector for space environment detection is discussed, on the basis of development and strategic needs of space exploration.
Companion Microsatellite in SZ-7 Flight Mission
Chen Hongyu, Zhu Zhencai, Zhou Yilin, Cao Caixia, Yu Yong, Li Dong
2009, 29(3): 319-325.   doi: 10.11728/cjss2009.03.319
Abstract(3310) [PDF 943KB](30)
Abstract:
The BX-1 micro-satellite, successfully released from the Shenzhou-7 (SZ-7) module, accomplished the purposes of providing the images of the SZ-7 and demonstrating the ability to inspect the orbital module and conduct proximity operations around the SZ-7 module. The BX-1 was a demonstrator for many new space technologies, including GaInP2/GaAs/Ge solar cells, lithiumion battery, micro-ammonia thruster, micro-attitude tracking controller, camera with double-focusing systems and micro-USB-responsor. The criterion of forming the stable elliptic orbit around the SZ-7 module is discussed in this paper. The evaluation of the BX-1 micro-satellite mission is provided by flight datum.
Gyrosynchrotron Emission of Space Plasma Clouds
Sun Weiying, Wang Chuanbing, Wu Ji, Wang Shui
2009, 29(2): 175-182.   doi: 10.11728/cjss2009.02.175
Abstract(3482) [PDF 588KB](31)
Abstract:
The high density plasma clouds with strong magnetic field will appear as CMEs propagating in the interplanetary space. The plasma clouds radiate electromagnetic wave in radio wave band. In order to study the characteristics of CME propagation, the gyrosynchrotron emission mechanism, which is the main radio radiation mechanism of the plasma clouds, is studied. The physical parameter of the plasma clouds (e.g., electron density, electron temperature, magnetic field and energy distribution) inside the CMEs can be derived according to the emission intensity or brightness temperature of them. In this paper, the emission, absorption and polarization characteristics of gyrosynchrotron emission as the optical depth are studied. The gyrosynchrotron emission process of isotropy and anisotropy plasma clouds with thermal and nonthermal electrons are also studied and summarized. Moreover, the expression of gyrosynchrotron emission intensity and brightness temperature is also provided as the refractive index is not equal to 1.
CHAOTIC MOTION OF MAGNETIC RIGID SATELLITE IN ORBIT NEAR EQUATORIAL PLANE OF THE EARTH
CHENG Gong, LIU Yanzhu
2000, 20(1): 69-73.   doi: 10.11728/cjss2000.01.069
Abstract(1671) [PDF 371KB](43)
Abstract:
The chaotic planar motion of a magnetic rigid satellite in a circular orbit nearthe equatorial plane of the earth is investigated in the present paper. The existenceof chaotic motion of the satellite is predicted by using Melnikov's method and verified by numerical computation in conjunction with the Poincare map. It is shownthat the periodic disturbance of the magnetic field of the earth can cause chaoticmotion of the satellite and the increase of the disturbance can intensify the chaoticmotion.
Comparison Between GISM Predictions and Ionospheric Scintillation Measurements Over Hainan Region
HU Lianhuan, NING Baiqi, LI Guozhu
2007, 27(5): 384-390.   doi: 10.11728/cjss2007.05.384
Abstract(2425) [PDF 2143KB](52)
Abstract:
In this paper, the Global Ionospheric Scintillation Model (GISM) has been introduced.Comparison between the model predictions with observations over Hainan region has been made using one year's data. The results show a good overall agreement between GISM predictions and observations in seasonal variation, diurnal variation and spatial distribution. In seasonal variation, GISM predictions agree in general with observations at moderate scintillation level, but there is more deviation at weak or strong scintillation levels. In diurnal variation, GISM predictions accord with observations on the whole, except for a delay of about one hour in the occurrence maximum. In spatial distribution, both observations and predictions show that occurrence in the south of Hainan is higher than that in the north.
Determine the Surface Tension and Contact Angle of Drop by Image Processing Method
NING Qiao, ZHU Zhiqiang, LU Xutao, YU Qiang, YUAN Zhangfu
2008, 28(1): 74-79.   doi: 10.11728/cjss2008.01.074
Abstract(2999) [PDF 2218KB](89)
Abstract:
The liquid experiment in space needs intelligence to deal with the surveillance image right away to obtain the goal parameters. A method is investigated to analyze the physical feature of a drop, such as surface tension, contact angle and volume through fitting contour of the drop picture. From the grey picture, generally contour of a drop is obtained by edge detection and segmentation algorithms. Constructed the Laplace equation of the drop, made contour approach process through comparing and using Newton-Raphson method, Runge-Kutta method and coordinate optimizing method. With the help of contour approach, physical feature of the drop is obtained. A new algorithm which nests Newton-Raphson method with One-dimensional optimization is presented. Compared with the original algorithm raised by Ref.\,[1], the new one reached convergence quickly with high accuracy. It is a key technique of the space experimental system for liquid experiment. The method is especially applicable for unmanned environment as well as non-contact measurement in the experiments.
Characteristics of Tropopause OveryWuhan and Haikou
Li Wei, Fan Chao, Yi Fan
2009, 29(4): 409-416.   doi: 10.11728/cjss2009.04.409
Abstract(3283) [PDF 734KB](47)
Abstract:
The temporal variation characteristics of local tropopause are derived from the routine Radiosonde data obtained at Wuhan (30.5$^{\circ}$N, 114$^{\circ}$E) and Haikou (20$^{\circ}$N, 114$^{\circ}$E) from 2000 to 2004. The annual variations of temperature, altitude and potential temperature of tropopause are compared with those over a tropical site, Truk. A similar annual trend between Haikou and Truk was found that maximum and minimum values were reached in summer and winter, separately, while an inverse annual variation over Wuhan was shown. By discussing the temperature disturbance, lapse rate at certain pressure levels and tropospheric thickness, it's concluded that tropopause was more determined by the stratospheric behavior. And this can be further confirmed by an intensive radiosonde observation over Wuhan from Jan 11 to 15 in 2006, conducted with a 3 hours interval. By that radiosonde observation, the diurnal variation of tropopause over Wuhan was studied and an obviously regular variation similar to that of Gandanki was found, although little difference exists between them
Thermal Design and Validation of DAMPE BGO Calorimeter
HU Yiming, CHANG Jin, CHEN Dengyi, LIU Shubin, FENG Changqing, ZHANG Yunlong
2017, 37(1): 114-121.   doi: 10.11728/cjss2017.01.114
Abstract(1428) [PDF 6197KB](55)
Abstract:
Dark Matter Particle Explorer (DAMPE) is one of the first scientific exploration satellites of China, aiming to search dark matter by measuring the spectrum of electron/positron and gamma ray. DAMPE mainly consists of four sub-detectors including Plastic Scintillator Detector (PSD), Silicon Tungsten Tracker (STK), BGO Calorimeter (BGO) and Neutron Detector (NUD). As the most important sub-detector of DAMPE, BGO calorimeter plays a key role in precisely measuring energy of the incident cosmic ray and identifying particles. In this paper, thermal design of the calorimeter is introduced. Based on this design, the Finite Element Analysis (FEA) on temperature field of the BGO calorimeter is performed with the given on-orbit conditions. In the end, Thermal Vacuum (TV) test has been carried out in March, 2015 to prove the FEA is correct and the methodology in this paper is effective.
Optimized Spherical Harmonic Function Model for Ionospheric Delay Correction
KANG Juan, WANG Ling, HUANG Wende
2015, 35(2): 159-165.   doi: 10.11728/cjss2015.02.159
Abstract(1110) [PDF 967KB](64)
Abstract:
Aiming at the ionospheric delay correction of single-frequency receiver, this paper proposes an optimized low-order spherical harmonic function model. Firstly, the description method of optimized ionospheric delay correction model is discussed and the objective and restraint condition of optimizing coefficients are defined. Then, according the characteristics that coefficients can be encoded, method and steps of using genetic algorithms to optimize coefficients are presented. Lastly, the accuracy analysis and comparison are made with Klobuchar based on the the ionosphere VTEC produced by CODE. The results show that accuracy of the optimized model is improved. It has an improvement about 1~2 TECU than the low-order spherical harmonic function model with the same number of coefficients and can better reflect the daily change of VTEC and the characteristics which vary with latitude.
Atmospheric Drag Coefficient Modification for Orbit Prediction Precision Improvement of LEO Space Objects
CANG Zhongya, XUE Bingsen, CHENG Guosheng, ZHU Xiaolu
2016, 36(2): 188-195.   doi: 10.11728/cjss2016.02.188
Abstract(1599) [PDF 1736KB](59)
Abstract:
Atmospheric drag is the primary disturbing force to LEO space objects since the atmospheric density is still considerable. This paper proposes a new method based on space environment indices and neural network model to modify drag coefficient. According to TLE (Two Line Element) sets, by simulating the orbit prediction and comparing prediction semi-major axis to real-time value, the optimal values of drag coefficients (B0sup*) are selected. It is found that optimal values are one or two days ahead the values in TLE, and they are all corresponded with F10.7 and Ap indices. Based on historic data, the neural network is built for drag coefficient correction to improve the orbit prediction precision. Result shows that the neural network model could timely response to space environment disturbance. This method is applied in Tiangong-1 (TG-1) and International Space Station (ISS) orbit prediction to verify its validity and universality, and it shows that the orbit prediction accuracy is improved by 50%~60% during geomagnetic disturbance while the errors are biggest. Generally, this method could improve the orbit prediction precision by 30%, the and success rate of improvement is about 80%.
Research on Simulation of Deep Charging for Spacecraft Dielectrics
WANG Ji, QIU Jiawen, QIN Xiaogang, MA Yali
2008, 28(3): 242-247.   doi: 10.11728/cjss2008.03.242
Abstract(2369) [PDF 2143KB](47)
Abstract:
Based on Monte Carlo simulation and Radiation-Induced Conductivity (RIC) model of charging dynamics, a new predicting method aiming at spacecraft dielectrics deep charging is brought forward to calculate charging density and internal electric field and is also validated by ground tests. The charging model of dielectrics is simplified as a compound structure consisting of shielding aluminum and multiple-layer plates in Geant 4. The injected current density and dose rate profiles of Teflon along depth are statistically accumulated and normalized with practical flux density. Then substituting these results into RIC model, the distributions of charging density and electric field in Teflon under the condition of backside grounded are numerically calculated. Finally, the profiles of space charging density in Teflon under various injecting electron fluxes are measured by Pulse Electro-Acoustic method (PEA). Numerical and ground tests show that charging density and electric field increase while the injected electron flux is enhanced for Teflon radiated by 100 keV electron. The peak of charging density is about 0.042 mm and the maximum electric field is closed to the grounded side. With universal characteristics of Geant 4 particles transfer simulation and RIC model, the predicting method is suitable for various spacecraft dielectrics.
Impact of Spectral Solar Irradiance Variations on the Energy Balance of the Earth
Gao Fengling, Hua Zezhao, Tao Leren, Cui Guomin, Xu Jialiang
2014, 34(4): 434-440.   doi: 10.11728/cjss2014.04.434
Abstract(1977) [PDF 780KB](167)
Abstract:
The total solar irradiance is usually adopted when studying the solar impact on the energy balance of the Earth at present. However, based on the Solar Radiation and Climate Experiment irradiance record, the impact of solar spectral variations on the global energy balance between December 2007 and the First Half 2010, which were in the descending and ascending solar phase respectively, is studied. The results show that the relatively larger total solar output in the First Half 2010 was mainly caused by the radiation enhancements in ultraviolet and infrared regions, with increments of 0.11% in 200~400nm and 0.05% in 760~4000nm respectively, while the radiation in visible region of 400~760nm decreased by 0.05%. According to the reanalysis of the daily ozone data from MLS Version 2.2, the concentration of stratospheric ozone also increased in the First Half 2010 at the same time. Especially, in February and March whose ultraviolet enhancements are relatively higher than those in other months, the ozone increments are also higher, with maximum of 0.6mL·m-3 and 0.62mL·m-3 respectively at altitudes of 33km and 40km. As a result, the radiation reduction in visible region and concentration increase in stratospheric ozone together contributed to the smaller solar radiation at the tropopause in the First Half 2010 as compared with that in December 2007, with the maximum reduction of 0.15W·m-2 in March 2010. The results mean that the increase in solar activity or total output may also cool the Earth-Troposphere system.
Remote Sensing Satellite RAW Data Format Analysis and Standardization Research
ZHANG Zhiqi, ZHANG Hongqun, LIU Dingsheng
2007, 27(1): 83-88.   doi: 10.11728/cjss2007.01.083
Abstract(3042) [PDF 1052KB](97)
Abstract:
The remote sensing satellite RAW data format is not only one of the focus problems during the operation and development in the remote sensing satellite ground station, but also a problem the remote sensing users concern about. At present, the definition of RAW data format is in great confusion both at home and abroad, and no corresponding technical definition has been available so far. It has brought serious limitation to the usage of expensive satellite data and also brought difficulty on deciding how to save the data for long time storage, it has had great influence on the further development in the remote sensing satellite ground station. By analyzing the characteristics of some main existing remote sensing satellite RAW format combined with the operation experience over 20 years in China, a general RAW data format is proposed in this paper. RAW format has been adopted to our prototype system and well operated. Surely it is quite difficult to found a kind of RAW format standard with excellent compatibility and maneuverability.
Inversion of Lunar Regolith Layer Thickness Using Microwave Radiance Simulation of Three Layer Model and Clementine UV-VIS Data
FA Wenzhe, JIN Yaqiu
2007, 27(1): 55-65.   doi: 10.11728/cjss2007.01.055
Abstract(2684) [PDF 3737KB](72)
Abstract:
A correspondence of the lunar regolith layer thickness to the lunar Digital Elevation Mapping (DEM) is proposed to construct the global distribution of lunar regolith layer thickness. Using Clementine UV-VIS multispectral data, the global spatial distribution of FeO+TiO2 content on the lunar regolith layer is calculated. Thus, dielectric permittivity of global lunar regolith layer can be obtained. Based on some measurements of physical temperature of the lunar surface, an empirical formula of physical temperature distribution over the lunar surface is presented. Based on aforementioned works, brightness temperature of lunar regolith layer in passive microwave remote sensing, which is planned for Chinese Chang-E lunar project, is numerically simulated by a three layer model using fluctuation dissipation theorem. Taking these simulations with random noise as observations, an inversion approach of the lunar regolith layer thickness is developed. Physical temperature of the top layer and the lower regolith can be inverted by the brightness temperature at high frequency channels using a two-layer model. The regolith layer thickness can be finally inverted by the brightness temperature at low frequency channel. Inversion error is also discussed. Numerical simulation and inversion approach in this paper make an evaluation of the performance for lunar passive microwave remote sensing, and can be applied to future data calibration and validation.
Analysis and Study of Ranging Code Performance Based on Deep Space Pseudo-Noise (PN) Ranging System
GAO Yang, YAN Yi, CUI Yongshun, YAO Xiujuan
2012, 32(1): 123-129.   doi: 10.11728/cjss2012.01.123
Abstract(2118) [PDF 552KB](28)
Abstract:
The selection of ranging codes influences many parameters of the deep space ranging system, such as the ambiguity distance, ranging resolution, acquisition time and hardware implementation, etc. In this paper, several ranging codes commonly used in the deep space ranging system are simulated, analyzed, compared and studied, especially for their spectrum, cycle, DC, ranging clock attenuation, acquisition time and ranging jitter error. The signal space figure method with in-phase/out-phase correlative coefficient is used to analyze the acquisition time. And in-phase/midphase integration loop, as a chip tracking loop, is applied to analyze the ranging jitter error. Also, the influences of acquisition time and ranging jitter error due to sinusoidal pulse shaping and squarewave pulse shaping are analyzed. Through the research and analysis, some results are proposed as that T4B is chosen as ranging code in deep space ranging system, DDS method is selected to create arbitrary chip phase shift, sinusoidal pulse shaping modulation and sinusoidal pulse shaping matched filter scheme are adopted, and in-phase/mid-phase integration loop is applied to track the ranging code.
Algorithm for CCD Star Image Rapid Locating
WANG Zhaokui, ZHANG Yulin
2006, 26(3): 209-214.   doi: 10.11728/cjss2006.03.209
Abstract(2541) [PDF 1336KB](49)
Abstract:
Rapid processing of large scale CCD star image is a key technique for new type of star sensor as well as space surveillance sensor. The foreground of CCD star image is differ form the background distinctly. Majority pixels of the image belong of the background. The typical histogram of CCD star image has a two-peak values structure. Base on those analyses, a strategy for star image's pretreatment was presented. The background and noise of the image is removed by a window transform of the pixel gray, all pixel whose gray value below the threshold will be set as a black pixel, the gray of which will be set as zero videlicet. The threshold is determined through the numeric statement of the background pixels by an iterative algorithm. Then a new algorithm for star point locating was presented by a two-step projection checking method. The horizon domains of the star points can be determined through the vertical projection checking of the image at first, then the horizon domain of each star point can be determined through the horizon projection in the horizon domains of the star points. The precise position of the star points is calculated using centroid method at last. The new algorithm is simpler and has smaller consumption of computing and memory than tradition connected domain methods. Experiments on real star images with size of 2048 × 2048 indicated the validity of the algorithm.
Using Tracking And Data Relay Satellite For Low And Middle Earth Orbit Satellite Launch And On-Orbit Control
Li Yuheng, Sun Haizhong, Zheng Jun
2015, 35(5): 611-617.   doi: 10.11728/cjss2015.05.611
Abstract(1431) [PDF 707KB](33)
Abstract:
With successful minimization of the user terminals of Tracking and Data Relay Satellite (TDRS) and the development in higher gain and wider half-power beam of antennas, especially the upcoming multiple-access ability of TDRS, it is highly possible to control low and middle earth orbit satellites and rocket launch merely by TDRS. This paper analyzes the advantages of TDRS controlling spacecrafts, supporting rocket lunch and strengthening response ability to the emergency control call for on-orbit satellite management. The results show that only a few TDRS with multiple-access antenna could control all China low on-orbit satellites. Although a TDRSS' user terminal is generally required to install an omni-antenna to response any emergency control call, this paper proposes a method that even a satellite equipped with a TDRS user terminal of a directional antenna can response to emergency control. It will further improve the low orbit satellite control's efficiency.
Time-Dependent Simulation of Electrical Field Configuration and Optical Emission of Sprite Halo
WU Mingliang, XU Jiyao
2005, 25(6): 510-515.   doi: 10.11728/cjss2005.06.510
Abstract(1941) [PDF 2024KB](57)
Abstract:
Using the two-dimensional, time-dependent quasi-electrostatic field (QEF) code, the configuration, time delay, duration and descending motion speed of quasi-static electric field caused by thunderstorm discharge was investigated, and the effects of atmospheric ionization and optical emission in mesosphere and low ionosphere caused by this QEF was also studied. Research show: the sprite halo initiates at 85 km and with a pancake-like shape, then the regions of breakdown and optical emission move downward at speed of 1.5 × 10^7m·s^-1, the regions of breakdown and optical emission gradually become an upward concave shape. Sprite halo lasts about 5.5 ms with a height range of 64-87km, and with a horizontal scale of 80 km. Moreover, simulation results indicate that appearance time of the maximum of optical emission occurs at the time of t = 2.1 ms, which is delayed to thunderstorm discharge. And the QEF does not monotonously decrease with the altitude increasing, it has complicated structure at symmetrical axes. In addition to, the QEF cause atmosphere breakdown ionization and lead to electron density increases (ionization coefficient 〉 attachment coefficeint) or decreases (attachment coefficient 〉 ionization coefficient). At altitude of 70 km, the increased electron density of Ne = 2.178 × l0^8 m^-3 is much bigger than the fair weather electron density of Ne = 6.329 × 10^5 m^-3.
Contact force simulation and test analysis of docking mechanism
Xiao Yuzhi, Shi Junwei, Guo Jiahua
2009, 29(1): 23-28.   doi: 10.11728/cjss2009.01.023
Abstract(3509) [PDF 695KB](23)
Abstract:
During the course of docking dynamic test, the contact force is beyond the index. Math model is built to simulate the test process, and the suggestion is given to solve the problem. According to the math simulation results, modified components were assembled to the docking systems. Finally, the results of the math simulation indicate that the force data contains the structure frequency information, and the later modal test for the spacecraft simulators validates the math model, and the suggestion is given that the docking dynamic test data should be filter.
A Possible Mechanism of Typhoon Effects on the Ionospheric F2 Layer
LIU Yimou, WANG Jingsong, XIAO Zuo, SUO Yucheng
2006, 26(2): 92-97.   doi: 10.11728/cjss2006.02.092
Abstract(2233) [PDF 2174KB](91)
Abstract:
During the period of typhoon, especially when typhoon is approaching the mainland, violent interaction between the wind and the sea surface, the wind and the mainland will greatly strengthen the turbulence in the lower atmosphere, and it will possibly raise the turbopause in altitude. Thus it will change the structure of the earth's atmosphere and influence the photochemical process of the upper atmosphere, and consequently influence the ionosphere. Based on the assumption that typhoon will raise the turbopause in altitude, the response of F2 layer of the ionosphere over the middle latitude of Japan (45°N, 142°E) was simulated, by using the one dimensional ionospheric model. The results of the simulation can qualitatively explain the following phenomena very well: f0F2 of the ionosphere will decrease while the reflecting surface in the ionosphere of the radio wave with a certain frequency will increase during the time of typhoon, hmF2 increases due to the raise of turbopause in this simulation. These results suggest that the rising in altitude of turbopause by typhoon is a very reasonable mechanism of typhoon effects on the ionospheric F2 layer.
EFFECTS OF NEUTRAL WINDS AND VERTICAL DRIFTS ON LOW-LATITUDE IONOSPHERE
LIU Libo, WAN Weixing, TU Jiannan, BAO Zongti
2000, 20(1): 23-31.   doi: 10.11728/cjss2000.01.023
Abstract(2093) [PDF 730KB](62)
Abstract:
Effects of variations of magnitude of E×B vertical drifts and neutral windson low-latitude ionosphere are investigated by using a two-dimensional low-latitudeionospheric time-dependent theoretical model. In the model ion transport equationsare solved by using splitting technique at fixed grid points along magnetic field lines,and densities and velocities of ions are outputted on the given geomagnetic meridian.Modelling results show that the influences of adjusted magnitude of E×B verticaldrifts and neutral winds on low-latitude f0F2 are dependent on magnetic latitudeand local time. And some features not reported previously are also mentioned inthe paper.
An Anisotropic Scattering Model Of Ionospheric Field-Aligned Irregularities
Zhang Yabin, Wu Jian, Guo Lixin, Xu Bin, Xue Kun, Zhao Haisheng, Xu Zhengwen
2015, 35(5): 549-555.   doi: 10.11728/cjss2015.05.549
Abstract(1121) [PDF 1277KB](63)
Abstract:
As influenced by geomagnetic field, electron density fluctuations of ionospheric irregularities are highly elongated in the direction of geomagnetic field, and the scattering of the irregularities are also highly directional, which could be potentially used as long-distance communication circuits in VHF band. Based on the characteristic of ionospheric Field-Aligned Irregularities Scattering (FAIS), an anisotropic scattering model of ionospheric field-aligned irregularities is proposed in the geomagnetic reference frame. The parameters such as path loss, delay spread and coherence bandwidth of forward and back scattering are calculated by the model. The results of Radar Cross Section (RCS) predicted by the model have a good agreement with data in literatures. The model given herein can be helpful to construct ionospheric irregularities scattering communication systems in VHF band.
National Report on Space Medicine Progress in 2014—2016
LI Yinghui, ZHANG Xiaoyou, WAN Yumin, DING Bai, LIU Zhaoxia, LING Shukuan, BAI Yanqiang, CHEN Shanguang
2016, 36(5): 781-787.   doi: 10.11728/cjss2016.05.781
Abstract(956) [PDF 119KB](60)
Abstract:
The progress of China Spaceflight makes a great impetus for the development of space medicine. With the developing of China Space Station, the national space medicine has attained great achievements. In this paper, the basic research of Space Medicine and its application in China during 2014-2016 are briefly reviewed.
STUDY ON SEU OCCURRED ON BOARD OF SEVERAL SPACE SHUTTLES
GU Shifeng, ZANG Zhenqun, SHI Liqin, WU Zhonghua
1998, 18(3): 253-260.   doi: 10.11728/cjss1998.03.253
Abstract(2137) [PDF 466KB](51)
Abstract:
In this paper, Single Events Upset(SEU) encountered by five low altitude orbit space shuttles with different inclinations and different altitudes launched in 1991 are investigated.The result shows that a number of SEUs can occur even in auroral area or south Atlantic abnormal area,threatening the security of space shuttles. Some Pertinent results and conclusions are obtained.
Research on Characteristics of X-class Solar Proton Flare
ZHANG Ye, SHI Liqin, CUI Yanmei, LIU Siqing
2017, 37(3): 249-261.   doi: 10.11728/cjss2017.03.249
Abstract(1125) [PDF 1833KB](63)
Abstract:
Solar Proton Events (SPE) often accompany with solar flares, and the probability that solar proton events triggered by X-class flares is larger than that triggered by other types of flares. In order to improve the forecast accuracy of solar proton events triggered by X-class flares, the relation between proton/non-proton flares and space environmental parameters, including X-ray integrated flux, source region, CME speed, CME angle width, ambient solar wind speed, and ambient X-ray flux, are analyzed statistically. The results show that the distributions of X-ray integrated flux, heliolongitude, CME speed, and CME angle width are different for non-proton and proton flares. Non-proton flares are mostly located at eastern part, where X-ray integrated flux is less than 0.3J·m-2 and CME speed is less than 1300km·s-1. While proton flares are mostly located at central and western part, where X-ray integrated flux is greater than 0.3J·m-2 and CME speed is greater than 1300km·s-1. Furthermore, halo CMEs are often associated with proton flares, while angle width distribution of CMEs that accompanied with non-proton flares is relatively disperse. For proton and non-proton flares, the distribution of their ambient solar wind speed and ambient X-ray flux are similar. According to the different characteristics of the SPEs for proton and non-proton flares, the accuracy of SPE forecast can be improved.
ALGORITHM STUDY ON AUTONOMOUS ORBIT DETERMINATION FOR LOW EARTH ORBIT MICROSATELLITES USING GPS
SONG Fuxiang, ZUO Wenji
2000, 20(1): 40-47.   doi: 10.11728/cjss2000.01.040
Abstract(1951) [PDF 585KB](56)
Abstract:
To realize GPS orbit determination for low earth arbit satellites, a navigationalgorithm called sequential UD covariance factorization algorithm is proposed inthis paper. Formulas of UD algorithm are given completely, and state equationsand measurement equations are derived in detail in the paper. Mathematical modelof the navigation system is built, which is composed of nine state vectors and eightobservation vectors. Finally, numerical simulation experiments are conducted. Simulation results indicate that UD algorithm can not only provide high positioningprecision but also be fit for computers onboard low earth orbit satellites.
Research and development status and its key technology analysis on multi-locking and releasing mechanism
Hu Ming, Hua Daolan, Liu Rongqiang, Deng Zongquan
2009, 29(1): 98-101.   doi: 10.11728/cjss2009.01.098
Abstract(2699) [PDF 521KB](49)
Abstract:
The research and developing status on locking and releasing mechanism at home and abroad are reviewed in this paper. And then some kinds of locking and releasing mechanism and its locking forms are analyzed, including their node types and locking forms. The key technology on multi-locking and releasing mechanism is studied especially, including influencing factors of design, driving and transmission forms and performing mechanism characteristics, which provide the basis for future project design and analysis.
Comparisons of Two Kinds of GPS Broadcast Ephemeris Parameter Algorithms
CUI Xianqiang, JIAO Wenhai, JIA Xiaolin, HE Tao Xian
2006, 26(5): 382-387.   doi: 10.11728/cjss2006.05.382
Abstract(2599) [PDF 1556KB](103)
Abstract:
The precision, efficiency and reliability of GPS broadcast ephemeris parameter algorithms are remarkably important in the real-time kinematic GPS navigation and positioning. Two kinds of GPS broadcast ephemeris parameters and their user algorithms are introduced in the last GPS interface specification. In this paper, the two algorithms are compared to provide some reference for the broadcast ephemeris parameter research or design. Firstly the new GPS broadcast ephemeris parameters and their user algorithms are briefly introduced, and the differences between the new and old algorithms are analyzed and it is found that the distinctness of the two user algorithms is consistent with those of the broadcast ephemeris parameters. Then the partial derivatives of the satellite position vector to the new GPS broadcast ephemeris parameters are presented based on the calculated expression of the satellite position, which is compared with those of the old GPS broadcast ephemeris parameters. Finally a set of simulation data is used to test and compare the new and old GPS broadcast ephemeris parameter algorithms. Calculation results show that the orbit characters of the MEO satellite can be accurately described by the two kinds of GPS broadcast ephemeris parameters, and the precision losses of the two fitting algorithms are almost several centimeters.
Study of Passive Receiving Observation Mode for Ionospheric Digital Ionosonde
Zhu Zhengping, Ning Baiqi, Sun Fenglou, Chen Kun
2009, 29(4): 389-396.   doi: 10.11728/cjss2009.04.389
Abstract(2411) [PDF 740KB](79)
Abstract:
In order to study ionospheric passive sounding method and technology, this paper realizes a new ionospheric passive sounding mode on the CADI platform. That is to say, this paper improves scan frequency receiving function of CADI's receiver, receives various space signals by using the receiver, extracts ionospheric characteristic parameters f0F2 and high frequency channel property parameters. The proposal and realization of the new passive sounding mode based on the ionospheric digital ionosonde for the first time not only alleviates the congestion problem of the ionospheric high frequency band, but also provides an economical and effective method for the ionosphere and high frequency channel monitoring. The paper will have an extended application perspective in the space environment monitoring and forecasting.
Progress in space debris research
Zhao Changyin, Zhang Wenxiang, Han Zengyao, Wang Hongbo
2010, 30(5): 516-518.   doi: 10.11728/cjss2010.05.516
Abstract(2192) [PDF 95KB](18)
Abstract:
During recent years, A de-orbit disposal of SinoSat 2 satellite and the depletion of the residual propellant after SC/LV separation for all LM-4 series launch vehicles were carried out. Stuffed Whipple Shields based on hypervelocity impact particles were developed. Routine observation and collision avoidance were performed. The main progress in space debris research will be introduced from three aspects: mitigation, spacecraft protection, observation and collision avoidance.
Research on Random Vibration for Satellite TDICCD Camera and Data Processing
CHEN Dingyue, ZHOU Renkui, LI Yingcai
2005, 25(3): 229-234.  
Abstract(2022) [PDF 1795KB](65)
Abstract:
Random vibration test of the satellite TDICCD camera is performed in this paper. Several engineering problems during TDICCD camera random vibration test were discussed and solving methods were pointed out. The relationship between the vibration environment and structural dynamic properties is analysed, as well as the vibration environment could pose the effect and hazard to TDICCD structure. In addition the testing's practical technique and the selective gist of the control methods are studied and introduced separately. Based on site-collected results of the satellite TDICCD camera vibrating signal, the paper analyzes the time-region division of vibrating signal and the selection principle of its parameters. The date analysis is carried out with signal processor and the camera's each state of parameters were obtained. Parameters of the block's dynamic characteristic can provide us a reliable reference to satellite TDICCD camera's antivibration and vibration isolation. These also are used as modification and scientific basis for finite element calculation of camera's modality.
MHD simulations on the interaction of the solar wind with the magnetosphere
Wang Chi
2011, 31(4): 413-428.   doi: 10.11728/cjss2011.04.413
Abstract(3538) [PDF 1246KB](78)
Abstract:
The magnetosphere is outermost layer of the geospace. Interaction of the solar wind with the magnetosphere is one of the key links among the space weather chain process from the Sun to Earth, thus becomes one of the key issues in space weather study. The characteristics of the geospace, including time-dependent, multiple components, and non-linearity, make the traditional analytic study very difficult. Numerical simulations as new means to investigate the coupling system, has played an important role in recent decades. The global MHD simulation about the magnetosphere started in 1970s, and limited to 2D initially. Since the intrinsic 3D characters of the magnetosphere, 3D MHD simulations thrived in 1980s. This paper briefly illustrates the characteristics of the 3D global magnetosphere MHD simulations, and their current status. The framework of the 3D global MHD magnetosphere simulation, and its application to the interaction of interplanetary shocks with the magnetosphere, large-scale current systems, reconnection voltage and cross polar potential drop, K-H instability in the magnetopause etc. are presented.
Analysis of geomagnetic navigation accuracy under magnetic storms
Guo Caifa, Zhang Lijun, Cai Hong
2011, 31(3): 372-377.   doi: 10.11728/cjss2011.03.372
Abstract(3619) [PDF 579KB](126)
Abstract:
Geomagnetic navigation is a new branch of the passive autonomous navigation technique. The theory of geomagnetic navigation was analyzed. The process of typical magnetic storm is described. The feasibility of geomagnetic navigation during magnetic storms is analyzed in this paper. With employment of experimental data, the measurement equations are obtained by using surface Spline method. Extended Kalman Filter (EKF) is applied to navigation calculation, and the navigation accuracy is discussed during different phases of magnetic storm. The simulations are calculated with theoretical model data and real magnetic storm data. Results show that the feasibility of magnetic navigation is verified during the initial and later recovery phases of all the storms. And the conclusion is also valid in all the phases of a storm which is less than or equal to moderate intensity. Positioning error is lower than 200 m, which meets the guidance requirement in the mid-course of flight vehicle.
Compression Effects of Interplanetary Shock to the Magnetosphere
Yao Li, Liu Zhenxing, Zuo Pingbing, Zhang Lingqian, Duan Suping
2010, 30(2): 113-120.   doi: 10.11728/cjss2010.02.113
Abstract(2632) [PDF 648KB](72)
Abstract:
On November 9, 2004, the WIND spacecraft detected a typical interplanetary shock. Before the shock, there is a sustaining weak southward magnetic field lasting about 50 min. Across the shock front, the magnetic field turns northward, and the solar wind dynamic pressure is abruptly enhanced, i.e., the shock is a strong Dynamic Pressure Pulse (DPP). The magnetosphere is compressed to a rather small region upon the impact of the DPP. During the impingement of the shock, the magnetospheric compression causes two-mode disturbances of the energetic particle at the geosynchronous orbit, i.e., particle flux enhancement due to the compression near dawn and dusk and dispersionless particle injection similar to substorm. The disturbances propagate from the dayside to the nightside. The energetic particle fluxes on the dayside first increase, and then after about 1 min, the particle fluxes near dawn and dusk on the nightside begin to increase. Finally, dispersionless particle injection is seen near the midnight. Furthermore, near the noon the responses of electron are prior to those of proton. Contrarily, near the midnight the responses of proton are prior to those of electron. By using GOES-10 and GOES-12 observations on two sides of the noon, it is found that the magnetic field on the dawn-noon sector is simply compressed, while for the magnetic field on the noon-dusk sector, Bx and Bz component decreases, but By component notably increases. The TC-1 spacecraft located at near-Earth low-latitude lobe region observes the shock-induced lobe SI phenomena.
Thermodynamics of Flashing/Freezing Process of a Droplet in Vacuum
Zhao Kaixuan, Zhao Jianfu, Chen Shuling, Du Wangfang
2011, 31(1): 57-62.   doi: 10.11728/cjss2011.01.057
Abstract(2629) [PDF 536KB](59)
Abstract:
To reveal the mechanism of the flashing/freezing process of a liquid droplet in vacuum, a new model of heat and mass transfer in the flashing/freezing process was established using a quasi-equilibrium process of mass and heat transfer. Based on the numerical results of the variation of droplet's size and temperature, influences of four factors, namely ambient pressure, ambient temperature, initial radius and temperature of the droplet, on the variation of pre-cooling time in the flashing sub-process, freezing time in the fast freezing sub-process and the final temperature of the process were analyzed in detail. Compared with the experimental data, the present model can predict the basic features of the process with a good reliability. The ambient pressure is the dominating factor determining the major features and the final temperature of the process. The initial temperature affects the flashing rate, while initial radius influences the pre-cooling time. The influence of the ambient temperature is too slight that can be neglectable.
2017, 37(4): 369-369.  
Abstract(334) [PDF 359KB](15)
Abstract:
A Data Preprocessing Method and Preliminary Results of All-sky Airglow Image
DUAN Boqiang, PAN Weilin
2017, 37(1): 94-104.   doi: 10.11728/cjss2017.01.094
Abstract(1412) [PDF 4881KB](82)
Abstract:
Atmospheric Gravity Wave (AGW) is one of the fundamental waves in the atmosphere, which plays a significant role in the dynamics and thermal balance of the Mesosphere and Lower Thermosphere (MLT) region. By tracing the atmospheric airglow radiation, all-sky airglow imager can effectively image atmospheric gravity waves. In this paper, an image processing method for the data of OH airglow imager at Xining Station (36.6°N, 101.7°E) is presented. The imager was independently designed by State Key Laboratory of Space Weather of the CAS National Space Science Center. A typical gravity wave-event was observed using this imager on 17 May 2015. Finally, the OH airglow data obtained by observation experiments in Xining (on 17 May 2015 at 21:00BLT to 05:00BLT on the next day) is analyzed by this method. The horizontal wavelength, phase velocity and propagation direction of the gravity wave are successfully extracted, which proved the method is feasible and robust.
An Introduction to Displacement Damage Dose Model and Its Applications
ZHANG Qingxiang, HAN Jianwei, SHI Liqin, ZHANG Zhenlong, HUANG Zhi
2005, 25(2): 132-137.  
Abstract(2035) [PDF 2002KB](53)
Abstract:
Photonics are increasingly used in space missions to promote performance of space burn system. The radiation issues for photonics are significantly different from those of Si digital microelectronics. It has been found that displacement damage effect is one of the most important damages for photonics used in space radiation environment and a few spacecraft anomalies have been attributed to displacement damage. So displacement damage have been studied seriously in recent year. In this paper, firstly the mechanism for displacement damage is introduced and the ways displacement damage affecting the performances of photonics are discussed; then displacement damage dose model which based on non-ionization energy loss is presented to predict the degradation of CTE in CCD, dark current in Si device and output power in solar cell. Finally, a program based on DDD model for CTE decline prediction in space environment is introduced. The difference between our prediction result with that of ESA SPace ENVironment Information System (SPENVIS) is less than 10%. In addition to that, the program can be used to evaluate the effect o shield for sensitive device and to convert the proton spectrum for a particular mission to a equivalent fluence at a specific proton energy. The study results will find widely applications in satellite radiation-harden design.
THE DYNAMIC OPTIMUM DESIGN OF LARGE DEPLOYED ANTENNA FOR SATELLITE
LUO Ying, DUAN Baoyan, YANG Dongwu, DI Jiejian
2004, 24(3): 203-210.  
Abstract(2026) [PDF 1769KB](22)
Abstract:
The deployable antenna has been applied widely with development of space science and technology. Recently, the cable net structure becomes more and more popularized for it is not only with light weight and little furl volume, but also able to be made in large size. Considering the flexible cable net deployable antenna, the structural characteristics of the large deployed antenna for satellite have been discussed. And an optimum design model searching for minimum weight (volume), considering both the size variables and prestress variables is studied. The reflect precision, eigenfrequency, strength and cable’s allowable stress is taken into account in the optimal design. The improved GA method is used to solve it with reasonable results.
BISPECTRAL ANALYSIS OF THE MF RADAR WINDS
HU Xiong, Zhang Xunxie, Kiyoshi Igarashi
1999, 19(3): 226-231.   doi: 10.11728/cjss1999.03.226
Abstract(2383) [PDF 359KB](52)
Abstract:
Bispectral analysis and dynamic spectral analysis are applied to the wind data of June, 1997, measured by MFradar in Yamagawa, Japan, to investigate nonlinear interactions among planetary waves, tidal waves and gravity waves in the mesopause region. Results show that there were strong diurnal tide, semi-diurnal tide and quasi-two-day wave activities, and some groups of three waves whose frequencies satisfied resonant conditions coexisted and their phases were coherent, which may suggest non-linear wave-wave interactions. Discussions on these nonlinear interactions between different kinds of waves are presented.
Analysis and Calculation on Collision Breakup Characteristics of Orbital Spacecraft
Li Yiyong, Shen Huairong, Li Zhi
2009, 29(2): 229-233.   doi: 10.11728/cjss2009.02.229
Abstract(3968) [PDF 589KB](71)
Abstract:
The collision breakup problem of orbital spacecraft is studied in this paper. The collision breakup algorithm of orbital spacecraft is presented based on NASA standard breakup model. Constraint conditions required for the breakup calculation are analyzed emphatically. Finally, the general utility simulation calculation program is implemented, and is verified to be correct by comparing with measured data of P-78 satellite breakup event. The research can be an important reference to predict and analyze damage characteristics of orbital collision events.
Research on artificial airglow during ionospheric modification by the release of SF6 gas
Huang Yong, Cheng Li, Zhang Fang
2012, 32(3): 348-353.   doi: 10.11728/cjss2012.03.348
Abstract(2437) [PDF 470KB](54)
Abstract:
Release of a chemically reactive gas such as SF6 into the ionosphere region can disturb its plasma environment. In this paper, in terms of diffusion equation of SF6 gas and mainly ion-chemistry reactions in ionosphere region, the density changes of ionospheric particles response to the release of SF6 gas are investigated, and the airglow volume emission rates and intensity from the SF6 gas released at ionospheric altitudes are calculated. The results show that the diffusion of released SF6 gas in ionospheric is very quick, and these SF6 gas molecules can cause a large scale depletion of ionospheric electron and O+ density, and the dominate negative ion of ionospheric region is converted into SF5-. During the releasing, the 777.4nm and 135.6nm airglows will be excited, the intensity of 777.4nm is much weaker, and the ionospheric temperature may play an important role in the airglow intensity. Comparing the results of our calculations with American IMS/SF6 experimental data, it shows good agreement, and the temperature of experiment local ionosphere can be exactly estimated through this comparison.
Design of an ASIC Chip for Spacecraft Integrated Avionics
Zhou Li, An Junshe, Fang Qingwen, Cai Fei
2014, 34(4): 497-504.   doi: 10.11728/cjss2014.04.497
Abstract(1495) [PDF 886KB](85)
Abstract:
It is a trend to put the common spacecraft engineering requirements into one chip, which can miniaturize spacecraft avionics and reduce the repeated work for spacecraft engineers. Based on the analysis of space application requirements, the system design of an ASIC (Application Specific Integrated Circuit) chip for spacecraft telemetry and command system is proposed. Firstly, the chip system architecture is described. Secondly, four key techniques of the ASIC chip design are presented in detail, including design of the chip working modes, design of onchip IP cores, design of reliability, and the design of low power consumption technology. 1553B RT working mode of this ASIC is different and special from other space chips. The system test results based on FPGA show the validity and reliability of the ASIC system design. Finally, some promising applications of the ASIC chip are described.
Microwave Type U and RS Bursts in the X2.2 Solar Flare on 15 February 2011
XUE Yu, WANG Shujuan, YAN Yihua, HUANG Chong, YU Sijie, WANG Rui
2015, 35(2): 133-142.   doi: 10.11728/cjss2015.02.133
Abstract(925) [PDF 4861KB](15)
Abstract:
Two groups of microwave type U and Reverse-Slope (RS) bursts after the Soft X-Ray (SXR) maximum were observed with the 2.6~3.8GHz spectrometer of Chinese Solar Broadband Radio Spectrometers (SBRS/Huairou) on 15 February 2011, when an X2.2 solar flare occurred in the Active Region (AR) NOAA11158. A Shear-driven Quadrupolar Reconnection (SQR) model was utilized to analyze these bursts and the two loops involved were found to be basically in the same spatial scale and have a height difference of about 1300km. These bursts were interpreted to be a result of a new reconnection process between the two similar-scaled loops.
AN IMPROVED GRID-BASED CORRECTION ALGORITHMS FOR SPARSELY OBSERVATION STATION REGION IN WAAS
WANG Yiju, YUAN Hong, WAN Weixing
2003, 23(2): 97-101.  
Abstract(2065) [PDF 982KB](48)
Abstract:
The correction method of additional time delay caused by ionosphere and atmosphere plays a more and more important role in satellite timing and positioning system. In many radio projects which using electromagnetic wave as a measuring tool have to deal with the additional time delay, such as GPS, LADGPS, WADGPS and WAAS. In this paper, a new additional time delay algorithm model for a sparsely observation station region in WAAS is established and studied.Based on the improved grid-based correction algorithm for ionospheric delay in WAAS[4] and the model given in this paper, after numerical simulating with GPS data, the result was obtained showing that the precision of new algorithm is better than original one in the case of sparsely observation station region.
Calibration Method of Electric Field
LUO Fushan, HE Yuhui, ZHANG Huawei, ZHANG Jian, ZHUANG Hongchun, HU Shengbo
2007, 27(3): 223-226.   doi: 10.11728/cjss2007.03.223
Abstract(2238) [PDF 1634KB](64)
Abstract:
The calibration method for the balloon-borne double-sphere electric field instrument, the micro-rocket-borne electric field instrument and the ground mill fieldmeter is introduced. The atmospheric electric field, relating with space physics and space environment, is a key parameter for studying various phenomena in earth science, such as lightning and earthquake, so the atmospheric electric field is becoming more and more important. With the lack of the national standards and military standards for the measurement and calibration of electric field, a set of calibration system is designed and developed to calibrate electric field instruments of different structures. The results are consistent with the theoretical calculation, and provides the foundation for the reliability of the electric field measurement data.
Fault Diagnosis of Satellite Based on IMM and Moving Horizon Estimation
ZHAO Shilei, WU Lina
2011, 31(5): 647-652.   doi: 10.11728/cjss2011.05.647
Abstract(2517) [PDF 482KB](80)
Abstract:
This paper studies the fault diagnosis problems of the satellite attitude control system. Since the satellite works in space, the attitude control system of satellite is easy to be effected by uncertainties and disturbances in the harsh working environment. Interacting Multiple Model (IMM) is one of the effective fault diagnosis methods of the satellite control system but it is subjected to strong noise or wrong data. For this reason, this paper proposes to combine the moving horizon estimation instead of the Kalman filter with the IMM algorithm. The moving horizon estimation, which adopts not the estimation error of one time but the interval estimation error of a time span, is used to estimate the system states and the transition probabilities. So it could effectively decrease the influences of the wrong data or strong noise. Finally, the mathematical simulation results for diagnosis problem of the satellite attitude control system are presented to show the effectiveness of the proposed scheme.
2013, 33(1): 128-128.  
Abstract(708) [PDF 312KB](9)
Abstract:
Research on autonomous navigation algorithm of deep space based on Line-of Sight vector
Zhu Shengying, Chang Xiaohua, Cui Hutao, Cui Pingyuan
2011, 31(4): 534-540.   doi: 10.11728/cjss2011.04.534
Abstract(2867) [PDF 583KB](48)
Abstract:
In this paper, an autonomous navigation algorithm is based on Line-of-Sight (LOS) vector in order to solve the orbit determination problem of deep space probe during the interplanetary phase. Considering the characters of the deep space mission, the Sun LOS vector and Earth LOS vector are served as the measurement of the navigation system. Following the measurement principle of the Sun senor, the corresponding measurement model and error expression of Sun LOS vector are derived. The measurement model of the pixel and line in the camera coordinates is given through the analysis of the navigation camera, and the measurement error of Earth LOS vector is deduced. The position vector and its error expression are derived in detail based on the geometric relation of the LOS vectors in the inertial space. Finally, the autonomous navigation algorithm is established utilizing extended Kalman filter, and is demonstrated by the practical data of Deep Impact mission.
Determination of the Kelvin-Helmholtz Wave Parameters on the Magnetopause in Single-spacecraft Observations
LIN Dong, WANG Chi, LI Wenya, TANG Binbin
2015, 35(4): 403-408.   doi: 10.11728/cjss2014.04.403
Abstract(901) [PDF 1436KB](28)
Abstract:
Kelvin-Helmholtz (K-H) waves are formed from the triggeringof the K-H instability on the magnetopause, which is a candidatemechanism for solar wind entry into the magnetosphere, especially undernorthward interplanetary magnetic field conditions. In this study, aK-H wave event was identified from the observation of probe Bof the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission on 15 May 2008. A new method to determinethe wave parameters of the K-H waves in single-spacecraft observationsis proposed. The dominant wave period is determined by three kinds ofspectrograms for three key parameters, namely the ion density, the iontemperature, and the z component of magnetic field. The phasevelocity is estimated by calculating the center-of-mass velocity of thedetected K-H vortex region. This approximation is validated bycomparison with other alternative methods. The method to determine thewave parameters is a first step to further study K-H wave properties and their relationship with interplanetaryconditions.
Calibration Results of Solar X-ray Detector Aboard on FY-2C
KONG Linggao, WANG Shijing, LIN Huaan, WEI Fei
2006, 26(5): 370-376.   doi: 10.11728/cjss2006.05.370
Abstract(2413) [PDF 3345KB](57)
Abstract:
The calibrating results of solar X-ray detector aboard on FY-2C are presented in this paper. The transducer of solar X-ray detector is proportional counter. The gas in the transducer is Ar. The solar X-ray detector can monitor the sun's X-ray flux above 4 keV in ten channels. The methods and results of experiments for calibrating are presented in detail. The radiation source used in these experiments are 241Am and 55Fe. The calibrating results are listed in six aspects: characteristics of plateau, efficiency, proportional characteristics, determining of energetic channels, energy resolution and time resolution. The plateau length is about 300 V. The plateau slope is less than 5%/100 V. The working voltage range of the detector is 1600-1900 V. The efficiency curve is calculated theoretically, and the material of the detector is taken into account. The experiments results show that the detector has good proportional characteristic. The time resolution of solar X-ray detector is 8.2 s. The solar X-ray detector aboard on GOES adopted ionization chamber, that is different from FY-2C. The detected results of solar X-ray detector aboard on FY-2C are compared with those of GOES. They fit well. The results show that the solar X-ray detector aboard on FY-2C works well to monitor the X-ray flux of the Sun and contribute much to the space environment monitoring.
THE ANALYTICAL TRAJECTORY OF THE CHARGED PARTICLE MOVING IN A NEUTRAL MAGNETIC FIELD
Xu Hong-lan
1981, 1(1): 2-14.   doi: 10.11728/cjss1981.01.002
Abstract(1758) [PDF 981KB](52)
Abstract:
Neutral magnetic field was found wide important applications in space physics and satrophysics[1-4].In a rectangular coordinate system x y and z, the neutral magnetic field is, given by Eq.(2-1), where h is a small northward magnetic field[5], a and e are the parameters of the field.When ε=0 the field is a neutral sheet.An analytical trajectory of the charged particle moving in this field has been calculated The results are:(1)By means of a perturbation method[5], we found that the motion of the charged particle in a neutral sheet field can be defined by the first approximation of motions either in a neutral magnetic field or in a neutral sheet field with a small northward component.The first, second and third approximation of the motion in a neutral magnetic field satify respectively the Eqs.(2-7);(2-8)and(2-9), and in neutral sheet with northward component they satify Eqs.(2-12), (2-13)and(2-14).(2) In the neutral sheet field, the whole region can be devided into a perturba-tion region and non-perturbation region(|x|≤L).Innon-perturbation region, the Alfven’s perturbation method can not be used, the analytical solution of the motion equation(2-7)is given by Eqs.(3-7)and(3-16), where z’ and the drift velocity Vz are given by Eqs.(3-17)and(3-15).In the perturbation region, the anlytical solution of Eq.(2-7)is given by Eqs.(4-8)and(4-22), where z’ and Vz are given by(4-23)and(4-18).The thrid approximation of the analytical trajectory and the trajectory evaluation by computer agree quite well, except for a slight deviation around the boundary of the perturbation region and the non-perturbation region.(3)The trajectory of the particle moving in a neutral sheet field can be devided into two motions, one is along a closed oscillation trajectory in the plane perpendicular with the magnetic field while its center drifts in a direction parallel to the neutral line, and the other along the magnetic line with an uniform velocity.In the non-perturbation region, the closed oscillation trajectory of particles with diference initial conditions are shown in Fig.2 by lines(1), (2), (3), (4)and(5)They are derived from Eqs.(3-7)and(3-17), and take a "8" shape motion.Lines(5), (6), (7)and(8)are derived from Eq.(4-8)and(4-23)in the perturbation region, and take a circular motion.There is a slight deviation between(5)and(5)The drift velocity in non-perturbation region determined by Eq.(3-15)has an opposite direction and a much higher value than that in the perturbation region.The projection of the trajectories on x-y plane corresponds to the particles with different initial conditions are shown in Pigs.1 and 3 by full lines, and the dashed lines denote the founda-mental and higer harmonic of the corresponding trajectories.Acomplete analytical form has been obtained from the above results.
Mosaic of Lunar Image From CCD Stereo Camera Onboard Chang'E-1 Orbitor
Wang Jingran, Chen Shengbo, Cui Tengfei
2010, 30(6): 584-588.   doi: 10.11728/cjss2010.06.584
Abstract(2464) [PDF 540KB](48)
Abstract:
In view of the image particularity of stereo camera onboard Chang'E-1 orbitor, the projection method was selected to complete the lunar nadir images mosaic of Apollo 12, Apollo 14 and Apollo 15 landing sites. Based on analyzing cylindrical projection, the coordinate formulae of lunar shearing 35º Mercator projection were obtained. Firstly, the latitudes, longitudes and DN values were read and written to files. A blank frame was established using the four vertices' latitudes and longitudes. Then grids were divided in vertical and horizontal directions, according to the resolution, length ratio and projection theory, realizing the frame's pixels. The DN mosaic was completed along with the coordinates matching, and the matching errors were controlled in less than one pixel. At the same time, the DN values were smoothed for the overlapped regions. Finally the DN values were restored to image, which was the mosaic image. The method has widespread use, and it can also be used for other tracks images mosaic.
Energy characteristics study of aerospace relay mirror system
Liu Chunyu, Jin Guang
2009, 29(1): 64-67.   doi: 10.11728/cjss2009.01.064
Abstract(3366) [PDF 519KB](37)
Abstract:
Aerospace Relay Mirror System (ARMS) as a new conceptional weapon used in reflection of High Energy Laser (HEL) in space is studied. It extends the attacking range of Ground Based Laser (GBL) weapons enormously. Relevant researches have been carried out for many years. The structure and operating theory of the entire system consists of ground-based high energy laser weapon and space-based relay mirror. The main work of this study was focused on the analysis of relay mirror energy character to deduce the relationship among the attacking range of weapon and diameter of ARMS and target irradiance. Calculation examples are also given. The result further proves the strong points and feasibility of ARMS in principles. It is summarized that more importance should be attached to ARMS development. The results given in this paper can be the reference of actual ARMS system to some extends.
Error correction technology based on CCSDS standard for remote sensing satellite
Han Jiawei, Zhang Hongqun
2009, 29(1): 112-116.   doi: 10.11728/cjss2009.01.112
Abstract(2464) [PDF 515KB](85)
Abstract:
There is always noise disturbance during the satellite data downlink. Almost all the satellite data is coded before downlink to enhance the ability of anti-disturbance. Among those many data processing ways to reduce the influence of the noise in the signal channel, the Consultative Committee for Space Data Systems (CCSDS) provides many kinds of coding ways to improve the data quality. In this paper, we will discuss the theory of error correction for PN, CRC, RS and Viterbi based on CCSDS standard firstly, and then take the Envisat satellite as an example to show the decoder procedure. The data quality is improved greatly after the data processing.
Wavelet Analysis of Quasi-27-Day Oscillations in the Solar Index F10.7
MA Ruiping, JI Qiao, XU Jiyao
2007, 27(2): 89-95.   doi: 10.11728/cjss2007.02.089
Abstract(3230) [PDF 3861KB](24)
Abstract:
Using the daily averaged values of the F10.7 for years 1956-2003, the Morlet Wavelet Transform is used to analyze the characteristics of quasi-27-day period oscillation and the relation between the oscillation and the solar 11-year cycle (Schwabe cycle). The result shows: The amplitude and period of quasi-27-day period oscillation have obvious short-term fluctuations. The change has very large difference in different years. In some years, the amplitude changes more than ten times and the period changes several days, even changes suddenly more than ten days during several days to tens of the day. In other years, the amplitude is large, but the fluctuation is small and the period was steady. The yearly averaged quasi-27-day oscillation amplitude has obvious change year after year and it is correlated with the solar 11-year cycle observably. Generally, the quasi-27-day oscillation amplitude is larger when yearly averaged F10.7 is bigger. But in the solar cycle 19 maximum years, the quasi-27-day oscillation amplitudes is smaller than maximum years of other cycles, although yearly averaged F10.7 of cycle 19 maximum years is bigger than other cycles. The quasi-27-day oscillation amplitude has obvious change year after year except some years (for example 1987), and the yearly averaged period change range is 24-31 days and is not correlated with the solar cycle. The averaged period of 48 years is 27.3 days. On the whole, the period trends shorter gradually, the period decreases about 1.5 days during 1956-2003. The reasons that conduces to the fluctuations of quasi-27-day oscillation is very complicated, it needs to be studied in the future.
Splitting based scheme for three-dimensional MHD with dual time stepping
Fu Huazheng, Feng Xueshang
2015, 35(1): 9-17.   doi: 10.11728/cjss2015.01.009
Abstract(1149) [PDF 3927KB](67)
Abstract:
A new hybrid numerical scheme of combining an E-CUSP (Energy-Convective Upwind and Split Pressure) method for the fluid part and the Constrained Transport (CT) for the magnetic induction part is proposed. In order to avoid the occurrence of negative pressure in the reconstructed profiles and its updated value, a positivity preserving method is provided. Furthermore, the MHD equations are solved at each physical time step by advancing in pseudo time. The use of dual time stepping is beneficial in the computation since the use of dual time stepping allows the physical time step not to be limited by the corresponding values in the smallest cell and to be selected based on the numerical accuracy criterion. This newly established hybrid scheme combined with positivity preserving method and dual time technique has demonstrated the accurateness and robustness through numerical experiments of benchmark problems such as the 2D Orszag-Tang vortex problem and the 3D shock-cloud interaction problem.
Joint Russian-Chinese Satellite-to-satellite Martian Radio Occultation Experiment
Sun Yueqiang, Du Qifei, Zhu Guangwu, Wu Ji, Tao Peng, Bai Weihua, Zhao Hua, Hu Xiong, Wu Xiaocheng, Zheng Jianhua
2009, 29(5): 475-479.   doi: 10.11728/cjss2009.05.475
Abstract(2966) [PDF 491KB](58)
Abstract:
Joint Russian-Chinese satellite-to-satellite Martian radio occultation experiment will be used to sound Martian ionosphere to derive electron density profiles. Compared with satellite-to-Earth radio occultation technique, satellite-to-satellite radio occultation technique has the better ability to receive higher signal-to-noise ratio radio signal and acquire more accurate profiles in a wider range (especially in areas of solar zenith angle of less than 43° and angle of larger than 138°. Joint Russian-Chinese satellite-to-satellite Martian radio occultation experiment is based on measurement of frequency shift between two radio signals penetrated the Martian ionosphere. The two coherent signals are irradiated from the transmitters. The frequencies of the signals are near 416.5 MHz and 833 MHz. The transmitters will be installed on Russian spacecraft Phobos-Grunt (FGSC) and the receivers will be installed on Chinese satellite YH-1. The relative frequency shift between two signals will reflect the property of Martian ionosphere.
Application of Magnetic Levitation of Diamagnetic Materials for Space Biology and Biotechnology
Cao Jianping, Yin Dachuan, Qian Airong, Tian Zongcheng, XU Huiyun, Huang Yongping, Shang Peng
2011, 31(1): 63-72.   doi: 10.11728/cjss2011.01.063
Abstract(3096) [PDF 752KB](41)
Abstract:
Weightlessness is one of the important physical characteristics of space environment. For several decades, weightless environment in space has been used for investigation and exploration in many scientific fields. Because of shortage and limit of experiments in real space environment, many kinds of ground-based simulated techniques and methods inspired by space experimental environments were developed for simulating the weightlessness of space environment and the effects of weightlessness. However, these techniques and methods have limitations not only in principle, but also in application for space biology and biotechnology. In this paper, we introduced a new technique for simulating weightlessness, magnetic levitation of diamagnetic materials produced by large gradient high magnetic field, and summarized the research progress by using this technique in crystal growth of proteins, molecular cell biology and integrated biology.
Status and Demand Analysis of Space-based Observation of Space Environment
Gong Jiancun, Liu Siqing, Shi Liqin, Chen Zhaofeng
2009, 29(3): 346-352.   doi: 10.11728/cjss2009.03.346
Abstract(3633) [PDF 621KB](47)
Abstract:
Space-based observation of space environment is not only an important method to understand space environment and its evolution law, but also an important way to obtain principle data source used for the operational space environment prediction to ensure the safety of human space activities. In order to promote the development of space-based observation in China, the characteristics of the current situation of domestic and foreign space-based space environment observation, as well as the operational observing abilities serving the space weather forecast are summarized at first in the paper. Then the space-based observation demand coming from space environment safety insurance operation is analyzed, and a preliminary strategy of domestic space-based observation development of space environment is studied.
ENERGY FLUX DENSITY DISTRIBUTION IN THE HIGH SPEED SOLAR WIND
LU Xianhe, WEI Fengsi, LU Jianyong, LIU Siqing
1998, 18(2): 104-110.   doi: 10.11728/cjss1998.02.104
Abstract(2127) [PDF 342KB](74)
Abstract:
Using the characteristical parameters of high speed solar wind observed by Ulysses,the energy flux distribution of high speed solar wind is obtained in the high latitudes.The results states clearly that the total energy flux density is about 2.1 × 10-3J·m-2·s-1 (normalized to 1AU), mainly dominated by kinetic energy flux density (about 58%)and what overcome the gravitational potential energy flux at one solar radius (about 39%). In order to drive the high speed solar wind, the input energy flux density must be over 7.1×102J·m-2·s-1 in the coronal source region of high speed solar wind.It is 40% larger than that of derivation from observations of previous satellites near the ecliptic plane. It is infered that there may exist two types of energy flux responsible for heating and accelerating the outflowing solar wind from the remote-sensing observations of the coronal source region. One has more short dissipatoon length, it will be dissipated within the very short space region (about 1-2Rs)and make the corona temperature rising up very quickly. The other is stored in the solar wind, it will be dissipated continuosly with the solar wind outflowing and accelerate the solar wind as well as heating solar wind.
Analysis of the Time Lag Between Geomagnetic Ap Index and Solar Cycle
XU Tong, WU Jian, WU Zhensen, FENG Jian, WANG Maoyan
2008, 28(3): 210-214.   doi: 10.11728/cjss2008.03.210
Abstract(2783) [PDF 1726KB](46)
Abstract:
The data of twelve-month running average of monthly mean Ap index from 1932 to 2006 is decomposed into two components, (Ap)R and (Ap)I. (Ap)R is a linear function of the twelve-month running average of monthly mean sunspot number R, which has the same phase with sunspot number R and is possible due to Coronal Mass Ejections and equatorial coronal holes. The latter is due to long lived solar wind sources such as polar coronal holes extending toward equator and is inconsistent with sunspot number R in phase. Analyzing of (Ap)I and polar coronal holes variation of cycle 20, in which the lag between twelve-month running average of monthly mean Ap index and twelve-month running average of monthly mean R is remarkable, it is testified that the (Ap)I component corresponds to polar coronal holes. Thus it is concluded that the variation of polar coronal holes is a very important factor, which contributes possibly to the lag time between Ap index and solar cycle.
Space Weathering Processes and Effects on the Moon
FU Xiaohui
2011, 31(6): 705-715.   doi: 10.11728/cjss2011.06.705
Abstract(4462) [PDF 739KB](98)
Abstract:
Space weathering on airless bodies (including Moon, asteroids, and comets) is the physical and chemical alteration due to irradiation from solar wind particles and bombardment by micrometeorites. This paper compiles current lunar space weathering results from lunar soil studies, and ion and laser irradiation simulations. On the basis of these, hypothesizes about origin of amorphous rim and nanophase Fe0 on lunar soil particles were analyzed. In current researches, the contribution of solar wind irradiation and micrometeorite impact in lunar space weathering effects could not be completely distinguished. And it is suggested that lunar space weathering model should not be directly invoked for asteroids and other bodies. In the future, more microstructure and chemical compositions of samples from lunar, asteroids and IDP, more appropriate simulations are essential for resolving of the above problems.
AN ACCURATE MAfHEMAfICAL MODEL FORSATELLITE EPHEMERIS
YANG Weilian
1999, 19(2): 148-153.   doi: 10.11728/cjss1999.02.148
Abstract(1753) [PDF 395KB](55)
Abstract:
An accurate mathematical model for calculating satellite ephemeris is givenin this paper, which is designed to apply to near the Earth and approximatelycircular orbits. The model uses 10 constant parameters to fit the secular and longperiodical variations of the orbit, while the short periodical variations caused bytesseral harmonics of the geopotential field are based on the known theoreticalresults. By sorting the terms with same frequency the formulae become quite simple.In addition, the model is also flexible to use and can be justified with differentaccuracy requirements up to 50 meters.
Radiation dose evaluation and analysis inside FY-3A satellite
Wang Chunqin, Sun Yueqiang, Cao Guangwei, Zhang Xianguo, Li Jiawei, Zhang Xiaoxin, Jing Tao, Shen Guohong, Zhang Shenyi, Huang Cong, Liang Jinbao, Shi Chunyan, Han Ying
2015, 35(1): 56-63.   doi: 10.11728/cjss2015.01.056
Abstract(1224) [PDF 2844KB](72)
Abstract:
FY-3A satellite can measure the radiation dose data from different directions during the missions from 2008 to 2012. In this paper, we describe total radiation dose from two directions, and dose rate variation with energetic particle flux. The result shows that different sections of the spacecraft receive different amounts of radiation dose, which is always consistent with space distribution of energetic particles. Absorbed dose rate changed greatly from several rad (Si)·d-1 during quite time to even more than tenfold during disturbances. The increased high energy electrons in polar regions during disturbances are responsible for significant increase of radiation dose. At last, FY-3A radiation dose during the operational period of the mission is compared with the results calculated by SPENVIS. It is obvious that observation data is more realistic to reflect the real space radiation environment.
Correlation research between the sunspot numbers and the cosmic rays based on wavelet and cross wavelet analysis
Weng Libin, Fang Hanxian, Zhang Yang, Yang Shenggao, Wang Sicheng
2013, 33(1): 13-19.   doi: 10.11728/cjss2013.01.013
Abstract(3109) [PDF 625KB](79)
Abstract:
The wave and cross-wavelet methods were used to analyze the periods of sunspot number and the month-averaged cosmic ray observed by Huancayo and Climax stations, and the correlation between sunspot number and the cosmic ray was discussed. As a result, spectral analysis indicates that except for the pronounced periodicities of 11 years observed both in solar sunspot and cosmic ray intensity, 1~6 months periodicities during the high solar activity, meanwhile, 6~8 and 1~22 months periodicities in the solar cycle 22 have been detected. Cross-wavelet shows a negative correlation between the solar sunspot and the cosmic ray, and the cosmic ray intensity lag the solar activity for about 8 months. The cosmic ray intensity in Climax was predicted by the sunspot number, and the relative error decreased from 3.8912% to 3.2386%. These methods can be used to study the period and relationship of other space parameters, and to make better performance on the predicting.
AN ANALYSIS OF THE U. S. STANDARD ATMOSPHERE, 1976
Sun Chao
1981, 1(1): 47-51.   doi: 10.11728/cjss1981.01.047
Abstract(2793) [PDF 371KB](63)
Abstract:
In this note an analysis of USSA 1976 has been made about its physical assumptions and atmospheric tables.The main results are:1.Temperature profile T(Z) may be defined with absolute temperature in full height range without using molecular-scale temperature TM. 2.The elliptical segment of T(Z) will give a sudden heat sink of the order of 10-7J/m3.s at 110 km which is too large.3.It seems the only systematic mistake in atmospheric tables is the coefficient of thermal conductivity.4.Adetailed discussion is given about the possible choices to connect the computations of the homosphere and the upper heterosphere.5.We suggert to introduce CO2 as a component in the upper atmosphere model and lower the computing interface down to 80 km.
Pitch Angle Distribution Research of Radiation Belt Protons Based on the NOAA Data
Yang Shichao, Zhang Xianguo, Wang Yue, Wang Chunqin, Chang Zheng, Qin Murong, Wang Shijin
2014, 34(4): 390-397.   doi: 10.11728/cjss2014.03.390
Abstract(1246) [PDF 690KB](43)
Abstract:
Using the NOAA-12 satellite data, a study on the Pitch Angle Distributions (PADs) of energetic protons is performed during the quiet period of space environment in the Sun-synchronous orbit. The 90° pitch angled proton flux and the anisotropy index n are calculated based on the empirical formula. According to the n values, it's found that the distributions can be classified into three categories: 90° peaked, flattop, and butterfly. For the radiation belt protons, the three types are all existed and have a significant spatial character. The 90° peaked distributions dominate at the edge of inner radiation belt; while at the higher L values region of outer radiation belt, the 90° peaked distributions decrease obviously and the flattop distribution and butterfly distribution gradually increase with the increase of L values. For the 90° peaked distributions, relationship between the anisotropy exponent n and the L values is studied. For inner radiation belt, the n values increase rapidly with the L values increasing; for outer radiation belt, the n values decrease gradually with the L values increasing. The distributions of the radiation belt protons are also studied in two different Magnetic Local Time (MLT) regions for the 250~800keV protons. The results show that the PADs are very similar at the inner radiation belt, but have obvious differences at the higher L values region of outer radiation belt. It indicates that the PADs of radiation belt protons have little dependency on the MLT at the inner radiation belt, while have more dependency on the MLT at the higher L values region of outer radiation belt.
Seasonal distribution of ozone and radiation field at the stratosphere
Shang Lin, Liu Yi, Wang Yong, Tian Wenshou
2015, 35(1): 40-49.   doi: 10.11728/cjss2015.01.040
Abstract(1224) [PDF 2574KB](85)
Abstract:
The coupled chemistry-climate model WACCM3 (Whole Atmosphere Community Climate Model) developed by NCAR is applied to study the seasonal variations of the stratospheric temperature, wind, ozone and radiation fields. The stratospheric quasi-zero wind layer at around 20~22km (i.e., atmosphere pressure range is 50~30hPa), where the wind speed is less than 5m·s-1 and is stable to the north of 40°N during July and August, is suitable for long-term stay of airships. There appears a belt of ozone at 30hPa over China and ozone concentrations are greater in the mid-latitudes than in the lower latitudes below 30hPa. There are significant seasonal spatial variations in solar heating rates in the stratosphere. In the upper stratosphere, the maximum solar heating rate reaches 100×10-6K·s-1 while in the lower stratosphere the maximum solar heating rate is only 10×10-6K·s-1. The solar heating rate is greater in June to August than in September over China. The solar heating rate is greater in the mid-latitudes than in the lower latitudes between 100hPa and 30hPa and is greater in the lower latitudes than in the mid-latitudes above 30hPa. The change of solar heating rate is small in August and September at 30hPa and 40hPa. The maximum diurnal variation of solar heating rate appears at 40°N at 30hPa. At 50hPa, the diurnal variation of solar heating rate is smaller than that at 40hPa and the maximum variation occurs farther south. The longwave heating rate is smaller in the lower latitudes than in the mid-latitude stratosphere. In particular condition of terrain, the ozone concentration, solar heating rate and longwave heating rate are smaller over Tibetan Plateau than other areas at the same latitude.
Statistical Analysis of Solar Cycle Distribution of Moderate Storms
Zhang Yong, Le Guiming, Zhao Haofeng, Yin Zhiqiang
2013, 33(5): 480-485.   doi: 10.11728/cjss2013.05.480
Abstract(2243) [PDF 757KB](64)
Abstract:
In this paper, the statistical analysis of solar cycle distribution of moderate geomagnetic storms (-100nT< Dst ≤-50nT) is investigated based on observed data. The results show that the yearly number of moderate storms have multi-peaks in each cycle with the highest peak appeared in the descending phase of the cycle. This means that the highest peak of moderate storms have a time lag with respect to the yearly number of sunspot numbers. The time lag is about 2~3 year. More than 70% moderate storms appeared in the descending phase of a solar cycle. During the solar maximum, there are less moderate storms occurred than that occurred in other period of a solar cycle. Monthly mean moderate storm numbers and smoothed monthly mean sunspot numbers is also investigated in this paper. The results show that the time of moderate storms peaks lag behind that of the time of sunspots peaks, the time of peaks of both moderate storms and sunspots is different, and the time differences are different in different solar cycles, ranging from a few years to just a few months.
Experiments and Calculations of the 100 kHz Sky-wave
Wang Xian-lin, Shen Li, Huang Ze-rong
1986, 6(3): 227-232.   doi: 10.11728/cjss1986.03.227
Abstract(1768) [PDF 408KB](68)
Abstract:
In this paper, the annual, monthly and day-to-day variations the 100 kHz Loran-C pulse signal are given for both before and afternoon times by analyses of some experimental results and calculations, An approximate formulae for estimating the observational phase, phase height of reflection and the triangulation height is also given.
Advances in the Researches of the Middle and Upper Atmosphere in China in 2012-2014
Chen Zeyu, Chen Hongbin, Xu Jiyao, Bian Jianchun, Qie Xiushu, LÜ Daren, Chen Wen, Ren Rongcai, Zhang Shaodong, DouXiankang, Li Tao, Hu Xiong, Hu Yongyun, Tian Wenshou
2014, 34(5): 669-687.   doi: 10.11728/cjss2014.05.669
Abstract(1060) [PDF 243KB](34)
Abstract:
In this report we summarize the research results by Chinese scientists in 2012-2014. The focuses are placed on the researches of the middle and upper atmosphere, specifically the researches related to ground-based observation capability development, dynamical processes, the property of circulation and chemistry-climate coupling of the middle atmospheric layers.
A Statistical Study on Seismo-Ionospheric Anomalies of the Total Electron Content for the Period of 56 M ≥ 6.0 Earthquakes Occurring in China During 1998-2012
Liu J Y, Chen C H, Tsai H F, Le H
2013, 33(3): 258-269.   doi: 10.11728/cjss2013.03.258
Abstract(2784) [PDF 1005KB](25)
Abstract:
This paper reports statistical results of Seismo-Ionospheric Anomalies (SIAs) of the Total Electron Content (TEC) in the Global Ionosphere Map (GIM) associated with 56 M ≥ 6.0 earthquakes in China during 1998-2012. To detect SIA, a quartile-based (i.e. median-based) process is performed. TEC anomalies for the period of earthquakes without being led by magnetic storms about 10 days are further isolated and examined to confirm the SIP existence. Results show that SIA is the TEC significantly decrease in the afternoon period 2-9 days before the earthquakes in China, which is in a good agreement with the SIA appearing before the 12 May 2008 M8.0 Wenchuan earthquake.
Research on micro-magnetic sensor based on giant magneto-impedance in amorphous wire
Wang Xiaomei, Teng Yuntian, Wang Xizhen, Wang Chen, Zhou Xun
2009, 29(1): 50-53.   doi: 10.11728/cjss2009.01.050
Abstract(4202) [PDF 526KB](48)
Abstract:
The principle and factors of the Giant Magnetic-Impedance (GMI) in amorphous wire are analysed in detail. The operating principle of the sensor based on GMI is analyzed, and the signal processing circuit of micro-magnetic sensor is designed. With the characteristics of micromation and low power consumption, magnetic sensor could be used in the space magnetic-measurement.
Design Of Optical System And Analysis Of Precision Of Star And Earth Simulator
Sun Gaofei, Zhang Guoyu, Liu Shi, Wang Lingyun, Gao Yujun
2015, 35(5): 641-646.   doi: 10.11728/cjss2015.05.641
Abstract(1243) [PDF 1853KB](98)
Abstract:
In order to realize the ground calibration and accuracy testing of sensor, a star and Earth simulator is needed to achieve the star simulation accuracy of less than 10" and Earth simulation accuracy of 0.05°. The simulator utilizes a high precision collimator and a high precision UV collimator as the projection optical system. A correction method for star position simulation error and Earth graphics simulation error is proposed to improve the simulation precision of the star and the Earth. Finally, the star angular distance is measured which accuracy is better than 10", and the accuracy of the Earth graphics is better than 0.05°. The investigation result indicates that the star and Earth simulator proposed in this paper is possible to satisfy the requirements of ground calibration and accuracy testing of the sensor.
THE ALTITUDE STABILITY OF THREE-AXIS LIQUID FILLED SATELLITE
Bao Guang-wei, Liu Yan-zhu
1993, 13(1): 31-38.   doi: 10.11728/cjss1993.01.031
Abstract(1905) [PDF 473KB](46)
Abstract:
This paper set up the equivalent mechanical model of the three-axis liquid filled satellite which has both translational and pitch-yaw disturbance. Then, using this model, the altitude stability of the satellite is investigated and a coincise analytic criterion is obtained.
Numerical study of EUV wave on 13 February 2009
Zhang Lei, Zheng Huinan, Liao Chijian
2013, 33(1): 6-12.   doi: 10.11728/cjss2013.01.006
Abstract(2632) [PDF 712KB](30)
Abstract:
EUV wave is observed in the extreme ultraviolet spectrum as large-scale disturbances phenomenon, often accompanied by a coronal mass ejection. Besides, EUV wave is, when displayed in EUVI 195 Å difference image, a bright ring propagating outside with the subsequent spread of the dark zone. The disturbance can often cover the whole solar disk. The current study explores the CME-EUV wave event that occurred at 05:35UT on 13 February 2009, based on the STEREO satellite observations and the three-dimensional Magnetohydrodynamic (MHD) numerical simulation. We know this CME with 340km·s-1 front velocity and 60° angular width from the COR1/STEREO-A observations. Viewing in EUVI/STEREO-B 195Å running difference images, a bright toroidal wave front propagates outside from the active region, with dimming area following the bright wave front. The fitting velocity of EUV wave from the observation data is 247km·s-1. The numerical simulation shows that the (fast-mode) wave, with legible bright front and dimming structure, propagates in a speed of 245km·s-1. The simulation results turn out to be consistent with the satellite observations and confirm that EUV wave is a fast-mode MHD wave.
Calculation of Flux Distribution of Energetic Proton at Low Altitude Space
CHENG Yonghong, XUE Bingsen
2005, 25(3): 185-190.  
Abstract(2247) [PDF 1497KB](54)
Abstract:
AP-8 model, CRRESPRO model and PSB97 model are introduced in this paper and used to calculate the flux distribution of energetic proton between low altitude 300 and 1100km, separately, and then the calculated flux distributions are plotted as contour graph by IDL software. AP-8 model flux is mainly modulated by galactic cosmic rays and is influenced directly by solar activity. Consequently, the proton flux is higher during the maximum part of the solar cycle than that during the minimum part. CRRESPRO model comprises conditions of active and quiet earth magnetic fields, which correspond to similar flux due to the short time difference of data collection at different earth magnetic conditions. Compared results between models show that AP-8 model flux is small, CRRESPRO model flux is large, and PSB97 model flux is between the two and is the nearest to the detected value. PSB97 model is compiled specially for low altitude (under 1000 kilometers) use and is applicable to calculate energetic proton flux at low altitude in current space environmental condition, significantly for prediction of energetic proton flux in SZ spacecraft orbit.
A Simulation Study of Onboard GPS Observations of LEOs
HAN Baomin, OU Jikun, QU Guoqing, LIU Lintao
2005, 25(1): 63-69.  
Abstract(2229) [PDF 2052KB](104)
Abstract:
The simulation of GPS observation on a moving low-earth-orbiter(LEO) is to simulate the measured signals that would be received by a GPS receiver on a LEO.Since a LEO and GPS satellites are in a three-dimensional coordinate system,the values of various errors and observation noise level can be well calculated and known in advance,so using GPS simulation of the observations of a onboard GPS receiver can be of great help for judging some important parameters in orbit determination such as ambiguity resolution method,Kalman filtering technique and so on.In this paper,the method of simulating GPS observations of an onboard GPS receiver is systematically studied.The emphasis is first put on principle and mathematical model.Then,the GPS dual-frequency P codes and carrier-phase observations of potential onboard GPS receivers are simulated by employing some elaborately selected error modes.The results show that the simulated observations of CHAMP satellite obtained from software developed by the author are very close to the real measurements in-situ and such is observation noise level,therefore the simulation method used in this paper can meet the needs of different users of GPS data.
Heating of Lower Ionosphere by Powerful HF Radio Wave
WANG Sicheng, FANG Hanxian, YANG Shenggao, WENG Libin
2012, 32(6): 818-823.   doi: 10.11728/cjss2012.06.818
Abstract(2521) [PDF 539KB](60)
Abstract:
The ionospheric heating by powerful HF radio wave can excite the disturbance of temperature, density and other parameters of ionospheric plasma. Based on Ohmic theory, the effect of high power radio wave on the lower ionosphere is studied, and the following conclusions can be drawn. Firstly, D region is the main absorption area of the radio wave, and the intensity of absorption decreases with the increase of radio wave frequency. When radio frequency is 6MHz (effective radio power is 200MW), the electron temperature increase can be up to nearly 520K, and electron density increase can reach about 7300cm-3. Secondly, the disturbance of electron temperature and density tend to be saturated after continuous heating. The time that the electron temperature needs to be saturated is of a scale of μs, while that of the electron density is ms. When stop heating, the electron temperature and density come back to the normal conditions quickly. Thirdly, the higher radio power is, the larger disturbance of electron temperature and density are caused, and the longer saturation time is needed. The saturation time at nighttime is longer than that at daytime under the same heating conditions.
Simultaneous TC-1 and Cluster Observations of FTE on 13 March 2004
Zhang Qinghe, Liu Ruiyuan, Huang Jiying, DUNLOP M W, Hu Hongqiao, Hu Zejun, BOGDANOVA Y V, WALSH A
2009, 29(2): 166-174.   doi: 10.11728/cjss2009.02.166
Abstract(4481) [PDF 883KB](69)
Abstract:
This paper analyzed the observations of the FGM and PEACE on TC-1 and Cluster Spacecraft between 12:15 and 12:25 UT on 13 March 2004. In this interval, the TC-1 spacecraft located in the magnetosheath southward the sub-solar magnetopause, and observed a standard magnetosheath FTE with a positive to negative bipolar characters at about 12:19 UT. The Cluster spacecraft array was encountering the plasma boundary layer near the high-latitude magnetopause in the northern hemisphere, crossing the magnetopause into the magnetosheath at about 12:23 UT. It also observed a standard magnetospheric FTE with a positive to negative bipolar characters at about 12:21 UT. With the similar features of the magnetic field structures and plasma data, these two FTE might be the same FTE moving through TC-1 and then Cluster. Since all 4 Cluster spacecrafts observed the FTE, the four-spacecraft techniques Minimum Directional Derivative/Difference (MDD) and Spatio-Temporal Difference (STD) were applied to calculate the dimension, motion and scale of these FTE. The inferred northwardly reconnected flux tube for the FTE is shown to move north-east and tailward with a quasi-2D structure and a scale of 1.21 Re. Whilst, the FTE motions are shown to be consistent with the expected motion of reconnected magnetic flux tubes over the surface of the magnetopause, arising from a predominantly low-latitude reconnection site during the prevailing upstream conditions. According to the predictions of the Cooling model, the motion of the FTE observed by TC-1 spacecraft is inferred, which implied that the speed and size of flux tube increase with its poleward moving.
Astrometric experiment for the 1m telescope at Weihai observatory
Lin Zhong, Peng Qingyu, Zhang Qingfeng
2011, 31(3): 344-349.   doi: 10.11728/cjss2011.03.344
Abstract(3446) [PDF 577KB](81)
Abstract:
The open cluster M39 was observed by the new 1-m telescope at Weihai Observatory, Shandong University in the night of Oct. 7, 2009. While observing, a Johnson I-type filter was used and the CCD was imaged in two orthogonal orientations, and thus 30 frames of images were delivered. After the CCD images were measured by 2-D Gaussian fit so as to obtain the star pixel positions, a number of constant plate models were attempted to solve the difference between observed positions and computed ones for each star. Our reduction of the observations showed that proper motions of the latest USNO UCAC3 star catalogue were explicitly not accurate. By contrast, those of the Platais's catalogue were found much better. This observations partly confirmed the errors in the proper motions of UCAC3 recently discovered by Roeser et al. Experiments have also shown that the best precision for a suitable bright star was about 4~5 milli-arcsec. It was believed that this new telescope could be used for high precision astrometry.
Characteristic analysis of ionosphere TEC at Wuhan station during 23rd solar cycle
Xu Zhenzhong, Wang Weimin, Zhang Ren, Yang Shenggao, Zhou Nan, Wang Sicheng
2013, 33(1): 28-33.   doi: 10.11728/cjss2013.01.028
Abstract(2691) [PDF 608KB](62)
Abstract:
By using Total Electron Content (TEC) at Wuhan station (30.5°N, 114.4°E), sunspot numbers and geomagnetic index from 1997 to 2007, some typical characters such as diurnal variation, seasonal variation, and semiannual variation, correlation with solar activity were analyzed. A case study was made on the responses and possible mechanism of ionosphere TEC to the magnetic storm during 13-17 April 2006. Analysis results show that diurnal variation exists constantly in high and low solar activity. Some features like semiannual anomaly and winter anomaly in TEC had been reported, but changed with solar activity. The correlation coefficient for yearly sunspot number with TEC is 0.9611. TEC correlates with the geomagnetic AE well. The response of TEC to geomagnetic storm may be caused by penetrating electric fields and neutral winds, and the specific mechanism needed to be analyzed in the future.
YH-1 Mars Probe's Key Technology and its Design Feature
Chen Changya, Hou Jianwen, Zhu Guangwu
2009, 29(5): 456-461.   doi: 10.11728/cjss2009.05.456
Abstract(2434) [PDF 616KB](43)
Abstract:
In this paper, the function and design as well as the key technologies (ultra-long-range communication technology, deep space exploration attitude determination and control technology, thermal control technology etc.) of China's first Mars probe are analyzed. The solutions of the key technologies are given after the analysis, and then the design features are summarized. Finally, the whole satellite of YH-1 has undergone tests under various experimental circumstances, including: vibration, noise, solar array deployment, illumination, leak detection, vacuum thermal testing and sophisticated power testing, etc. In all these tests, YH-1 behaves normally. This paper can provide a good reference for the following tasks related to the development and production of the probe and following missions.
Forecasting of Ionospheric TEC One Hour in Advance by Artificial Neural Network
WENG Libin, FANG Hanxian, MIAO Ziqing, YANG Shenggao
2012, 32(2): 204-208.   doi: 10.11728/cjss2012.02.204
Abstract(3231) [PDF 490KB](75)
Abstract:
A handy method of forecasting the ionospheric TEC one hour ahead by Artificial Neural Network (ANN) is presented in this paper. Considering of the practical application, the observations of TEC are used as inputs without any other data. The input parameters are the present observation of TEC, the first difference and relative difference of TEC, and the local time. The output is the TEC one hour ahead. Ionospheric TEC data evaluated from GPS measurements at Xiamen receiving station is used to checkout the forecasting method. The relative error is 9.3744%, and the cross correlation coefficient between the observed and forecast TEC values is 0.96678. The accuracy rate of relative error less than 15% is 79.59%, during the geomagnetic storms, but 98.81% for the quiet or moderate geomagnetic conditions. These conclusions suggest that the value of forecasting is very the geomagnetic level. It is shown that the Artificial Neural Network is promising in forecasting of ionospheric TEC one hour ahead.
Variations of Thermosphere Density Based on Joint Analysis of In-Situ Measurement Data From Shenzhou Spacecrafts
SUN Lilin, QIN Guotai, ZHU Guangwu
2012, 32(2): 216-222.   doi: 10.11728/cjss2012.02.216
Abstract(1921) [PDF 288KB](39)
Abstract:
Based on the measurements made by Atmospheric Density Detectors (ADDs) onboard Chinese spacecraft Shenzhou 2-4, the variations of thermosphere density are revealed. During the quiet period, the density at spacecraft altitude of 330~410km exhibited a dominant diurnal variation, with high value on dayside and low value on nightside. The ratio of the diurnal maximum density to the minimum ranged from 1.7 to 2.0. The ratio shows a positive correlation with the level of solar activity and a negative correlation with the level of geomagnetic activity. When a geomagnetic disturbance comes, the atmospheric density at the altitude of 330~410km displayed a global enhancement. For a strong geomagnetic disturbance, the atmospheric density increased by about 56%, and reached its maximum about 6~7 hours after the geomagnetic disturbance peak. The density asymmetry was also observed both in the southern and northern hemisphere during the geomagnetic disturbance peak.
REE AND OTHER TRACE ELEMENT CHEMISTRY OF CaS IN QINGZHEN CHONDRITE (EH3) AND THEIR ORIGIN IMPLICATIONS
Chen Yong-heng, Wang Dao-de, E. Pernicka
1992, 12(2): 129-138.   doi: 10.11728/cjss1992.02.129
Abstract(2929) [PDF 952KB](43)
Abstract:
INAA of 14 single oldhamite grains extracted from the Qingzhen chondrite (EH3) for refractory (La,Ce,Sm,Eu,Yb,Lu,Ca,Sc,Hf,Th),volatile (Na,Cr,Zn,Se,Br etc.) and siderophile elements (Fe,Ni,Co,Ir,Au,As) reveals that oldhamite is highly enriched in refractory elements,acting as the principal carrier of REE and contains about 80% of all REE in the bulk rock of the Qingzhen enstatite chondrite.Furthermore,LREE has larger enrichment relative to HREE in the Qingzhen oldhamite.In general,the oldhamite form metal-sulfide as-sembleges is more enriched in REE than that from the matrix,i.e.the earlier the oldhamite grains condensed,the more they are enriched in REE.Meanwhile,it is also enriched in volatile elements such as Se,Br etc.In terms of the trace element distribution of the Qingzhen oldhamite it is a high-temperature condensate from the nebula with the solar composition and its condensate origin are suggested.
Spectral Analysis on Time Series of Calibration Parameters of CHAMP Accelerometer
XU Tianhe, YANG Yuanxi
2005, 25(2): 143-148.  
Abstract(2379) [PDF 1613KB](51)
Abstract:
The theory and algorithm of determining system errors of CHAMP accelerometer are presented based on energy conservation method. The time series of scale factor, bias and bias drift is analyzed using about two and a half years' accelerometer data of CHAMP from August 2001 to December 2003. The long-term and principal periods variations are obtained by using LS spectral analysis as well as the robust one. The results show that there are clear periodic variations in the time series of scale factor, bias and bias drift. For scale factor, the principal periods are 441 d, 220 d, 126 d and 13.4 d. 441 d and 220 d periods make great contributions to scale factor. For bias, the principal periods are 220 d, 126 d and 13.4 d, and they make almost the same contributions. For bias drift, the principal periods are 220 d, 13.4 d and 9d, and 13.4 d makes the greatest contribution. There are obvious long-term variations in the time series of scale factor and bias except bias drift. It is shown that the results of the robust spectral analysis are superior to that of LS one in the whole. Further investigations about why there are long-term and period variations in system errors of CHAMP accelerometer are necessary.
Design of Orbit Debris Environment and Collision Alert System
MA Zhihao, CHEN Lei, ZHOU Bozhao
2005, 25(4): 298-303.  
Abstract(2239) [PDF 1766KB](35)
Abstract:
Since the number of targets near the earth orbit has already been beyond 9000, it is necessary and much important to analyze targets near the mission orbit to bring the mission to access both before the launch and during the orbital mission. NORAD maintains general element perturbation element sets (Two-Line Element Sets, TLEs) on all resident space objects. In turn, these element sets are provided to users. These element sets are periodically refined so as to maintain a reasonable prediction capability on all space objects. At the same time, NORAD developed a set of models named SGP/SDP series as models for propagation of NORAD element sets. Five mathematical models for prediction of satellite position and velocity are available. And the NORAD element sets are currently generated with either SGP4 or SDP4 depending on whether the satellite is near-Earth or deep-space. These two models, SGP4 for "near-earth" objects and SDP4 for "deep space" objects, are widely used in satellite tracking software and can produce very accurate results when used with current NORAD two-line element datum. A brief review is taken at these element sets and propagation models first. Then through the precision analysis, it is believed that using SGP4/SDP4 models for taking quick collision alert among space targets is suitable. Based on this conclusion, an orbit debris environment and collision alert system was designed. In this system, targets and the corresponding TLEs are saved in a database based on MS SQL Server, and the data visual is realized by OpenGL. The orbit propagation models being used is SGP4/SDP4 since this model is the generator of current TLEs and will be supported in the future.
NONLINEAR INTERACTION AMONG PLANETARY WAVE AND INERTIALGRAVITY WAVES IN THE MIDDLE AND UPPER ATMOSPHERE
XIONG Jiangang, YI Fan
2000, 20(2): 121-128.   doi: 10.11728/cjss2000.02.121
Abstract(2298) [PDF 504KB](136)
Abstract:
The evolution equation of planetary wave and inertial-gravity waves are ob-tained from the anelastic equations based on a weakly nonlinear assumption. nomthe resonance surface and increase rate curve, it is found that the planetary waveprefers to interact with large scale inertial-gravity waves. By using the equivalentgravity wave assumption of tidal wavest the interaction among the typical 2 daysplanetary wave, semidiurnal tide and 9.6 hours inertial-gravity waves are investi-gated in detail. The exchange of energy between planetary wave and semidiurnaltide is found to proceed more strongly than the exchange between them and the9.6 hours inertial-gravity gravity. The variability of tidal and planetary wave am-plitudes may be caused by nonlinear interaction between them.
Recent Development in the Space Utility System of China's Manned Space Flight Program
Gu Yidong, Guo Jiong
2010, 30(5): 388-391.   doi: 10.11728/cjss2010.05.388
Abstract(2235) [PDF 419KB](32)
Abstract:
This paper briefly introduces the history of China's Manned Space Flight Program and concludes the experiments done since 2008, namely, a small satellite and a material science experiment. An outlook of future Chinese Space Station is also described at the end.
Comparison Between the TIMED Observed Global Temperature Distribution and the NRLMSISE-00 Empirical Atmospheric Model
XU Jiyao, JI Qiao, YUAN Wei, MA Ruiping
2006, 26(3): 177-182.   doi: 10.11728/cjss2006.03.177
Abstract(2454) [PDF 5451KB](55)
Abstract:
In this paper, the comparison between the TIMED observed global temperature distribution and the temperature calculated by the NRLMSISE-00 empirical atmospheric model is made. The comparison indicates that in the altitude region between 20-70km, the global temperature structure calculated by the NRLMSISE-00 empirical atmospheric model is consistent with the satellite observation. However, the comparison shows that in the mesopause region, there is obvious difference between the NRLMSISE-00 empirical atmospheric model and the satellite observation. In the vernal equinox season, there is a stable Mesospheric temperature Inversion Layer (MIL) in the lower latitude (20°S-20°N) mesopause region in the satellite observed global temperature data. But the NRLMSISE-00 empirical atmospheric model can't produce this feature. The satellite observation indicates that there are two distinctive levels worldwide of the mesopause altitude. One is at about 100 km, another is at about 85 km. This characteristic can't be exhibited by the NRLMSISE- 00 empirical atmospheric model. On the other hand, there is large difference of the temperature distribution between the empirical atmospheric model and the satellite observation in the lower thermosphere.
Global Background Wind of Middle Atmosphere From Aura Data
LIU Sanjun, XIONG Jiangang, WAN Weixing, NIN Baiqi
2007, 27(5): 400-408.   doi: 10.11728/cjss2007.05.400
Abstract(2808) [PDF 3678KB](69)
Abstract:
Global background wind is derived from atmospheric pressure, temperature and density measured by MLS instrument onboard the Aura satellite in this article. The temperal and spacial variations of middle atmospheric wind are also analyzed. Comparisons of the derived Aura wind with WuHan meteor radar and Australian Adelaide observatory prove that the variations of Aura wind associated with time and space are in agreement with the observed results. Comparative result with HWM-93 indicates that the variations of Aura wind associated with time and space are nearly the same as HWM-93, and Aura wind is in better agreement with HWM-93 below 80 km than that above 80 km. The difference of zonal wind from directly observed data is no more than 20 m/s, and the relative difference is less than 18%, and Aura wind speed is larger than HWM-93.
Influence of ionospheric diurnal variation on the estimated GPS differential code bias
Li Lingxi, Zhang Donghe, Hao Yongqiang, Xiao Zuo
2015, 35(2): 143-151.   doi: 10.11728/cjss2015.02.143
Abstract(1253) [PDF 1120KB](36)
Abstract:
The condition of smooth temporal and spatial change of ionosphere should be demanded in all the methods to estimate the GPS Differential Code Bias (DCB) from GPS observation. Nevertheless, because the ionosphere usually exhibits variation to different degrees, this condition is just an approximation. Therefore, it can be indicated that the stability of GPS DCB estimated from GPS observation is affected by the ionospheric status. With SCORE DCB estimation method and GPS data obtained at BJFS (middle latitude) and XIAM (low latitude) stations in 2001 and 2009, the satellites DCBs are estimated respectively. Especially, the influence of ionospheric diurnal variation on the DCB stability is verified. It is found that the condition of the ionospheric diurnal variation affects the stability of satellites DCBs estimated from GPS observations, and the satellite DCBs estimated from nighttime GPS data are more stable than that from daytime data. The stabilities of estimated DCBs from BJFS data in 2001 and 2009, and those from XIAM data in 2009 exhibit heavy dependence on local time, but the difference is not obvious for the DCBs estimated from XIAM data in 2001. XIAM station is located near the equatorial ionospheric anomaly, and the ionosphere of this region exhibits notable variations even in the nighttime in solar maximum phase. This may be the reason for the weak dependence of estimated DCBs on local time.
The Ion Distribution Function From Maxwell Molecule Collision Model and Calculations of Incoherent Scatter Spectra
Xue Kun, Guo Lixin, Wu Jian, Xu Bin, Fang Chaofeng
2009, 29(3): 287-295.   doi: 10.11728/cjss2009.03.287
Abstract(3188) [PDF 719KB](75)
Abstract:
With regard to anisotropic plasmas, the Maxwell molecule collision model is used to describe ion-neutral collisions of Boltzmann equation. The viscous and heat flow are included in transport equations based on the two-Maxwellian distribution. The expressions of the ion drift velocity, ion parallel and perpendicular temperature, stress tensor and heat flow for parallel and perpendicular energy can be obtained by solving the transport equations. The ion velocity distribution of Maxwell molecule collision model can be obtained using the 16-moment approximation. According to the Sheffield's theories, the incoherent scatter spectra are calculated. In comparison to relaxation collision model, it is reasonable to use the Maxwell molecule collision model to describe the collision process of the non-Maxwellian ionospheric plasma in E region.
Modeling Research of 10.7 cm Solar Radio Flux 27-day Forecast (I)
Liu Siqing, Zhong Qiuzhen, Wen Jing, Dou Xiankang
2010, 30(1): 1-8.   doi: 10.11728/cjss2010.01.001
Abstract(2459) [PDF 683KB](75)
Abstract:
Due to the application requirement of high layer atmosphere density model and ionosphere model, the forecast method research of 10.7 cm solar radio flux (F10.7 index) is one of the important subjects. The middle term forecast of F10.7 is more difficult than the long term and short term forecast because of the lack of comprehending physical progress and the laws of solar active region revolution. The main middle term forecast methods of F10.7 are time-sequence model and empirical model in consideration of observational information of solar active region. In this paper, autoregression method was applied to the F10.7 27-day forecast research. The period of forecast experiment was from May 1, 1996 to April 12, 2007. According to the results of forecast error analysis, the prediction precision was satisfying when solar activity was low and F10.7 showed obvious 27-day periodic tendency, but was unsatisfying when large region appeared on the disk or disappeared from the disk rapidly. Compared with the forecast result of American Air Force (AAF) forecast from September 21, 2005 to June 7, 2006, the prediction Accuracy of autoregression method was similar to that of AAF. From all of these, we can see this linear predictive method could reflect F10.7 27-day periodicity, and was applicable for F10.7 27-day forecast in a certain extent. The research result in this paper is a basis of the further work of constructing precise model of F10.7 middle term forecast.
Technical Configuration and Simulation of NAIS-H for the MIT Mission
LU Li, S McKenna-Lawlor, J Balaz, SHI Jiankui, YANG Chuibai, LUO Jing
2014, 34(3): 341-351.   doi: 10.11728/cjss2014.03.341
Abstract(1025) [PDF 5970KB](33)
Abstract:
Energetic Neutral Atoms (ENA) are generated within the Earth's magnetosphere through charge exchange between magnetically trapped energetic ions and cool neutral gasses. An ENA imager can potentially record the arrival directions and energies of magnetospheric ENAs, as well as provide (indirectly) global images of the spatial and energy distributions of their parent ion populations. Preliminary technical configuration and simulation of the Neutral Atom Imaging System for high energy neutral atoms (NAIS-H) designed for the Chinese Magnetospheric-Ionospheric-Thermospheric (MIT) mission are described. In inherited the design concept of NUADU and focus on the main scientific objective of MIT and the orbit, a preliminary technical overview of this instrument is provided. The simulations under a dipolar magnetic field model show that the instrument has the capability to monitor global dynamic processes with high temporal and spatial resolution.
Simulation of Microwave and Sub-millimeter Wave Radiation from 1 to 3000GHz of Planetary Atmosphere
FU Jia, WANG Zhenzhan
2017, 37(2): 192-201.   doi: 10.11728/cjss2017.02.192
Abstract(1418) [PDF 4876KB](85)
Abstract:
In order to simulate the radiative transfer characteristics of planetary atmosphere in the microwave and sub-millimeter wave bands, the absorption coefficient from 1 to 3000GHz of the gases in planetary atmosphere are calculated by using line-by-line integration method. Based on the parameters of gas molecules in HITRAN database, such as the transition frequency, line strength and so on, the absorption feature of each gas molecule is simulated and compared with the common atmosphere radiative transfer model in microwave and sub-millimeter wave bands. As an example, the radiation transport characteristics of Earth's atmosphere are analyzed, and the atmospheric radiation brightness temperature of different frequency band using limb sounding method is simulated using the radiative transfer equation. The results can provide the model and theoretical basis for atmospheric composition detection simulation, the selection of detection frequency band and the retrieval of atmosphere profiles of Earth and other planets.
Design and thermal analysis of space dual-axis solar array drive assembly
Li Jianhui, Li Ruixiang, Qian Zhiyuan
2011, 31(3): 390-394.   doi: 10.11728/cjss2011.03.390
Abstract(3827) [PDF 621KB](191)
Abstract:
his paper introduced a lightweight Dual-axis solar array drive assembly (SADA), aiming at two key technologies of lightweight and long life. The Dual-axis SADA consists of A-axis which provides 360º of rotation and power transfer through the use of a slip ring device and B-axis which provides ±90º of travel and incorporates a simple flex loop for power transfer. The accelerated life test of key moving parts of SADA including the slip ring and the harmonic reducer were preformed and passed. The designed principle prototype of SADA has some merits, such as compact structure, good stiffness and light weight. The thermal analysis of the Dual-axis SADA had been preformed. The measures of thermal control are presented by comparing temperature distribution under different schemes.
Study on fabrication technology of reaction bonded silicon carbide mirror blank for space
Zhang Ge, Zhao Rucheng, Zhao Wenxing
2011, 31(3): 401-405.   doi: 10.11728/cjss2011.03.401
Abstract(3197) [PDF 624KB](57)
Abstract:
Silicon Carbide (SiC) is a new type of candidate material for large-scale lightweight space born mirror. Its low thermal distortion, high stiffness, high optical quality, and its dimensional stability are better than other traditional optical substrate materials such as ULE, Zerodure, Beryllium (Be) and so on. In this paper, the lightweight silicon carbide space mirror blank was fabricated by reaction sintering. Lots of large scale SiC green bodies were prepared by a gel-casting method with the lost mould technology. And the size of the largest SiC green body with sandwich structure is 1080 mm × 820 mm now. After drying, burning out the organic elements and reaction sintering, the reaction bonded SiC (RB-SiC) mirror blanks were fabricated. The test results of ground mirrors show that the structure of RB-SiC is fully solid, and the mechanical and thermal properties of RB-SiC are excellent in elastic modulus of 330 GPa, bending strength of 340 MPa, fracture toughness of 4.0 MPa&#8226;m1/2 and Coefficient of Thermal Expansion (CTE) of $2.6\times 10-6 K-1. The surface roughness (RMS) of the polished mirror is better than 3 nm, which means SiC is a fine candidate material for the spaceborne mirror.
ON THE ATTENUATION OF THE VLF RADIO WAVES IN THE EARTH'S IONOSPHERE
LI Kai, PAN Weiyan
1999, 19(1): 42-46.   doi: 10.11728/cjss1999.01.042
Abstract(2079) [PDF 320KB](45)
Abstract:
The attenuation of the VLFradio waves in the Earth's ionosphere is analyzedand computed. Using the Fourier Tansformation, one may obtain the formulation which indicates the attenuation changing with ionospheric collision frequenciesand the geo-magnetic orientations. Numerical results of the relations between theattenuation and the ionospheric collision frequencies under several geo-magneticorientations are given.
Attitude Control of Space Robot System With Dual-Arms by Optimal Motion Planning
TANG Xiaoteng, CHEN Li
2006, 26(5): 403-408.   doi: 10.11728/cjss2006.05.403
Abstract(2121) [PDF 3124KB](32)
Abstract:
The optimal nonholonomic motion planning for free-floating space robot system with dual-arms is discussed. Based on the linear and angular momentum conservations of the system, the system state equations for control design are established, so the nonholonomic motion planning objective of attitude control for space robot system is transformed as the solution of a canonical nonlinear control problem. The optimal control scheme for the proposed system is studied, and a numerical algorithm for computing approximate optimal control of the system is developed. The optimal motion planning approach proposed above possesses the advantages of obtaining the desired angles of the base's attitude and arms' joints only by controlling the arms' joints motion. A planar free-floating space robot system with dual-arms is simulated to verify the proposed approach.
Simulation of Radiometric Calibration of Spaceborne SAR by Amazon Rainforest
TAO Kun, ZHANG Yunhua, GUO Wei, YUN Risheng, KANG Xueyan
2006, 26(4): 309-314.   doi: 10.11728/cjss2006.04.309
Abstract(3193) [PDF 2221KB](158)
Abstract:
Radiometric calibration is a powerful means to quantify the SAR (Synthetic Aperture Radar) system performance. Compared with that before launching, there is a considerable distortion of the antenna elevation pattern after the spaceborne SAR is in orbit, which will debase the quality of SAR images greatly. An accurate measurement of the antenna elevation pattern is an important aspect of spaceborne SAR radiometric calibration. The external calibration of distributed targets based on the uniform backscattering is an optimal choice to measure the double-way antenna elevation pattern. Amazon rainforest is the most stable, most uniform and flattest distribute external target in the world. With a backscattering almost independent of the incidence, Amazon rainforest is regarded as an ideal radiometric calibration site. However, because the SAR data sets collected by our own spaceborne SAR are still unavailable at present, the estimation of unknown parameters of SAR antenna pattern model based on the simulated spaceborne SAR power image has been investigated in this paper. A successful computer simulation of how to determine the antenna elevation pattern in orbit by simulated Amazon rainforest SAR power images has been made, which is significant for the radiometric calibration of spaceborne SAR in our country.
Aspects of global magnetospheric processes
P. Song, V. M. Vasyliūnas
2010, 30(4): 289-311.   doi: 10.11728/cjss2010.04.289
Abstract(2612) [PDF 669KB](42)
Abstract:
Magnetospheric global modeling is a method to link observations from distant regions via physical laws and has long played a unique and crucial role in space physics. It, different from computer simulations, represents the highest level of abstraction of the physical understanding of the processes that cause observed phenomena. It results in various specific models. While it appears in the form of cartoons, it is based on and has to be qualitatively consistent with physical laws. With the advancement of computer simulations, clues to the connection between physical laws and observation can be perceived much more easily than as ever before. However, computer simulation results are highly dependent on the used boundary conditions and numerical methods which may or may not represent the reality, even if the initial conditions are properly set. Therefore, simulations can easily mislead the investigations. Furthermore, a simulation result needs to be examined using diagnostic tools, such as field line tracing and streamline tracing programs. There are uncertainties in these diagnostic methods. The errors can be very large in certain areas under certain conditions. For example, a small error may link two different field lines or stream lines. The interpretations of the simulation results can be misled by these errors. The knowledge of global modeling can be useful in identifying the inconsistencies in the simulations and the flaws in the theoretical interpretation from the simulations. This review-tutorial article outlines the principles of the global modeling and discusses the successes and flaws of several global models.
An Adaptive Fuzzy Controller for Satellite Maneuver Control
WANG Shuquan, YIN Xunhe, ZHAO Guangheng
2006, 26(1): 54-58.   doi: 10.11728/cjss2006.01.054
Abstract(2372) [PDF 1829KB](48)
Abstract:
An adaptive fuzzy controller for Satellite Maneuver Control (SMC) is outlined. The typical fuzzy controller has a quick transient response and a very good robustness quality, and can easily incorporate human expert knowledge in the form of fuzzy rule "intelligence". But to construct the fuzzy rule base we must hold enough expert knowledge in advance, sometimes it's a difficult work. So the adaptive method is incorporated into the fuzzy control system, thus by adjusting the parameters of the fuzzy system, a proper fuzzy rule base can be got. And because the analysis is based on the Lyapunov function, the system is insured to be stable. Comparison of the system's performances with no language information and with only one language information is given, shows that with only one language information the system can reach a very high quality. Finally, simulation results substantiate the robustness quality of the adaptive fuzzy control system.
Solar Activity Dependence of Ionosphere Ion Upflow in the Polar Topside
FU Shuai, JIANG Yong, ZHAO Kai, JIANG Yi, SU Yucheng
2017, 37(1): 28-38.   doi: 10.11728/cjss2017.01.028
Abstract(1134) [PDF 4095KB](63)
Abstract:
The influence of solar activity on ionosphere ion upflow was studied, over the northern and southern hemispheric polar topside. The observations were obtained from the Defense Meteorological Satellite between 1995 and 2005. Results show that the response characteristics of upflow events on solar activity are roughly consistent for the two hemispheres, that is, ion upflow fluxes and ion densities are generally larger during high solar activity than those during low solar activity, but ion vertical velocities and upflow occurrence rates show an opposite variation trends, i.e., they are higher and more frequently seen under the conditions of low solar activity, respectively. Besides, we further calculated the mean value of upflow parameters in the southern hemisphere. The ratios of them under high and low solar activity conditions are about 2.26, 3.35, 0.71 and 0.51. Furthermore, the results also show that it is the ion densities instead of ion vertical velocities that have profound effect on the upflow fluxes. The causes of such a dependence is briefly analyzed. Under different levels of solar activity, ionosphere ion densities are different because of the variations of ionization rates and ion-neutral collision frequencies. The collision frequency between ion and neutral atmosphere is closely related to the ion density. Therefore, the ion upflow occurrence rate in the polar topside ionosphere depends on the level of solar activity.
Collision Probability Analysis and Application of Cataloged Space Debris
CHENG Tao, LIU Jing, WANG Ronglan, YU Youcheng
2006, 26(6): 452-458.   doi: 10.11728/cjss2006.06.452
Abstract(2947) [PDF 1513KB](97)
Abstract:
With the expansion of the human's activity in exploring, utilizing the outer space, protecting space environment have become the most significant task in space navigation. Since the neglect of the space debris environment in the past century, the total number of orbital space debris increases rapidly, which leads to an unacceptable large risk of collision to spacecraft. Space Debris Collision Avoidance (SDCA) is the only strategy to reduce the risk of collision, when the dimension of space debris is lager than 10 cm. The decision whether the avoiding maneuver is necessary depends on the analysis of conjunction, the rigorous calculation and assessment of collision risk between spacecraft and debris and compare to the collision criterion. This paper initially introduces the flow of the Space Debris Collision Avoidance System (SDCAS), with comparing of the two kinds of warning criterion, the main topic on method of collision probability is evoked. Collision probability is a new type of warning criterion, which not only takes the miss distance into consideration, but regards all the geometrical parameters during the approach as the factor to the collision risk, combining with all influence of these parameters. Eventually, with the detailed analysis, the effect of the covariance or uncertainty to the collision probability has been drawn to the surface, which plays an indispensable role in measuring the risk of collision. The attitude of the error ellipse which is constructed by the covariance has also affect the result of collision probability. Based on the analysis of covariance, the method of collision probability posts many advantages to the Box method. Especially, the rate of false warning has been decreased dramatically.
STUDY ON SPACECRAFT ANOMALY CAUSED BY SPACE ENVIRONMENT
ZANG Zhenqun, GU Shifeng, SHI Liqin, WU Zhonghua
1998, 18(4): 342-347.   doi: 10.11728/cjss1998.04.342
Abstract(2323) [PDF 370KB](97)
Abstract:
In this paper, about 10 years' dare of the spacecraft anomaly caused by space environment for the satellites (including SCATHA, TDRS-1, GPS and GOES) running near or on geosynchronic orbits are analyzed. For these anomaly, their yearly, monthly, hourly in local bine as well as different anomaly type distribution characters are studied respectively. The result shows that diversified space environment causes various types of spacecraft anomaly due to its different effects on spacecraft. (1) No general character exists for effects of long-term and/or short-term solar activities on spacecraft anomaly. (2) From a view of long-term, SEUs are mainly caused by heavy ions from galactic cosmic ray and solar proton event is not important to SEUs. (3) The study and prediction about space environment are very important and necessary to analysis, recognition, prediction and shielding for spacecraft anomaly.
Extracting of Periodic Components in the Solar Activity Using EMD Method
LI Qiang, WU Jian, XU Zhengwen, WU Jun
2007, 27(1): 1-6.   doi: 10.11728/cjss2007.01.001
Abstract(3126) [PDF 2423KB](91)
Abstract:
EMD (Empirical Mode Decomposition) technique has indicated the advantages and potentials in applications related to processing the nonlinear and non-stationary time series. In this paper, EMD method is adopted to study the solar cycles on various time scales. Using the EMD method, the averages of monthly medians of sunspot numbers of 110 years (1894-2003) and 55 years (1949-2003) can be decomposed into a series of modes and a trend respectively, including 1.3~1.4 years periodic component, 25~30 months QBO (Quasi-Biennial Oscillation) component, 11-year solar cycle component and 22 year Hale cycle component. Among those, the ll-year solar cycle mode with the largest amplitude has the high correlations with original sunspot numbers. In a nutshell, the EMD method other than the traditional and conventional methods can bring us the isolated characteristics of the solar variations on various time scales.
A Method to Correct the Characteristic Curve of a Langmuir Probe and the Possibility to Measure Plasma Electron Temperature Through Ion-Acoustic Waves
WANG Wenqing, XIAO Zuo
2005, 25(3): 204-207.  
Abstract(2163) [PDF 1199KB](93)
Abstract:
A proper method is proposed in this paper to eliminate the additional electric current by electrons with high energy in the Langmuir V-I characteristic curve when plasma consists of two groups of electrons at different temperatures and under the condition that Te>>Ti. The study showed that after this correction the result of electron temperature measured is more reasonable. Another method to obtain electron temperature using Ion-Acoustic Wave speed was also studied in this paper. The ion-acoustic wave in this experiment was excited by either tone-burst test wave method or by CW test wave method. The comparison of the electron temperature of the plasma using the above correction method with that calculated from ion-acoustic wave (IAW) speed shows that the average error of electron temperatures from IAW speed Te (about 0.1 eV) is much smaller than that from Langmuir V-I characteristic curve (about 0.44eV, after the above mentioned correction). It can be concluded that to make an additional correction is a good way to raise the accuracy of electron temperature measurement while using IAW method seems better in certain cases.
AN EXPERIMENT RESEARCH ON TECHNIQUE OF ATTITUDE DETERMINATION WITH DOUBLE SATELLITES
ZHENG Wei, WU Jie, HU Xiaoping, ZHAO Jiankang
2000, 20(3): 257-261.   doi: 10.11728/cjss2000.03.257
Abstract(1904) [PDF 280KB](46)
Abstract:
The method of attitude determination with double satellites is discussed indetail in the paper, and the actual experiment of attitude determination with onlytwo GPS satellites is conducted. The long-short baseline method and sequenceoptindzation method are synthetically used to estimate carrier phase ambiguity.The experiment results indicate that the success rate of attitude deterndnationexceeds 90% and the mean square error of attitude can be less than 0.5°, whenbaseline length be 1 m around.
Statistical study on the ascending time of solar energetic particle events
Jian Yi, Lai Min, Ding Liuguan
2014, 34(6): 785-793.   doi: 10.11728/cjss2014.06.785
Abstract(1143) [PDF 1234KB](38)
Abstract:
A total of 66 great gradual Solar Energetic Particle events (SEPs) from 1997 to 2006 were selected for analysis. The correlations were analyzed between the ascending time of the SEPs in time profile and the heliographic longitude of the source active region. The Coronal Mass Ejection (CME) and flares were also investigated in the ascending stage of the SEP flux profile. The results of statistical analysis indicate that the source regions of these great SEPs are mainly distributed in the western hemisphere, particularly within the area from 45° east longitude to 45° west longitude relative to the magnetic footpoint. In the presence of fast solar wind, the ascending time in low-energy channel has a good correlation with the relative longitude and the ascending time increases with the distance from magnetic footpoint. However, the correlation is unobvious in high-energy channel. Correlations have not been observed between the ascending time of the SEPs associated with full halo CMEs and the source region longitude. However, the relations between the ascending time of the SEPs and source longitude are well fitted with quadratic curves. The analytical results show that the flare acceleration process played an important role in the gradual phase of SEP time profile, especially for the SEPs associated with partial halo CMEs.
THE APPLICATION AND COMPARISON OF GPS POSITIONING DATA ON HY-1 SATELLITE
LU Chunling, ZHANG Wu
2004, 24(3): 226-232.  
Abstract(1886) [PDF 1361KB](48)
Abstract:
HY-1 Satellite was launched successfully on May 15th, 2002. It is the first ocean color observation satellite in China. On the other hand it is the first long life experimental and operational small satellite in China. The on-board GPS receiver was successfully used in navigation and give out the precise time. The positioning principle, flow chart and application of the GPS receiver on HY-1 satellite are introduced in this paper. A method to confirm and verify the on orbit positioning data is discussed. Using the Two Line Elements (TLE) from NASA web, the satellite orbit is calculated by the Satellite Tool Kit (STK) software so to obtain the nadir positions, then, the real GPS data at that time are processed and converted to the nadir positions. The nadir geodetic positions from GPS data are compared with those from the TLE. The difference of nadir positions between GPS and TLE methods are given. It is very helpful to give the comparison using the real on-board data.
Research of Wireless Sensor Networks for Intra- Spacecraft Environmental Monitoring
ZHOU Li, CAO Song, AN Junshe
2012, 32(6): 846-854.   doi: 10.11728/cjss2012.06.846
Abstract(3149) [PDF 816KB](66)
Abstract:
Wireless interface service is now one of the most interesting and newest avionics technologies. The wireless technology will be used widely in space exploration in the future. Considering the characters of the intra-spacecraft environmental monitoring, a system scheme based on wireless sensor networks is designed, in order to decrease the power consumption as well as the spacecraft mass and volume. A low power RF chip and the ZigBee protocol stack Z-Stack of TI are used to design a demonstrator. The network structure and the sensor node architecture, including its hardware and software design, are described. The demonstrator can monitor the environmental parameters of the intra-spacecraft and its instruments, e.g., temperature, humidity, the instruments' voltage and current. Experiments have been carried out. The results indicate that the sensor nodes' power consumption is extremely low, the mesh network architecture is robust and flexible, and the use of ZigBee Pro for WSN can achieve stable transmission of data between multiple terminals.
Movement Reliability of Rotation Joint of Umbrella Antenna
HU Taibin, CHEN Jianjun, ZHANG Jianguo, LI Xiaoping
2005, 25(6): 552-557.   doi: 10.11728/cjss2005.06.552
Abstract(2284) [PDF 1723KB](75)
Abstract:
Aiming at the rotation joints in deployment mechanism of umbrella antenna used in a certain satellite, the movement reliability has two parallel performance functions: the performance function according to rotation work and that according to rotation moment. Corresponding to the beginning phase, outspreading phase and the phase that the net has pressing force, the expressions of two performance functions were established respectively according to the position relations of all components. Secondly, two-kind reliabilities can be calculated from the two performance functions by means of the random functional moment method and the second moment method for reliability analysis. The movement reliability of one rotation joint can be got from two parallel reliability models. Finally, the change curve of the movement reliability of umbrella antenna outspread mechanism with outspreading angle was analyzed with an example. To the whole outspreading course, the reliability has the trent of first increase and then decrease, and the reliability of the beginning phase was smallest.
Magnetospheric physics in China: 2008—2010
Cao Jinbin, Liu Zhenxing, Pu Zuyin
2010, 30(5): 445-455.   doi: 10.11728/cjss2010.05.445
Abstract(2326) [PDF 180KB](34)
Abstract:
In the past two years, most of the works on magnetospheric physics were made by using the data of Double Star Program and Cluster missions. However some works were still conducted by computer simulation or using the data from other space missions and ground geomagnetic observations. This paper briefly review these previous works based on papers selected from the 28 publications from April 2008 to April 2010. The subjects covered various sub-branches of magnetospheric physics, including geomagnetic storm, magnetospheric substorm and etc.
Simulation Studies on Seasonal Variations of the Stratospheric Dynamics and Trace Gases Using Coupled Chemistry-Climate Model WACCM-3
Liu Yi, Liu Chuanxi
2009, 29(6): 580-590.   doi: 10.11728/cjss2009.06.580
Abstract(3643) [PDF 969KB](44)
Abstract:
The coupled chemistry-climate model WACCM-3 (Whole Atmosphere Community Climate Model) developed by NCAR is applied to study the seasonal variations of the stratospheric wind, temperature and trace gases such as O3, CH4, N2O, H2O, HCl, HNO3. Comparisons of the ECMWF/ERA-40 dynamics and observed trace gases from HALOE, MLS, CLEAS on UARS satellite show that the WACCM-3 simulation forced by the climatological Sea-Surface Temperature can generally reproduce the observed characteristics in the seasonal cycles of the stratospheric zonal winds, temperatures and chemical tracers. However, some obvious biases exist in model dynamics, which are closely associated with biases in the distributions of trace gases. Especially, the circumpolar westerlies during austral winter (July) and spring (October) in WACCM-3 model are too strong, which can cause a stronger barrier to the poleward transports of warm air and long-lived trace gases (e.g., CH4, N2O, H2O) in Antarctic lower stratosphere. Moreover, this cold bias also enhances the denitrification and dehydration effects during the formation of Polar Stratospheric Cloud (PSC), on the surface of which more HCl are activated through a series of heterogeneous reactions. As a result, the simulated concentrations of chemical tracers (e.g., CH4, N2O, H2O, HCl, HNO3) are prominently lower than observations in the Antarctic lower stratosphere during wintertime and springtime. In addition, there are also biases in the tropical stratospheric easterlies and the meridional transports of stratospheric tracers (e.g., O3, CH4, N2O, H2O), since WACCM-3 does not generate a Quasi-Biennial Oscillation (QBO) in tropical stratospheric winds.
Study of Refractivity Retrievals Based on GPS Radio Occultation Mean Bending Angles
SONG Yaxiong, FU Yang, HU Xiong, GONG Xiaoyan, YAN Wei, ZHAO Zengliang, DU Xiaoyong
2016, 36(3): 312-322.   doi: 10.11728/cjss2016.03.312
Abstract(844) [PDF 5504KB](47)
Abstract:
The retrieval step from bending angle to refractivity requires background information.Retrieval schemes in different GNSS-RO processing centers use different types of background data, which is the source of inconsistency of the generated radio occultation climatologies In this paper, the COSMIC excess-phase data during Jan.,Apr.,Jul.and Oct.of 2008 was used to study the retrieving of monthly mean refractivity from monthly zonal mean bending angles The comparison results show that:it is not necessary to apply statistical optimization to individual bending angles, since the approach based on mean bending angles and the standard method produce nearly identical mean refractivity below 40 km;and above 50 km.The approach based on mean bending angles is better than the standard method when compared with mean refractivity generated from ECMWF data.
SCALAR AND VECTOR MAGNETIC ANOMALY MAPS FOR CHINA DERIVED FROM MAGSAT DATA
An Zheng-chang, Xu Yuan-fang, Wang Yue-hua, D. R. Barraclough, D. J. Kerridge
1992, 12(2): 123-128.   doi: 10.11728/cjss1992.02.123
Abstract(2160) [PDF 594KB](59)
Abstract:
The Magsat Investigator-B magnetic tapes are the source of data for this study.The lati-tuhe and longitude ranges of data are from 10°N to 60°N and 70°E to 140°E.In order to get the crustal anomaly field,the main field,magnetospheric,ionospheric and induction fields from the Magsat data must be subtracted.The GSFC (12/83) model is used to correct the internal field,external field and induction field.In order to improve pass to pass consistency,the 2nd-order polynomial in latitude is used to fit the crustal anomaly field for each pass,and subtract the fitted values from the crustal anomaly field to get the final crustal anomaly field.The region studied is divided into cells,the size of each cell is one degree in latitude and longitude.The value of the anomaly field at the center of each cell is taken as the mean values of the data falling into the cell.Based on hte grid point values,the contour maps are produced.They include: 1.The X,Y,Z and F anomaly maps derived from dawn data only;2.The X,Y,Z and F anomaly maps derived from dusk data only;3.The X,Y,Z and F anomaly maps derived using dawn and dusk data combined.The contour interval is 2nT.It is considered that the consistency between the dawn and dusk maps is good.The satellite magnetic anomalies in and near China are between-10nT and 10nT.The magnetic anomalies show good correlation with the regional tectonic features of China: Pre-Cam-brian cratons such as Tarim,Yangtze and Sontliao Cratons are positive anomaly areas.The Tibet plateau is negative anomalp area.The satellite anomalies represent the lateral variations in the magnetization of the lowe crust.
Introduction and interpretation of fluid mechanical experiments by Don Pettit on International Space Station
Li Jianqiang, Yuan Zhangfu
2009, 29(1): 140-144.   doi: 10.11728/cjss2009.01.140
Abstract(3524) [PDF 634KB](40)
Abstract:
The microgravity experiments "Saturday Morning Science'' carried by Don Pettit, senior science astronaut, in 2003 on International Space Station was introduced in the present paper. The experiments video which has become available on NASA website demonstrates a variety of surprising phenomena which are highly related to the basic sciences in fluid convection, mechanics, crystallography, kinematics and so on. The experiments include 14 fluid experiments and 7 mechanical experiments. Only fluid experiments were narrated in this paper, particularly "Marangoni convection'' and "thin film crystallizer'' were compared with their counterparts on ground and the effects of microgravity on relevant phenomena were analyzed.
Research on photometric correction of lunar image from CCD stereo camera onboard Chang'E-1 satellite
Chen Chao, Qin Qiming, Lu Yan, Wang Jinliang, Zhang Ning
2013, 33(1): 120-127.   doi: 10.11728/cjss2013.01.120
Abstract(2753) [PDF 4475KB](84)
Abstract:
In order to fit coefficients of the phase function more accurately and obtain some accurate results, Lommel-Seeliger factor has been revised according to the characteristics of CCD stereo camera data of Chang'E-1. By effective revision, the incidence angle and instrument viewing angle effect have been removed. The corrected image data fit much better with the variable trend of phase angle. Then photometric correction on the CCD stereo camera data of Chang'E-1 has been carried out pixel by pixel using the improved Lommel-Seeliger photometric correction model introduced by the revised Lommel-Seeliger factor. Finally, this algorithm has been verified by two groups of data from different latitudes of the same orbit and different view angles of the same area, respectively. The experimental results show that this method could effectively correct the inconsistency of the spectral characteristics of the object induced by the change of observation conditions. Moreover, using this method, photometric correction shows better performance even at brighter or darker areas.
Response of Mesosphere and Lower Thermosphere to a Localized and Time-Variable Thermal Source
XIE Bian, ZHANG Shaodong
2006, 26(5): 331-337.   doi: 10.11728/cjss2006.05.331
Abstract(2041) [PDF 2294KB](12)
Abstract:
By using the alternative-direction-implicit scheme, a two-dimensional fully nonlinear compressible atmospheric dynamic model is established, with which, the responses of the mesosphere and lower thermosphere to a localized and time-variable thermal source and a momentum forcing source in the troposphere are numerically simulated respectively. And then the energy density, the horizontal and vertical wavenumber and the frequency of the response are analyzed. The numerical results show that the response carrying the energy propagates from the troposphere and lower stratosphere upward to the mesosphere and lower thermosphere within a relatively narrow horizontal field which is symmetrical about the horizontal location of the heat source. The effect of the heat source upon the response is much stronger than that of the momentum forcing source. It is different in affecting the frequency, the horizontal wave length and the vertical wave length of the induced gravity wave. The horizontal wave length can be determined by the horizontal scale of the heat source, the frequency of the response is almost the same with the heat source with high frequency in the simulation, but the vertical wave length of the response is much larger than the vertical scale of the source. Usually, the longer the horizontal scale of the thermal source is, the larger the vertical wave length of the induced gravity wave.
A Satellite-borne Miniature Ion Mass Spectrometer for Space Plasma
Kong Linggao, Zhang Aibing, Zheng Xiangzhi, An Yaya, Wang Wenjing, Tian Zhen, Guan Yibing, Liu Chao, Ding Jianjing, Sun Yueqiang
2015, 35(6): 755-762.   doi: 10.11728/cjss2015.06.755
Abstract(1197) [PDF 296KB](46)
Abstract:
The miniature design technology is an important trend in space exploration. Mass spectrometer is used extensively in the space environment detection. The miniature ion mass spectrometer utilizes a 127° cylindrical electrostatic analyzer accompanied with a Time of Flight (TOF) unit based on ultrathin carbon foil to measure the energy spectra and composition of space plasma. The Time of Flight technique has been used broadly in space plasma measurement. A new type of miniature method for the ion mass spectrometer is introduced. The total mass of the instrument is 1.8 kg and the total power consumption is 2.0W. The calibration results show that the energy measurement range is 8.71~43550eV, the energy resolution is 1.86% and the ion mass from 1 amu (1 amu = 1.67 × 10-27 kg) to 58 amu can be resolved by the miniature mass spectrometer. The miniature ion mass spectrometer also has a potential to be increased in the field of view by an electrostatic deflecting system to extend its application in space plasma detection. The miniature ion mass spectrometer has been selected for pre-study of Chinese Strategic Priority Research Program on Space Science.
Modeling and Measurement of Rigid Wheel-soil Interaction for a Lunar Rover
Tao Jianguo, Hu Ming, Gao Haibo, Deng Zongquan, Quan Qiquan
2008, 28(4): 340-344.   doi: 10.11728/cjss2008.04.340
Abstract(2675) [PDF 1976KB](76)
Abstract:
Based on soil's press-sinkage and shear models of terramechanics and passive earth pressure of soil mechanics, mathematical models of wheel-soil interaction are constructed for a rigid wheel of lunar rover moving or steering on deformable soil. For analysis of effect of soil parameters and wheel slips to rigid wheel locomotion, the wheel's performance parameters on different soil are computed through these models, such as drawbar pull, moving torque and steering torque to different slips. A novel test-bed is set up to test wheel's performance parameters, and experimental results of a rigid wheel on the soil validate the effectiveness of presented models.
Short-term Forecast of f0F2 Based on Ionospheric Storm Empirical Model and Kalman Filter
Xu Tong, Wu Jian, Wu Zhensen, Huang Chaojun, Wei Guohui, Feng Jian
2009, 29(2): 202-207.   doi: 10.11728/cjss2009.02.202
Abstract(3952) [PDF 657KB](70)
Abstract:
With the time weighted accumulation index ap(τ), an empirical storm model of the relative deviation of f0F2 from its monthly median is established. It shows good accuracy only at strong geomagnetic disturbed condition in summer and equinoxes, but less accuracy result for winter. The wide used method in weather, ydrography, etc., Kalman filter, is used to update the coefficients of the empirical model and expected to make better improvement. The test with the ionosound data of hourly values from 1986 to 1995 at Changchun illustrates that the root-mean-squre error of the forecasted values in one hour advance is 0.76 MHz in winter, 0.68 MHz in summer and 0.61 MHz in equinoxes, respectively. The root-mean-squre error in different seasons are from 0.87 MHz to 1.43 MHz in the case of ap(τ)>100, i.e. the super strong geomagnetic disturbed condition. Simultaneously the method is compared with IRI2001 including the STORM model for several disturbed events, which shows the ability of updating the model coefficients and prospect of application.
Nonlinear Interactions between the Quasi 5-day Wave and Tides Based on Meteor Radar Observations at Mauiormalsize
GU Jingxiao, HUANG Chunming, HUANG Kaiming
2015, 35(4): 445-452.   doi: 10.11728/cjss2014.04.445
Abstract(944) [PDF 1663KB](46)
Abstract:
Nonlinear interactions between the quasi 5-day wave and tides based on meteor radar observation in the Mesosphere and Lower Thermosphere (MLT) at Maui are studied in this paper. Strong sum interaction between quasi 5-day wave and diurnal tide, and evident difference interaction between quasi 5-day wave and semidiurnal tide are observed during the time of attention. However, their difference and sum counterparts are clearly weaker. The secondary waves generated from those interactions beat with the tide and show intense modulation at the period of 5 days which confirms the existence of their interactions. Additionally, correlation coefficients among these waves are calculated to further explore their interactions and find that they can persist for several days although they are highly intermittent. The energy exchange among these waves can be reversible during the observational time. The periods when the significant difference interaction between the quasi 5-day wave and semidiurnal tide occur are much shorter than those when the significant sum interaction between the quasi 5-day wave and diurnal tide occur. Moreover, these two strong interactions can take place simultaneously. In generally, this study provides the proof of nonlinear interactions between quasi 5-day wave and tides which were seldom reported before.
SCINTILLATION SPECTRA INVESTIGATIONS DURING THE EVOLUTION OF IRREGULARITIES IN THE EQUATORIAL F REGION
Zhen Wei-min, Long Qi-li, Ma Jian-min, Cao Chong
1995, 15(2): 143-147.   doi: 10.11728/cjss1995.02.143
Abstract(1934) [PDF 378KB](63)
Abstract:
Power spectra are calculated for the amplitude scintillation of VHFsignal at an equatorial station,Haikou.Theoretical simulation is also performed.Alot of set-ntillation events last for a long time.Temporal variation of amplitude scintillations arising due to the presence of irregularities in the night time equatorial Fregion is studied during the early and late stages of evolution of these irregularities.The higher frequency portion of the power spectra in the late stage are found to be steeper than these in the early stage.It can be attributed to the decay of irregularities with wavelength of several hundred meters in the late stage.The higher irregularity drift speed is found in the late phase.
Deployment Dynamic Analysis of Circular Truss Deployable Antenna With Friction
ZHAO Mengliang, GUAN Puling
2006, 26(3): 220-226.   doi: 10.11728/cjss2006.03.220
Abstract(2182) [PDF 2146KB](51)
Abstract:
Through a design of circular truss deployable antenna model, the primary layout and deployable mechanism and the primary technique requirements are introduced in detail. In order to provide reference for optimization design and predict the dynamic performance of the deployable structure in orbit accurately, deployment dynamic analysis of the structure with friction is essential. The movement property of deployable space truss structure is analyzed with the Moore-Penrose generalized inverse method. A practical mathematic algorithm is presented to formulate the constraint equations and the relevant Jacobian matrices, and to simulate the constraint conditions of the structural deployment effectively. By studying the non-linear action mechanism of the friction during deployment, the dynamic equations of Coulomb friction and viscous friction for the deployable structures are established. Based on the above work, deployment dynamic analysis of circular truss deployable antenna with friction is carried out. The deployment dynamic of a circular truss deployable structure is simulated with friction effects and without friction. The numerical simulations show that the analytical process is efficient for deployment dynamic analysis of circular truss deployable antenna with friction.
FREE FLOW ELECTROPHORESIS SEPARATING MODEL PROTEINS UNDER THE MICROGRAVITY
DING Shijian, LIU Tao, SONG Jinfang, WU Gaode, SHAO Xiaoxia, XIA Qichang, WU Hanji, JIANG Yuanda, ZHANG Zhiyuan, LIU Wenxi, FENG Xuezhang, MA Yuli, LI Qin
2004, 24(3): 233-240.  
Abstract(1802) [PDF 1910KB](56)
Abstract:
Separation of two colored model proteins, cytochrome C and hemoglobin, were conducted in the specially self-designed free flow electrophoresis device A3-2 using zone electrophoresis mode under 1 g- and μg- conditions. The results demonstrated that the higher resolution of free flow electrophoresis acquired under the microgravity is obtained. Both onboard LBD detection and measurement of the seperation by the spectrometer demonstrated that the distance between the zone maxima of the two proteins were increased and the dispersion of hemoglobin decreased. The experiments also included: (1) The effect of the glycerol concentration on the separation results; (2) Post-flight analysis of the contents of the fractions. The separation results of 10%, 7%, 4%, 2% and 0% glycerol concentration in the electrophoresis buffer are compared and no significant effect of the glycerol on the separation results are found. So the glycerol and its disadvantages for the clean and storage of the device were excluded finally. Gel electrophoresis and mass spectrometry analysis of the contents of the fractions confirmed that two proteins have been effectively separated.
A COMPENSATION OBSERVER METHOD FOR THE IMPROVEMENT OF PERFORMANCE OF LOW- SPEED REACTION WHEEL
WANG Bingquan, LI Ying, YANG Di
1999, 19(4): 362-367.   doi: 10.11728/cjss1999.04.362
Abstract(2196) [PDF 381KB](45)
Abstract:
The dynamic equation of the low-speed reaction wheel used to stabilize a satellite's three-axis attitude is put forward on the base of Dahl friction model, andaccording to this the phenomenon that the reaction wheel's speed crossing zero disturbs satellites attitude is analyzed. Anonlinear observer is used to estimate thefriction torque in order to compensate it. Simulation results prove that this methodcan compensate the reaction wheel low-speed friction, and improve attitude pointingaccuracy and stability.
The Research on Main Satellite Bobbin Cylinder Incorporated With Main Heary Structure and Bracket of Large-Volume Tank
CHEN Changya, WANG Deyu
2005, 25(2): 149-153.  
Abstract(2256) [PDF 1335KB](74)
Abstract:
With the background of the large-scale of modern satellite structure and propellant tank, a format of main satellite bobbin cylinder incorporated with main heary structure and bracket of large-volume tank, are proposed aiming at lowering the centroid and increase the fundamental frequency. The new structure type can meet the requirements of both the design of tank volume and the mechanical transferring efficiency from payload of main structure to carry. The numerical computation of finite element method indicates that the proposed structure format can meet the requirement of relevant structure performances and can server as the referential configuration of satellite structural design in the future. The main bobbin structure is weaved by high modulus carbon fiber, the cylinder of which is embedded a carbon fiber board inside. The designability and spreading weavablility should be made full use of to produce it according to the need.
Tidelike Periodicities of Ionospheric Sporadic E Observed at Low Latitude Hainan Station
Wang Guojun, Shi Jiankui, Wang Xiao
2013, 33(5): 501-508.   doi: 10.11728/cjss2013.05.501
Abstract(2026) [PDF 2636KB](46)
Abstract:
The time series of the ionospheric Sporadic E (Es) critical frequency (f0Es) and its virtual height (h'Es) were performed on a large database of DPS-4 ionograms recorded at Hainan station (19.5°N, 109.1°E) in 2004 to investigate the features of tidelike periodicity variations in low latitude. On yearly spectra, there was pronounced 8-hour periodicity in low latitude Es in addition to the well known 24-and 12-hour tidal variations. The yearly average phases of 24-, 12-, and 8-hour periodicities for f0Es (h'Es) were at 13:00LT (13:00LT), 11:00LT (09:00LT), and 09:30LT (09:30LT). On every two-month spectra, the results showed that (1) the 24-hour periodicity in Es was the most pronounced in each season; (2) The 12-hour periodicity in Es was outstanding in each season except in January-February months; (3) The 8-hour periodicity was remarkable in equinoxes and July-August months for f0Es, and it was notable in almost each season for h'Es; (4) The 6-hour periodicity mainly occurred in November and December for f0Es, whereas for h'Es it appeared more in summer and winter, and weakly in equinox months. It is clearly distinct from previous results by the fact that the 6-and 8-hour periodicities in Es layer at Hainan station can occur in winter or other seasons. The 6-and 8-hour periodicities in Es layer most probably are caused by the quarter-diurnal and terdiurnal tide components, which needs to be investigated further by combining the observations and modeling of local tide.
STORM-TIME INCREASE IN COSMIC RAY INTENSITY AND ITS CHARACTERISTICS
Ye Zong-hai, Sun Xiao-qing
1992, 12(4): 270-278.   doi: 10.11728/cjss1992.04.270
Abstract(2189) [PDF 771KB](140)
Abstract:
The cosmic ray increases due to considerable depressions of cosmic ray cut off rigidity during large geomagnetic storms are investigated.Data from 11 superneutron monitors in world network are analyzed for six geomagnetic storms of various type during 1984-1989.The results show that the storm-time increases are due to existence of westward equatorial ring currents developing or intensifying during geomagnetic storms.The stronger the geomagnetic storm,the larger the storm-time increase.The storm-time increases have obvious latitude effect or geomagnetic cut off rigidity dependence.Beijing station is at the obvious region for the storm-time increase,and storm-time increases are of local tune dependence.This enhancement is larger at the daytime than at the nighttime.Showing that the intensifying ring current is asymmetrical.
Distribution of CMEs in different angular width and its relationship with the phase of sunspot numbers in solar cycle 23
Meng Weijuan, Le Guiming, Lin Zhaoxiang, Zhang Yong, Yang Xingxing
2013, 33(3): 225-230.   doi: 10.11728/cjss2013.03.225
Abstract(2616) [PDF 488KB](61)
Abstract:
In this paper we statistically analyzed the distribution of the numbers of CME with different angle width during the period of 1996-2008. Then we obtained the relationship between the number of CME with some typical angle width varying with time and that the sunspot numbers varying with time. The analytical results indicate that the numbers of CME within angle width 0° ~ 180° make up 95%, full-halo CMEs make up 2.83%, and the quantities of CME within angle width 301° ~ 359° make up very little proportion of all CMEs. The CMEs of angle width 0° ~ 60° have three peaks, which doesn't match the characteristics of sunspot numbers varying with time. There is no two-peak distribution of the numbers of CME within angle width 121° ~ 180°. Moreover, the distribution of full-halo CMEs has a typical two-peak structure, with the first peak appearing in 2001 and the second peak appearing in 2005, which is not synchronized with the distribution of sunspot numbers.
Using IGS-TEC data to analyze the variation of EIA crest over South China Region
Huang Linfeng, Jiang Yong, Wang Jingsong, Huang Jiang
2015, 35(2): 152-158.   doi: 10.11728/cjss2015.02.152
Abstract(1398) [PDF 2247KB](42)
Abstract:
Variation of the Equatorial Ionospheric Anomaly (EIA) crest over South China region during the solar activity increasing periods is analyzed using the Total Electron Content (TEC) data from International GPS Service (IGS) between November 2010 and October 2011. The variation of the EIA crest in TEC shows an obvious seasonal and semiannual variation. Locations of the daily EIA crest have quite a large range of scatter in both universal time and latitude, but the similar seasonal or semiannual variation is not seen in the location of the anomaly crest. The variation of EIA crest in TEC shows a very good correlation with the solar flux, but do not correlate well with the geomagnetic activity.
Design and implementation of high reliability image data transmission unit on the space application
GUO Lin, JIANG Yuanyuan, CHEN Jianfei, CAO Song, LI Huijun, CHEN Xiaomin
2011, 31(4): 541-546.   doi: 10.11728/cjss2011.04.541
Abstract(2660) [PDF 752KB](23)
Abstract:
SpaceWire is an onboard data-handling network for spacecraft which offers high-speed, low power, simplicity, low cost, and architectural flexibility. The unit uses SpaceWire protocol to implement high speed image data transmission for space application. The FPGA can control the system to realize initialization and handling of data packets transmission, interruption and error status. The reliability design approach of FPGA was elaborated on, including the design of state machine, asynchronous clock domains, data transmission and error recovery. The unit can be used successfully in the 140Mbit/s image data transmission. For the burst error of link, the unit can recover the error data in a certain period of time, which can guarantee the validity and stability of data transmission.
Overview of the Advance for Mars Exploration Using Microwave Remote Sensing
JIN Yaqiu, FA Wenzhe, XU Feng
2008, 28(3): 264-272.   doi: 10.11728/cjss2008.03.264
Abstract(2752) [PDF 1260KB](84)
Abstract:
Exploration of Mars and other planets is a great mission in development of space remote sensing and deep space exploration. A brief review of the Mars exploration, e.g. available research results such as the distribution, structure and dielectric properties of Martian subsurface layers and the possibility of water existence etc., is presented. Microwave remote sensing technology shows great potential in future Mars exploration mission. Based on the advancement of both active and passive remote sensing in Earth science, some approaches to explore Martian regolith layers and possible detection of water existence in Martian subsurface layers are proposed. Scattering model of inhomogeneous media with rough interfaces for Mars exploration, imaging mechanism and numerical simulation are developed. The Mueller matrix solution of inhomogeneous media under pulse incidence are numerically simulated to illustrate funtional dependence on the planet characteristic parameters. Microwave radiometry and multi-data fusion technolonogy for Mars exploration are also presented. Some examples and technical key points are discussed.
Progress on space medicine in 2008—2010
Li Yinghui, Liu Zhaoxia, Zhang Xiaoyou, Bai Yanqiang, Chen Shanguang
2010, 30(5): 499-503.   doi: 10.11728/cjss2010.05.499
Abstract(2444) [PDF 90KB](30)
Abstract:
Space Medicine is a special subject to be rising with the development of manned spaceflight. In China, Space Medicine has achieved great development during the past two years. In this paper, the basic research of Space Medicine and its application in China during 2008--2010 were briefly introduced.
A Review of Density Holes Upstream of Earth's Bow Shock
G K Parks, E Lee, N Lin, J B Cao, S Y Fu, J K Shi
2011, 31(6): 693-704.   doi: 10.11728/cjss2011.06.693
Abstract(2688) [PDF 1442KB](64)
Abstract:
Larmor size transient structures with density depletions as large as 99% of ambient solar wind density levels occur commonly upstream of Earth's collisionless bow shock. These “density holes” have a mean duration of 17.9±10.4 s but holes as short as 4 s have been observed. The average fractional density depletion (δn/n) inside the holes is 0.68±0.14. The density of the upstream edge moving in the sunward direction can be enhanced by five or more times the solar wind density. Particle distributions show the steepened edge can behave like a shock, and measured local field geometries and Mach number support this view. Similarly shaped magnetic holes accompany the density holes indicating strong coupling between fields and particles. Current densities as large as 150 nA·m-2 are observed at the leading compressed edge. The waves are elliptically polarized and rotating in the sense of ions (left hand) in the plasma frame. The waves appear to grow and steepen as the density holes convect with the solar wind toward the Earth. The transient nature of density holes suggests that the temporal features could represent the different stages of nonlinear evolutionary processes that produce a shock-like structure. The density holes are only observed with upstream particles, suggesting that back-streaming particles interacting with the solar wind are important. The significance of these observations is still being investigated.
Evaluation of the Prediction Ability of the NeQuick Model on f0F2 Over Asia-Australic Sector
LU Linling, LIU Libo
2008, 28(3): 222-229.   doi: 10.11728/cjss2008.03.222
Abstract(2491) [PDF 3385KB](45)
Abstract:
In this paper, with the observed critical frequencies of F2 layer at eight ionospheric observatories in Asia-Australic sector, the prediction ability of the NeQuick model on f0F2 over Asia-Australic sector were investigated. The agreement between the prediction by the NeQuick model and the observed f0F2 data in this sector is quite satisfactory. The model prediction error is bigger in the northern hemisphere than in the southern hemisphere, bigger in the years with high solar activity than in those with low solar activity, and in spring and autumn than in winter and summer. The RMSE is bigger in the years with high solar activity than in those with low solar activity.
DRIFT SHELL TRACING METHOD AND THE SECULAR VARIATION OF INNER RADIATION FLUXES
FANG Xiaohua, PU Zuyin
2000, 20(2): 150-158.   doi: 10.11728/cjss2000.02.150
Abstract(1751) [PDF 495KB](60)
Abstract:
The AE-8/AP-8 models, which were constructed by NASA with satellite obser-vation data in the 1960s and 1970s, have long been considered to be the standardtrapped radiation models. It seems that they will continuously be used for a certainperiod of time in the future. The weakening of the geomagnetic field causes the driftshell of a charged particle to descend and the structure of the Trapped RadiationBelt to deform. Thus it is of importance to correctly use the AE-8/AP-8 models inthe contemporary era. However, up to now there seems to be no consensus on thisissue- On the basis of physical analysis, we propose the Drift Shell Tracing Method(DSTM) in this paper to solve the problem. The DSTM provides a reasonable wayto apply the standard trapped radiation models within the adiabatic approximation. The calculation results indicate that the change of the geomagnetic field playsa significant role in the particle redistribution in the inner zone. It is found that inthe past three decades,the central location of the particle South Atlantic Anomaly(SAA) has drifted westward almost 20° in longitude and northward almost 1Oo inlatitude. In the altitudes of 300-400 kilometers, the intensity of proton flaxes hasvaried dramatically and the flux difference at the same location can even be up to3-4 orders of magnit1lde.
Mission Planning and Modeling Analysis for Unmanned Aerial Exploration Vehicle on Mars
YAO Keming, WANG Xiaolan, LIU Yanbin, LU Yuping, XIAO Dibo
2012, 32(1): 8-13.   doi: 10.11728/cjss2012.01.008
Abstract(2863) [PDF 644KB](38)
Abstract:
With the development of socio-economy and technology, more and more people from various countries pay more attention to deep-space exploration. Mars is the closest planet where life is possible. So, Mars exploration is a hot issue on international deep space exploration in recent years. There are many advantages for the use of unmanned aerial exploration vehicles on Mars, including the wide range of exploration, the visualization of terrain changes, etc. In this paper, the overall mission planning is described for unmanned aerial exploration vehicle on Mars, and the difference between flight on earth and on Mars is discussed. Then the longitudinal nonlinear model is established for unmanned aerial exploration vehicle on Mars, and Taylor expansion is applied to the nonlinear model at the trim point, hence to obtain the linear model. By further analysis of the linear model, the stable performance and flight characteristics have been grasped for unmanned aerial exploration vehicle on Mars. These work will provide the platform for the follow-up research for Mars Unmanned Aerial Vehicle (UAV) navigation and control method.
Global Ionospheric Response to the Geomagnetic Storm Event of April 6-7, 2000
ZHANG Manlian, Sandro M. Radicella
2005, 25(3): 173-180.  
Abstract(2124) [PDF 2228KB](11)
Abstract:
A great geomagnetic storm occurred during April 6-7, 2000, with the Dst index reaching a minimum value of about-320 nT. Using the ionosonde and digisonde data from about 25 stations distributed globally, the morphology of the ionospheric response to this geomagnetic storm event is studied by comparing the storm-time disturbed value of f0F2 with its quiet time reference value. To identify the mechanism responsible for the ionospheric disturbances during this event, a comparison is made between the ratio of disturbed to undisturbed values of NmF2 and of the neutral composition concentration ratio (no/nN2). The results of data analysis showed that during the main and early recovery phases of the geomagnetic storm, a negative ionospheric F2 layer storm occurred globally. The maximum negative deviation of f0F2 from its quiet time reference value occurred during the early recovery phase of the geomagnetic storm. During the late recovery phase of the geomagnetic storm, positive ionospheric disturbances occurred in some stations, particularly in those high latitude stations. It is showed that the main characteristics of the ionospheric disturbances during this geomagnetic storm event are consistent with that expected from the storm effects resulted from storm-induced thermospheric circulation system.
Observation Of Sporadic Sodium Layer Over Haikou Of China In 2010
Zhang Tiemin, Wang Jihong, Liu Hanjun
2015, 35(5): 566-573.   doi: 10.11728/cjss2015.05.566
Abstract(1504) [PDF 946KB](108)
Abstract:
Sodium lidar observations of Sporadic Sodium Layers (SSL) in 2010 at a low-latitude location (Haikou, China, 20.0°N, 110.3°E) are reported in this paper. The wavelength of the dye laser is set to 589nm by a sodium fluorescence cell. The energy and divergence of the beam are about 45mJ and 1mrad, respectively. The repetition rate of Nd:YAG laser is 30Hz. The backscattered fluorescence photons from the sodium layer are collected by a telescope with a 1000mm diameter primary mirror. From 38 SSLs events detected in about 458h of observation, an SSL occurrence rate of 1 event every 12h at our location was obtained. This result, combined with previous studies at a mid-latitude location (Wuhan, China, 31°N, 114°E), and compared with the SSLs at a low-latitude location (Brazil, 23°S, 46°W), reveals that the SSL occurrence can be frequent at a low-latitude location of Haikou, China. The profiles of a peak density of the SSL were very spatial symmetry on Dec. 30, 2010. With respect to the correlation with sporadic E, the ionosphere data obtained by an ionosonde operated at Danzhou, China (19.5°N, 109.1°E), about 160km southwest of Haikou lidar station, have been examined. By statistical analysis of 13 events, when simultaneous SSL data and ionograms are available, a considerable correlation was found between sporadic E layers and the SSLs. The sporadic sodium layers have average downward vertical velocities at Haikou, China.
Determination of X Ray Pulsar Pulse Time of Arrival at Spacecraft
Yang Tinggao
2008, 28(4): 330-334.   doi: 10.11728/cjss2008.04.330
Abstract(2784) [PDF 922KB](75)
Abstract:
X ray pulsar can be used for spacecraft autonomous navigation. Pulsar clock can be used to stabilize onboard clock. Utilization in space of X ray pulsar clock is based on high precision determination of pulsar pulse Time of Arrival (TOA) at spacecraft. A method to obtain X ray pulsar pulse profile with individual photon arrival time records by onboard X ray detect system was discussed. In the case that an onboard clock is used as time reference for X ray pulsar timing recorded individual photon arrival time (spacecraft proper time) should be converted to barycentric dynamic time (TDB). Doppler effect due to orbit velocity of spacecraft during observation period may blur observed pulse profile. To mitigate smearing effect to pulse profile further transformation of recorded photon arrival time to Solar System Barycenter (SSB) is required using estimated approximate spacecraft position by spacecraft dynamics. Then obtained X ray pulsar pulse profile is compared with its standard template pulse profile to derive an observed pulse arrival time. Algorithm of determining X ray pulsar TOA at spacecraft with high precision was reviewed. Detailed analysis method to determine TOA in Fourier frequency domain was introduced and compared to analysis method in time domain.
Dangerous Conjunction Analysis Of Space Objects Based On Random Point Simulation Method
Cang Zhongya, Xue Bingsen, Cheng Guosheng, Zhu Xiaolu
2015, 35(5): 596-602.   doi: 10.11728/cjss2015.05.596
Abstract(1263) [PDF 1355KB](54)
Abstract:
The position, velocity and prediction error information of space objects can be obtained by using two-line element set and SGP4 model. Based on these results, a new method to calculate the collision probability is proposed, which is called the random point simulation method. There are two differences when this new method is compared with the traditional method of integral in conjunction plane. One is to concern the effects of error bias, which means the error ellipsoid no longer center on the predicted position. The other is to focus on simulating all possible conjunction situations and do not ignore error in each direction. The feasibility of this method is verified by analyzing cases, and results show that the maximum collision probability no longer appears in the time of closest approach because the error bias is not zero. Meanwhile, simulation results indicate that the positional relationship between two objects has also deviation in the direction of relative velocity, so the collision probability by random point simulation method is smaller than that of integral method. Different collision warning methods correspond to different warning thresholds, and 10-6 can be determined as the warning threshold of random point simulation method based on the case analysis in this paper.
In Situ Observation on Generation of Gaseous Inclusions in BBO Crystal
PAN Xiuhong, JIN Weiqing, HONG Yong
2005, 25(6): 543-546.   doi: 10.11728/cjss2005.06.543
Abstract(2195) [PDF 1127KB](47)
Abstract:
The inclusions in BBO single crystal can influence the ultimate crystal size as well as crystal properties. In this paper, the generation process of inclusions in BBO crystal by flux method is observed using Schlieren technique coupling with differential interference microscope.Results show that gaseous inclusions usually form at the inner part of perfect crystals and distribute near the interface. These indusions over generated originally from some small hexagonal cells. The formation and distribution of inclusions are significantly influenced by the development of crystal steps. The steps height and width may strongly constrain the develpment of inclusions, which results in the formation of inclusion clusters on the steps. The possible mechanism of inclusion generation is also discussed. It is noted that the main reason caused inclusions is the volatilization of some elements at high temperature.
PLASMA CURRENT SHEET STUDIED BY MEANS OF PARTICLE MOTION
Xu Rong-lan
1982, 2(1): 21-30.   doi: 10.11728/cjss1982.01.021
Abstract(1589) [PDF 784KB](38)
Abstract:
In this paper,we studied a one-dimensional plasma current sheet by means of the regular pattern of motion of charged particles moving in a neutral sheettmagnetic field.Aguiding centre theorem similar to that of Alfven's was used,the "8" shaped motion in non-perturbation region (where the magnetic field is small or equal to zero) is divided into two "circular" motions.Bach circular motion is equivalent to a magnet.So the "8" shaped motion is equivalent to two magnets in opposite directions.The electric current of plasma is derived from j=en+c(这里有图片19820103-21-1.GIF)×M where the distribution function of plasma is a function of constant motion.We found that the current sheet is mainly due to the "inverse drift" motion in the non-perturbation region.We have also studied the relation between charged particle motions and the magnetic field,and derived a self-consistent magnetic field.
SOLAR RADIATION MEASUREMENT ON SHENZHOU-3 SPACECRAFT
YU Bingxi, FANG Wei, YAO Haishun, AN Yu, GONG Chenghu, LI Zhe, JIN Xifeng, LU Daren
2004, 24(2): 119-123.  
Abstract(2222) [PDF 459KB](91)
Abstract:
TSI (Total Solar Irradiance) has been measured by solar constant monitor, which is composed of three SIAR (Solar Irradiance Absolute Radiometer), on board of Shenzhou-3 spacecraft from March to September in 2002. The structure of the cavities has been improved, the substitution winding being embedded in the wall of each SIAR’s cavities, so the absolute precision is heightened. Solar irradiance was measured when the sun scans over the field of view of each absolute radiometer respectively. The data is coincident with the data simultaneously measured by EOS/ACRIM in 0.2%.
A Variable-Structure Controller of Small Satellite Attitude Maneuver With Reaction Wheels
HE Donglei, CAO Xibin
2005, 25(6): 558-563.   doi: 10.11728/cjss2005.06.558
Abstract(2253) [PDF 1415KB](54)
Abstract:
Generally speaking, the Euler angle is usually used to describe the attitude of small satellites. In this case, however, singularity exists during large angle maneuver of small satellites. In contrast, such singularity can be avoided when the attitude is described by the quaternion. In this article, with regard to nonlinear properties of small satellite attitude contol systems actuated by reaction wheels, the attitude kinematics is described by the error-quaternion so that the large angle maneuver of the satellite can be converted into the problem of regulation of the error-quaternion. Sliding surfaces were designed on the basis of error-quaternion and an equivalent variable-structure controller introducing angular velocity acceleration feedback term was derived based on Lyapunov theorem. Simulation results show that the the proposed SMC law can improve the convergence rate, reduce the overshoot value of angular volecity during the maneuver and the demand of initial control torquer. In the meanwhile global stability and robustness of the method considering parameter uncerties and external disturbances such as sunlight pressure moment, the surplus magnetism moment of satellite and the pneumatic moment can also be guaranteed.
Simulation to Exploring Boom of TC-2 Satellite in Technical State Improving Design
YANG Xuan, YANG Hua, QIAO Zhihong, REN Weijia
2012, 32(2): 284-288.   doi: 10.11728/cjss2012.02.284
Abstract(2052) [PDF 748KB](59)
Abstract:
A highly reliable two-segment deployable boom has been developed and manufactured for the Double Star Program. Two spacecrafts, one for equatorial, the other for polar orbit are equipped each with two mechanisms. One boom deploys two flux-gate magnetometers, the other a search coil magnetometer. The paper discusses the structure and mechanical problems of TC-2 satellite’s exploring booms in technical state improving design, and analyzes the mode, structure static strength as well as the clamp expanding process of exploring boom in TC-2 satellite. Results show that the boom clamp’s frequency only had small change after altering the pyrotechnical rod cutter and it would not have influence on the satellite’s frequency. The improved clamp can bear dynamic load, and its maximal stress and strain are all within the allowed range of material. Moreover, the clamps do not intervene with other parts when they are deployed, which can meet the satellite’s request.
Morphology of Ionospheric Disturbances Over Kokubunji During Geomagnetic Disturbances
ZHAN Liang, LIU Libo, WAN Weixing, ZHAO Biqiang
2007, 27(5): 391-399.   doi: 10.11728/cjss2007.05.391
Abstract(2594) [PDF 6037KB](39)
Abstract:
In this paper, with the observed critical frequencies of F2 layer at Kokubunji (139.5°E,35.5°N) during 1959 to 2004, the dependence of the variations of NmF2 on the geomagnetic activity, solar activity, season and local time are statistically investigated. The results show that there are more positive ionospheric storm effects than negative ones over KokuSunji. In summer, negative storm effects prevail during high solar activity, whereas positive storm effects are usually observed during low solar activity; in winter, positive storm effects dominate regardless of solar activity conditions; and in equinox, negative storm effects with smaller amplitude are often seen during high solar activity, and positive storm effects often take place during low solar activity conditions. The correlation analysis between the disturbance of NmF2 and ap index also illustrates the above-mentioned feature. Furthermore, our results show that there is a time delay of 12-15 hours between the ionospheric maximum negative disturbances and the maximum geomagnetic perturbation, and the time delay of the ionospheric positive disturbances are 3 and 10 hours, respectively. In addition, it is also found that under high geomagnetic activity conditions, positive disturbances are often seen in the evening, and negative disturbances in the morning.
Electrostatic Structure of the Electron Phase-space Holes Generated by the Electron Two-stream Instability with a Finite Width
SANG Longlong, WU Mingyu, LU Quanming
2017, 37(5): 517-523.   doi: 10.11728/cjss2017.05.517
Abstract(885) [PDF 6407KB](47)
Abstract:

Space satellite observations in an electron phase-space hole (electron hole) have shown that bipolar structures are discovered at the parallel cut of parallel electric field, while unipolar structures spring from the parallel cut of perpendicular electric field. Particle-in-cell (PIC) simulations have demonstrated that the electron bi-stream instability induces several electron holes during its nonlinear evolution. However, how the unipolar structure of the parallel cut of the perpendicular electric field formed in these electron holes is still an unsolved problem, especially in a strongly magnetized plasma (Ωe > ωpe, where Ωe is defined as electron gyrofrequency and ωpe is defined as plasma frequency, respectively). In this paper, with two-dimensional (2D) electrostatic PIC simulations, the evolution of the electron two-stream instability with a finite width in strongly magnetized plasma is investigated. Initially, those conditions lead to monochromatic electrostatic waves, and these waves coalesce with each other during their nonlinear evolution. At last, a solitary electrostatic structure is formed. In such an electron hole, a bipolar structure is formed in the parallel cut of parallel electric field, while a unipolar structure presents in the parallel cut of perpendicular electric field.

Improved equivalent rotation vector based attitude updating algorithm of strapdown inertial navigation system under highly dynamic environment
Du Jiyong, Zhang Fengming, Li Jianwen, Huang Guorong, Dai Feng
2013, 33(1): 85-91.   doi: 10.11728/cjss2013.01.085
Abstract(2349) [PDF 467KB](34)
Abstract:
The navigation algorithm of Strapdown Inertial Navigation System (SINS) under highly dynamic environment is studied, which is the key technology to improve the accuracy of SINS. The quaternion and equivalent rotation vector algorithms of resolving the attitude matrix were analyzed, and the equivalent rotation vector algorithm was developed in view of the application problem under highly dynamic environment. Aiming at adapting the algorithm to the application in highly dynamic flight environment, an improved equivalent rotation vector algorithm was proposed on the basis of coning motion environment, and the calculation error was derived. The performance was compared to one-sample and three-sample rotation vector algorithms. Simulation results indicate the effectiveness of the improved algorithm.
Dynamic Distribution Features of Energetic Proton in South Atlantic Anomaly Based on the Observation of SAMPEX
LÜ Jingtian, ZHANG Xiaoxin, LIN Ruilin, HE Fei, JIANG Yong
2015, 35(2): 192-202.   doi: 10.11728/cjss2015.02.192
Abstract(1075) [PDF 8444KB](59)
Abstract:
After lots of experiments by using 19~27MeV differential energetic proton data based on the observation of SAMPEX from July of 1992 to June of 2004, it is found that the change of F10.7 and altitude have a great influence on the distribution of differential energetic proton flux in South Atlantic Anomaly. During the geomagnetic quiet time at 540±25km altitude, the energetic proton flux in South Atlantic Anomaly decreased with the increasing of F10.7, and the variation trend was flat when F10.7≥115sfu. It is found that there was obviously an anti-correlation between the absolute value of SYM-H and the differential energetic proton flux in South Atlantic Anomaly for storms with SYM-H<-50, and also there was a lasting effect on differential energetic proton flux in South Atlantic Anomaly. In addition, the proton flux could be significantly reduced in South Atlantic Anomaly during the main phase, while the proton flux showed a substantial resuming trend in the recovery phase of geomagnetic storms.
Research of the Optical Effects of Space Weathering on Lunar Regolith Based on the Nonlinear Mixing Model
Wu Yunzhao, Zheng Yongchun, Zou Yongliao, Xie Zhidong, Xu Xisheng
2010, 30(2): 154-159.   doi: 10.11728/cjss2010.02.154
Abstract(2656) [PDF 575KB](55)
Abstract:
The reflectance spectrum of lunar soil is mainly dominated by its composition and the degree of exposure to space weathering processes such as micrometeorite bombardment and solar wind implantation. The spectral alteration effects of space weathering should be removed for accurately investigating the composition of the lunar surface using remote sensing data. It can contribute to develop the method for decoupling the spectral effects of composition and maturity to improve the inversion accuracy by exploring the optical effects of space weathering on lunar regolith. Because unweathered soil is hard to acquire, it's unable to compare the spectra between the weathered and unweathered soil directly. This paper provided a simple way to investigate the optical effects of space weathering. First, the mixed spectra is acquired according to the mineral contents and spectra measured from the lunar soil using the Hapke model. Then the modeled spectra of lunar soil were compared with the real spectra measured by Brown University. Investigation results showed that the space weathering can reduce the overall reflectance of lunar soil, and the shorter waveband the greater reducing; that it can increase the continuum slope to the spectrum, which makes the spectra redder; and it can also reduce the absorption depth and spectral contrast, and the absorption peak near 2.0μm was reduced more than that near 1.0μm. These factors should be taken into consideration when the element contents are retrieved using remote sensing technology.
Application of primer-vector theory in close intercept optimization
Wang Guoliang, Zheng Jianhua
2011, 31(3): 361-365.   doi: 10.11728/cjss2011.03.361
Abstract(3355) [PDF 435KB](67)
Abstract:
In this paper, the optimum of the fuel consumption in close impulse interception within a fixed period of time by principal vector theory was mainly studied. Then a mathematical model of space interception of short distance based on the theory of orbital dynamics was set up. According to the principal vector theory, a theoretic criterion was put forward to determine whether the optimum of impulse interception has been attained, and an optimization technique for the interception was raised too. The effectiveness of the optimization was verified by lots of simulation examples. In the latter part of the paper, the fuel consumptions of the space interceptions at different time were simulated, compared and analyzed, and at last a technique to achieve optimal fuel consumption of the interception was brought forward.
Research on characterized graphics matching method of autonomous optical navigation for lunar explorer
Mu Rongjun, Gao Mingyang, Liu Bin, Hu Ying
2014, 34(6): 858-866.   doi: 10.11728/cjss2014.06.858
Abstract(942) [PDF 3502KB](41)
Abstract:
This paper focuses on the characterized graphics matching based navigation method of precise landing on the moon, which mainly consists of feature point extracting, characterized graphics constructing and matching. Based on the property that the relative distance between two characterized points is unchanged, by establishing the connected rules of two characterized points, the method is adopted to overcome the problem of graphics matching with translation, rotation and scale changes. The algorithm is tested with multiple real lunar pictures, and the emulational experiment results approve the effectiveness of the method. Navigation method based on the characterized graphics matching is validated by designing a numerical simulation. The simulations reveal that the method that can gain the position and speed of vehicle with high precision in nearly real-time is an effective solution to lunar precise landing.
Research on the Planning Method for Astronomy Observation Mission
Wu Haiyan, Meng Xin, Zhang Yuzhu, Li Ligang
2013, 33(5): 561-568.   doi: 10.11728/cjss2013.05.561
Abstract(2085) [PDF 2111KB](66)
Abstract:
Space science satellite's astronomy observation mission planning is a complex multi-objective optimization problem. A multi-objective model is proposed based on abstraction of the mission planning elements and the constraints. Three scheduling criteria are considered, including minimizing important tasks unscheduled time, resource cost and scan tasks unscheduled time. Furthermore, Multi-objective Observation Mission Planning Algorithm (MOMPA) is put forward using the proposed model. The MOMPA solves conventional observation mission planning problem using the iteration constrained adjustment in population evolutionary methods. In order to validate MOMPA's performance, the mission planning test cases are designed. The short-term test case has 12 tasks with one week's observation period and the long-term test case has 36 tasks with three months' observation period. These experiments are conducted and analyzed, and results showed that MOMPA is applicable to astronomy observation planning in various scales.
Research Progress and Prospect of Exoplanetary Atmospheres and Habitable Exoplanet Sciences
TIAN Feng, HU Xiong, WU Ji
2016, 36(6): 815-827.   doi: 10.11728/cjss2016.06.815
Abstract(1069) [PDF 719KB](52)
Abstract:
The most fundamental question driving the search and characterization of exoplanets is whether life and habitable planets are ubiquitous. More than 3000 exoplanets have been discovered since 1995, about 20 of which are potentially habitable and this number could be increased dramatically in the next decade. Observation of the atmospheres of potentially habitable exoplanets is becoming the hot spot in planetary sciences. In this review we summarize the research progress regarding exoplanetary atmospheres and propose a practical roadmap, the implementation of which could accelerate the development of exoplanetary sciences in China in the near future.
THE INFLUENCE OF HIGH ENERGY ELECTRONS AND CONTAMINATION ON LANGMUIR PROBE DIAGNO-STICS OF GAS DISCHARGED
Zhou Huai-bei, Wang Wen-qing, Sun Chuan-li
1989, 9(3): 180-186.   doi: 10.11728/cjss1989.03.180
Abstract(1564) [PDF 409KB](32)
Abstract:
In the typical method of Langmuir Probe diagnostics of laboratory plasma, only iorr current correction is made. In fact, some electrons escaped from the filament, are accelerated through DCelectric field, they make electron temperature observed by probe "greater" than its real value. The error of electron temperature distorted by high energy electrons is as large as 80%-200%. At the same time, the measurement error of saturated electron current caused by high energy electrons is 70%-150%, that is also the measurement error of electron density. The error caused by the probe surface contamination is also discussed.
An Algorithm for the Orbital Evolution of Space Debris from Breakup Events
GONG Songbo, XU Minqiang, CUI Pingyuan, LI Shuang
2005, 25(4): 304-308.  
Abstract(1799) [PDF 1393KB](47)
Abstract:
Space debris created by man's space activities has brought great risks to launch and operation of spacecrafts, especially in the following few years, there will be more and more space activities in the world. So it is necessary to know situation of current space debris environment and predict its development in the future, thus to provide important reference to protection design and operation of spacecrafts and measures of diminishing amount of space debris. An important component of the debris population that is presented in this paper is the debris generated by on-orbit breakup events. It is collision and explosion event that inflames most the increasing rate of the total amount of the space debris. Breakup events include collision and explosion events. Consequently the ability to model different breakup events is a vital part of a long-term debris environment model. In this paper, the orbital evolution of space debris from the spacecraft breakups has been done a through mathematical analysis. A detailed research on the mechanisms of space debris generation, evolution and annihilation from the view point of evolutionary mode is also given. The velocity increments of space debris from spacecraft breakups are presented. Based on the velocity increments, the orbital elements of space debris are gained. Then the cumulative number and orbital distribution of space debris are analyzed due to atmospheric drag perturbation. Finally, the relevant results are gave and compared with the results of CODRM. The results indicate the feasibility of the algorithm.
INTERACTION BETWEEN THE POWERFUL HIGH-FREQUENCY RADIO WAVE AND THE LOWER TERRESTRIAL IONOSPHERE
HUANG Wengeng, GU Shifen
2003, 23(3): 181-188.  
Abstract(1842) [PDF 672KB](37)
Abstract:
The terrestrial ionospheric plasma can be heated by a powerful ground-based high-frequency radio wave, which results in the disturbance of the electron temperature and density. In this paper, a self-consistent model of interaction between the powerful HF radio wave and the lower ionosphere is presented. In this model, the self-absorption effect of radio wave is emphasized. For specific transmitter’s parameters (in this paper, PER = 200 MW, f= 7.0 MHz are used, which is at the range of many transmitters), under the daytime ionospheric background, the calculated results show that the self-absorption effect is obvious, when h < 90 km, but the effect can be ignored for h > 90 km. The results also show that the maximum electron temperature enhancement is at the altitude of 70 km, which is three times of the undisturbed background. With the assumption of a recombination in lower ionosphere, the percentage of electron density enhancement is decreasing with the increase of ionospheric heights. For example, at the altitude of 70km, it is 55% or so, but at 120km altitude, it is about 4%.
Bent Pipe Satellite Network System and Area Routing Method
YUAN Jiang, WANG Yu, MENG Xin
2006, 26(4): 315-320.   doi: 10.11728/cjss2006.04.315
Abstract(3042) [PDF 809KB](80)
Abstract:
There are two kinds of architecture for the Satellite Network (SN): On-Board Processing (OBP) and Bent-Pipe (BP). Although OBP has been attracted more attention in the research area due to its performance advantage, BP is still used by some of the satellite systems for its low system cost. It is obvious that the incompatibility between BP systems may cause resource waste and thus sharing resource can help to cut down the system cost further. Therefore, a general SN routing method Area Routing (AR) is proposed. AR can provide not only shared source for different SN system but also network access for sky flying satellites. In this paper, the connection of the satellites is discussed, and the concept of connection analysis is introduced. By using the connection analysis and simulation tool, the best configuration of satellite connection for both coverage and accessibility is demonstrated.
Earthward Convective Bursty Flows in the Center Plasma Sheet
Zhang Lingqian, Wang Jiye, Liu Zhenxing, Shi Jiankui
2011, 31(1): 20-26.   doi: 10.11728/cjss2011.01.020
Abstract(2635) [PDF 500KB](55)
Abstract:
With 4 s resolution data of FGM and HIA on Cluster/C1, the earthward Convective Bursty Flows (CBF) inside the region of -19 Re < x < -9 Re, -10 Re < y < 10 Re and -5 Re < z < 5 Re were statistically analyzed in the GSM coordinate. According to the statistical results, the CBF inside the Central Plasma Sheet (CPS) has distinctly ``braking'' inside 13~15 Re, and ``absence'' around 11.5 Re. The further detail analysis of the velocity of the CBF showed that the CBF move mainly toward the earth. The speed of the CBF has no clear decrease while moving earthward. In addition, the CBF have stronger perpendicular velocity inside 13 Re than outside 15 Re. This implied that the ``absence of BBF'' is not due to the deflection of the high-speed flows. The ``braking'' and ``absence'' of BBF may be closely related. The joint observations of TC-1 and Cluster satellites are important for understanding the transport process of the CBF in the CPS.
DISCRETE VARIABLE STRUCTURE CONTROL OF FLEXIBLE CANTILEVER BEAM
CAI Guoping, HONG Jiazhen
2004, 24(2): 145-151.  
Abstract(2036) [PDF 596KB](64)
Abstract:
Active control method for the vibration reduction of flexible cantilever beam is investigated in this paper. The independent modal space control method is used as control strategy, in which modal control law is designed using discrete-time variable-structure control method. Extraction of modal variables from actual measurements and transformation of actual control forces from modal control forces are discussed. Determination methods of discrete-time switching surface and variable-structure modal control law are presented. Effectiveness of the proposed control method is verified through a numerical simulation in the end of this paper.
Global hybrid simulation of magnetic reconnection in the magnetosheath
Pang Ye, Lin Yu, Deng Xiaohua
2010, 30(4): 333-342.   doi: 10.11728/cjss2010.04.333
Abstract(2692) [PDF 455KB](38)
Abstract:
A three-dimensional (3-D) global hybrid simulation is carried out for the generation and structure of magnetic reconnection in the magnetosheath due to interaction of an interplanetary Tangential Discontinuity (TD) with the bow shock and magnetosphere. Runs are performed for solar wind TDs possessing different initial half-widths. As the TD propagates through the bow shock toward the magnetopause, it is greatly narrowed by a two-step compression processes, a "shock compression'' followed by a subsequent ``convective compression''. In cases with a relatively thin solar wind TD, 3-D patchy reconnection is initiated in the transmitted TD, forming magnetosheath flux ropes. Multiple components of ion particles are present in the velocity distribution in the magnetosheath merging, accompanied by ion heating. For cases with a relatively wide initial TD, a dominant single X-line appears in the subsolar magnetosheath after the transmitted TD is narrowed. A shock analysis is performed for the detailed structure of magnetic reconnection in the magnetosheath. Rotational Discontinuity (RD)/Time-Dependent Intermediate Shock (TDIS) are found to dominate the reconnection layer, which and some weak slow shocks are responsible for the ion heating and acceleration.
Engineering Analysis on a Satellite Attitude Control Thruster Plume at High Altitudes
CHENG Xiaoli, WANG Qiang, YAN Xiqin
2006, 26(1): 59-63.   doi: 10.11728/cjss2006.01.059
Abstract(2618) [PDF 2233KB](67)
Abstract:
An engineering estimation method has been developed to calculate satellite attitude control thruster plumes at high altitudes, and the main exhaust gas species distributions are analyzed numerically. The grid generation technique is introduced to split the thruster nozzle exit section into cells, each of which is considered an independent point source, respectively. Hence, a modified free molecule model suitable for the nozzle exit local conditions is obtained. It consists of four primary formulae for density, mass flux, normal pressure and transitional energy flux, and three formulae for velocity, transitional temperature and internal energy flux. A nitrogen plume exhausted from a axisymmetric nozzle is firstly calculated. Numerical outlet conditions obviously influence upon analysis results for flow variables, especially, dynamic and thermodynamic variables. Then, an MBB 10N bipropellant thruster multi-species plume is investigated numerically. Comparisons are presented between the modified model and experiment, and good agreement is found for density distributions. Moreover, the levels of agreement are superior to those using the original single point source free molecule model. Pressure and internal energy vary more rapidly in the plume. It is unlike light molecule species that heavy molecule species mainly focus along the plume axis and their density distributions show a more dominant direction, i.e. axial direction.
THE SELECTION OF REAR SHAPES OF PRIMARY MIRRORS IN SPATIAL OPTICAL REMOTE SENSOR
WU Qngwen, LU'E, WANG Jiaqi, XU Biao
1997, 17(2): 172-177.   doi: 10.11728/cjss1997.02.172
Abstract(1974) [PDF 471KB](53)
Abstract:
The necessity of using lightweight primary mirror in spatial optical remote sensor is statal in this paper. The suffoce figure of primary mirrors in shapes of double-concave,plain-rear, single-arch and double-areh is computal, Which works out a conclusion that double-concave mirror is the best one, supported in three-point pattern The regularity of wave front error (RMS value) vs. normalized radius r / R is studied, which indicates that the best support radius is 0.74
ADAPTIVE CONTROL FOR SPACE MANIPULATOR TO TRACK THE DESIRED TRAJECTORYIN JOINT SPACE
CHEN Li, LIU Yanzhu
2000, 20(4): 348-355.   doi: 10.11728/cjss2000.04.348
Abstract(2245) [PDF 465KB](73)
Abstract:
In this paper, the dynamics and control problems of free-floating space manip- ulator systems are studied. It is verified that the dynamic equations of free-floating space manipulator systems can be linearly dependent on a group of inertial parameters. Based on the results and with the augmentation approach, an adaptive control scheme for space manipulator systems with unknown payload parameters to track the desired trajectory in joint space is developed. The control scheme proposed above is structurally and computationally simple, because of an effective exploitation of the system dynamics. In particular, it requires not the measuring of the position, velocity and acceleration of the base. A simulation study of two-link planar space manipulator system is presented; it is shown that the control scheme proposed is feasible and effective.
A SIMULATION STUDY ABOUT EFFECTS OF MICROGRAVITY ON CELLULAR MORPHOLOGY AND STRUCTURE OF RAT'S CARDIAC MUSCLE
YUE Ming, ZHANG Xiaoyou, WANG Gongzhi, DING Bai, ZENG Yuzhang, TAN Yingjun
1998, 18(1): 75-80.   doi: 10.11728/cjss1998.01.075
Abstract(2153) [PDF 536KB](35)
Abstract:
A laboratory simulation is made to show the effects of microgravity on the cellular shape and structure of rat's cardiac muscle. The cell's cultural system is put into a simulated microgravity environment. It is found that cellular morphology changes from slim to round in optical microscope and cytoskeloton changes from columnar morphology to radial morphology through marked Actin in fluorescence microscopy. Cellular area of cardiac muscles becomes significandy decreased by 40% and cellular long-short axes ratio decreased by 70% through micromeasurement.
Estimation of Sqe Current System Focus by Means of Geomagnetic Data at Middle and Low Latitudes
Xu Wen-yao
1987, 7(2): 117-127.   doi: 10.11728/cjss1987.02.117
Abstract(1561) [PDF 635KB](47)
Abstract:
The relationship of geomagnetic field at the earth's surface with Sqe current systems is analysed. It is pointed out that there exsist some differences between the true focus of the Sqe current system and the "apparent focus" determined by using Sqe variations in the geomagnetic field at the earth's surface. Practical approaches to estimating Sqe current focus by means of geomagnetic data are discussed and examined by using geomagnetic data during the period of IGY/C.
Case Study of Interaction Between Interplanetary Magnetic Cloud and Heliospheric Current Sheet
FENG Xiang, WEI Fengsi, FENG Xueshang
2011, 31(6): 725-738.   doi: 10.11728/cjss2011.06.725
Abstract(2874) [PDF 1106KB](89)
Abstract:
Based on 105 Magnetic Cloud (MC) events detected by WIND spacecraft from 1995 to 2007, according to whether the MC collided with the Heliospheric Current Sheet (HCS), the MC events are devided into two types, namely, colliding and non-colliding. The preliminary results are as follows. Firstly, there are 51 MCs which may have collided with the HCS, and that is about 49% of the total incident. Secondly, when a MC collided with the HCS, dynamic interactions tend to inhance in the region between magnetic cloud and heliospheric current sheet, such as appearance of local magnetic field directional discontinuity structures, decreased magnetic field strength, increased proton temperature, irrupt changes of some components of proton velocity, enhancement of ionacoustic waves or Langmuir waves. These phenomena are possibly related to magnetic reconnection in the colliding interaction regions. In case of non-colliding, these characteristics are not evident. Thirdly, in at least 15 cases, the magnetic polarity of the background magnetic fields in front of the magnetic cloud and the one behind the magnetic cloud are opposite, or the reverse point of magnetic polarity was inside the magnetic cloud, which means the magnetic cloud was moving cross the HCS. Lastly, bright fronts and bright cores of MCs have been observed in some events. These very preliminary results are beneficial to understanding the process of interaction between magnetic cloud and the heliospheric current sheet, however further researches are still required.
A Review of the Ionospheric Investigations in China: Progress During 2008—2010
Wan Weixing
2010, 30(4): 362-381.   doi: 10.11728/cjss2010.04.362
Abstract(2377) [PDF 255KB](53)
Abstract:
In the ionospheric research, various progresses have been made during the last two years. This paper reviews the recent works of Chinese scientists. For convenience, the contents include: ionospheric storms and space weather; ionospheric irregularities and scintillation; ionospheric variability; ionospheric disturbances; ionospheric response to solar eclipses; ionospheric coupling with atmosphere and lithosphere; ionospheric climatology; ionospheric modeling; and ionospheric prediction and application.
The Progress of Chinese Space Medicine
YUAN Ming, JIANG Shizhong
2005, 25(4): 273-279.  
Abstract(2383) [PDF 2965KB](74)
Abstract:
Space medicine is a new special medicine which is rising with the development of manned space program and has acquired great development during the space exploitation since established. In the early of 1990s, manned space flight program was initiated in china. However, the history of development for Chinese space medicine commenced in 1950s. Especially during the past ten years, the initiation of Chinese manned space flight program has brought great opportunity to Chinese space medicine. Presently, the first manned space flight has acquired consummation in china. Space medical specialists have experienced the trial of the first manned space flight as well as the first Chinese astronaut who has landed safely and healthily. During the past 40 years, the area of research in Chinese space medicine has gradually expanded, including the subjects such as gravitational physiology, cell and molecular biology, space environmental medicine, space psycology and space implemental medicine et al. The studies in Chinese space medicine are developing steadily. In the following Chinese manned space program, many difficulties will be more complex and need to be resolved for the success of spaceflight program. At the same time, this is also a challenge to the Chinese scientist. The article will briefly introduce the basic and applicational research of Chinese space medicine including their progress and give the outlook of their challenge and opportunity in the future.
NUMERICAL STUDY FOR THE SEMI-ANNUAL VARIATION OF ELECTRIC FIELDS AT THE MID-AND LOW-LATITUDES
YU Tao, WAN Weixing, LIU Libo, LEI Jiuhou, LI Xiaoyin
2004, 24(3): 182-193.  
Abstract(1875) [PDF 3261KB](47)
Abstract:
With a theoretical model of ionospheric electric fields, the yearly variation of ionospheric electric fields at mid- and low-latitudes under the condition of low solar and quiet geomagnetic activities were studied. The main results are as follows: when the ionospheric electric fields are calculated individually in the northern or southern hemisphere without including the influence of the other hemisphere (uncoupled), the electric fields in both hemispheres vary in an obvious annual pattern with an anti-phase; when the electric field was calculated simultaneously in both hemispheres with the influence of the other hemispheres (coupled) included, the electric field varies in a predominant semi-annual pattern. Moreover, quite good consistency was found between the behaviors of semi-annual variation calculated by our theoretical electric field model and an empirical model of Richmond. A simple circuit with the coupling between the northern and southern hemispheres was introduced to interpret the semi-annual variation of electric field. Results from the circuit model reveal that the coupled electric field would show a pronounced semi-annual variation due to the ’coupling effect’ along the magnetic field lines between two hemispheres, whereas the uncoupled electric field have an annual variation in respective hemisphere.
AUTOMATIC OUT-SIGHT TRACING FOR BALLOON-BORNE HIGH ENERGY ASTRONOMICAL TELESCOPE
LIN Baojun, QU Weizhen, WU Bobing, ZHANG Xiyuan, LI Tipei, XUE Jingxuan
1998, 18(3): 242-246.   doi: 10.11728/cjss1998.03.242
Abstract(2079) [PDF 267KB](19)
Abstract:
Based on the previous HAPI-4 control system,a balloon-borne attitude pointing control system digitalization is implemented by using 16 bits 80C196 single-chip processor for the first time. Meanwhile, by means of Global Positioning System(GPS), high precision Positioning and absolute time calibration is fulfilled. Also,a small,high density tape recorder is used as the balloon-borne data flow storage,and out-sight telemetry and teleconmmand is implemented by using INMARSAT system.Thus,a new balloonborne high energy astronomical telescope control system is brought about.
Global optimization of gravity-assist trajectory with deep space maneuvers
Li Xiaoyu, Zheng Jianhua
2013, 33(1): 72-78.   doi: 10.11728/cjss2013.01.072
Abstract(2472) [PDF 487KB](98)
Abstract:
The problem of optimal design of a multi-gravity-assist space trajectory with deep space maneuvers is studied. Based on the zero-sphere-of-influence and patched conic hypothesis, the deep space trajectory is split into segments linked by deep space maneuvers and gravity assists. After introducing an auxiliary angle and B plane, the outgoing excess velocity could be expressed analytically. The deep space maneuver was computed by solving Lambert problem and trajectory propagation. The differential evolution algorithm is used to handle afore mentioned global optimization problem. Three cases to Jupiter, with gravity sequences of Venus-Earth-Earth (VEE), Venus-Earth-Mars-Earth (VEME) and Venus-Earth-Venus-Earth (VEVE) have been optimized.
Analysis on Determining Warning Threshold of Space Objects
ZHOU Weiping, SHEN Ming, GUO Xiaozhong, GAO Pengqi, ZHAO You
2017, 37(3): 312-321.   doi: 10.11728/cjss2017.03.312
Abstract(1318) [PDF 1196KB](46)
Abstract:
The method of collision probability is usually used to realize the work of collision assessment and warning of space objects, thus improving accuracy of collision assessment and warning is very important. The collision probability criterion is collision probability threshold. By investigating and analyzing the related bibliography from both domestic and international researchers, a comprehensive description on determination of collision probability threshold of space objects is presented. The determination of covariance matrix, the calculation of collision probability and the flux calculation of debris are introduced in detail. Taking International Space Station (ISS) for instance, of which, the debris flux was calculated and the incidence from space environment was analyzed. The conclusion that collision probability threshold of ISS may be overrated is reached by comparing with previous results.
Simulation of Electrons' Trajectories in the Lunar Electric and Magnetic Field
Feng Yongyong, Zhao Hua, Liu Zhenxing
2011, 31(2): 165-169.   doi: 10.11728/cjss2011.02.165
Abstract(2365) [PDF 592KB](78)
Abstract:
The increasing interest in lunar exploration requires a better understanding of environment at the lunar surface. Like any object in plasma, the surface of the Moon charges to an electric potential that minimizes the total incident current. Surface charging is an universal process affecting all airless regolith-covered bodies. However, there are still many details that remain unclear and need to be discussed to understand those possible processes such as ion sputtering and electrically-driven dust transport. There are also many subjects that require further study, such as the temporal and spatial variation of lunar surface charging. Simulation and analysis of trajectories of the electrons under different conditions would help to predict surface potential, which in turn would benefit the understanding of the lunar environment. In this paper, the solar wind electrons which are moving toward the moon surface are traced to study the effect of surface potential on solar wind electrons reflected by the lunar crustal magnetic field. Statistic of number of electrons that reflected under different conditions is also analyzed. The calculations and simulations show that the variation of either magnetic field or potential difference does play an important role in the changing traces of electrons. Furthermore, the changes by the variations could be told from analysis of the results. Thus, the magnitude of crustal field and potential could be inferred from the data of instrument of LP (Lunar Prospector satellite). New devices could also be designed or developed in the coming lunar projects. Surface potentials are not always present on the Moon, so we could collect and analyze data under different conditions and thus obtain more precise results. However, there is one more important circumstance needed to be considered that the craft would be charged in the lunar environment. How to eliminate the influence of charged craft and get a more precise result are important problems for us to explore in the future.
Thermal-Structural Analysis of Deployable Truss Antenna
YANG Yulong, GUAN Fuling, ZHANG Shujie
2005, 25(3): 235-240.  
Abstract(2284) [PDF 1362KB](32)
Abstract:
A finite element model of a deployable truss parabolic antenna is made that deployable trusses are divided into one dimensional transient radiation-conduction rod elements and reflector net is divided into two dimensional transient radiation-conduction membrane elements. Analytical assumption are proposed, temperature function of rod element is linear and temperature function of membrane element is quadratic. In order to obtain all-sided thermal-structural features of antenna, the sun radiation flux is simulated by six cases, which are defined by the angle between sun radiation and antenna net. Based on the model, temperature field and thermal deformation of the antenna are calculated and analyzed. The thermal-structural features of deployable truss antenna and the influence of deployable truss on the whole temperature field and thermal deformation of antenna are presented.
Integrated Design of Payload Based Dark Matter Particle Explorer
DONG Lei, LI Huawang, ZHU Cheng, ZHU Zhencai, CHANG Liang
2017, 37(2): 229-237.   doi: 10.11728/cjss2017.02.229
Abstract(1245) [PDF 3020KB](70)
Abstract:
The Dark Matter Particle Explorer (DAMPE) is the first high energy detection satellite in China, and its scientific goal is to find the evidence of dark matter particle existence by investigating the composition and energy spectra of primary cosmic rays, especially for electrons, positrons and gamma rays, over the dynamic range from 5GeV to 10TeV. The DAMPE is composed by BGO calorimeter, plastic scintillation array detector, silicon array detector and neutron array detector, and is the largest payload ratio satellite. This paper introduces the technical schemes of DAMPE, including technical index, orbit, working mode and system composition, and the integrated design of structure, thermal control and EMC in DAMPE.
THE COMPUTATION OF ATOMIC OXYGEN FLUXAND FLUENCE ON THE SURFACES OFARTIFICIAL SATELLITES AND ITS DISCUSSION
FAN Quanfu, TIAN Jianhua
1999, 19(2): 167-172.   doi: 10.11728/cjss1999.02.167
Abstract(2322) [PDF 418KB](34)
Abstract:
In this paper, a model for computing Atomic Oxygen (AO) flux and fluenceis developed under relatively ideal conditions. The effects of some factors (orbitaltitude, solar activity, incident angle and inclination) on AOflux and fluence aremainly discussed.
Attitude And Translation Control For Spacecraft To Approach To A Tumbling Non-Cooperative Object During The Final Phase
LIU Hailong, HAN Xu, SHI Xiaoping
2015, 35(5): 603-610.   doi: 10.11728/cjss2015.05.603
Abstract(1016) [PDF 940KB](67)
Abstract:
This paper considers the process of motion synchronization of chaser satellite and target satellite in space. The problem of final approach to a non-cooperative tumbling target is studied in this paper. The accurate orbit and attitude dynamics model of two relative motion spacecrafts with arbitrary eccentrics is established. In order to insure the safety of final approach, the traditional linear synchronization rotating approach strategy is improved by designing an exponential decay reference trajectory to decay relative velocity with decreasing relative distance and reach zero when the chaser is hovering. The proportional-derivative-decouple relative attitude controller and relative orbit controller is proposed. The simulation shows the process of the relative velocity of the chaser decay to zero. The stability of the control law is demonstrated through Lyapunov analysis and effectiveness of controller is verified by the numerical simulation.
SOME FEATURES OF THE IONOSPHERE AT THE CREST REGION OF THE EQUATORIAL ANOMALY
Chen Pei-ren
1990, 10(3): 221-229.   doi: 10.11728/cjss1990.03.221
Abstract(2382) [PDF 690KB](35)
Abstract:
The northern crest of the equatorial anomaly covers Southern China, therefore, the investigation of the ionospheric features of equatorial anomaly at crest is the key for understanding ionospheric characteristics over China. In this paper, 6 related topics are reviewed: 1. Day-to-day variations and the post sunset enhancement of the equatorial anomaly; 2. The movement of the crest; 3. Longitudinal structure of the equatorial anomaly; 4. Intensitive scintillation and fast Faraday fading caused by bubble effects; 5. The ionization ledges in the topside ionosphere and the neutral anomaly; 6. Low-latitude electron precipitation, which is symmetric to the magnetic equator.
Statistics of the interplanetary magnetic fields observed at 0.72 AU and 1 AU
Li Xiaoyu, Zhang Tielong
2010, 30(4): 356-361.   doi: 10.11728/cjss2010.04.356
Abstract(2549) [PDF 248KB](41)
Abstract:
This paper presents the Interplanetary Magnetic Field (IMF) observations at 0.72 AU measured by Venus Express (VEX) and 1 AU by Advanced Composition Explorer (ACE) in 2007. The distributions of daily averages of $B$ are lognormal in both locations. The multiscale structure of the magnetic field fluctuations was described by studying the increments of $B$ over a range scales from 10 min to 21.3 hours. All the Probability Distribution Functions (PDFs) can be described quantitatively by Tsallis distribution function. On the ecliptic plane from 0.72 AU to 1 AU, the entropy index q increases with distance over all scales, indicating the intermittency of turbulence is growing. The widths of the PDFs at 0.72 AU are larger than those at 1 AU at all scales, which indicating the turbulence at 0.72 AU is more intense than that at 1 AU. This helps us understand the nature and development of the magnetic field fluctuations.
Simulation of GPS/LEO Radio Occultation Based on Satellite Tool Kit
Fu Jun, Qian Shan, Zhang Shifeng, Cai Hong
2010, 30(6): 567-572.   doi: 10.11728/cjss2010.06.567
Abstract(2959) [PDF 584KB](49)
Abstract:
High precision of GPS/LEO Radio Occultation (RO) technique in atmospheric profile retrievals is achieved. There are a few of GPS/LEO RO projects abroad at present, but related in-depth experiment had not been done in China, which restricted the development of domestic RO technique greatly. Research method of GPS/LEO radio occultation based on Satellite Tool Kit (STK) is presented, and then condition of RO occurrence and formula of calculating position of tangent point are addressed according to principle of GPS/LEO radio occultation. With the criterion process of RO having been simulated by STK, the occultation data is obtained. Index of atmosphere refractivity is gained by inversion according to known atmosphere model based on the assumption of the spherical symmetric atmosphere. It indicated a better precision of inversion data through the comparison between atmosphere model and inversion data, and the feasibility of simulation of GPS/LEO RO experiment by STK is validated.
Impact of Geomagnetic Storms on L-band Ionospheric Scintillation Over Equatorial Region
YANG Shenggao, FANG Hanxian, LI Gang, NIU Jun, WANG Kai
2012, 32(6): 812-817.   doi: 10.11728/cjss2012.06.812
Abstract(2923) [PDF 548KB](42)
Abstract:
Using the observation data at Vanimo station, the amplitude scintillation intensity and the occurrence rate were analyzed during the two classic different strong magnetic storms. Mechanism of the magnetic storm influence on the scintillation was discussed preliminarily by Rayleigh-Taylor instability linear theory. The results show that the magnetic storm could either triggering or inhibiting the scintillation, which relates to the season and the local time of the different period of the magnetic storm. If the magnetic storm main phase occurs from midnight to dawn, the scintillation may be triggered by the eastern ward electrical field, and if the magnetic storm recovery phase takes place during the pre-midnight, it may be inhibited by the western ward electrical field. The electrical field variation during the magnetic storms is possibly the main factor that influence the scintillation, but it needs further study to prove.
An Observation-Based Model of Solar Wind Background
XIANG Changqing, FENG Xueshang, FAN Quanlin, YAO Jiusheng
2006, 26(3): 161-166.   doi: 10.11728/cjss2006.03.161
Abstract(2197) [PDF 2609KB](28)
Abstract:
Photospheric magnetic field measurements and coronal polarized brightness observations are used as constrains to develop a single-fluid solar wind background model, which includes proton density, bulk velocity and magnetic field. Proton temperature will be dealed with in further studies, The synoptic maps of K-corona polarized Brightness (pB) at 1.36 solar radii observed by MKIII in High Altitude Observator (HAO) are applied to derive corona density according to the solar wind density model constructed by Guhathakurta in 1996. In order to determine the global magnetic field, the synoptic maps of photospheric magnetic field in Wilcox Solar Observatory (WSO) are adopted to be the bottom boundary condition of the model of horizontal current and current sheet (HCCS) established by Zhao in 1994. Researches on observations during Ulysses' first and second polar flybyes made by Phillips in 1995 and McComas in 2003 demonstrate that the solar wind momentum flux density scaled to 1 AU is almost invariant except that it is slightly small in the latitude of ±10°-30°, thus the solar wind speed can be derived from this conclusion and the obtained density data. The model is applied to study the solar wind background in Carrington Rotation (CR) 1918 and the results are roughly consistent with the observations in solar minimum. However, the area of high density and slow speed is slightly larger than that observed and thus the density model needs to be further improved.
Pdqg-R Subdivision Mode And Encoding In Heliocentric Coordinate System
Hu Yasi, Shi Peng, Duan Ran
2015, 35(5): 626-633.   doi: 10.11728/cjss2015.05.626
Abstract(1164) [PDF 2332KB](77)
Abstract:
With the quick increase of space data, in order to meet the higher demand of data visualization and data access efficiency, reasonable data organization and management is needed. Based on the existing 2D subdivision models, for the ecliptic plane and meridian plane which are over the Sun centroid, a new model, PDQG-R (Plane Degradation Quad-Tree Grid), is put forward. Encoding scheme of grids is also given. Taken solar wind data as an example, the model not only resolves the problem that grids near to heliocentric are too dense, but also meets the requirement that resolution in radius is not equal to that in longitude and latitude. Besides, it provides hierarchical multi-resolution data, and can support the organization and management of massive space data effectively.
Sloshing of Liquid in Spherical Tank at Low-gravity Environments
Wang Zhao-lin, Deng Zhong-ping
1985, 5(4): 294-302.   doi: 10.11728/cjss1985.04.294
Abstract(1987) [PDF 492KB](40)
Abstract:
In the paper, the sloshing of liquid in a spherical tank is investigated under low-gravity conditions. After determination of the equilibrium shape of free surface of liquid, using a method concerning a kind of characteristic functions, expanded into po-lynominal expressions, the free and forced sloshing problem had been solved.The computer results for sloshing frequencies, dynamical coefficients and damping ratio had been obtained.
Image matching analysis and experiment of spaceborne camera swayed in the end of orbit life
Yang Xiubin, Jiang Li, Jin Guang
2013, 33(3): 337-345.   doi: 10.11728/cjss2013.03.337
Abstract(2423) [PDF 779KB](44)
Abstract:
Satellite sways matching image is established by analyzing the bottlenecks problem of that the data read-out frequency is too large, and the serious mismatch shift which spaceborne TDI CCD camera might face in the end of orbit life. Based on orbital decay height, the model of swaying match image is designed, the relation between orbit height and angle of the matching image is calculated, quantitative analysis on the feasibility of image motion vector, deviant angle, image distortion are carried out, and then satellite attitude pointing accuracy and stability which meet the requirement of imaging are analyzed through Monte Carlo methods. Finally, physical simulation of TDI CCD camera swaying-imaging is conducted on the mini-type three-axis air bearing table constructed for attitude control simulation of small satellite. Simulation results suggest that the MTF simulation and cross-correlation function of the similarity measurement are both more than 0.85, and satellite swaying to match image can meet the imaging requirement well in the end of the orbit life.
Technique of reconstructing ionospheric TEC map with the data of single station based on the background field by using IRI
Weng LIbin, Fang Hanxian, Yang Shenggao, Wang Sicheng
2011, 31(4): 453-458.   doi: 10.11728/cjss2011.04.453
Abstract(3163) [PDF 623KB](112)
Abstract:
Owing to the sparse data, the reconstructing ionospheric maps are not accurate enough by using the interpolation methods directly, especially in the verges. In order to obtain better TEC maps, the reconstruction was performed by Inverse Distance Weighting and Kriging Methods with IRI-2007 used as the background field. The test produced a better performance according to using Cross-validation method. As a result, the new technique decreased the errors effectively, especially in the verges, and the proportions of absolute errors between -0.25~0.25 TECU at all grid points in the reconstructing ionospheric map were improved by 70\% and 100\%. Meanwhile statistic errors showed a normal distribution. The reconstructed precision can be improved by using more exact background or successive correction method.
Experimental research on the momentum wheel failure physical model
Fan Youwen, Yang Xiaoli, Li Chunwei, Qing Tao
2009, 29(1): 78-86.   doi: 10.11728/cjss2009.01.078
Abstract(3134) [PDF 954KB](67)
Abstract:
For momentum wheel product's development and lifetime assessment, the physical failure model test is conducted. Because the momentum wheel failure is represented as the failure of its bearing assembly lubrication system, the bearing assembly is selected as the test model. In this paper, we has analyzed the real working environment of momentum wheel bearing assembly, determined the ground simulation specification of the test model, then the effecting factors of bearing assembly lubrication system failure are analyzed, after that to determine the sampling scheme. Finally, the mathematical presentation of the failure of bearing assembly lubrication system is given. For the assurance of momentum wheel product lifetime assessment, it is believed to produce two important tribology matching tests during production is necessary.
HYBRID SIMULATION OF MAGNETIC RECONNECTION IN ANISOTROPIC PLASMA
GUO Jun, LI Yi, LU Quanming, WANG Shui
2003, 23(2): 81-88.  
Abstract(2106) [PDF 2208KB](21)
Abstract:
The process of magnetic reconnection in an anisotropic plasma is studied based on two and half dimensional hybrid simulation. The results agree with theories. It is found that the growth rate of instability is enhanced greatly and the speed of magnetic reconnection is increased in the presence of pressure anisotropy (P/P = 1.5) compared with that in pressure isotropy. In a pressure anisotropy (P/P = 0.6) fire hose instability appears, which will restrain the tearing mode instability and magnetic reconnection. Because of the fire hose instability and the restraint of the tearing mode, the width of magnetic island in a pressure anisotropy (P/P = 0.6) is narrower than that in pressure isotropy. In addition, compared with the results based on MHD simulation, the effect of pressure anisotropy in our hybrid simulation is less obvious, which may be caused by the different conditions used in different simulation modes.
Study on the Adaptability of the Empirical Storm-time Ionospheric Correction Model STORM in China Region
Wang Shikai, Liu Wen, Lu Zhuanxia, Guo Yanbo, Kong Qingyan, Feng Jing
2010, 30(2): 132-140.   doi: 10.11728/cjss2010.02.132
Abstract(2910) [PDF 637KB](45)
Abstract:
Based on the ionospheric f0F2 data from 9 ionosonde stations in China region during a solar activity cycle from 1976 to 1987, the level and the distribution characteristic of the ionospheric storms along seasonal bins and geomagnetic latitudes are statistically investigated. It is found that the small and medium level storms occur more frequently in spring and autumn and the frequencies in different seasonal bins have relationship with the geomagnetic latitudes. A comparison between the storm-time predicted f0F2 values and the monthly median ones shows that the median model can be improved effectively by the STORM model except in winter. It is important of adding Chinese storm-time data and enhancing the prediction accuracy in winter to improve the STORM model. And developing an appropriate storm-time index to predict f0F2 is a key point in the future.
Experimental Research on Solar Array Drive Assembly Internal Charging Effects
SHI Liang, LIU Qing, CHEN Yifeng, YANG Shengsheng, QIN Xiaogang, LI Detian, WANG Jun
2017, 37(3): 344-349.   doi: 10.11728/cjss2017.03.344
Abstract(1267) [PDF 1948KB](58)
Abstract:
Solar Array Drive Assembly (SADA) is a crucial component of the electrical transfer sub-assembly of the modern long life and large power satellite. The internal discharging and secondary arc in SADA, which happened under the high-energy electron environment, can lead to spacecraft abnormity and malfunction. Experimental platform has been built by using the two-beam accelerator. In the experiment, the electron energy is 2MeV, the beam density is 5pA·cm-2, the working voltage of SADA is from 50 to 150V, and the working current is from 0.5 to 1.5A. The charging potential of test sample can reach equilibrium after 5 hours of irradiation. The electric field can reach about 5×106V·m-1. The time of discharge increases apparently with the increase of the working voltage at the same operating current. It shows that the electric field formed by the working voltage and the electric field formed by the high energy electron deposition will be superposed, which leads to the increase of the risk of SADA discharge. According the experiment results, the design of SADA anti-internal electricity can be improved by adopting the following methods. By reducing the bulk resistivity of SADA dielectric disk and improving the design of conducting ring structure, the electric field on the dielectric disk formed by the voltage between the conductive rings can be reduced.
Comparative Study of Three AUSM Algorithms and Simulated Application on the Solar Wind
WANG Tao, LI Huichao, ZHANG Man, FU Huazheng
2015, 35(4): 393-402.   doi: 10.11728/cjss2015.04.393
Abstract(1329) [PDF 3814KB](70)
Abstract:
Numerical simulation of MHD (Magnetohydrodynamics) is an important method to study solar-terrestrial physics phenomena. In this paper, three AUSM algorithms, i.e., AUSM, AUSM+, AUSMPW+, were compared in conjunction with the HDC method to eliminate the divergence of the magnetic field. The AUSM+ algorithm is found to be better than the AUSM algorithm and the AUSMPW+ algorithm through the results of Rotor example and Orszag-Tang vortex example. Further, the AUSM+ algorithm is used to simulate the coronal with a six-component grid system. The results show that this algorithm can correctly calculate the large-scale structure of the corona. Also, the HDC method can maintain the divergence-free constraint on the magnetic field.
Analysis of Effects of Simulated Microgravity on Signaling Pathways Involved in Osteogenic Differentiation of Human Mesenchymal Stem Cells
HUANG Guoping, ZHENG Qiang, YANG Jinfeng, GUO Chunjuan, SHEN Dan, SHI Dongyan, XU Yulin, PAN Zhijun, WANG Jinfu
2008, 28(1): 87-96.   doi: 10.11728/cjss2008.01.087
Abstract(2073) [PDF 2855KB](58)
Abstract:
Microgravity (MG) results in reduction of bone formation. Bone formation is bound up with osteogenic differentiation from human mesenchymal stem cells (hMSC) in bone marrow. We simulated MG to determine its effects on osteogenesis of hMSC and used activators or inhibitors of signaling factors to modulate osteogenic differentiation. Under osteogenic induction, MG reduceds osteogenic differentiation of hMSC and decreaseds the expression of osteoblast gene markers. The expression of Runx2 was likewise inhibited. However, the expression of PPAR$\g$2 increased. MG also decreased phosphorylation of ERK, but increased phosphorylation of p38MAPK. SB203580, a p38MAPK inhibitor, was able to inhibit the phosphorylation of p38MAPK, but not able to reduce the expression of PPARγ2. Bone morphogenetic protein (BMP) increased the expression of Runx2. Fibroblast growth factor 2 (FGF2) increased the phosphorylation of ERK, but did not increase significantly the expression of osteoblast gene markers. The combination of BMP, FGF2 and SB203580 significantly reversed the effect of MG on osteogenic differentiation of hMSC. Our results suggests that simulated MG inhibits the osteogenic differentiation and increases the adipogenic differentiation of hMSC through different signaling pathways. Therefore the effect of MG on the differentiation of hMSC could be reversed by the mediation of signaling pathways.
Research on Control and Experiment of a New Lunar Rover
Ge Weiping, Liu Tun, Yuan Laohu, Zhao Zhiping
2010, 30(2): 160-164.   doi: 10.11728/cjss2010.02.160
Abstract(2244) [PDF 644KB](30)
Abstract:
Because of the complexity of the lunar environment, the lunar rover, as a complex multi-body system, has many characteristics in its dynamics behavior and its control. The analysis is more difficult than that of simple system. The mathematical models of lunar rover control, such as dynamics, motion constraints and kinematics, are presented in this paper. The harmonious control is explained by the sample of running across a ravine. For imitation of the lunar gravitational circumstances, a single wheel test device based on gas lubrication was designed. The range of the kinematic and dynamic parameters of each wheel can be determined by that device.
Progress of microgravity material research during the period of 2007—2009
Chen Nuofu, Bai Yiming, Chen Wanchun, Zhou Yanfei, Luo Xinghong, Yu Yude
2010, 30(5): 504-515.   doi: 10.11728/cjss2010.05.504
Abstract(2364) [PDF 780KB](63)
Abstract:
Orbital experimental researches on crystal growth of Mn-doped GaSb and Bi2Se0.21Te2.79 are briefly summarized. The space experiments were completed in September of 2007 on broad the Foton-M3 satellite of Russia. Ground-based researches on the solidification behaviors of Al-Al3Ni, Al-Al2Cu, Ag-Cu eutectic, Al-Pb monotectic and Cu-Co peritectic alloys in a 50-meter-high drop tube were investigated. New experimental results on the ultrasonic field and the temperature recycling induced to chiral symmetry breaking of NaClO3 crystal also were reported in the present paper.
Analysis of solar pressure perturbation impacting on satellite attitude-orbit coupling
Cui Wen, Wang Jiasong, Baoyin Hexi
2012, 32(3): 424-429.   doi: 10.11728/cjss2012.03.424
Abstract(2832) [PDF 497KB](63)
Abstract:
With the increasing precision of satellite geodesy, the precision of satellite orbit determination should be improved correspondingly. Currently, the orbit accuracy of Topex, Jason-1, Jason-2 and a series of marine geodetic satellites has already reached a centimeter level. Thus, the satellite dynamics model should also be further improved. Considering the solar array with regular rotation, simplifying the geometry of satellite as Boxing-Wing model which is common in high-precision orbit determination, the solar radiation pressure and moment of Topex satellite are calculated in orbit. Considering the situation of satellite attitude-orbit coupling, the changing of orbital semi-major axis and the satellite attitude caused by the solar pressure perturbation are analyzed. During the calculation of one orbital period, the effect by solar pressure for orbital semi-major axis is about 9cm, and for roll angle and pitch angle both are about 6 degrees, which should not be ignored in high-precision orbit calculations and attitude control.
Fault Tree Analysis of the Space Cable-strut Deployable Articulated Mast
HU Ming, DENG Guobing, CHEN Wenhua, QIAN Ping, LIU Dongxu, PAN Jun
2012, 32(4): 598-604.   doi: 10.11728/cjss2012.04.598
Abstract(2117) [PDF 536KB](45)
Abstract:
Combined the application environment of the space cable-strut deployable articulated mast, the fault tree of the deployable mast is established by considering the deploying failure of the mast as the top event based on the analysis of its composition and deployment mechanism, whose quantitative and qualitative analysis is finished for the fault tree of the deployable mast. And then the results of the probability of failure, important degree of probability and criticality are obtained and the main factors leading to the deploying failure of the mast are found out. The results show that the accurate deploying of the mast is influenced by lack of driving force, jamming on its roller card of the corner wheel and precision failure, which provides the foundation for the deploying reliability analysis of the space cable-strut deployable articulated mast
Asynchronous Differential Space-Time Block Codes Based On Spreading Techniques Over Satellite Communication
ZHANG Jianwu, ZHANG Qianhua
2015, 35(5): 634-640.   doi: 10.11728/cjss2015.05.634
Abstract(938) [PDF 1750KB](40)
Abstract:
In satellite cooperative communication system, delay errors caused by different delay between different channels with large scale relays brings loss of BER. Traditional solutions generally use differential codes to estimate channel parameters dynamically in the receiving end of a satellite communication system. In this paper, orthogonal codes in spread spectrum technique systems are used to distinguish signals from different relay satellites. In this paper, spread spectrum codes table is used to extract signals from different relay satellites, then to carry out a space-time decoding. As can be seen in simulation results, differential space-time blocks codes with spreading has a better BER than the one without spreading. It solves the problem of random delay, so that the receiving end of the channel should not to estimate channel parameter. The complexity of the receiving end is significantly reduced.
Comprehensive Reliability Assessment of High Reliable Space Electronic Products Based on General Failure Rate
FU Hongyong, LIN Baojun, CHEN Fuen
2007, 27(3): 250-252.   doi: 10.11728/cjss2007.03.250
Abstract(2189) [PDF 553KB](46)
Abstract:
According to the Bayes theorem, the comprehensive reliability assessment of high reliable electronic products in astronautics is studied theoretically and a method for the number of equivalent tasks is given, A calculation method from the tested and applied parameters of components is put forward. Finally a practical example for a certain space electronic product is presented.
Development and advisement of the earthquake electromagnetic satellite
Teng Yuntian, Wang Xizhen, Wang Xiaomei, Zhou Xun
2009, 29(1): 87-92.   doi: 10.11728/cjss2009.01.087
Abstract(2475) [PDF 625KB](53)
Abstract:
A lot of examples indicate that there is interrelation between earthquake and ionosphere, which is the theoretic element for development of earthquake electromagmetic satellite. In this paper, development and trend of earthquake electromagmetic satellite of some countries are analyzed and some proposals for research on it at present are put forward. As conclusion, it may be necessity to build an integrative constellation composed of electromagmetic, InSar, gravity, IR and other satellite to realize earthquake prediction.
Space astronomy in China: 2008—2010
Gan Weiqun, Zhang Shuangnan, Yan Yihua, Chang Jin
2010, 30(5): 424-426.   doi: 10.11728/cjss2010.05.424
Abstract(2330) [PDF 65KB](69)
Abstract:
In 2008 to 2010, the main activities in Chinese space astronomy were focused on: fulfilling the long-term plan of Chinese space astronomy; initiating the long-term plan of Chinese space astronomy; undertaking some astronomical missions set by CNSA in ``Development Program of Space Science for 2006--2010''. This paper summarizes in brief all these activities.
Electrostatic transportation of lunar dust: a review
Gan Hong, Wang Shijie, Li Xiongyao
2013, 33(2): 135-142.   doi: 10.11728/cjss2013.02.135
Abstract(2724) [PDF 548KB](74)
Abstract:
Electrostatic levitation and transportation of lunar dust had been one of the most interesting and controversial problems since the Apollo era. It is not only significant clues to study the evolution of lunar surface material, but also a key factor which should be considered in lunar mission. On lunar surface, the dust grains are electrostatically charged by electron deposition, photoemission, and secondary electron emission. With the charge processes, an electrostatic field might be formed on lunar near-surface. As a result, dust grains could be lifted. However, the electrostatic levitation and transportation process of lunar dust grains are still not clear. Shortage in comprehension of electrostatic properties of lunar dust grains, simulation of electrostatic levitation and transportation, and landing detection of lunar dust environment might be the main factors which limit the further knowledge of electrostatic levitation and transportation of lunar dust grains. To satisfy the need of lunar science and future lunar missions, development of lunar dust simulant, measurement of electrostatic properties of lunar dust, simulation of electrostatic levitation and transportation, and detection of lunar dust environment are important aspects in the study of lunar dust in the future.
Development of TDI CCD Camera Image Simulator
Zhang Liu, Sun Qiuxiang, Jin Guang
2010, 30(1): 91-96.   doi: 10.11728/cjss2010.01.091
Abstract(3198) [PDF 730KB](57)
Abstract:
TDI (Time Delay and Integration) CCD camera has been used widely in space-based reconnaissance. But this kind of camera introduces large amounts of image smear. To analyze the image smear sources, a space TDI CCD mathematical model which scans the camera pixels corresponding relations with the point of scenery was established. It can be used to reckon cumulating image smear where the TDI CCD imaging exceeded the corresponding pixel horizontal and vertical offset. Based on the space TDI CCD mathematical mode, a TDI CCD camera imaging emulator software is developed with VC++ 6.0. To provide a real satellite TDI CCD imaging simulation space environment for the emulator software, a satellite attitude control single-axis simulation flotation was established. The TDI CCD camera imaging emulator software and the satellite attitude control single-axis simulation flotation constitute the real-time space TDI CCD camera imaging simulation platform, which can dynamically simulates the real-time effect of satellite attitude error to the image process of space TDI CCD camera imaging with nominal deviant angle adjustment. Simulation results show that the angular velocity of yaw angle has the greatest impact on image quality, and roll attitude angle almost has no effect on image quality, which are consistent with the real TDI CCD image.
Design And Testing Of An Ionospheric Doppler Receiver
Chen Yanlong, Zhang Yuannong
2015, 35(5): 574-580.   doi: 10.11728/cjss2015.05.574
Abstract(862) [PDF 963KB](31)
Abstract:
As an important part of the Earth space environment, ionosphere variations have a very important impact on the daily life and activities and living of human beings. Ionosphere disturbance always manifests itself as a complex temporal and spatial variation process. Therefore, to strengthen the real-time monitoring of ionosphere disturbance and study the physical mechanism of the ionosphere disturbance is an important topic of space physics. Software defined radio technology is deployed to design an ionosphere Doppler receiver. Consisting of PXI bus and digital chips including DSP and FPGA, the receiver uses GPS as a module to synchronize time and frequency. Its system parameters can be set flexibly. Receiving high frequency signals from the Shanxi astronomical observatory, the receiver can get real-time ionosphere Doppler shift information caused by ionosphere disturbance. A signal processing software using MATLAB language processes the received high frequency signals. Observations show that the receiver is proved to be an effective means to obtain the ionosphere disturbance information in different spatial scales by data processing since it can analyze the change in Doppler shift of the echo signal of an ionosphere as time changes.
THE EVOLUTION OF HARD X-RAY ENERGY SPECTRUM IN SOLAR FLARES
LIN Huaan
1999, 19(4): 295-300.   doi: 10.11728/cjss1999.04.295
Abstract(2657) [PDF 531KB](75)
Abstract:
The hard X-rays of solar flares are produced by Bremsstrahlung interaction ofhigh energy electron beam impinging on solar atmosphere. Based on a simple physical model of flare loop, and under the assumption that the high energy electronswith synchronous variation between the beam flux and spectrum index are injectedfrom the top of the loop, some calculated results about hard X-ray spectrum evolution with different atmosphere density are obtained in this paper. These resultsshow: in low density area, such as in the top of loop, the hard X-ray spectrum hassoft-hard--hard evolution property, in high density area, such as in the foot points ofloop, the spectrum possesses soft-hard-soft variation. The time duration of injectingelectrons will influence the height of region in the loop where the one type of hardX-ray spectrum evolution will transform into the other one.
Simulation of Nequick Parameters of Galileo Satellite Navigation System
XIE Jie, ZHANG Bo, HOU Bo, YAO Zhicheng, LIU Guangbin
2012, 32(6): 881-886.   doi: 10.11728/cjss2012.06.881
Abstract(3483) [PDF 527KB](64)
Abstract:
The simulation model of Galileo ionospheric parameters based on IGRF is proposed to solve the problem that ionospheric parameters estimation is related to geomagnetic coordinates. Using IGRF, the geomagnetic elements of the geomagnetic field and the Electron Density can be computed at a given location and time, sequentially, the ionospheric parameters of Galileo can be calculated. The simulation results show that the ionospheric delay calculated by this model is consistent with the value observed by IGS, and the precision is higher than those by other models, which proves that the high precision simulation of the Galileo ionospheric parameters is realized.
Research on the Effect of Opacity on Solar Coronal Soft X-ray OⅧ Spectral Line
Zhang Qingguo, He Jian, You Jinghan
2014, 34(4): 384-389.   doi: 10.11728/cjss2014.04.384
Abstract(1071) [PDF 503KB](50)
Abstract:
To study the effect of opacity on solar plasma X-rays in solar coronal region, using the basic theory of photon escape factor in spectral analysis, the effect of opacity on intensity ratio of solar OⅧ 1.897nm and 1.601nm spectral lines is analyzed. Under optically thick conditions, theory of the effect of photon escape factor on the intensity ratio of the solar spectral lines is discussed. In the calculation, the optically depth of OⅧ spectral lines is discussed, and finally the effective emission thickness of OⅧ ion in solar plasma is estimated. Results show that under optically thick conditions, the opacity has great effect on solar OⅧ spectral line, and the effective emission thickness of OⅧ ion is greater than that in other solar ultraviolet spectral line. This is important for plasma diagnose in solar plasma emission layer.
Application of Additive Manufacturing Technology for Space
WANG Gong, LIU Yifei, CHENG Tianjin, LIU Ming
2016, 36(4): 571-576.   doi: 10.11728/cjss2016.04.571
Abstract(1477) [PDF 1815KB](115)
Abstract:
Chinese Space Station has planned a large number of scientific experiments and applied research. On-orbit support is critical for the accomplishing of manned space mission during the full life cycle of space station. Nevertheless, resources supplied by cargo aircrafts are difficult to be sustainable. The space additive manufacturing technology is a revolutionary and strategic technique for future space exploration, which has the potential to realize manufacturing on the station demand, and will facilitate deeper space exploration by saving logistics from Earth. 3D printing is an important modeling technique to support space manufacturing with its efficiency and flexibility. The latest research of the on-orbit additive manufacturing is summarized, and its on-orbit application pattern is analyzed by taking account of the requirements of Chinese space station and its manned space missions. Moreover, the challenges and solutions of applying additive manufacturing on-orbit are analyzed.
Study on the Short to Medium Term Forecast Model of Solar Proton Event
CUI Yanmei, SHI Liqin, LIU Siqing
2017, 37(3): 262-269.   doi: 10.11728/cjss2017.03.262
Abstract(1134) [PDF 2724KB](106)
Abstract:
Solar proton event forecast is very important to guarantee the security of spacecrafts and astronauts. According to the short to medium term space mission, the solar proton fluences whose energy are greater than 10MeV, 30MeV and 60MeV are statistically analyzed. It is found that the probability of solar proton fluences has a normal distribution, and their standard deviations and expectations are logarithmic functions over different time period from Day 1 to 365. Consequently, a short to medium term forecast model of solar proton fluences is built, which can forecast the solar proton fluences whose energy are greater than 10MeV, 30MeV and 60MeV with certain confidence levels for different time period. Therefore, this model is very helpful to safely carry out the space mission which task period is less than 1 year.
THE RELATIONSHIP BETWEEN FIELD-ALIGNED CURRENT AND SUBSTORM PHASE
Jiao Wei-xin.
1996, 16(2): 140-144.   doi: 10.11728/cjss1996.02.140
Abstract(2201) [PDF 345KB](71)
Abstract:
ISEE 1 and 2 measurements of magnetic changes across nightside fieldaligned currents (FACs) in the inner magnetosphere are examined to determine the average ionospheric extrapolated characteristics and properties of regin 1 and 2 currents as a function of substorm phase. The properties of these currents studied include current intensity, density and layer width. It is found that there is a close relation between FACs and substorm phase. Both region 1 and region 2 currents intensity reach their peak during the expansion phase. The average value of intensity in region 1 is about 1.4 times greater in region 2. The current densities in region 1 and 2 behave same with current intensity, i.e from the growth phase to expansion phase, the density increases and from the expansion phase to the recovery phase it decreases.
Influence of Satellite Departure and Experiment Research on Integrated Positioning With Two Geostationary Satellites and GIS
ZHENG Chong, WU Jie, ZHOU Bozhao, YUAN Yanbo
2005, 25(2): 138-142.  
Abstract(2016) [PDF 1499KB](59)
Abstract:
A calculate model is presented in this paper, which is used to study both positioning with two Geostationary satellites and integrated positioning with two Geostationary satellites and geographic Information System (GIS). With the model, how the ephemeris error influence the precision of positioning with two Geostationary satellites and how the position of the satellites influence the integrated positioning when they were added 1° departure in longitude and latitude are studied. The result shows it does not debase the accuracy of the integrated positioning with two Geostationary satellites and geographic information system, to add a small departure on the satellites position. Also, the conclusion is explained by geometry. At the end of the paper, an experiment was done which proved the integrated positioning with two Geostationary satellites and geographic information system can surely improve the precision of positioning with Geostationary satellites.
THE PRELIMINARY THERMAL ANALYSIS AND THERMAL CONTROL DESIGN FOR POLAR ORBIT LUNAR SATELLITES WITH SOLAR PANELS IN SINGLE DEGREE OF FREEDOM
ZHANG Jiaxun, WEN Yaopu, LI Jingdong
2004, 24(1): 51-57.  
Abstract(2141) [PDF 720KB](45)
Abstract:
In this paper, the thermal control designs of polar orbit lunar satellites are summarized, and take a polar orbit lunar satellite with solar panels in single degree of freedom as an example. Then, the analysis of this satellite about its outer heat flux and heat dissipation in space are conducted when it is flying towards the moon and orbiting around the moon. Based on the results of the analysis, the thermal design scheme of this lunar satellite is presented, and the problems about the thermal control of the payloads, the problems about the thermal control of the instruments and equipment on the ±y side, and the application of the thermal louver technique are described.
Analysis and Test of Anti-Jamming Performance for DS/FH TT&C System
Pan Dianfei, Cheng Naiping, Hao Jianhua
2013, 33(5): 540-547.   doi: 10.11728/cjss2013.05.540
Abstract(2095) [PDF 3142KB](69)
Abstract:
Based on the Minimum Performance Constraint (MPC), a synthetic analysis method was presented for the DS/FH TT&C system under jamming conditions. This method can evaluate the anti-jamming performance more effectively and comprehensively. Taking three classical interference environments as example, i.e. tone jamming, pulse interference and highly dynamic condition, the effects of different jammings on MPC with varying parameters are investigated. To overcome the deficiencies such as too many steps, poor efficiency and high cost in the anti-jamming capability test, the testing order of the attributes is modeled as an optimal route problem using Ant Colony Optimization (ACO) algorithm. Simulation results show that the proposed analytical model is correct and effective. The conclusions are evaluated to be significant and referable for the choice of DS/FH TT&C system jamming test schemes.
Study on Space Object Tracking in Space-based Optical Surveillance
Li Jun, An Wei, Zhou Yiyu
2009, 29(3): 326-331.   doi: 10.11728/cjss2009.03.326
Abstract(2680) [PDF 708KB](65)
Abstract:
Utilizing space-based observer to achieve effective surveillance on space objects is the direction and trend of the space surveillance. Based on the analysis on the characteristics of the space optical surveillance, the passive tracking method for the surveillance data is put forward, according to extracting the linear moving information of the streak of the space object in surveillance image frame. And the corresponding tracking initiation method is also given. The data flux in information processing is reduced, and the comparative tracking precession can be provided at the same time.
Electromagnetic Energy Transfer across the Magnetopause
JING Hao, LÜ Jianyong, JIANG Yong, WANG Ming, HU Huiping, LIU Ziqian
2014, 34(3): 269-277.   doi: 10.11728/cjss2014.03.269
Abstract(1251) [PDF 2011KB](98)
Abstract:
A three-dimensional adaptive magnetohydrodynamic (MHD) model is used to examine the electromagnetic energy flow from the solar wind to the magnetosphere. The magnetopause is determined by finding approximately the inner edge of the void encompassed by the solar wind stream lines, and the magnetopause is divided into nightside and dayside part by polar cusp region. This study found that the magnetopause energy transfer has close relations with solar wind conditions. The magnetopause area also effects energy transfer. For northward IMF, most of the electromagnetic energy flux inflow occurs near the polar cusps on magnetopause; for southward IMF the largest electromagnetic energy input into the magnetosphere occurs at the tail lobe behind the cusps. Under southward IMF conditions, more electromagnetic energy input can be identified as increasing solar wind density while it does not enhance as much for northward IMF. Our results suggest that the mechanisms proposed to electromagnetic energy transfer are mainly due to reconnection. If the electromagnetic energy coupling between the solar wind and the magnetosphere can be interpreted as a proxy for the reconnection efficiency, the efficiency during northward IMF is about 10%~30% of that for southward IMF under the solar wind conditions we considered.
Numerical Study of Electrostatic Ion Beam-Density Drift Instabilities in the Geomagnetic Tail
Zhou Guo-cheng, Cao Xiang-dong
1990, 10(2): 101-106.   doi: 10.11728/cjss1990.02.101
Abstract(2057) [PDF 420KB](87)
Abstract:
The mechanism of the generation of the broadband electrostatic noises (BEN) in the plasma sheet boundary layer is studied in this paper. The model plasma consists of warm background electrons, warm earthward ion beams and cold tailward ion beams. It is shown that electrostatic ion beam-density drift instabilities can be excited in the broad range of the frequency, the peak growth rate is found in the low frequency region at the large propagation angle, and the considerable growth rate in the high frequency region at the small propagation angle. The direction for the peak growth rate is determined by the ratio of the ion beam velocity to the density gradient drift velocity. The results are consistent with observations of the magnetotail BEN.
Simulation Study on GRO and LRO Events
WANG Shuzhi, LIU Congliang, ZHU Guangwu, BAI Weihua, DU Qifei, SUN Yueqiang, XIA Junming, MENG Xiangguang, WANG Xianyi, ZHAO Danyang, WANG Dongwei, CAI Yuerong, WU Di
2017, 37(2): 207-213.   doi: 10.11728/cjss2017.02.207
Abstract(1599) [PDF 3426KB](74)
Abstract:
Combining the GRO (Global Navigation Satellite System Radio Occultation) and LRO (Low Earth Orbit Radio Occultation) techniques to probe the Earth's atmosphere is a main development direction of RO (Radio Occultation). In this study, the mathematical criteria of a RO event have been described. Then the effects of the main orbit parameters of LEO satellite on the RO events amount and their global distribution have been discussed by a simulation study. The results showed that:the lower the LEO satellite orbit is, the more GRO events are; when the inclination is between 30° and 75°, there are more GRO events and their Earth coverage is higher. The LRO events distribute on the Earth evenly when the LEO-LEO RO satellite set in the polar orbits. This study can provide a scientific reference for GRO and LRO satellite constellation design.
Integrated Control for Crystal Growth Furnace in Space
Yu Qiang, Yu Haofeng, Liu Wei
2011, 31(1): 87-92.   doi: 10.11728/cjss2011.01.087
Abstract(2331) [PDF 582KB](77)
Abstract:
Crystal growth furnace in space is a complex system which has the characteristics of pure-delay, strong-coupling and nonlinearity. To meet the high precision temperature control of the crystal growth, a new integrated control software for crystal growth furnace in space is presented. The software has the modules of system identification, parameter tuning, computer-aided simulation and real-time system control. The correlation coefficient and the least squares method are used to accomplish the identification of the process model, the parameters of the controller are tuned by Hooke-Jeeves mode searching method, PID and Feed-forward algorithm are used to control the multi-zone furnace together. To simulate the process of controlling, it can adjust the parameters of the controller. After attaining a result of meeting requirement, it uses the parameters of the controller getting in simulation to control the furnace in real time on line. Through the integrated control software, we achieve batter results, when the three zones temperatures rise to 700ºC, the stabilities of the three zones are all less than ± 0.3ºC. The strong-coupling among these three zones are suppressed clearly. The basic principle, powerful functionality, attractive features are discussed in details. The application of this software shows its effectiveness.
THE INFLUENCE OF DISPERSIVE AND DISSIPATIVE EFFECTS ON THE FORMATION OF ALFVEN SOLITON WAVES
Feng Xue-shang, Lu Jian-yong
1996, 16(4): 260-265.   doi: 10.11728/cjss1996.04.260
Abstract(1999) [PDF 257KB](52)
Abstract:
Using some variable transformations and analytical integration, the analytical solitary wave solutions are obtained for the dispdrive DNLS equation and dissipative MKdV equation, which describe the propagation of Alfven waves in various plasma medium. Meanwhile, the ekistence conditions of soliton-like solutions are given.
A NOVEL UNIVERSAL DEMODULATOR FOR REMOTE SENSING SATELLITE
PAN Changyong, GUO Xingbo, YANG Zhixing
1999, 19(1): 82-87.   doi: 10.11728/cjss1999.01.082
Abstract(1872) [PDF 270KB](87)
Abstract:
Anovel universal demodulator for remote sensing satellite is proposed and realized in this paper. Compared with traditional multiple-function demodulator, thisdemodulator is much simpler mainly due to a new kind of filter and programmablebit synchronizer. This device has already been field tested with satisfactory result.
Research of the Evadible Period and Satellite Orbit Maneuver
Wang Jianfeng, Liu Jing, Liu Lin
2009, 29(2): 234-239.   doi: 10.11728/cjss2009.02.234
Abstract(2753) [PDF 558KB](50)
Abstract:
With the expansion of the human's activity in exploring, utilizing the outer space, the total number of orbital space debris increases rapidly, which leads to an essential danger to the spacecrafts and astronauts in the future. Space environment protection is becoming the most important task in space navigation. In order to ensure the success of space mission, the low-orbit objects are more important. The forecast and alarm system of space debris is an important application of space object scouting around the earth. In order to avoid the collision between two objects, the orbit change of at least one of the two objects before their collision is necessary. In this paper, some analyses on the relationship between the increment of speed and variations of orbits are studied. Some strategies for orbit maneuvers are also given. At the same time, some research on the over pass durations from the ground stations is done. These works provide effective technique support for the forecast and alarm of space debris and spacecrafts.
Navigation device scheme and information processing method of RLV
Mu Rongjun, Han Pengxin, Cui Naigang
2009, 29(1): 117-123.   doi: 10.11728/cjss2009.01.117
Abstract(4157) [PDF 790KB](67)
Abstract:
Through the research on orbital characteristics of RLV (Reusable Launch Vehicle), navigation device design scheme on different orbital sections is put forward. In allusion to requests of higher fault tolerant property, intelligentized level and dynamic ability, an integrated navigation information processing method based on DBNs theory with fault tolerant capability is proposed. By dynamic selective DBNs controller for navigation sensors and their
combination, active and dynamic optimal deployment and real time health monitoring are achieved.
A revisit of the phobos events
Wing-Huen Ip
2011, 31(2): 150-153.   doi: 10.11728/cjss2011.02.150
Abstract(2690) [PDF 147KB](49)
Abstract:
The magnetic field disturbances detected by the Phobos-2 spacecraft in 1989 have been suggested to be caused by a ring of dust and/or gas emitted from the Martian moon, Phobos. The physical nature of these ``Phobos events'' is examined using results from related investigations over the last twenty years. It is concluded that there is no clear evidence at present to support the association of magnetic field disturbances in the solar wind with Phobos. The situation will be further clarified taking advantage of the multi-spacecraft observations of the Yinghuo-1(YH-1), Mars Express and MAVEN missions beginning in 2012. It is expected that many novel features of solar wind interaction with Phobos (and possibly also Deimos) itself will also be revealed.
First Observation and Analysis of Seasonal Variation of the Ionosphere D Region Electron Density at Kunming
LI Na, CHEN Jinsong, DING Zonghua, ZHAO Zhenwei, WU Jian
2014, 34(6): 809-814.   doi: 10.11728/cjss2014.06.809
Abstract(1252) [PDF 1702KB](78)
Abstract:
The observed data by Kunming MF radar (25.6°N, 103.8°E) from August 2008 to July 2009 are employed to investigate the seasonal variation of the ionosphere D region electron density during low solar activity. The obvious characteristics in D region electron density is semiannual variation with the observed values larger in spring and autumn, smaller in su mmer and winter, which is different from the simulated result by International Reference Ionosphere (IRI). The result conforms to that observed by digital ionosonde. Then, comparison with that of zonal wind shows very good correspondence of changing trend between them. Finally the reasons leading to the correspondence are discussed.
Magnetic field detection method of China seismo-electromagnetic satellite
Zhou Bin, Cheng Bingjun, Zhang Yiteng, Zhang Zhenqi, Wang Jindong, Li Lei
2014, 34(6): 843-848.   doi: 10.11728/cjss2014.06.843
Abstract(1259) [PDF 2220KB](33)
Abstract:
China Seismo-Electromagnetic Satellite (CSES) is the first domestic satellite for electromagnetic science experiment in near Earth orbit. Space magnetic field detection is one of the primary scientific objectives of CSES, which is based on long-term steady vector magnetic measurement. Flux-gate magnetometer and Coupled Dark State magnetometer are employed to detect vector and scalar magnetic field respectively. Using fitting method, we could get absolute accuracy data of vector magnetic field. A method about flux-gate magnetometer vector data calibration is introduced using scalar magnetic field data, and it ensures the accuracy of vector magnetic field data. The performance of this method is evaluated by simulation, and it gives an accuracy of 1 nT.
APPLICATIONS OF BP NEURAL NETWORKS IN FORECASTING SUNSPOT NUMBERS FOR SOLAR CYCLE 23
TIAN Jianhua
1997, 17(3): 255-260.   doi: 10.11728/cjss1997.03.255
Abstract(2041) [PDF 412KB](36)
Abstract:
BP neuraI networks were designed, thened and used t0 caregorize the data set andrecognize pattems in sunspot number vallation during the ascent and descent of solarcycles- A hist0rical data set of smo0thed monthly mean sunsPOt numbers for l75O ADtO the first half of l995 AD and the predicted values f0r the latter half of l995 tol996 were used. We 0btained good simulation results of the ascending Periods and smoothed monthly mean sunspot numbers for each ascent Period of Solar Cycle l-22and fairly good forecasting results of the ascending Period and the maximum ofsmoothed monthiy mean sunspot number for Solar Cycle 22- Flnally, the paper givesthe following eshmared values for Sol4f Cycle 23: The maximum of smoothedmonthly mean sunspot number is l96 and the ascending Period is 38 months-
Deep Space TT&C Equipments of YH-1
Xiong Weiming, Xie Chunjian, Liang Xianfeng, Bai Yunfei, Qu Chenyang, Wang Zhugang, Guo Lili, Geng Hao, Deng Yongsheng, Jiang Yaxiang, Wang Wei, Cao Zhiyu, Zhao Tao
2009, 29(5): 490-494.   doi: 10.11728/cjss2009.05.490
Abstract(3201) [PDF 554KB](78)
Abstract:
A new upsurge of deep space exploration has arisen internationally during the 21th century. The TT&C (Tracking, Telemetry, Control ) technologies of deep space are very important. The YH-1 microsatellite is the first deep space explorer of China. In this article, the deep space TT&C characteristics, the key technologies of the YH-1 TT&C sub-system are introduced. The configuration and technical performance are provided concisely. The functions of TT&C for YH-1 microsatellite are: the telemetry link (downlink: from the microsatellite to the ground station) that transmits engineering data (spacecraft and instrument health and status measurements) and science data (including image data); the telecommand link (uplink: from the ground station to the microsatellite) that transmits the control information and commands to the microsatellite. The orbit parameters can be measured by one-way tracking, one-way Doppler frequency and VLBI. The microsatellite TT&C is working of X-band. In order to simplify the TT&C sub-system of the microsatellite, a transmitter and a receiver are used, instead of a transponder. The TT&C equipments onboard are designed with redundancy, which total weight is about 10kg.
Space Research Plan of China's Space Stationormalsize
GU Yidong, GAO Ming, ZHAO Guangheng
2016, 36(5): 595-599.   doi: 10.11728/cjss2016.05.595
Abstract(926) [PDF 102KB](67)
Abstract:
China's manned spaceflight missions have been introduced briefly, and the research planning of space sciences for China's Space Station (CSS) has been presented with the topics in the research areas, including:life science and biotechnology, microgravity fluid physics and combustion science, space material science, fundamental physics, space astronomy and astrophysics, earth sciences and application, space physics and space environment, experiments of new space technology. The research facilities, experiment racks, and supporting system planned in CSS have been described, including:multifunctional optical facility, research facility of quantum and optic transmission, and a dozen of research racks for space sciences in pressurized module, etc. In the next decade, significant breakthroughs in space science and utilization will hopefully be achieved, and great contributions will be made to satisfy the need of the social development and people's daily life.
NUMERICAL CALCULATION OF POINT EFFECTS OF ELECTRIC FIELD NEAR THESURFACE OF A SATELLITE
ZHUANG Hongchun, CHEN Tianchen, HUANG Jianguo
2000, 20(3): 242-250.   doi: 10.11728/cjss2000.03.242
Abstract(1924) [PDF 441KB](75)
Abstract:
Taking advantage of charge simulation method and potential coefficient methodfor ellipsoids, point effects of electric field near the surface of a satellite are calculated nummerically. Antenna point effects on a high voltage spherical satellite arecalculated as an example.
Study of Multisensor Image Fusion Technology
WU Zhenyu, WANG Peng, MA Meng
2006, 26(1): 48-53.   doi: 10.11728/cjss2006.01.048
Abstract(2358) [PDF 1842KB](59)
Abstract:
In this paper, it is paid attention to the image fusion technology, in the field of image fusion, there are two major algorithm, one is color transformation. Images can be represented differently in RGB color and IHS color, the elements of images in IHS color are calculated, and then achieve the fusion of different images. This method used to play a important role. From the 1980s, another new mathematic tool began to be developed. It is wavelet analysis. Image fusion based on color transformation and wavelet transformation have been achieved in the environment of Matlab. The characters of color transformation have been studied. The characters of fusion images got from different levels of wavelet transformations coefficients are studied and difference of different level wavelet transformations are analyzed, the relations between the wavelet transform levels and the ratio between the different images' space resolution are given in order to get good fusion images, and effects of different wavelet on image fusion are also analyzed.
Effects of Solar UV Radiation on Space Optical Films
Wang Yingjian, Wang Yongmei
2009, 29(2): 222-228.   doi: 10.11728/cjss2009.02.222
Abstract(3828) [PDF 721KB](41)
Abstract:
Optical remote sensing is an important means for spaceborne remote sensing, and optical films also have been applied widely in temperature control and energy supply systems of satellite. Their performance in space environment plays an important role for satellite operation in orbit, especially for satellite life and safety. This paper gives the physical mechanisms of the effects of solar UV radiation on optical films, and analyses its rule of this effects. In addition, the influences of atom oxygen erosion, energetic particles and electrostatic charging on the optical films degradation induced by under solar UV irradiation have been analyzed. The experimental results about the effects of solar UV radiation on space-based optical system coatings are also reviewed. Finally the suggestions for contamination protection are provided.
Influence of Microgravity and Electromagnetic Field on the Solidification of Metallic Alloys
WANG Xiaodong
2016, 36(4): 455-458.   doi: 10.11728/cjss2016.04.455
Abstract(1021) [PDF 5664KB](29)
Abstract:
Solidification or crystal growth of metallic alloys is crucially determined by flow, heat and mass transfer, whilst the external imposed fields like electromagnetic field or gravitational environment can significantly influence these transfer processes. In this paper, two experiments are briefly presented to exhibit above influence on the microstructure evolution of metallic alloys, particularly on the Columnar-Equiaxed Transition (CET). Firstly, a sound rocket-based experiment demonstrates the effect of microgravity by comparison with that of ground-based experiment, and the quite different microstructure reveals that the natural convection plays an essential role in the solidification. Secondly, a quasi-two-dimensional solidifying experimental benchmark is presented to exhibit the natural and forced convection on the micro/macro segregation of the metallic alloys. The natural convection has been observed through the evolution of temperature field measured in real time, and this experiment exhibit the solute segregation naturally formed in the liquid and mushy zones. The forced convection driven by a traveling electromagnetic field interferes with solute segregation directly. Lastly, their influence mechanisms are analyzed and perspective of China's research strategy for material science in space is addressed.
Entropy Parameter of Jupiter’s Magnetosphere
Lu Bin, Chen Chuxin
2013, 33(5): 465-472.   doi: 10.11728/cjss2013.05.465
Abstract(2052) [PDF 586KB](19)
Abstract:
The nonconservation of entropy in space plasmas can result from magnetic reconfiguration as well as nonadiabatic processes such as plasma transport and energy transport. The theory of plasma transport in Earth's plasma sheet depends critically on the entropy parameter PV5/3, where P is particle pressure and V is the volume of a closed flux tube containing one unit of magnetic flux. The stability and dynamics of the magnetosphere could be indicated by the change of entropy parameter. This paper shows the distribution of entropy parameter in the Jupiter's stable magnetosphere model using the analysis method in Earth's plasma sheet. The entropy parameter increases by four order of magnitudes quickly between 5Rj and 55Rj and then decline slowly. The result shows that the magnetosphere is unstable beyond 55Rj. The paper also shows the contour of the entropy parameter after the fictitious magnetic reconnection. It points out that the reconnection near the equatorial plane is caused by the rupture and reconnection of the flux tube which transports tailward.
Central Radiation Model of Proton Radiation Belt
Tao Hongren, Lin Ruilin, Shi Liqin, Liu Siqing, Zhang Xiaoxin, Gong Jiancun
2015, 35(3): 293-305.   doi: 10.11728/cjss2015.03.293
Abstract(1650) [PDF 3288KB](46)
Abstract:
According to the databases of AP-8 and CRRESPRO proton radiation belt models, comparison between both models on the magnetic equator is carried out and reasons for their differences are presented. The model of proton radiation belt for the peak radiation region is developed by using the analytic function, which includes the submodel for relationship between the L value corresponding to the peak value of omni-directional proton differential flux (Lc) and the proton energy, and the submodel for relationship between the peak value of omni-directional proton differential flux Jmax and the proton energy. Finally, the observation of energetic proton on the magnetic equator from RBSP A satellite's REPT telescope is used to compare with the results from AP-8 model, CRRESPRO model and the central radiation model. It is found that the values of omni-directional proton differential flux for 78.9, 102.6 and 208MeV channels from RBSP A satellite are obviously larger than those from the three models, but the values of Lc from RBSP A satellite are very close to those from AP-8 model and the central radiation model, and RBSP satellite also observes the hidden secondary proton radiation belt presented by CRRESPRO Quiet model.
Effect of clinorotation on cellular structure, photosynthetic activity, carbohydrate and astaxanthin metabolism of Haematococcus pluvialis
Zhang Yu, Hu Chunxiang, Zhang Delu
2013, 33(3): 293-301.   doi: 10.11728/cjss2013.03.293
Abstract(2662) [PDF 760KB](107)
Abstract:
During 20 days of simulated microgravity using clinostat (two-dimensional), the cellular structure, photosynthetic activity, primary and secondary metabolism of Haematococcus pluvialis were investigated. Results showed that the cell shape appeared abnormal and the volume became smaller than the ground control's. Ultrastructure analysis revealed that the starch grains seemed smaller and the thylakoid membranes were more randomly distributed and loosened after 20 days of clinorotation. Chlorophyll content decreased during the early period of clinorotation, but increased in the late phase. Carotenoid content and photosystem II efficiency decreased during the whole clinorotation. It could be presumed that the decreased photosynthetic efficiency might have some relation with the decreased pigment synthesis and the structure changes that happened on chloroplast after clinorotation. The smaller starch grains, together with the decreased starch content were probably due to an increased hydrolysis of amylase during clinorotation. The increased sucrose and trehalose played a protective role in the accommodation to early clinorotation. However, this led to a decrease of glucose and fructose utilized for the synthesis of protective disaccharides. In the middle phase of clinorotation (i.e. the acclimation period), a compensatory synthesis of chlorophyll, glucose and fructose was observed, whereas synthesis of sucrose and trehalose reduced. The decreased astaxanthin production during the whole clinorotation was due to the depressed carotenoid participating in the astaxanthin synthetic pathway.
Use of QUAD Method for GPS-based Orbit Determination of LEOs
HAN Baomin, OU Jikun, QU Guoqing, LIU Lintao
2005, 25(3): 224-228.  
Abstract(2052) [PDF 1354KB](24)
Abstract:
Kalman filtering technique can be used as optimal estimation of motion state of a LEO (Low-Earth-Orbiter); it can be applied directly to real time Orbit Determination (OD), or to Precise Orbit Determination (POD) with post-processing mode. The OD accuracy using Kalman filters depends on a priori knowledge of system models, noise statistics, especially quality of observations from onboard GPS receiver on LEO. When using Kalman filtering technique for GPS-based OD of LEOs, the gross errors in observation equation must be well dealt with firstly. Having analyzed the characteristics of solving gross errors in pervious methods, QUasi-Accurate Detection (QUAD) of gross errors method has been employed to detect and correct gross errors in observations. The advantages of this method are:accuracy rate of detecting gross errors is high; multiple gross errors can be detected at the same time. In addition, UD decomposition technique and Sage adaptive filter are employed to overcome the instability of numerical value computation and divergence of filter that properly occurred. At last, a simulation example of CHAMP satellite is used to demonstrate the feasibility and validity of new method presented in this paper.
Study of Computerized Ionospheric Tomography Under Ionospheric Storm Conditions
Yu Xiao, Ou Ming, Liu Dun, Ma Baotian, Deng Zhongxin, Chen Li, Zhen Weimin
2010, 30(3): 221-227.   doi: 10.11728/cjss2010.03.221
Abstract(2635) [PDF 680KB](29)
Abstract:
The characteristics and development of the low-and-mid latitudinal ionospheric storm during the magnetic storm in November, 2004 are studied using GPS observations from 6 stations along 115°E meridian. The results from tomographic reconstruction method show that the ionospheric storm during this magnetic storm mainly exhibits the positive storm phase, and the positive deviations of electron density are not only latitude dependent but also height dependent. The Equatorial Anomaly (EA) crest moves poleward as a result of enhanced energy deposition into the high latitude ionosphere. The electron density and TEC gradually recover to the quiet level in the first recovery phase. These results are in good agreement with previous studies, and the ionospheric effects can be attributed to the storm circulation theory superimposed with the movements of EIA crest.
Star position correction of dynamic star simulator based on distortion effect
Sun Gaofei, Zhang Guoyu, Liu Shi, Gao Yujun, Xu Ke
2014, 34(6): 887-893.   doi: 10.11728/cjss2014.06.887
Abstract(1197) [PDF 2515KB](77)
Abstract:
In order to realize the testing and calibrating of star sensor spectral detection capability, a set of ground calibration system which can simulate the stellar spectra is developed, and the stellar simulation accuracy is required to be better than 10%. Spectral distribution controllable and light intensity adjustable light simulation system is adopted to be the core device to simulate changes in stellar spectra, collimating optical system with high image quality is designed to make the star map exit parallel light and present the star map at the exit pupil of optical system, then the high accuracy star map simulation with stellar spectra information is completed. Finally, using Lighttools, the spectral simulation model of calibration system is established and simulation results show that the stellar spectra simulation accuracy is better than 10%.
Full wave calculation of VLF wave penetrated into satellite altitude ionosphere
Zhao Shufan, Shen Xuhui, Zhang Xuemin, Pan Weiyan
2015, 35(2): 178-184.   doi: 10.11728/cjss2015.02.178
Abstract(1030) [PDF 1616KB](64)
Abstract:
Obvious anomalous VLF, ULF, SLF signals related with earthquake have been recorded by satellites. Research on finding electromagnetic anomaly in the ionosphere may become an important way for earthquake prediction. The calculation of VLF wave propagating in the ionosphere can provide theoretical results for extracting abnormal signals related with earthquake from satellite observation data. The ionosphere has been set to be lossy and anisotropic horizontal multi-layer media. The propagation matrix method had been used to solve the full wave equation. The reflection and polarization coefficient of two characteristic waves in the ionosphere has been calculated. The poynting flux and horizontal components of electromagnetic fields varying with altitude have also been simulated. The numerical results show that it is easier for the vertical polarized wave to penetrate into the ionosphere than parallel polarized wave. The left-handed polarization wave suffers severe attenuation in D region for the strong absorption. The right-handed polarization wave is transmitting mode, and the wave energy is saved in the magnetic field. The attenuation of the wave is lower when the frequency is smaller which means it may be more efficient for us to study the magnetic field of the lower frequency wave to find the electromagnetic abnormals of earthquakes.
The Mathematical Analysis of Heart Rate Response Curve During Treadmill Exercise and Its Application
Yan Xiao-xia, Shen Xian-yun, Xu Li-hua, Zhuang Xiang-chang
1988, 8(3): 215-222.   doi: 10.11728/cjss1988.03.215
Abstract(1710) [PDF 653KB](32)
Abstract:
In this paper,the dynamic change of heart rate was used to study its whole response on physical load by means of mathematical method and to evaluate the response capacity of the cardiovascular system.11 subjects (6 young physical workers and 5 middle aged mental workers) were selected for the treadmill tests under three diferent loads (submaximal,medium and light) and two different physiological functional states (before and after 20 days bed rest).By means of least square method,optimal fitting expressions of heart rate response curve were established during exercise and recovery peroid respectively.Through the study of different load and different physiological functional states,physiological meaning of each parameter in equations was established.Five independent parameters were obtained,they were selected as indicators for evaluation of the response capacity of cardiovaslular system under exercise loading and can be used to differentiate three different loads and two different physiological functional states.This study provided the scientific basis for the selection of candidates and medical monitoring as well as for the study of response characteristic of the cardiovaslular system.
Research Progress of Solar Corona and Interplanetary Physics in China: 2010-2012
ZHAO Xinhua, XIANG Changqing
2012, 32(5): 618-646.   doi: 10.11728/cjss2012.05.618
Abstract(2671) [PDF 297KB](34)
Abstract:
The scientific objective of solar corona and interplanetary research is the understanding of the various phenomena related to solar activities and their effects on the space environments of the Earth. Great progress has been made in the study of solar corona and interplanetary physics by the Chinese space physics community during the past years. This paper will give a brief report about the latest progress of the corona and interplanetary research in China during the years of 2010?2012. The paper can be divided into the following parts: solar corona and solar wind, CMEICME, magnetic reconnection, energetic particles, space plasma, space weather numerical modeling by 3D SIP-CESE MHD model, space weather prediction methods, and proposed missions. They constitute the abundant content of study for the complicated phenomena that originate from the solar corona, propagate in interplanetary space, and produce geomagnetic disturbances. All these progresses are acquired by the Chinese space physicists, either independently or through international collaborations.
Effects of enhancing power on received signal quality in satellite navigation system
Lv Zhicheng, Nie Junwei, Liu Zengjun, Wang Feixue
2013, 33(1): 101-107.   doi: 10.11728/cjss2013.01.101
Abstract(2580) [PDF 871KB](22)
Abstract:
The GPS modernization program plans to add M-code navigation signals which have the feature of beam power enhancement in the frequencies of L1 and L2. Taking GPS L1 M-code signal as example, the received signal quality, affected by power-enhanced signal from the aspects of spectral overlap as well as equivalent carrier-to-noise ratio of the received signals, is analyzed. Simulation results show that when GPS L1 M-code signal enhancement is within the range of 20dB, the anti-jamming performance of power-enhanced signal will be improved significantly and the equivalent carrier-to-noise ratio of non-power-enhanced signal drops less than 2dB. When the signal enhancement range surpasses 20dB, the quality of non-power-enhanced signal will drop rapidly attributing to the interference from power-enhanced signal. While, when keep on increasing the signal power, the value of equivalent carrier-to-noise ratio of power-enhanced signal will no longer increase after having reached certain extreme value.
Effect of ion dynamics on the evolution of electron phase-space holes
WANG Peiran, LU Quanming, WU Mingyu, WANG Shui
2013, 33(4): 413-417.   doi: 10.11728/cjss2013.04.413
Abstract(2167) [PDF 504KB](50)
Abstract:
The evolution of two-dimensional (2D) electron phase-space holes (electron holes) has been previously investigated with electrostatic Particle-in-Cell (PIC) simulations, which neglect ion dynamics. The electron holes are found to be unstable to the transverse instability, and their evolution is determined by the combined action between the transverse instability and the stabilization by the background magnetic field. In this paper, the effect of ion dynamics on the evolution of an electron hole is studied. In weakly magnetized plasma (Ωe < ωpe, where Ωe and ωpe are electron gyrofrequency and plasma frequency, respectively), the electron hole is still unstable to the transverse instability. However, it evolves a little faster and is destroyed in a shorter time when ion dynamics is considered. In strongly magnetized plasma (Ωe > ωpe), the electron hole is broken due to the lower hybrid waves, and its evolution is much faster.
Guidance, Navigation and Control Technology for Lunar Surface Exploration
XING Yan, TENG Baoyi, LIU Xiang, MAO Xiaoyan
2016, 36(2): 196-201.   doi: 10.11728/cjss2016.02.196
Abstract(1943) [PDF 2734KB](102)
Abstract:
The lunar rover of Chang'E-3 probe was the first explorer of China roaming on the surface of extratellurian celestials, which had the totally different Guidance, Navigation and Control (GNC) technology from the Earth orbital spacecrafts. The main requirements of the rover for GNC system included autonomous navigation, environment perception, obstacle recognition, path planning, emotion control, and so forth. Several key technical breakthroughs had been achieved in GNC system of Chang'E-3 lunar rover-Jade Rabbit, such as autonomous position and attitude determination, multi-wheel motion control on lunar surface, Binocular Stereo Vision based autonomous environment perception and path planning, structure-light vision based obstacle avoidance, and lunar terrain and light condition analog simulation for experimentation on Earth, etc. In this paper, we discussed the mission overall requirement, key technology, and ground experiment of guidance, navigation and control system of Chang'E-3 Lunar Rover.
Real-time Monitoring of Ionosphere Changes in the Shanghai Region by GPS Technology
WANG Hu, WANG Jiexian, BAI Guixia, ZHU Weidong
2011, 31(5): 602-606.   doi: 10.11728/cjss2011.05.602
Abstract(2583) [PDF 525KB](50)
Abstract:
A method of real-time monitoring ionosphere based on GPS technology is described in this paper. The regional ionosphere model is constructed using GPS phase-smoothed pseudorange measurements. The ionosphere delay and instrumental bias are also calculated. Because the instrumental bias is stable, its value can be obtained after a period of time. Using this value, realtime instrumental bias can be forecasted. After deducted the instrumental bias from GPS signal, the real-time ionosphere information can be extracted in path of signal propagation. To validate this method, the data of Shanghai regional GPS network are used and a real-time regional ionosphere model is created. The results show the internal precision of this regional ionosphere model are better than 3TECU.
Modeling and Analysis of Radiometer Effect on the Inner-satellite
Liu Hongwei, Wang Zhaokui, Zhang Yulin
2010, 30(3): 243-249.   doi: 10.11728/cjss2010.03.243
Abstract(2239) [PDF 509KB](27)
Abstract:
Radiometer effect is a kind of thermal noise caused by temperature gradient. It is one of the main interfering factors to the inner-satellite, and is important to measure gravitational field. By analyzing the cause, the model of inner-satellite radiometer effect was established by the kinetic theory of gas molecules. In the model, the inner-satellite radiometer effect was divided into two parts. One was the reaction force and its torque caused by gas molecules which escaped from inner-satellite surface. The other was the force and its torque caused by collision of gas molecules which escaped from the cavity wall on the outer-satellite. Then the influence of various parameters to inner-satellite radiometer effect was analyzed and methods of reducing the inner-satellite radiometer effect were found. The results showed that through lowering the pressure and temperature gradient in cavity, as well as using materials with low surface-mass ratio, the acceleration caused by radiometer effect could be reduced.
CONTACT-IMPACT DYNAMIC ANALYSIS OF SPACECRAFT IN THE COURSE OF SPACE DOCKING
YU Dengyun, QU Guangji, ZENG Xin, WANG Ning
1998, 18(1): 62-68.   doi: 10.11728/cjss1998.01.062
Abstract(1818) [PDF 454KB](57)
Abstract:
The contact-impact dynamics in the course of spacecraft docking is the basis of research and design of docking mechanism of manned-space vehicle. According to the docking mechanism of androgynous and peripheral type, a contact-impact dynamic model and an explicit expression of impact load are given in this paper by using the vector mechanics and visco-elasticity. The targeting calculation and statistical analysis of an engineering sample is used to illustrate the method, and a satisfying result is obtained.
An Improved Algorithm for Nowcast of Kp Index
WANG Geng, LUO Bingxian, LIU Siqing, GONG Jiancun
2016, 36(2): 153-166.   doi: 10.11728/cjss2016.02.153
Abstract(1479) [PDF 3307KB](107)
Abstract:
The planetary three-hour-range Kp index is widely used in space weather services. Due to the two weeks' time delay of the release of Kp index, the real-time estimation of the Kp index becomes essential for space weather forecasting organizations. In this paper, an improved algorithm for real-time Kp estimation on the basis of Takahashi's procedure was developed. The new algorithm improved the accuracy of Kp estimation by distinguishing the day-to-day variations of geomagnetic field's regular variation and taking account of both the diurnal and seasonal variations of magnetic disturbance. The statistical result shows that the Prediction Efficiency (PE) increased from 0.77 to 0.84 using Fredericksburg's data, from 0.88 to 0.92 using the nine stations network's data. Using the data from Beijing Ming Tombs observatory (BMT) from 2000 to 2006, the PE increased from 0.70 to 0.80 compared with the Takahashi procedure. The error of the estimations differs from universal time, season and the scale of magnetic disturbance. The RMS error reached maximum for Kp=7. Analysis of Kp using the SuperMAG indices indicated that the asymmetric distribution of Kp stations affects the Kp nowcast performance.
Study for Model of Inter-Frequency Combinations of Galileo and GPS
CHANG Qing, YI Bingxin, ZHANG Qishan, XIAO Zuo
2007, 27(1): 77-82.   doi: 10.11728/cjss2007.01.077
Abstract(2266) [PDF 639KB](54)
Abstract:
Based on introducing signals in space of Galileo system and under the condition that the ambiguity is kept as integers, this paper defines the phase combination observations of the 4 Galileo and GPS L2 carriers. The relevant error impact is analyzed and the method for defining the ranges of searching combination coefficients is expatiated. Accordingly two sets of applied interfrequency combination observations with typical characters are also listed. Finally, some valuable inter-frequency combinations are given.
Ionospheric Plasma Bubbles Observed in Large Longitude Range During a Medium Magnetic Storm on 5 April 2006
LI Jinghua MA Guanyi, CHEN Yanhong, SHEN Hua, LIU Siqing, HUANG Wengeng
2008, 28(2): 123-131.   doi: 10.11728/cjss2008.02.123
Abstract(2288) [PDF 2852KB](66)
Abstract:
During a medium magnetic storm on 5 April 2006, ionospheric plasma bubbles have been studied in a large area using data from the Global Positioning System (GPS) observation sites between 70ºE and 210ºE in longitude, 20ºS and 40ºN in latitude. The plasma bubbles were found between 160ºE~90ºE, and 12ºS~33ºN, appeared at about 1~1.5 hour after local sunset. The plasma bubbles occurred earlier and survived longer in the southern hemisphere than those in the northern hemisphere. And in the development process of the plasma bubbles, at about 1100 km the upward drift speed was about 300 m/s mapped onto the magnetic equator. The plasma bubbles tilted during the development. The existence of the eastward electric field was supposed to be the cause triggering the plasma bubbles.
RADIAL EXPANSION OF A SYMMETRICAL CME BETWEEN TWO CORONAL STREAMERS
Zhang Gong-liang
1995, 15(4): 253-262.   doi: 10.11728/cjss1995.04.253
Abstract(1646) [PDF 2863KB](28)
Abstract:
The CME event on May 6,1980,occurring between a pair of coronal streamers,is discussed in this paper.An empirical kinematical model is proposed for describing the motion of outer loop of the event,n which the observed profile of loop is fitted in terms of the Cassini function in a moving coordinate system.The development of the loop can be distinguished into two different phases.During the first phase,when the loop lay between the helmet structures of streamer pair,the development of event is dominated by expansion of angular width with the asymmetrical axis shifting to northern latitudes;the speed of radial expansion and outward motion were rather low with remarkable acceleration.During the second phase,when the outer loop moved beyond the height of helmet structure of coronal streamer,the angular expansion ceased;the motion approached to an expansion and lift mainly in the radial direction with uniform speed and invariable angular width.As the loop moved outward,both the top and center heights increased with time, however,the bottom remained nearly fixed.Based on the above observational characteristics,a possible mechanism is put forward for the formation of the event.
Theoretic Analysis on a New Technique of Dust-based Active Debris Removal
LI Yiyong, CHEN Yong, LI Zhi, JIA Yongsheng
2015, 35(1): 77-85.   doi: 10.11728/cjss2015.01.077
Abstract(1338) [PDF 2299KB](58)
Abstract:
It is believed that the number of debris located near Low Earth Orbit (LEO) has approached the tipping point, which is the threshold for collision cascade. The Active Debris Removal (ADR) has come to be very necessary. Method on a new technique for cleaning space junk at the low earth orbit through dust-based ADR system has been proposed and researched by the U.S. Naval Research Laboratory. In this paper, special theoretical analysis on the new method is made. Firstly, the basic hypothesis and interaction mechanism models between single fraction and artificial dust are built, and the interaction results are calculated and analyzed quantitatively. Then, space debris density distribution is analyzed, the action effect of the new method is studied, and some basic conclusions are obtained. These results will help to understand the new method objectively.
Estimating of RCS of AFAS Based on Ionospheric Heating
Lv Libin, Li Qingliang, Yan Yubo
2009, 29(6): 558-562.   doi: 10.11728/cjss2009.06.558
Abstract(2492) [PDF 398KB](61)
Abstract:
In the experimental researches of ionospheric heating, an interesting phenomenon was found: irregularities were excited in the heating experiment, which could scatter radio waves in a special way. The scattering is highly sensitive to the direction of geomagnetic field, and it is termed as AFAS (Artificial Field Aligned Scattering). A number of experimental researches were carried out by using the Platteville high power heating facility and other communication equipments. From these researches, people found that the RCS (Radar Cross Section) of AFAS is quite great, which may be as large as 80dB&#8226;m2. This is very useful for scattering communication. To study the application of the AFAS in communication, the estimation of RCS is important. A mathematical model was developed, which is based on the theoretical and experimental researches of the ionospheric heating, the characteristics of the scattering on F region and the scattering theory of irregularities. Comparison of the results between model and theory show that the model is applicable. Using the model, the RCS of AFAS in the frequency range of 20 MHz and 100 MHz were calculated, and a RCS of 80dB&#8226;m2 was obtained at low-level of VHF. Our calculation supports that the maximum of RCS occurs when the radar beams are in the direction perpendicular to the magnetic field.
Quasi-27-Day Variations of Ionospheric NmF2
Ma Ruiping, Xu Jiyao, Yuan Wei, Jiang Guoying, Liu Xiao
2009, 29(4): 368-376.   doi: 10.11728/cjss2009.04.368
Abstract(2855) [PDF 907KB](43)
Abstract:
The data observed at 11 ionosonde stations in the East Asia/Australia sector during 1969---1980 and the band-pass filter method have been used to analyze the characteristics of the quasi-27-day variations of daytime NmF2 and the relativity between NmF2 and the solar activity index F10.7. The results are summarized as follows. In most years, the short period (2~70 days) spectra of F10.7 and NmF2 have obvious maxima around 27-day period. In the quasi-27-day variations, the standard deviations of F10.7 and NmF2 have evident variability year-to-year. The average standard deviation of F10.7 is 10.9\%. The standard deviations of NmF2 depend on geomagnetic latitude, the minima appear at equator and they become greater with increasing latitude. The average standard deviation of NmF2 of 11 stations is about 8.2%. In the quasi-27-day band, F10.7 and NmF2 have notable correlation. The probability of the significant correlation at 0.05 significance level exceeds 90%. The average time delay between variations of the NmF2 and F10.7 is about 2 days. As a whole, the quasi-27-day variations of NmF2 primarily attribute to the quasi-27-day variations of the solar EUV flux.
CHARACTERISTIC VELOCITY OF MHD SHOCK
Zhang Gong-liang
1981, 1(2): 111-117.   doi: 10.11728/cjss1981.02.111
Abstract(2398) [PDF 451KB](37)
Abstract:
According to the similarity between the boundary conditions on the MHD discontinuity and the equations of the MHD simple wave, a physical quantity U* called the characteristic velocity of MHD shock has been introduced. U* is defined by Eq. (4) as the ratio of the jump of total presure p* to that of density p, and equal to the geometric mean value of the shock velocities Wrelative to the up and down streams (Eq. (5)), approaching to the MHD wave velocity Uin the weak shock limit.The system of equations (7) express the shock relations with U* as the strengthparameter, where u, v =H/√4πρ and U± are respectively the velocity of fluid relativeto the shock front, and of the Alfven and the magnetosonic waves. These relations simplify the usual shock calculations and degenerate into the formulae for the MHD simple wave (Eq. (11)) in the infinitesimal jump limit.The fast, slow, and intermediate shock can be distinguished by Eq. (12-a, b, c) respectively. It is interesting to note that the jump formulae (7-a) and (13) show explicitly the transmission relations among the various modes of MHD shock and wave (Eq. (16-a, b, c) for the above three modes respectively), which are nothing but the immediate consequence of the compressive nature of shocks together with the conservation of mass (Eq. (14) and Eq. (15)). However, it needs a lengthy derivation to prove Eq. (16) without introducing U*.
Utilization of modified spherical coordinates for satellite to satellite bearings-only tracking
Li Qiang, Shi Lihui, Wang Hongxian, Guo Fucheng
2009, 29(6): 627-634.   doi: 10.11728/cjss2009.06.627
Abstract(2458) [PDF 261KB](116)
Abstract:
A new satellite to satellite passive tracking method using Bearings-Only measurements in Modified Spherical Coordinates (MSC) is proposed. The system dynamics and measurement process are presented in three-dimensional MSC, and then the tracking method is deduced in details based on the Cartesian method. Performance of the new method is validated through computer simulations, which proved that the proposed method is effective in terms of the estimation accuracy and convergence time compared with the Cartesian method no matter the Initial State Errors (ISE) and measurement errors are large or small.
MF Radar Observations of Phase Relationships Between Tidal Horizontal Wind Components in the Mid-latitude Winter Lower Thermosphere
LIU Renqiang, Lu Daren
2007, 27(6): 481-490.   doi: 10.11728/cjss2007.06.481
Abstract(2794) [PDF 3885KB](37)
Abstract:
Wind measurements obtained from Wuhan/China MF radar during winter 2001 are used to study the phase relationships between tidal horizontal winds in lower thermosphere. The tidal initial phases in any time window are uniformly defined in radians. The meridional and zonal initial phases of each tide exhibit a similar time variation trend at each height and this induces a near phase difference at three consecutive heights. However, in most of the 14 days, △φ4 and △φ12 are quasi-quadrature while △φ8 is unexpectedly quasi-in-phase. The appropriate tidal meridional and zonal quadratic phase coupling (QPC) equations are estimated respectively. The supposed terdiurnal phases and those observed agree well. By subtracting the estimated tidal zonal QPC equation from the meridional, a tidal phase difference correlated equation is obtained. The supposed terdiurnal phase differences and those observed again agree with each other. Within the 14th time window, all the three tides are generally elliptically rather than circularly or linearly polarized. However, both △φ24 and △φ12 in this window are quasi-quadrature at all heights while △φ8 are quasi-in-phase at 92.0 and 94.0km. So the estimated tidal QPC equations, the deduced tidal phase difference correlated equation, the observed terdiurnal quasi-in-phase phase differences and the typical tidal polarization plots are all indications of real QPC between the observed 24, 12 and 8 h tides.
Statistical Analysis of Type Ⅲ Bursts in the Centimetric-Decimetric Wavelength Region
MA Yuan, XIE Ruixiang, ZHENG Xiangmin, WANG Min, YAN Yihua
2011, 31(6): 716-724.   doi: 10.11728/cjss2011.06.716
Abstract(2418) [PDF 655KB](80)
Abstract:
A statistical analysis of multi-band type Ⅲ bursts observed with the spectrographes in the ranges of 625~1500MHz, 2600~3800MHz and 5200~7600MHz during the 23rd solar cycle (from July 2000 to September 2004) is carried out in the paper. The main statistical results, e.g., distribution of type Ⅲ bursts, duration, frequency drift rate (normal and reverse slopes), degree of polarization and frequency bandwidth are given. The results indicate that the average values of the frequency drift rates and frequency bandwidths increase with the frequency. The average values of the durations and degrees of polarization are neither constant nor uniform varying over broad frequency extent. Most of type Ⅲ bursts are distributed within the range from 625 to 3800MHz, and decrease with the increase in frequency. This distribution result means that the places of electron acceleration and energy release are mainly within the decimetric range, and the characteristic of frequency range is possibly related with the magnetic configuration on decimetric wavelengths, and the position of the electron acceleration in the reconnection region of magnetic field nearby the place of the main flare. However, there are large number type Ⅲ bursts in the range of 5200~7600MHz. This diagnostic means that the place of electron acceleration is in the broad range of the corona. The radiation mechanisms of type Ⅲ bursts on centimetric-decimetric wavelengths most probably include the coherent plasma radiation or the emission processes of electron cyclotron maser.
Impact of the Uncertainties of Input Parameters on the Atomic Oxygen Density Derived From OH Nightglow
Gao Hong, Xu Jiyao, Chen Guangming, Yuan Wei, Schulte W, Mikhalev A V, Medvedeva I V
2009, 29(3): 304-310.   doi: 10.11728/cjss2009.03.304
Abstract(3752) [PDF 604KB](165)
Abstract:
When the atomic oxygen density in the mesosphere and lower thermosphere region is derived by means of photochemical model calculations from OH nightglow emissions, a retrieval uncertainty, i.e. uncertainty of the density values obtained this way arises from the uncertainties of the input parameters. The retrieval uncertainty due to the uncertainties of atmospheric parameters and OH(8-3) band volume emission rate, the retrieval uncertainty due to the uncertainties of rate coefficients, and the retrieval uncertainty due to the uncertainties of all input parameters are analyzed using as an example the sudden death quenching model for OH airglow. The parameters the uncertainties of which have the largest contributions to retrieval uncertainty are found. The results show that all three retrieval uncertainties increase with altitude. The retrieval uncertainties caused by the uncertainties of the temperature and emission rate yield the largest contributions to the first retrieval uncertainty. The retrieval uncertainties caused by the uncertainties of the coefficients b(8) and A(8-3) yield the largest contributions to the second retrieval uncertainty.
Study on Inter-Satellite High Accuracy Ranging Technology for Gravity Satellite
SHEN Jian, SHE Shigang, Wang Kai, HE Dan, HUANG Yichang
2007, 27(4): 342-346.   doi: 10.11728/cjss2007.04.342
Abstract(2425) [PDF 1887KB](58)
Abstract:
Satellite-to-satellite tracking is one of the most promising and valuable methods for gravity field determination. The high accuracy inter-satellite ranging system is the major payload of gravity exploring satellite using satellite to satellite tracking in low-low model. K Band Ranging system (KBR) on the Gravity Recovery and Climate Experiment (GRACE) satellite is a micron-level ranging system. The geopotential is determined by processing precise range or range rate observed between the two satellites. GRACE has ushered in a new era for satellite measurement of the Earth system. The tremendous advances made by GRACE have led to an interest in launching a follow-on mission with even more ambitious scientific goals. A higher accuracy laser interferometric ranging system is proposed for GRACE follow-on mission. A strawman flight design, an error budget, and a demonstration laboratory breadboard are developed in foreign country. Based on the study of KBR and laser ranging system's measurement principle, the fundamental structure of KBR was presented in this paper. The key technology of these two ranging system and the current research level of our country are analyzed in detail. At the same time, some suggestions are proposed for the future inter-satellite ranging project of China.
A Statistical Study on Signal to Noise Ratio of GPS Beacon
XIONG Bo, WAN Weixing
2006, 26(5): 326-330.   doi: 10.11728/cjss2006.05.326
Abstract(3597) [PDF 3033KB](41)
Abstract:
The Signal to Noise Ratio (SNR) of GPS satellites beacon is mainly influenced by the gain of GPS satellites transmitter and receives on the ground, the geometrical distance between GPS satellites and receives, the elevation of the receives and the ionosphere medium attenuation. In this paper, a method is proposed to separate ionospheric attenuation from the observation of SNR. The technique was used to analyze the data observed at MANA station (273.751°E, 12.149°N) in 2003, and to construct a mean diurnal change pattern of the ionosphere medium attenuation. Comparing with the attenuation value calculated using IRI. It shows that the result fits with IRI well in the change of the attenuation value of SNR with the local time, when GPS signal radio vertically penetrates through the ionosphere.
Progress for Spaceborne Microwave Remote Sensing in China
JIANG Jingshan, LIU Heguang, DONG Xiaolong
2008, 28(5): 370-373.   doi: 10.11728/cjss2008.05.370
Abstract(2184) [PDF 1051KB](97)
Abstract:
In this paper,technological progress for China's microwave remote sensing is intro-duced.New developments of the microwave remote sensing instruments for meteorological satellite FY-3,ocean dynamic measurement satellite(HY-2),environment small SAR satellite(HJ-1C) and China's lunar exploration satellite(Chang'E-1),geostationary orbit meteorological satellite FY-4M,are reported.
EFFECTS OF SOLAR ACTIVITY ON EUV ABSORPTION PROCESSES IN THE UPPER ATMOSPHERE
Chen Yao-wu, Xu Xiu-juan, R. J. Hung
1992, 12(2): 111-117.   doi: 10.11728/cjss1992.02.111
Abstract(1969) [PDF 501KB](67)
Abstract:
Using a set of aeronomical parameters,such as absorption cross sections for the dominant thermospheric constituents,EUV flux data from the Atmosphere Explorer Satellites and Hedin’s MSIS-87 neutral thermospheric model,the variations of penetration heights of solar EUV radiation with maximum and minimum solar activities are numerically calculated.For transmit-tance being l/e and 0.1/100,the variations of panetration height of EUV radiation in wavelength range 50-1050 A divided in 37 wavebands are also obtained.The results indicate the penetration heights are obviously controlled by solar activities,and the larger the transmittan-ce is,the closer the correlative relation of penetration height with solar activity is.At the solar zenith angles near normal astronomical sunset,the solar activity leads to increasing the penetration heights on one hand,and to decreasing the Chapman’s function,which reduces the penetration height on the other.These effects could physically explain some ionospheric phenomena observed at local sunset.
Transport of the Interplanetary Fluctuations to the Magnetopause
Du Heng, Wei Feng-si, Y. C. Whang
1988, 8(1): 26-34.   doi: 10.11728/cjss1988.01.026
Abstract(1647) [PDF 741KB](58)
Abstract:
Fluctuations in solar wind velocity and magnetic field or relatively large amplitude on a time scale of the order of minutes are presented in interplanetary space essentially all the time.These fluctuations are transported to the region immediately outside the boundary surface of the magnetosphere.They may play an important role in the interaction of the magnetosheath plasma with the magnetopause.The interplanetary fluctuations first make a jump across the earth's bow shock.After the jump,some fluctuations are carried to reach the boundary surface of the magnetosphere.The amplitude of fluctuations at the surface of the magnetosphere is considerably amplified as compared with the interplanetary fluctuations.The solar wind conditions upstream of the bow shock control over the amplification factor This simulation study suggests that large Alfvenic fluctuations are presented at the boundary surface of the magnetosphere if the upstream fluctuations are large.The amplification factor becomes very large when the upstream magnetic field is nearly perpendicular to the sun-earth line and the amplification factor also increases with incressing plasma beta value and/or increasing Alfvenic Mach number.The effect of the state of upstream anisotropy on the amplification factor is relatively small.The present of large fluctuations indicates that no steady laminar flow exists in the boundary layer of the magnetosphere.
Measurements and Analysis of Plasma Column Discharge Impedance
XU Jie, ZHAO Guowei, LIANG Zhiwei, WANG Zhijiang, XU Yuemin
2007, 27(4): 315-320.   doi: 10.11728/cjss2007.04.315
Abstract(2077) [PDF 1962KB](19)
Abstract:
Recently a large number of surface-wave plasmas experimental data have been accumulated, so their modeling is well advanced and they have found applications in various fields of research and technology. An experiment to measure surface-wave plasma column discharge impedance has been designed, using the principle of impedance matching in transmission line. Refer to the method to work out the radiation impedance and loss impedance of metal antenna, plasma column discharge impedance is calculated in the simplest cases and compared with experimental results. It is shown that surface-wave plasma column discharge impedance plays an important part in analyzing the efficiency of plasma source and diagnosing plasma parameters such as densities, temperatures. This study will be of great importance for further scientific and engineering work in order to meet the demands of the various diverse plasma technological applications.
RESTRAINED VARIABLE STRVCTURE CONTROL FOR A CLASS OF FLEXIBLE SATELLITE
LIU Chunmei, SHEN Yi, HU Hengzhang
2000, 20(1): 81-88.   doi: 10.11728/cjss2000.01.081
Abstract(1742) [PDF 444KB](41)
Abstract:
In this paper, a new method for the attitude control of a class of flexible satelliteunder restrained control is presented. The target of the variable structure systemis changed step by step according to the bounded control, which makes the controlinputs under the bound of the execution. Thereby a equivalent unbounded variablestructure control system comes into being which satisfies the reaching condition ofsliding mode.
Comparison Between the CHAMP/STAR Derived Thermospheric Density and the NRLMSISE-00 Model
WENG Libin, FANG Hanxian, JI Chunhua, ZHANG Yang
2012, 32(5): 713-719.   doi: 10.11728/cjss2012.05.713
Abstract(2837) [PDF 555KB](60)
Abstract:
The derived thermospheric density from the CHAMP/STAR accelerometer observations has been compared with NRLMSISE-00 model, and the major results can be summarized as follows. The thermospheric density is lager in Equinoxes than Solstices, and this is much more notable in high solar level. The ratio between dayside and nightside thermospheric density in low-latitude during the high solar level is about 4 but reduces to 2 in low solar activity, and 3 to 1.5 in middle-latitude. NRLMSISE-00 model can capture the main character of the neutral density, but has lower performance during strong geomagnetic activities. This model overestimates density derived from satellite, and the relative errors are 16.512%, 20.004%, 18.915%, 18.245%, 25.161%, 33.261% and 41.980% from 2002 to 2008. The relative error in high latitude is 27.337%, but low-middle latitude is 24.047%. The model has a better performance under the conditions of middle solar activity level, and the relative error is about 15%.
ON FEATURES OF THE MAGNETOSPHERICCOUPLING EXAMED BY GEOMAGNETIC DWITH HIGH TIME RESOLUTION
SHEN Changshou, ZI Minyun, GAO Yufen, SUO Yucheng, WU Jian
1999, 19(2): 134-140.   doi: 10.11728/cjss1999.02.134
Abstract(2179) [PDF 501KB](95)
Abstract:
Minutely mean values of geomagnetic data from each 11 stations nearby100°E GMand 300°E GMmeridians respectively are used to analyze the detailedfeatures of magnetospheric disturbances during a magnetic storm on November 26,1994. It is shown by the evolutions of H- and z-components, that the variationso f both region 1 and region 2 field-aligned currents are very important processesin the magnet osphere-ionosp here coupling. The coupli ng effect s in t he auror al areaare distinct obviously from that in mid--and lowWelatitudes. And the influence degreefor stations along different meridians is neither the same. The disturbance energyfrom the magnetosphere and the shielding effect of the region 2 field--aligned currentmay cause an abrupt intensification of ionospheric currents, and an eastward fieldand current may appearg which could last for about half an hour, in mid-andlow-latitudes at night side. Meanwhile, ionospheric plasmas of the F-region will belifted by E×B drift effect, which then leads to a simultaneously enhancement of h'F(minimum vertual height for F-region) at many stations nearby a same meridian.
Experimental Study on Two-Phase Flow and Power Performance of DMFC
Utilizing the Drop Tower Beijing
Zhao Jianfu, Guo Hang, Ye Fang, Wan Shixin, Wei Minggang, Wu Feng, Lu Cuiping, Ma Chongfang
2008, 28(1): 17-21.   doi: 10.11728/cjss2008.01.017
Abstract(2034) [PDF 1604KB](25)
Abstract:
Utilizing the Drop Tower Beijing/NMLC, the characteristics of two-phase gas-liquid flow and power performance of a direct methanol fuel cell (DMFC) are studied experimentally in normal and microgravity conditions. It's found that CO2 bubbles in anode channels of DMFC move much slowly in microgravity, and that their shapes change from ellipsoid to globosity and their sizes increase with time, even block the whole channel and then the flow pattern changes into slug flow gradually. Larger current density, more easily is it to block the channel. It's also shown in the power curves that there exists an evident influence of gravity in the regime of the concentration polarization. The diminution of the power performance of DMFC in microgravity increases with the degree of the concentration polarization.
Research in Solar Dynamo Theories
WU Jianqing, YANG Zhiliang
2011, 31(5): 573-586.   doi: 10.11728/cjss2011.05.573
Abstract(2903) [PDF 939KB](68)
Abstract:
Various activities of the Sun, such as flare, coronal mass ejections, solar wind, which will affect the normal work of satellites, radio communication and electric power system. Therefore, researching the activities of the Sun has great significance for human. Moreover, these activities are dominated by the magnetic field. The purpose of study the solar dynamo theories is not only to unpuzzle the correlation and variation among various activities, but also to explain the origin and character of the magnetic fields on the Sun. The paper briefly reviews the relevant observational data pertaining to sunspots and solar cycle first and researches evolution if the solar dynamo theories. Then the three basic elements of the dynamo, the differential rotation, meridional circulation and magnetic diffusivity, with the fundamental equations of magnetic field generation are introduced. Magnetic induced equation is the first basic equation for dynamo theories and the first item of induced equation is from Ohm s law. What s more, mean field dynamos which contain Babcock-Leighton dynamo, interface dynamo and flux transport dynamo, non-axisymmetric dynamo, MHD simulation and small scale dynamo are described. The advantages and shortcomings of them are presented respectively. Finally, the existing problems and possible development in the future for solar dynamo theories are suggested.
Quasi-cyclic expansion and encoding algorithms for protograph LDPC codes
Li Zhongliang, Xia Guojiang
2011, 31(3): 406-411.   doi: 10.11728/cjss2011.03.406
Abstract(2430) [PDF 482KB](38)
Abstract:
Recently, a new class of Low-Density Parity-Check (LDPC) codes constructed from a template was introduced. This kind of codes were called protograph codes. The protograph serves as a blueprint for constructing LDPC codes of arbitrary size whose performance can be predicted by analyzing the protograph. Protograph LDPC codes perform very well and suit for high-speed encoding and decoding. However, there are few researches on expansion and encoding algorithms for them. In this paper, using isomorphism between matrix ring and polynomial ring, we propose efficient quasi-cyclic expansion and encoding algorithms for protograph LDPC codes. Simulation results show that the protograph LDPC codes which were constructed by the algorithm proposed in this paper, outperform the best known unstructured irregular LDPC codes with the same maximum node degrees.
Martian Space Environment Magnetic Field Investigation---High Accuracy Magnetometer
Zhou Bin, Zhao Hua, Wang Jindong, Chen Siwen, Liao Huaizhe, Zhu Guangwu, Wang Chi, Z hang Xin, Li Lei, Sun Yueqiang, Feng Yongyong, Zhou Jingxuan, Tao Ran
2009, 29(5): 467-474.   doi: 10.11728/cjss2009.05.467
Abstract(2949) [PDF 811KB](60)
Abstract:
This paper presents the purpose, design and methods of the exploration of Martian Space Environmental Magnetic Field by Yinghuo-1 (YH-1). YH-1 is the first Chinese Martian Space Environment Exploration Orbiter, which would be launched with Russian spacecraft ``Phobos-Grunt'' in October, 2009, and will reach Mars orbit in September, 2010. The main scientific objectives of the YH-1 mission are related with Martian space magnetic field structure and dynamic processes, and a fluxgate magnetometer was considered to be one of the most import payloads in the YH-1 orbiter. The instrument is designed to work in harsh environment around Mars orbit and to collect high resolution data in operational orbit. Two three-component fluxgate type sensors are installed in one boom with separation distance of 45 cm, and gradiometer mode is used to minimize the remnant field of platform. The boom is located at the tip of the deployable solar panel, and the distance between the center of the spacecraft and the outer sensor is about 3.2 m. The operation temperature of YH-1 magnetometer sensors is expected in the range -130~+75°C and the dynamic range is ±256 nT in 16-bit resolution. With a very low noise level below 0.01 nT·Hz-1/2, this magnetometer can measure three-component magnetic field from DC to 10 Hz. The magnetometer will work together with a Plasma Package onboard this orbiter to complete exploration of Martian space environment. The total mass of this magnetometer package is about 2.5 ,kg, and power consumption is 6.8 W.
Chang'e-3 Lander's Scientific Payloads Test
Jia Yingzhuo, Dai Shuwu, Wang Lei, Liu Mingjie
2015, 35(5): 588-595.   doi: 10.11728/cjss2015.05.588
Abstract(1082) [PDF 3809KB](61)
Abstract:
Chinese Chang'E-3 spacecraft includes a lander and a robotic rover. The scientific objectives of the Chang'E-3 mission were to examine the texture, mineralogy, and structure of the local lunar terrain; to determine the distribution and composition of minerals, rocks, and soils surrounding the landing sites; and to operate an ultraviolet astronomy camera on the Moon and image the distribution of He+ in Earth's plasmasphere by detecting its resonantly-scattered emission at 304 Å. Four kinds of scientific instruments are chosen as the payloads for Chang'E-3 lander, which include topography camera, lunar optical telescope, extreme ultraviolet imager and descent imager, etc. This paper mainly introduces Chang'E-3 lander's scientific payloads ground test, including test schemes and results.
Real-time Monitoring Regional Ionospheric Variety of China with BDS Observations
DONG Enqiang, CAO Yueling, GONG Lei, LIU Xiaoping, CHANG Zhiqiao, WU Xiaoli
2017, 37(1): 67-74.   doi: 10.11728/cjss2017.01.067
Abstract(1231) [PDF 2642KB](41)
Abstract:
BDS provides uninterrupted PNT service for Asia-Pacific area since 27 December 2012, when China released an official version of the complete BDS Interface Control Document (ICD) for open service Signal-In-Space (SIS). Because BDS signals working at three frequencies, ionospheric delay can be calculated with pseudo-range dual-frequency combination technique and a new technique to monitor ionospheric variety over China is established. Lower-middle latitude area of China is in the ionospheric equator anomalies region and large grads ionospheric varieties often occur within the area of north latitude 20°±5°. Daily variety characteristic of ionospheric delay measured with BDS GEO satellites is analyzed by using BDS real-time pseudo-range observation and adopting carrier phase smoothed pseudo-range. China region ionospheric map is painted in 1°×1° scale with polyhedral fitting every 5 minutes and the average fitting error RMS of all Ionospheric Punch Point (IPPs) is 2.778TECU. The ionospheric anomalies around China monitored with BDS observation shows that the VTEC peak difference between adjacent two days can be 60TECU when large scale ionospheric anomaly occurs.
Quantitative Analysis of Effect of Atmospheric Delay Error on InSAR Data Processing
YU Jingbo, LIU Guolin, CAO Zhentan, CUI Juan, LIU Hui
2012, 32(5): 720-729.   doi: 10.11728/cjss2012.05.720
Abstract(3453) [PDF 878KB](22)
Abstract:
The effect approximate relationship formulas of the phase measurement error on height measurement by InSAR and deformation measurement by two-pass, three-pass and four-pass differential InSAR and the effect formulas of atmospheric delay error on the interferometric phase are put forward respectively, taking simultaneously into account the basic principles of the repeat track InSAR measurements. Then, the effect approximate relationship formulas of the atmospheric delay error on height measurement by InSAR and deformation measurement by two-pass differential InSAR, three-pass differential InSAR, four-pass differential InSAR are deduced respectively based on the above formulas. In the last place, the useful conclusions of the effect of atmospheric delay error on InSAR data processing are drawn by taking ERS-1 satellite system simulation experiments as an example and by talking over and analyzing the effect of atmospheric delay error on height measurement by InSAR and deformation measurement by two-pass differential InSAR, three-pass differential InSAR and four-pass differential InSAR etc.
Directional filtering due to mesospheric wind shear on the propagation of acoustic-gravity waves
Yu Yonghui, Chen Wei, Wang Yachong
2013, 33(1): 53-62.   doi: 10.11728/cjss2013.01.053
Abstract(2183) [PDF 728KB](32)
Abstract:
Gravity waves with periods close to the Brunt-Väisälä period of the upper troposphere are often observed at mesopause altitudes as short period, quasi-monochromatic waves. The assumption that these short period waves originate in the troposphere may be problematic because their upward propagation to the mesosphere and lower thermosphere region could be significantly impeded due to an extended region of strong evanescence above the stratopause. To reconcile this apparent paradox, an alternative explanation is proposed in this paper. The inclusion of mean winds and their vertical shears is sufficient to allow certain short period waves to remain internal above the stratopause and to propagate efficiently to higher altitudes. A time-dependent numerical model is used to demonstrate the feasibility of this and to determine the circumstances under which the mesospheric wind shears play a role in the removal and directional filtering of short period gravity waves. Finally this paper concludes that the combination of the height-dependent mean winds and the mean temperature structure probably explains the existence of short period, quasi-monochromatic structures observed in airglow images of mesopause region.
Study of Method to Compute Ionospheric S4 Index Based on GPS Signal
CHEN Fenghua, YUAN Hong
2007, 27(1): 23-28.   doi: 10.11728/cjss2007.01.023
Abstract(2965) [PDF 2920KB](70)
Abstract:
Ionospheric scintillations are rapid variations in the amplitude and phase of radio signals resulting from density irregularities in the ionosphere. Ionospheric scintillations influence adversely the performance of satellite communication system and the precision of navigation system. In this paper, the traditional computational method of ionospheric S4 index based on GPS signal is analyzed. In view of the insufficiency of the primitive S4 index computational method and the correction method, a new correction method is proposed. In order to test these methods, further study which is based on data from GPS receivers has been made. The result indicates that the primitive S4 index computational method and the correction method are feasible and reliable.
Effect Analysis of Orbital and Attitude Parameter Error on TDI-CCD’s Line-shift Frequency and Veer Angle
LI Xinfeng
2008, 28(3): 254-259.   doi: 10.11728/cjss2008.03.254
Abstract(2540) [PDF 1367KB](43)
Abstract:
Unlike other references which usually concentrate on geometric methods, kinetic approach is adopted to analyze the motion of space-born TDI-CCD camera's target, for a convenient analysis of kinetics, a series of coordinates is chosen. The velocity vector of the nadir is expressed in the sensor coordinate after some transformations which are functions of orbital and attitude parameters. For a nadir-pointing satellite, the first-order approximation of attitude parameters in the velocity vector is obtained with the tiny alignment error. From the relations between target's motion and orbital and attitude parameters, it takes little effort to derivate equations of line-shift frequency and veer angle with respect to orbit and attitude parameters, these explicit formulas of line-shift frequency and veer angle facilitate the procedure of analytical decision of error budget, especially in the primary design phase of a space mission. This application is illustrated by some typical LEO mission examples following the analysis.
Whistler Waves Excited by Loss-cone Distribution Electrons
Zhou Lihui, Lu Quanming, Guo Jun, Wang Shui
2009, 29(4): 402-408.   doi: 10.11728/cjss2009.04.402
Abstract(2928) [PDF 746KB](84)
Abstract:
One-dimensional particle-in-cell simulations are performed in this paper to investigate the nonlinear evolution of whistler waves excited by the electron temperature anisotropy of loss-cone distribution, and compared with the results of bi-Maxwellian distribution. The simulation results indicate that the dominant frequencies in linear growth stage, which contain the most power, are the same in both situations, and that the electron temperature parallel to the background magnetic field is enhanced by the excitation of the waves. The whistler waves with the dominant frequency can be excited earlier with loss-cone distribution and the power is more concentrated in higher frequency (shorter wavelength). The excitations of whistler waves in different anisotropies and different magnetic fields are also studied.
Study on high energy electron flux enhancement events and whistler chorus wave
He Tian, Liu Siqing, Zheng Jinlei, Gong Jiancun
2013, 33(2): 170-175.   doi: 10.11728/cjss2013.02.170
Abstract(2671) [PDF 750KB](54)
Abstract:
The local acceleration mechanism is one of the crucial factors for the high energy electron flux enhancement events in the outer radiation belt. There are two substantial preconditions for this acceleration mechanism. The first and the most important one is the presence of enough low energy electron (on the order of tens to hundreds of keV), so-called seed electron; the other is the enhancement of plasma waves including whistler chorus waves which can contribute to the electron acceleration by wave-particle interaction. Geomagnetic field data observed by Memambetsu (L=1.57) observatory are used to extract Pi1 pulsation during 2004-2006. The linear correlation between Pi1 pulsation duration and seed electron flux (LANL 50~225keV) is greater than 0.7, which indicates that the Pi1 pulsation duration is a good indicator of seed electron flux. After the investigation of three magnetic storms events in 2005, the evidence had been found for acceleration of seed electrons to high energies by whistler chorus waves and the positive correlation between the chorus waves' spectral density and high energy electron flux.
Approach for Predicting the Energetic Electron Flux in Geosynchronous Earth Orbit
GUO Ce, XUE Bingsen, LIN Zhaoxiang
2013, 33(4): 418-426.   doi: 10.11728/cjss2013.04.418
Abstract(2567) [PDF 648KB](118)
Abstract:
Geosynchronous Earth Orbit (GEO) is in the earth's outer radiation belts, where energetic electrons are enriched. The flux of energetic electron will surge after the geomagnetic disturbance, which is one of the causes for the failure of satellites. So, it is important to predict the electron flux on the geosynchronous orbit in order to prevent the satellite from harming. As the enhancement of electron flux is controlled by many conditions and its temporal and spatial evolution is complex, it needs to analyze various data to make the prediction model. In this work, energetic flux data from GOES-12 was statistically analyzed together with geomagnetic Ap index and solar wind velocity and combination of input parameters was determined. An artificial neural network based model was built and trained with the data mentioned above. The prediction of electron flux of E >2MeV one day ahead has been made and the result was good that the prediction efficiencies were 0.766, 0.808 and 0.882 for the year of 2008, 2009 and 2010, which is a little better than other models. The prediction for electron flux of FY-2D satellite was made applying the GOES-12 prediction result by analyzing the flux related characteristics. The statistics showed that the E >2MeV electron flux measurement of the two kinds of satellite become similar when the flux was above 108 cm-2·d-1·sr-1. Because the deep charge effect become significant when E >2MeV electron flux exceed 108 cm-2·d-1·sr-1, the energetic electron alert for FY-2D satellite was made with the result by GOES prediction and got good result.
Analysis on Relativistic Electron Flux Enhancement Event at GEO in April 2010
ZHENG Jinlei, ZHONG Qiuzhen, CHEN Liangxu, LIU Siqing, DING Zhu
2012, 32(4): 488-500.   doi: 10.11728/cjss2012.04.488
Abstract(2687) [PDF 2441KB](102)
Abstract:
The relativistic electron flux enhancement event at GEO in April 2010 is analyzed in contrasting with other 6 similar events from 2004 to 2010. Solar wind and geomagnetic conditions which might trigger this event were analyzed. Analytical results indicate that the relatively weaker magnetic storms were prone to make the high flux part of relativistic electrons closer to GEO orbit, and whistler wave acceleration mechanism probably played important roles. The injection depth of seed electrons was closely related to magnetic storm intensity. Dst index curve is well fitted with the lower edge of higher flux region of 30~100keV electrons. The injection depth of seed electrons determined the region where mass of >300keV electrons appeared. Because of the relatively weak storms in the relativistic electron flux enhancement event, the seed electrons injected into a shallow region which was close to geosynchronous orbit, leading to relativistic electron flux abnormally enhancement in geosynchronous orbit. The intense substorms in relativistic electron flux enhancement event at GEO in April 2010, which generated sufficient seed electrons and enhanced the wave-particle interaction, was an essential factor leading to relativistic electrons flux enhancement.
Study of Magnetospheric Shielding Effect With Energetic Particles Data From Chang’E-1
Wang Jie, Qin Gang
2013, 33(5): 532-539.   doi: 10.11728/cjss2013.05.532
Abstract(2119) [PDF 621KB](68)
Abstract:
Since about one fourth of the lunar orbit is inside the terrestrial magnetosphere, whether the Earth's magnetosphere can provide substantial magnetic shielding for energetic particles in the lunar orbit or not is essential for preparing human's exploration on lunar bases. Chang'E-1 is China's first lunar satellite, which is in a polar orbit of approximately 200km above the Moon's surface. In this paper, the data of energetic particles flux measured by the High-energy Particle Detector (HPD) onboard Chang'E-1 is analyzed, and the flux of protons at different energy channels within the energy range of 4~400MeV inside and outside the Earth's magnetosphere is compared. It is found that there is no significant decrease in the flux of protons at all the energy channels when the Moon is within the Earth's magnetotail compared with that when the Moon is in the solar wind, which indicates that the terrestrial magnetosphere could not provide any substantial magnetic shielding for the space energetic particles in the lunar orbit.
Attitude Control of Large Angle Maneuver for Microsatellite Using Variable Speed Control Moment Gyros
LIU Jun, HAN Chao
2007, 27(4): 336-341.   doi: 10.11728/cjss2007.04.336
Abstract(2537) [PDF 1406KB](18)
Abstract:
The multi-projects rapid attitude maneuver problem for agile microsatellites with VSCMG (Variable Speed Control Moment Gyros) as actuators was investigated. VSCMG is a recently introduced actuator for spacecraft attitude control, and it is a hybrid one between two types of internal torque generators; namely, a conventional control moment gyro and a reaction wheel. These actuators can provide unique torque, angular momentum and slew rate capabilities to microsatellites without any increase in power, mass or volume. This will help microsatellites become more agile. The attitude dynamic equation of a spacecraft with VSCMG attached was presented, the attitude was described by MRP (Modified Rodrigues Parameters). A nonlinear feedback controller based on Lyapunov stability condition was developed under various physical constraints, including the actuator saturation, slew rate limit, control bandwidth limit, etc. A numerical simulation was presented on the sample of the attitude maneuver of a microsatellite with VSCMG. Simulation results demonstrate the effectiveness and robust performance of the proposed nonlinear feedback control system.
STUDY ON ATTITUDE DYNAMICS OF A LIQUID-FILLED SPACECRAFT WITH ELASTIC APPENDAGES
CHENG Xuduo, WANG Zhaolin, LI Junfeng
2000, 20(3): 271-277.   doi: 10.11728/cjss2000.03.271
Abstract(1638) [PDF 428KB](59)
Abstract:
In this paper attitude dynamics of liquid-filled spacecraft with elastic appendagesis studied- Motional equations of liquid, motional equations of system and motionalequations of particle of elaJstic plates are obtained by using the theorem of angu-lar momentum, the conservation law of angular momentum and Newton's motionallaw. When elastic plates deploy at uniform velocity of plates motional equationsof plates are alternated. Using Runge-Kutta method, the plate's amplitudes ofvibration are obtained. Using motional equations of system,the attitude angularvelocities of spacecraft are obtained.
Use Double Channel Solar Irradiance Flux to Compute the E10.7 Index
FAN Lei, WEI Fei, FU Yang, ZHAO Wei, FEI Zengping
2013, 33(4): 403-409.   doi: 10.11728/cjss2013.04.403
Abstract(2100) [PDF 714KB](76)
Abstract:
Solar Extreme Ultraviolet (EUV) plays an important role in space weather research and forecasting. The E10.7 index is the integrated EUV energy flux at the top of the atmosphere. Solar 2000 model combines the best of empirical and physics-based models to provide a wide variety of solar irradiance products for science and engineering applications, including E10.7 integrated EUV flux etc. In this paper, the physics significance of the E10.7 index is described, and a new computation method of E10.7 index is also described in details. Double channel solar irradiance flux were used to compute the E10.7 index. At first the experiential coefficients were obtained based on the empirical expression and historical solar irradiance data picked up from the Solar2000 model. Then the new method was applied to solar irradiance flux data from the year of 2000 to 2005, and successfully yields the E10.7 index. The differences between the compute result and the result from Solar 2000 model were achieved. The comparison results show that the mean relative deviation is within 10% with a maximum deviation less than 20%.
Adaptive Control for Free-Floating Dual-Arm Space Robot System in Joint Space
HONG Zhaobin, CHEN Li
2007, 27(4): 347-352.   doi: 10.11728/cjss2007.04.347
Abstract(2682) [PDF 1283KB](11)
Abstract:
In this paper, the dynamics and control problems of free-floating dual-arm space robot system is studied. With the momentum conservation of system, the kinematics and dynamics of system are analyzed. It is verified that the dynamic equations of the system can be linearly dependent on a group of inertial parameters. Based on the results and with the augmentation approach, an adaptive control scheme for space robot system with unknown payload parameters to track the desired trajectory in joint space is developed. The control scheme proposed above is structurally and computationally simple, because of an effective exploitation of the system dynamics. In particular, it doesn't require measuring the position, velocity nor acceleration of the base. And the numerical simulation is carried out, which confirms the controller proposed is feasible and effective.
Numerical study about the nonlinear instability of the Sweet-Parker thin current sheet with shearing flows
Ni Lei, Yang Zhiliang
2011, 31(4): 429-435.   doi: 10.11728/cjss2011.04.429
Abstract(2886) [PDF 589KB](21)
Abstract:
In this paper, numerical simulation results of nonlinear Plasmoid instabilities are presented. A two dimensional incompressible MHD code is used to calculate the results. The adaptive mesh refinement and MPI techniques are enable in this code. Harris sheets are used as the initial equilibrium conditions and small perturbations of the current density are applied to make the system unstable. Sequences of plasmoid instability processses for different Lundquist numbers have been studied. The Harris sheets will always evolve in to thinner Sweet-In this paper, numerical simulation results of nonlinear Plasmoid instabilities are presented. A two dimensional incompressible MHD code is used to calculate the results. The adaptive mesh refinement and MPI techniques are enable in this code. Harris sheets are used as the initial equilibrium conditions and small perturbations of the current density are applied to make the system unstable. Sequences of plasmoid instability processses for different Lundquist numbers have been studied. The Harris sheets will always evolve in to thinner Sweet-Parker current sheets with shearing flows in the early stage. As the Lundquist number S ≥ 105, the Sweet-Parker thin current sheets are unstable and secondary islands appear. The critical aspect ratio for the unstable Sweet-Parker thin current sheet is around 65. The larger the Lundquist number is, the thinner the Sweet-Parker sheet, and the more secondary islands appear. These secondary islands are ejected out along the current sheet, grow bigger with time and coalesce with each other in the later stage. The reconnection rate of the current sheet has been increased a lot due to secondary instabilities. The peak reconnection rates in each reconnection processes for different Lundquist number are picked about to study the relationship between the Lundquist number and the reconnection rate, which has been found no longer scales with Lundquist number as S- 1/2, but weakly depends on S.
Operation and application of A, B satellites for environment and disaster monitoring and forecasting
Wang Jianyu, Liu Yinnian, Fang Zhiyon, Yang Siquan, Nie Juan, Wu Wei, Liu Sanchao, Wang Lei, Wang Qiao, Wei Bin, Wang Changzuo, Zhang Feng, Yu Jin, Li Zhaozhou
2010, 30(5): 486-492.   doi: 10.11728/cjss2010.05.486
Abstract(2674) [PDF 1402KB](31)
Abstract:
Environment and disaster monitoring and forecasting small satellite constellation A and B satellites (HJ-1-A, B) are called "environment and disaster reduction satellites A and B'' for short. The constellation adopts a 10:30 LT sun-synchronous circular orbit, with orbit altitude of 649 km. HJ-1-A and HJ-1-B are distributed with a phase difference of 180º in the same orbital plane, so as to enhance the time resolution of earth observation. The satellites have orbit maintenance capability, the lifetime is 3 years. Both satellites adopt CAST968 platforms. Two wide-coverage multispectral CCD cameras with resolution 30 m and width 700 km, a super-spectral imager with resolution 100 m and width 50 km as well as a data transmission subsystem of 120 Mbit/s are deployed on HJ-1-A, which also carries Ka communication testing equipment of Thailand. HJ-1-B has two wide-coverage multispectral CCD cameras (the same as satellite A), one infrared camera with resolution 150 m and width 720 km and a data transmission subsystem of 60 Mbit/s. The coverage period of the wide-coverage multispectral CCD camera is 48 hours. The revisit period of super-spectral imager is 96 hours and the coverage period of infrared camera is 96 hours.
The Influence of Upper Boundary Conditions on the Polar Ionosphere
LIU Shunlin, ZHANG Beichen, LIU Ruiyuan, XU Zhonghua
2005, 25(6): 504-509.   doi: 10.11728/cjss2005.06.504
Abstract(2512) [PDF 1758KB](85)
Abstract:
A one-dimensional high-latitude ionospheric model, in which the continuity, momentum and energy equations are solved self-consistently in the altitude range between 110 and 610km, is used to study the ionospheric responses to different upper boundary conditions. It is found that upper boundary conditions may influence significantly profiles of ionospheric quantities at higher altitudes. A larger upward O^+ velocity at the upper boundary results in lower hmF2 and F region electron densities, and consequently higher electron temperatures. The difference in hmF2 between an upper boundary velocity of 0.0 m/s and 200 m/s reaches about 76 km. The altitude profiles of temperatures are quite different from each other corresponding to different upward ion velocities and heat fluxes from the magnetosphere. The Coulomb collisions between electrons and ions play an important role in shaping the electron temperature profiles at altitudes higher than the hmF2. The simulated electron temperature height profiles are similar to the measurements made in earlier studies. The altitude profile of electron temperature above 200 km is influenced by both downward heat fluxes and field-aligned O^+ velocities, while the ion temperature and the electron density have their responses at altitudes higher than 250km. Proposals are given while specifying the upper boundary conditions in the simulation of the high-latitude ionosphere.
Effects of Extreme Heavy Rainfall in the Troposphere on the Ionosphere
XU Guirong, WAN Weixing, NING Baiqi
2005, 25(2): 104-110.  
Abstract(1906) [PDF 2163KB](72)
Abstract:
In this paper, the meteorological influences on ionospheric variability have been studied. We analyzed the effects on the ionosphere from the five extreme heavy rainfall cases happened in Wuhan from 1958 to 1998 by means of the superposed epoch method. The results show that when the extreme heavy rainfall happens:(1) the blanket frequency of Es(fbEs) and the critical frequency of Es(f0Es) drop distinctly; (2) the minimum virtual height of F-layer (h'F) and the peak height of F-layer (hpF) decrease limitedly, and when the extreme heavy rainfall is more severe, the decreases of h'F and hpF are more obvious; (3) the extreme heavy rainfall has few or no effects on the other characters of the ionosphere. In the paper, it is thought that the meteorological influences on the ionosphere are due to dynamical processes; it occurs as the result of upward-propagating tides, planetary waves and gravity waves originating from or accompanying the extreme heavy rainfall.
EFFECTS OF NONLINEARITY ON THE CHARACTERISTICS OF GRAVITY WAVES
ZHANG Shaodong, YI Fan, WANG Jingfang
1999, 19(4): 321-326.   doi: 10.11728/cjss1999.04.321
Abstract(2489) [PDF 397KB](44)
Abstract:
By analyzing the numerical results of nonlinear propagation of a Gaussiangravity-wave-packet in isothermal atmosphere, the effects of nonlinearity on thecharacteristics of gravity waves are studied quantitatively. The analyses show that:during the nonlinear propagation of gravity-wave--packet, affected by nonlinearity,the vertical wavelength show a decrease and the mean flow show clear enhancement.On the other hand, though there exists nonlinear effects, the linear dispersion relation and polarization are still feasible, which indicates that the dispersion relationand polarization based on linear gravity wave theory can be applied extensively innonlinear cases.
Study of Ionospheric Irregularities in the Vicinity of SED Region During a Super Geomagnetic Storm
Huang Li, Yuan Zhigang, Deng Xiaohua, Nie Zhiying, Lin Minhui
2009, 29(6): 552-557.   doi: 10.11728/cjss2009.06.552
Abstract(2348) [PDF 612KB](63)
Abstract:
Small-scale ionospheric irregularities can cause strong amplitude and phase scintillations of radio wave signals passing through the ionosphere. In this paper, the phenomena of Storm Enhanced Density (SED) were studied during a super geomagnetic storm in October 2003 by using the TEC data of IGS. Rate of TEC Index (ROTI) is calculated with the observed data of GPS. The ROTI has been used to analyze the spatial and temporal distribution of small scale ionospheric irregularities in the vicinity of SED region. It shows that the irregularities near the SED border were gradually increased with the development of geomagnetic storm during the main phase, and the distribution density reached its maximum value in the latter part of the main phase, and then was reduced during the recovery phase. Initially, the irregularities were mainly distributed in latitudes 40º~45ºN. Subsequently, the irregularities drifted to higher latitude, and were mainly distributed in latitudes 45 º~55ºN. This study provides an important theoretical foundation on revealing the propagation characteristics of radio waves passing through the vicinity of SED region.
SIMULATION OF SPACE COLLISIONLESS SHOCK WITH IDEAL MHD EQUATIONS
LU Qiming, YANG Weihong
2004, 24(3): 161-168.  
Abstract(2187) [PDF 1764KB](20)
Abstract:
The collisionless shocks are the common phenomena in the interplanetary and interstellar space. They are also the important fundamental subject in the research of plasma physics, space physics and astrophysics. Numerical simulation is widely used in the study of collisionless shocks. Corresponding to the particle simulation, the method of solving the ideal MHD equations with WENO scheme has been presented to simulate the space collisionless shock. Based on the method, the interaction between the quasi-perpendicular collisionless shocks and two kinds of interplanetary structure——C inversed magnetic field and plasmoid with high density has been studied, and the results have also been compared with those of particle simulation, to consider the feasibility and the accuracy of MHD method in the simulation of collisionless shock. The comparison between the results of two method shows that, the MHD simulation can provide most results that are observed in the particle simulation, thus it is feasible to simulate the quasi-perpendicular collisionless shock with MHD method when the dynamic effects can be omitted. It also has a higher computational efficiency than the particle simulation, and will be easier to extend to the 2D or 3D simulation. However, the MHD simulation does not include the effect caused by single particle. So it lacks the capacity to describe the dynamic effects such as the dissipation and detailed structure of collisionless shocks. If the phenomena caused by these effects are not so important in specific research topics, the MHD simulation still can provide satisfied results. In some other cases, MHD simulation can be a convenient way to forecast the behavior of large-scale particle simulation.
Ionospheric Disturbances Produced by Artificially Chemical Releases
HUANG Wengeng, GU Shifen
2005, 25(4): 254-258.  
Abstract(2317) [PDF 1263KB](30)
Abstract:
Active experiments in the ionosphere, which give rise to artificial disturbances of electron density, are usually conducted by the injection of chemical clouds at ionospheric altitudes. Their effect has often been called an ionospheric hole simply to dramatize the localized nature of the disturbances, which had been observed in many experiments. For example, the injection of rocket exhaust neutral molecules into ionosphere, predominantly H2O and H2, can result in ionospheric electron density depletion. Main physical mechanism in these experiments is due to ion and molecule exchange reactions, which enhance the effective rate of recombination of electron. Ionospheric disturbances produced by artificially chemical releases have many applications in radio propagation and exploring ionosphere and plasma physics study. In terms of diffusion process of neutral gas and relevant chemical reactions in terrestrial ionosphere, the theoretical model of ionospheric modification created by active chemical releases is investigated in this paper. The influences of injected H2O and SF6 gas on the ionosphere under exponential atmosphere background are theoretically calculated, respectively. The results show that diffusion process of the injected neutral gas at ionospheric height is very quick, and the two released chemical materials can produce localized electron density depletions in F-regions, and those released materials, which have slow diffusion speed and large chemical reaction rates, will substantially affect ionosphere, and facilitate formation of artificial ionospheric hole.
Robust Variable Structure Control for Free-Floating Space Robot System With Dual-Arms in Joints Space
TANG Xiaoteng, CHEN Li
2007, 27(5): 435-440.   doi: 10.11728/cjss2007.05.435
Abstract(2193) [PDF 1634KB](20)
Abstract:
In this paper, the kinematics and dynamics of free-floating space robot system with dualarms are analyzed. It is shown that the dynamic equations of the system are nonlinearly depending on inertial parameters. In order to overcome these problems, the system is modeled as under-actuated robot system, and the idea of augmentation approach is adopted. It is demonstrated that the dynamic equations of the system can be linearly dependent on a group of inertial parameters. Based on the results, a robust variable structure control scheme for free-floating space robot system with dualarms with uncertain inertial parameters to track the desired trajectory in joint space is proposed, and a planar space robot system with dual arms is simulated to verify the proposed control scheme. The advantage of the control scheme proposed is that it requires neither measuring the position, velocity and acceleration of the floating base with respect to the orbit nor controlling the position and attitude angle of the floating base. In addition to this advantage, it is computationally simple, more suitable for real time applications.
A New Ground-based Fabry-Perot Interferometer for Measurement of the Thermospheric Wind
WANG Houmao, WANG Yongmei, FU Jianguo, ZHANG Zhongmou
2016, 36(3): 352-357.   doi: 10.11728/cjss2016.03.352
Abstract(1124) [PDF 1029KB](69)
Abstract:
As the thin air in the upper atmosphere (about 250 km),passive optical measurement is considered as the most efficient method for wind retrieval of the upper atmosphere.Because of high energy utilization and high spectral resolution,Fabry-Perot Interferometer (FPI) is one of the most widely used instruments for wind measurements.In this paper,a tiny ground-based FPI is designed by using a band-pass filter behind etalon and Galilean telescope system for wind observation of the upper atmosphere.The instrument is mainly composed of five parts including front optics sky-scanner,the etalon,Galilean telescope and filter,detector,and laser calibration system.The size of the instrument is 1.34 m×0.58 m×0.35 m,and the FPI is convenient to be transported from one place to another.Based on the instrument,several days of experiments are carried out at Langfang (39.40°N,116.65°E) station and Kelan (38.71°N,111.58°E) station for a detailed validation.The averaged wind deviation at Kelan sites between our FPI and American A-NCAR FPI is 11.8 m·s-1 when airglow is weak,which suggests good agreement between them.
Optical Prototype and Experimental Results of Geosynchronous Orbit Dynamic Monitoring System
LUO Hao, MAO Yindun, YU Yong, ZHANG Huiyan, TANG Zhenghong
2017, 37(3): 350-360.   doi: 10.11728/cjss2017.03.350
Abstract(1161) [PDF 3613KB](97)
Abstract:
There are a large number of Geosynchronous Orbit (GEO) targets with variable motion form. In order to protect space activities and master the space activities happened in our exclusive orbit space, it is necessary to develop the dynamic monitoring of GEO. In December 2015, an optical prototype of GEO dynamic monitoring system was set up in Gaomeigu observation site of Lijiang observatory. Observation experiments were carried out by use of the prototype from December 2015 to February 2016. The results show that 27 GEO targets can be continuously monitored, and 2 of them are uncatalogued by North American Aerospace Defense Command (NORAD). The observation precision for GEO targets of the prototype is derived as well as 4" in azimuth and 1" in elevation. The target orbit is improved according to the multi-cycle observations, and in the absence of orbit control occurring, the precision of 24-hour and 48-hour position forecast is better than 9" in azimuth and 2" in elevation. Taking 3 GEO targets as examples, the preliminarily analysis and verification of the orbit variation events are carried out by use of the observation data.
Design of YH-1 Payload Data Handling Unit
An Junshe, Chen Xiaomin, Shi Junfeng, Zhou Shengyu, Wu Qi, Lv Liangqing, Zhang Zhongwei
2009, 29(5): 486-489.   doi: 10.11728/cjss2009.05.486
Abstract(3225) [PDF 571KB](86)
Abstract:
According to the request of Payloads, it is necessary to design a safe and reliable Payload Data Handling Unit (PDHU) for YH-1 satellite. The functions of PDHU are data collection, data processing, data storage and system power supply. PDHU affords an operating system, which is convenient for software development. Under the circumstances of Mars exploration, a channel encoding method which adopts the non-interlaced RS-Convolutional Concatenated Code is used to ensure the communication between the space and the Earth.
NUMERICAL STUDY ON PLASMOID-LIKE STRUCTURES IN THE MAGNETOTAIL
DU Jian, JIN Shuping
2004, 24(3): 169-181.  
Abstract(1866) [PDF 3163KB](65)
Abstract:
In view of the distribution features of the temperature and density across the different regions of the quiet magnetotail, the same non-uniform distributions of the temperature and density are used as the initial state of the simulation study. In this report, three cases with the different distributions of initial By component are investigated. The numerical results illustrate the characteristic evolution of three kinds of magnetic structures. For the varying magnetic field at a given point in the neutral sheet, the hodograms of the typical events are performed. From another point of view, the hodograms of three cases show the features of flux rope structure, plasmoids with Complex closed magnetic field lines and two-dimension "magnetic island", respectively. It was demonstrated from the observations that most plasmoids in the magnetotail are the flux rope structures with a large core field. Monitoring the development of a flux rope structure, the profiles of the directional velocity vx, vy, vz and magnetic field strength B in it as a function of the distance x are given. The computing values of vx and B are approximately consistent with the observed values in the near and middle tail by Geotail. Moreover, in comparison with Jin et al.’s simulation with a constant initial temperature, in the present work the temperature of plasmoids increases and the density of plasmoids decreases notably, and so the difference between the numerical results and observation is reduced.
Effects of Atmospheric Gravity Waves on the Mesosphere and Lower Thermosphere Circulations
HU Xiong, ZHANG Xunxie, ZHANG Dongya
2005, 25(2): 111-117.  
Abstract(1997) [PDF 409KB](46)
Abstract:
Atmospheric gravity waves generated in the lower atmosphere, carrying momentum and energies, propagated upward and usually became saturated and breaking in the Mesosphere and Lower Thermosphere (MLT) due to their increasing amplitudes versus increasing height. Linear saturation parameterizations of atmospheric gravity waves were applied with the β-channel quasi-geostrophic mean flow equations to qualitatively investigate influences of gravity waves on MLT circulations. Three waves with 0m·s-1, 20m·s-1,-20m·s-1 horizontal phase speeds respectively were taken as a parameterization of the discrete spectrum of gravity waves. Simulations show that the accelerations due to waves can be 100m·s-1/d and eddy diffusion coefficients can be 120m2/s in the mesosphere, which balance the Coriolis force due to MLT meridional circulations and induce great departures of the zonal mean zonal winds from the radiation balance zonal winds. The calculations of the zonal mean zonal winds of MLT are qualitatively consistent with the MF radar observations and model profiles both in winter and summer time.Resultsshow gravity waves play significant role in MLT circulations.
Optimum design based on full stress ruler and test for truss of space camera
Jia Xuezhi, Zhang Lei, Jin Guang
2013, 33(3): 346-352.   doi: 10.11728/cjss2013.03.346
Abstract(2150) [PDF 911KB](55)
Abstract:
Since it is hard to design the truss structure in space camera which has both low weight and high stiffness, the rule of full stress is proposed to optimize the truss section. The design rule and request of the optical system are introduced. By selecting the truss weight as the optimization object, gravitation transmutation and first frequency of secondary mirror as the restriction condition, and the inside and outside diameters of truss section as the optimization variables, the optimization model based on full stress rule is established. The optimized inside and outside diameters of truss section are 40mm and 50mm respectively, the optimized weight of truss is 6.3kg, while the first frequency is 121Hz. The mode analysis, gravitation transmutation analysis and temperature raise of 15℃ analysis later indicate that the truss optimized can satisfy the needs of the optical system. Finally, 0.2g vibration test and dimensional stability test are inflicted to the truss, which shows that the first frequency of the truss is 119Hz, and that the transmutation of the secondary mirror is less than 5". The truss optimized has the characteristic of compact structure and fine dimensional stability which meet the needs of space camera well. It lays a foundation for development of space camera with large caliber, long focus and light weight.
THE EFFECTS OF THE VERTICAL WAVELENGTHOF THE GRAVITY WAVES ON ESF
ZHANG Tianhua, ZHANG Donghe, XIAO Zuo
1999, 19(2): 128-133.   doi: 10.11728/cjss1999.02.128
Abstract(2167) [PDF 311KB](74)
Abstract:
The results of numerical simulation show that not only gravity waves are theseeds of ESF, but also their vertical amplitudes and the wavelengths of gravity wavesinfluence the evolution of ESFin different ways. The work we done gave a nonlinearexplanation on the various morphological features of ESFs.
A COMPARISON OF APPROACHES TO DERIVING EQUIVALENT WINDS FROM IONOSPHERIC F-LAYER CRITICAL PARAMETERS
LIU Libo, LEI Jiuhou, LUAN Xiaoli, WAN Weixing, NING Baiqi
2003, 23(2): 89-96.  
Abstract(1932) [PDF 2249KB](55)
Abstract:
Dynamic information (neutral winds and electric fields) near the peak of the ionospheric F-layer can be obtained from ionospheric critical parameters (f0F2 and hmF2) with different approaches. The physical basis of these approaches is the fact that neutral winds and electric fields strongly control the evolution of the ionosphere near and above the F-layer peak, especially the peak height of the F-layer. These approaches can be classified into three categories: traditional and revised servo approaches, data assimilation and approaches with the aid of ionospheric models, and the new approach introduced by Libo Liu. The first kind of approaches is based on the servo theory which was originally proposed by Rishbeth et al. (1978). A key point of this kind of approaches is that the equivalent wind is assumed to be proportional to the displacement of the peak height of the ionospheric F-layer from its equilibrium height without wind. Although it has achieved great success (Titheridge, 1995), the servo theory approach needs the no-wind equilibrium height, which is difficult to be accurately determined due to the large time constants for the ionosphere reaching an equilibrium state, especially in the day time. The second one includes those with the aid of an ionospheric theoretical model. Some need only an ionospheric model to provide the relationship between the neutral winds and the height displacements. In essence, they should belong to the serve theory approaches. The others make use of the idea of data assimilation, i.e., making the parameters from the model consistent with the observations as well as possible. The adjusted atmospheric parameters during the calculations are assumed to be the values at the actual situations. The approach proposed by Libo Liu avoids deducing equivalent winds from the displacement of the observed peak height from the no-wind equilibrium height, thus it is very simple and does not need to determine the no-wind equilibrium height which may limit the accuracy of the deduced winds as the servo theory approaches did.Equivalent winds derived from F-layer critical parameters by using these approaches are compared with the measurements with Millstone Hill Incoherent Scatter Radar during day 177-180 of the year 1990. Another example shows the consistence of an observation of the FPI wind at Beveridge (37°S, 144°E), Australia, with the equivalent winds derived from the Digisonde 256 observation at the same site. Both case comparisons can qualitatively evaluate the validity of the third approach.
Size and Shape of Magnetopause in the Noon-midnight Meridian Plane Based on the MHD Simulation
Liu Huilian, Huang Zhaohui
2011, 31(1): 15-19.   doi: 10.11728/cjss2011.01.015
Abstract(2791) [PDF 461KB](43)
Abstract:
A quantitative model about the location and Shape of Magnetopause (MP) in the noon-midnight meridian plane is given by analyzing the computing data from three-dimensional global MHD simulation of the magnetosphere. Data processing results show the function which was presented by Ref.[3] based on the satellite observational data can also be used to describe MP in noon-midnight meridian plane. The location and shape of the MP in the noon-midnight meridian plane are more complicated than those in the equatorial plane. Although the MP in cusp region is ignored, the location and shape of MP need still be fitted by two different curves. The dynamic pressure of the solar wind (Dp) and the north-south component of the interplanetary magnetic field (IMF Bz) are two main factors determining the size and shape of MP. While for northward IMF Bz, r0 increases with increasing northward Bz; for southward IMF Bz, the standoff distance r0 decreases with increasing southward IMF Bz. On the whole, r0 increases when Bz turns northward from southward, and the influence of Bz on r0 becomes weaker. r0 is mainly affected by the dynamic pressure Dp, r0 decreases with Dp increasing. The other variable α, the level of tail flaring, increases with southward IMF increasing, which means the magnetopause flares more strongly and more magnetic flux transfers from the dayside to the nightside. The value of α rises slightly with Dp increasing, which implies that Dp also helps to some extent flux transfer from the dayside to the nightside.
Structure Design and Thermal Deformation Analysis of Large Spaceborne Flat Slotted Antenna
FAN Wenjie, LI Xiaopeng, CHEN Bo
2014, 34(6): 894-898.   doi: 10.11728/cjss2014.06.894
Abstract(943) [PDF 3258KB](68)
Abstract:
Large spaceborne flat slotted antennas recently boom rapidly in the field of space applications. The structural element of large flat slotted antenna is introduced. A new connected scheme of antenna is put forward and unidirectional floating fixing method is applied to outside four flange of antenna. This fixing method could ensure that antenna move along one certain direction freely when temperature rises or drops. Thermal deformation is analyzed in ultimate high temperature and ultimate low temperature. The results are thermal deformation RMS value in Y direction decreases from 0.53 mm to 0.3 mm in ultimate high temperature and decreases from 0.33 mm to 0.1 mm in ultimate low temperature. It shows that the thermal deformation RMS values satisfy the design requirements on board, so electrical performance can be assured.
Capacity and Validation of Fabry-Perot Interferometer Wind Measurements in Shanxi of China
HUANG Cong, YU Tao, ZHANG Xiaoxin, WANG Jingsong, WU Qian, LI Tao, ZONG Weiguo, DUN Jinping, CUI Yingji
2015, 35(6): 707-714.   doi: 10.11728/cjss2015.06.707
Abstract(1136) [PDF 4902KB](103)
Abstract:
This article introduces the instrument structure of Fabry-Perot Interferometer (FPI), the capacity of wind measurements, the process of data reduction procedure, data quality control plan and data validation works which was deployed at Kelan Meteorological Bureau (39°N, 112°E) in Shanxi, China. The FPI of Kelan has the ability to measure the Doppler shift of airglow emissions (OH892.0nm, OI557.7nm, OI630nm) at mesopause and in thermosphere to derive horizontal wind vector and atmosphere temperature at heights of 87km, 97km and 250km, respectively. From late of 2011 to middle of 2014, a series of more than 6000 measurements at each height are derived according to manufacture data quality criteria. In data validation works, the Horizonal Wind Model (HWM) was applied to do the cross-comparison with Kelan FPI's observations. The comparisons show that the general trends of Kelan FPI's wind measurements are consistent with HWM's outputs and there exists difference of seasonal variation. The comparison results prove that the data quality control plan works and the measurement accuracies are 5.7m·s-1 at 87km, 1.3m·s-1 at 97km and 4.1m·s-1 at 250km height. In general, Kelan FPI's wind measurements are reliable and useful for investigations of the wind morphology in the mesosphere and thermosphere.
Strong Range Spread-F Characteristics Observed in Hainan During Intense Storm
WANG Guojun, SHI Jiankui, WANG Xiao, LIU Zhenxing, Zherebtsov G, Olga P
2007, 27(5): 379-383.   doi: 10.11728/cjss2007.05.379
Abstract(2845) [PDF 1591KB](52)
Abstract:
The response of equatorial ionosphere during geomagnetic storms is one of the important issues related to space weather studies and how they affect the occurrence characteristics of equatorial spread-F is one of the prominent research fields. In this study, the Strong range Spread-F (SSF) data from DPS-4 digisonde during the five strong storms (Dst 〈 -100nT) period in 2004 in Hainan (19.4°N, 109.1°E, MLat. 9.0°N) China are used to investigate the effects of geomagnetic storms on SSF. The results show that there are three storms, the minimum Dst of which lied in the period 2200-0200 LT and SSF occurred during the main or earlier recovery phase of these storms, the role of directly penetrated electric field of magnetosphere maybe the only important factor for occurrence of SSF. The other two storms whose minimum Dst lied in the dayside also trigger SSF during the night of recovery phase of one storm and initial phase of another super intense storm. The SSC of the later super storm led to penetrated electric field towards to lower latitude/equator of ionosphere which triggered SSF. During the storms, SSF occurred only before midnight or started midnight and continued after midnight. The comparisons between the results of Dabas et al. and ours also discussed.
CALCULATE AND APPLICATION OF THE GPS SATELLITE CLOCK OFFSET
JI Shanbiao, ZHU Wenyao, XIONG Yongqing
2001, 21(1): 42-48.  
Abstract(2209) [PDF 558KB](47)
Abstract:
The characteristics of GPS satellite clock is analysed, and a method to calculate the satellite clock offset is given based on ground GPS station in this paper. With developed algorithm and software, one meter accuracy for low orbit satellite determination is achieved from data of ground tracking station.
Explicit Expression and Influencing Factor Analysis of Collision Probability Between Space Objects
Bai Xianzong, Chen Lei
2009, 29(4): 422-431.   doi: 10.11728/cjss2009.04.422
Abstract(2895) [PDF 762KB](103)
Abstract:
The explicit expression of the collision probability is deduced under the assumption that the orbit is a circle. The collision probability is expressed as an explicit function of the encounter geometry (crossing altitude difference and time difference of the line of intersection of the two orbital planes, orbital planes included angle, etc) and position error variance in RSW coordinates. With the help of the explicit expression, the influencing factors of the collision probability were analyzed. Effects of factors such as altitude difference, time difference, orbital planes included angle, position predicted error variances and the equivalent radius of two objects were discussed. Some significant conclusions were obtained.
THE STUDY OF THE HEATING PROCESSES IN STRATOSPHERE,MESOSPHERE AND LOWER THERMOSPHERE
XU Jiyao, WANG Yingjian
1998, 18(2): 146-151.   doi: 10.11728/cjss1998.02.146
Abstract(1970) [PDF 431KB](70)
Abstract:
In this paper, the heating rate produced by photochemical processes in stratosphere,mesosphere and lower thermosphere is calculated. And the atmospheric cooling rate is calculated as well using Fondchev's code. Using one dimensional tine dependent photochemical model, the diurnal variation of heating rate in the height region of 20-140 km is studied. Tis work provides theoretical basis for studying the atmospheric tidal waves.
Research of Geospace Magnetic Field Response to the Solar Wind Disturbances
Ding Liuguan, Jiang Yong, Xu Fei
2011, 31(2): 170-175.   doi: 10.11728/cjss2011.02.170
Abstract(2714) [PDF 509KB](43)
Abstract:
The goespace magnetic field response to the solar wind disturbances including interplanetary shocks, solar wind dynamic pressure increase and decrease is analyzed comparatively. The geosynchronous magnetic field has positive response to all the disturbances strongly near the noon meridian, and has positive response in the nightside of the magnetosphere weakly. However negative responses were sometimes observed in the nightside. From our results, the geomagnetic index SYM-H always shows positive response to the disturbances of solar wind. The amplitude of geosynchronous response d Bz could be determined by the square root of the solar wind dynamic pressure near the noon meridian with good correlation the same as the geomagnetic indices. The d Bz at the geosynchronous orbit near local noon and the amplitude of sudden impulses (dSYM-H) on the ground are highly correlated under the circumstances action of IP shock or solar wind dynamic pressure increase, differentiating from the dynamic pressure decrease distinctly. It is shown that the IP shocks have some commonness with the solar wind dynamic pressure increase in affecting on the geospace magnetic field.
Application of ADER Scheme in MHD Simulation
ZHANG Yanyan, FENG Xueshang, JIANG Chaowei, ZHOU Yufen
2012, 32(2): 170-781.   doi: 10.11728/cjss2012.02.170
Abstract(2438) [PDF 388KB](69)
Abstract:
The Arbitrary accuracy Derivatives Riemann problem method (ADER) scheme is a new high order numerical scheme based on the concept of finite volume integration, and it is very easy to be extended up to any order of space and time accuracy by using a Taylor time expansion at the cell interface position. So far the approach has been applied successfully to flow mechanics problems. Our objective here is to carry out the extension of multidimensional ADER schemes to multidimensional MHD systems of conservation laws by calculating several MHD problems in one and two dimensions: (ⅰ) Brio-Wu shock tube problem, (ⅱ) Dai-Woodward shock tube problem, (ⅲ) Orszag-Tang MHD vortex problem. The numerical results prove that the ADER scheme possesses the ability to solve MHD problem, remains high order accuracy both in space and time, keeps precise in capturing the shock. Meanwhile, the compared tests show that the ADER scheme can restrain the oscillation and obtain the high order non-oscillatory result.
Analysis of the Chinese GEO Satellite Anomaly on 9 March 2012
TIAN Tian, WU Yaoping, CHANG Zheng, LI Ming, MA Liang, WEI Yali, ZHU Guoyang
2015, 35(6): 687-695.   doi: 10.11728/cjss2015.06.687
Abstract(1130) [PDF 5356KB](83)
Abstract:
Based on the GOES-15, SDO, SOHO satellites and geomagnetic indices data, the Chinese GEO satellite anomaly on 9 March 2012 was studied. The space weather conditions at the time of the GEO-X satellite anomaly are being analyzed, and SEAES-GEO (Spacecraft Environmental Anomalies Expert System for Geosynchronous Orbit) method is used to calculate the internal charging hazard quotient, the single event effects hazard quotient and the surface charging hazard quotient. The hazard quotient was divided into three types with red-yellow-blue color coding which represents different hazard rating. Results showed that the hazard quotient for internal charging was less than 3 and the surface charging hazard quotient was about 0.0011, safely in the green at the time of the failure. The hazard quotient for single event effects reached 46.3, which was correlated to high energetic protons produced during solar flares, very danger in the red at the time of the failure. The results thus imply that the single event effect is quite probably the reason that caused the GEO-X satellite anomaly on 9 March 2012.
PATH PLANNING FOR SPACE MANIPULATOR WITHOUT DISTURBANCE ON VEHICLE'S ATTITUDE
Gu Xiao-qin, Liu Yan-zhu
1996, 16(4): 322-325.   doi: 10.11728/cjss1996.04.322
Abstract(1841) [PDF 257KB](37)
Abstract:
The problem on path planning of a space manipulator is discussed in this paper. The path planning methods avoiding or decreasing the disturbance on vehicle's attitude for a predetermined trajectory or initial and final positions of the payload of manipulator are suggested.
Anisotropy Analyses of Cosmic Ray Before the Geomagnetic Storm on Sep. 24, 1998
Wang Jing, Liu Siqing, Xue Bingsen, Gong Jiancun
2009, 29(5): 495-501.   doi: 10.11728/cjss2009.05.495
Abstract(2708) [PDF 724KB](64)
Abstract:
Cosmic rays are energetic particles originating from outer space that impinge on Earth's atmosphere. Almost 90\% of all the incoming cosmic ray particles are protons, about 9\% are helium nuclei and about 1\% are electrons. The nuclei that make up cosmic rays are able to travel from their distant sources to the Earth because of the low density of matter in space. Nuclei interact strongly with other matter, so when the cosmic rays approach Earth they begin to collide with the nuclei of atmospheric gases. These collisions, in a process known as shower, result in the production of many pions and kaons, unstable mesons which quickly decay into muons. Muons are ionizing radiation, and may easily be detected by many types of particle detectors such as bubble chambers or scintillation detectors. Based on the muon measurement data of 30°, 49°, 64° of East, West, South, North components of cosmic ray from Nagoya station, the north-south and west-east anisotropy of cosmic ray just before geomagnetic disturbances and quiet days is analyzed by use of Haar wavelet. It was found that fluctuations of the anisotropy of cosmic ray before geomagnetic disturbances increased due to the approaching of CME because the shock front and strong IMF induced by CME and the coefficient of wavelet always increased monotonously more than 10 hours ahead the geomagnetic storm, which hopefully could be the premonitory properties of the eruption of severe geomagnetic storm.
THE INFLUENCE OF BACKGROUND WINDS ON INTERNAL GRAVITY WAVES IN DISSIPATIVE ATMOSPHERE
DING Feng, WAN Weixing, YUAN Hong
2000, 20(2): 129-135.   doi: 10.11728/cjss2000.02.129
Abstract(2004) [PDF 458KB](54)
Abstract:
By using ray-tracing method, features of propagation of internal gravity wavesunder the influence of winds are calculated- The results indicate that the cut-offregion of gravity waves seems not affected by winds, while reflecting and propagat-ing regions are significantly innuenced. The reflecting region reduces when gravitywaves propagate downwind and expands when against wind. In propagating region,propitions winds shorten the attenuation distance of slow gravity waves and reducetheir propagating height, while converse winds lengthen the attenuation distance ofslow gravity waves and rise the attenuation height. Further analysis shows that thediversity of gravity wave propagation features is caused by the effect of winds onthe processes of gravity wave attenuation and reflection.
Thermal design and flight validation of HJ-1-C
Wang Lei, Wen Yaopu
2015, 35(2): 224-229.   doi: 10.11728/cjss2015.02.224
Abstract(1332) [PDF 1945KB](60)
Abstract:
HJ-1-C is a Synthetic Aperture Radar (SAR) satellite of the Chinese Environment and Natural Disaster Monitoring constellation launched on November 19, 2012. The SAR payload uses mesh parabolic reflector antenna and solid-state transmitter to transmit high power in centralized manner. Based on the design concept that passive thermal control would be preferred over active thermal control for its simplicity and inherent reliability, HJ-1-C satellite thermal control system were provided in accordance with the HJ-1-C satellite working characteristics and space thermal environment on its orbit. The presentations about thermal design techniques, scheme and key problems solved are given. Moreover, onboard performance of the satellite on its orbit was analyzed. The flight telemetry data showed that the thermal control design was reasonable and well satisfied with the temperature requirements of the electronic equipments and payloads, which ensured the safety and reliability operation of satellite.
CHANGABLE PULSE WIDTH LIDAR SIMULATION AND RECORDED DATA ANALYSIS
Wu Feng, Liang Zhen-mei, Luo Fu-shan
1995, 15(1): 66-72.   doi: 10.11728/cjss1995.01.066
Abstract(2251) [PDF 426KB](81)
Abstract:
Conception of ideal LIDAR received power Pm and real received power are suggested. By numerical calculation,relations of Pr/Pm with height under different laser pulse width,various background,β layer and receiving gate width are obtained.The results are applied in observational data analysis and results which show the feature of aerosol and molecule scattering up to 50km in Beijing.
THE INFLUENCE OF THE SOLAR WIND ON THE RETARDATION OF ROTATION OF THE SUN
Li Lin-sen
1990, 10(4): 274-279.   doi: 10.11728/cjss1990.04.274
Abstract(2123) [PDF 345KB](38)
Abstract:
In this paper, the influence of the solar wind on the retardation of rotation of the sun is examined. The theoretical expressions for the relative variation rate and secular variation of angular velocity of rotation are derived. For the relative variation rate, the effect of mass loss due to solar wind is negligible; but for the secular variation, it can not be neglected The results of numerical computation are given. The relative variation rate(这里有图片19900405-274-1.GIF)/ω= -5.4× 10-10/year. The curve of secular variation in 107 year is plotted in Fig. 1.
Gravity Wave Activities in the Lower Atmosphere Over Wuhan, China
LIU Yingjie, YI Fan
2005, 25(6): 516-521.   doi: 10.11728/cjss2005.06.516
Abstract(2328) [PDF 1729KB](51)
Abstract:
Radiosonde observations provided by Wuhan Center Station of Meteorology (30.5° N, 114.4° E) between January 2001 and December 2003 are used to study the spatial and temporal variations in gravity wave activities in the lower atmosphere over Wuhan, China. Time series of horizontal kinetic energy show an obvious seasonal variation with the maximum in winter when jet is strongest and the mimimum in summer when there doesn't exist the jet. Using a hodograph analysis, it is found that about 46.4% of the waves are propagating upward in the height range of 1-9 km, while roughly 73.8% of the waves are propagating upward in 14-25 km, in agreement with the assumption that gravity waves are generated by the jet stream near 11 km. Further examination reveals that within the height range of 14-25 km gravity waves are mostly propagating upward in summer while quite a portion of gravity waves propagate downward in winter, which might be caused by reflection. The intrinsic frequencies are mostly 1-3 times the inertial frequency. Horizontal wavelengths of several hundred kilometers are inferred. The vertical wave lengths are centered on 3-3.5 km during 1-9km, but 4.5-5.5km during 14-25km.
THE PRESSURE CORRECTION OF THE COSMIC RAY DATA IN YANGBAJING
TANG Yunqiu, LU Hong, LE Guiming, TAN Youheng, ZHANG Jilong
2004, 24(3): 219-225.  
Abstract(2110) [PDF 1488KB](36)
Abstract:
In this paper, the pressure correction of the cosmic ray intensity in Yangbajing is investigated. Pressure correction is not only related to the atmospheric pressure, but also to the solar activities. The absolute value of barometric coefficient is biggest when the level of solar activities is highest. And the barometric coefficient is related to the sampling time of data. In the same time, using different sampling time got different barometric coefficient. The pressure correction is made to the raw data of Tibet neutron monitor, and the barometric coefficients of single channel and eight multiplicity channels are calculated.
The Implementation and Verification of RS(255, 223) Decoder According to CCSDS Specification
SHI Junfeng, WANG Yu, SUN Huixian
2005, 25(4): 309-314.  
Abstract(3091) [PDF 1627KB](62)
Abstract:
A RS (Reed-Solomon) code is an excellent linear cyclic block code in the error control field. It has found widespread use in deep space exploration and has been adopted by the spatial organizations such as CCSDS, NASA, ESA for its powerful random and burst error correcting ability. The research project adopts a new reformulated inversionless BM (Berlekamp-Massey) algorithm to fulfill a RS(255, 223) decoder according to CCSDS specification. In this paper, the algorithm, verification method and the verification platform based on PCI bus interface of the RS(255, 223) decoder have been introduced. The experiment result and the comparison of the theoretic and testing error probability of the decoder have been mentioned. The test result proves the complexity of the proposed decoder is only about 180 000 gates and has a throughput of 400 Mbps using FPGA. The error correcting ability of the decoder is normal.
Non-axisymmetric Magnetostatic Equilibrium in Cylindrical Coordinates and Its Application to Sunspots
Hu You-qiu, Xu Wei-dong
1985, 5(2): 75-83.   doi: 10.11728/cjss1985.02.075
Abstract(1667) [PDF 512KB](17)
Abstract:
The present paper describes a general solution to the three-dimensional, two-con-ponent magnetostaitic equations in cylindrical coordinates, assuming the total pressure (sum of gas pressure and magnetic pressure) is a function of the altitude only. By adjusting the two arbitrary functions appearing in the general solution one may produce various patieular solutions which are not subjected to any limitation of perturbation conditions while applied to solar phenomena. Moreover, it is found that a particular solution as to qualitatively elucidate the asymmetry of sunspots in shape in addition to the filamentary structure in sunspots.
Nonlinear feedback control of fractionated spacecraft electromagnetic formation flying in low-Earth orbit
Hu Min, Zeng Guoqiang, Dang Zhaohui
2012, 32(3): 417-423.   doi: 10.11728/cjss2012.03.417
Abstract(2429) [PDF 607KB](41)
Abstract:
A method for designing the nonlinear feedback control law is proposed in this paper for the electromagnetic formation flying system of fractionated spacecraft in low Earth orbit. Firstly, the magnetic force model and the Earth's magnetic field model are established, respectively. The effects of the Earth's magnetic field on the electromagnetic formation flying system in low Earth orbits are analyzed. Secondly, the high precision relative orbit dynamics model is presented. Then, a nonlinear feedback control law for relative orbit is proposed based on the Lyapunov's stability theorem. Finally, two fractionated modules electromagnetic formation maintenance scenario is simulated. The simulation results show that the magnetic disturbance force can be ignored; but the disturbance torque cannot be ignored. Furthermore, the fractionated spacecraft electromagnetic formation flying is fully controllable and the approaches proposed are feasible.
Study of Surface Charging and Discharging Effects on Solar Array Drive Assembly
Li Rui, Liu Jikui, Xu Yuemin, Wang Youping, Liu Lei, Chang Xiao, Wu Fengshi, Sun Hailong
2014, 34(3): 360-366.   doi: 10.11728/cjss2014.03.360
Abstract(1273) [PDF 802KB](72)
Abstract:
The spacecraft surface charging and discharging resulting from the space plasma environment is one of the main causes of spacecraft abnormity and malfunction. Solar Array Drive Assembly (SADA) is a crucial component of the electrical transfer sub-assembly of the modern long life and large power satellite, which is used to rotate the solar array to follow sunlight for maximum energy acquisition, as well as transfer power and signals from the solar array to satellite. SADA is installed at the interface of spacecraft body and outer space, so it is directly exposed to the space plasma environment and prone to the adverse effects of charging and discharging. When SADA malfunctions, the satellite will lose energy and results a failure of the whole satellite. In order to test the influence of surface charging and discharging by the space plasma environment on SADA, especially its power transfer reliability and safety, a plasma environment simulation device simulating the plasma environment in the GEO orbit, was utilized to conduct experimental test on a SADA. The SADAs utilizing different dielectrics demonstrated similar effects in the space plasma environment. The test result also demonstrated that the surface charging and discharging would not influence the normal functionality of SADA with proper design. The test result will serve as a good foundation for the design of future space mechanisms like SADA for higher reliability and safety.
Simulation of three-dimensional Earth's bow shock
Hu Huiping, LÜ Jianyong, Zhou Quan, Wang Ming, Yang Yafen, Liu Ziqian, Pei Shixin
2015, 35(1): 1-8.   doi: 10.11728/cjss2015.01.001
Abstract(1664) [PDF 2275KB](63)
Abstract:
We use a physics-based global Magnetohydrodynamic (MHD) model to investigate the location and shape of the Earth's bow shock. The bow shock locations in the simulations are identified by an automated search algorithm and is fitted by simple analytical functions. A global three dimensional bow shock model is constructed to include the effect of magnetopause and is parameterized by the fast magnetosonic Mach number, solar wind ram pressure, interplanetary magnetic field strength, and magnetopause curvature radius. The model results are compared and agree well with the previous empirical and simulation models. We also find that both the shock standoff distance and the shock flaring angle decrease monotonically with increasing the fast magnetosonic Mach number. The size and location of bow shock on the equatorial plane and the meridian plane show obvious asymmetry.
Ray Direction in a Warm Electron Magnetized Plasma
Wang Zhen-song
1986, 6(1): 43-51.   doi: 10.11728/cjss1986.01.043
Abstract(1731) [PDF 522KB](49)
Abstract:
The directions of the group-velocity vectors of waves of various frequencies in a warm-electrons only plasma are given. Some important properties of the direction of group-velocity vectors are revealed. It is shown in particular that there is a plasma wave propagating near the resonant region of the wave in the corresponding cold plasma. The electron plasma wave can link with the ordinary wave or the extraordinary waves. This makes waves capable of propagating in a broader range of angles than in a corresponding cold plasma.
IONOSPHERIC SCINTILLATION OF COSMIC RADIO NOISE AND THE STRUCTURAL PARAMETERS OF IONOSPHERIC IRREGULARITIES
Chen Zhong-sheng, Ma Guan-yi
1995, 15(3): 196-206.   doi: 10.11728/cjss1995.03.196
Abstract(2314) [PDF 801KB](72)
Abstract:
Based on the assumption that the Cosmic Radio Noise is an isotropic backgrouna electromagnetic radiation, by use of the ray-optics method the expression of the scintillation power spectrum of electron density space fluctuation is obtained,which obeys the inverse power low of the ionospheric irregularities.Compared with that of Radiostar and satellite beacon scintillation.the ionospheric scintillation of cosmic radio noise reduces the number of variables,the variable introduced by relative movement no longer exist.The effect of the structure parameters Ly、ly、p、η, on the power spectrum is also studied using numerical simulation. As a result, it is found that more than 60% of the irregular strutures associated with the data recorded by Riometer during the period of the ionospheric absorption events have Ly> √λZ and 0.2<η <0.5.
THE CURRENT COLLECTION BY HIGH VOLTAGE SOLAR ARRAY FROM THE SPACE PLASMA
Gu Shi-fen, Shi Li-qing, Song Li, Tian Bao-ning
1995, 15(1): 42-46.   doi: 10.11728/cjss1995.01.042
Abstract(1977) [PDF 323KB](44)
Abstract:
In this paper,a theoretic model of current collection is developed.the model makes it easier to calculate the current collected by high voltage solar array (HVSA)from the space plasma.Through analysis of the physical process we suggest that plasma coupling power loss for HVSAdesigning should not be neglected.
Advance in X-Ray Pulsar Navigation Technology
SHUAI Ping, CHEN Shaolong, WU Yifan, ZHANG Chunqing, LI Ming
2007, 27(2): 169-176.   doi: 10.11728/cjss2007.02.169
Abstract(2561) [PDF 3132KB](36)
Abstract:
The pulsars are the result of a massive star that has exhausted its nuclear fuel and undergone a core-collapse resulting in a supernova explosion. Its radius is roughly 10 km and mass near 1.4 solar. There are the very strong gravitational, electronic and magnetic fields for the pulsar. The pulsar might emit in the radio, infrared, visible, ultraviolet, X-ray and gamma-ray of the spectrum. Meanwhile, the navigation parameters for the spacecraft on the low earth orbit, deep space and interplanetary flight can, including the position, velocity, attitude and time, be determined highly-accurately by detecting the X-ray radiation of pulsars. And then the spacecrafts are able to flight and operate autonomously. Therefore, the potential of using the X-ray Pulsar Navigation (XPNAV) is very high. Firstly, the history of XPNAV is described briefly in this paper. Secondly, the basic principles, information flow charts and autonomous navigation algorithms are studied in detail as an main part. Moreover.the key techniques of XPNAV, including the all-sky surveying and data processing for the X-ray pulsars, pulse-arrival-time measuring and error correcting, X-ray detector and weak signal processing, establishment and maintenance of the space-time reference, and robust filtering of the autonomous information processing, are also presented. Finally, the essentiality and feasibility to study XPNAV are also shown in some detail.
Geostationary Satellite's End-of-Life Predication Based on Propellant-Remaining Estimation
LI Jiancheng, YANG Yongan, AN Jinwen
2006, 26(3): 193-196.   doi: 10.11728/cjss2006.03.193
Abstract(2580) [PDF 238KB](74)
Abstract:
With the application of the geostationary satellites, the problem how to prediction the in-orbit life of the satellites is taken into account, especially the satellites with liquid propellant. The methods of propellant measurement and management have been studied by many people, and the assignment and the end-of-life prediction is thought to be a necessary work in satellite engineering. This paper discusses the factors that may influence the in-orbit life of geostationary satellite, such as space environment, capability of the equipment, the wasting fuel and the ground operation. The propellant mass is proved to be the main factor in engineering. The end-of-life prediction accuracy analysis should be based on the on-board sensor accuracies and satellite telemetry processing accuracies. The methods of how to measure and estimate the propellant-remaining of the Chinese satellite are given as PVT method, BookKeeping (BK) method, and combined method (PVT+BK). The prediction methods of the satellite give the average life, the reliable life and the actual life. The engineering example shows the predication method based on propellant-remaining is reasonable.
Motion Equation of Satellite in XNAV
Fei Baojun, Pan Gaotian, Xiao Yu, Han Chunhao
2011, 31(2): 254-259.   doi: 10.11728/cjss2011.02.254
Abstract(2844) [PDF 484KB](218)
Abstract:
In X-ray pulsar-based navigation model for satellite autonomous position determination, whether in theory or in view of measurement precision, the equations of time-of-arrival measurement and satellite's motion, observation equation and state equation must all base on same reference system. In the solar system Barycentric Reference Systems (BCRS), that is an inertial frame in DSX system, current time measurement equation can be used, but the perturbing acceleration of satellite consists not only the multipole of Earth, gravitation perturbation of Sun and Moon and radiation pressure of Sun, but also relativistic effect. Because the satellite's position error caused by relativistic effect is about 10 meter in quantity order. In the Geocentric Reference Systems (GCRS), that is a non-inertial frame, the relativistic effect term can be neglected in the motion equation of satellite. Because the error caused by this effect is about 10 centimeter. But time measurement equation in BCRS must transform to GCRS. As a result of the above, the navigation model can be more precision and complete.
A CME EXPANDING IN BOTH THE RADIAL AND LATERAL DIRECTIONS
Zhang Gong-liang
1996, 16(1): 1-6.   doi: 10.11728/cjss1996.01.001
Abstract(1849) [PDF 464KB](73)
Abstract:
The angular expansion of the 5 May 1980 event is large in the outer loop,but insignificant in the inner loop; the expansion made the outer front flattering,and the streamer moving and bending. In comparison with the event in successionoccurring in the same solar region on the next day, the characteristics of theradial motion are different in the time domain, but similar in the space domain.Physical implications of above features are discussed in the paper.
Thermal Analysis of the Solar Array in the Lunar Orbit
LI Peng, CHENG Huier
2006, 26(4): 303-308.   doi: 10.11728/cjss2006.04.303
Abstract(2843) [PDF 2019KB](207)
Abstract:
Lunar detection is the beginning of the deep space detection. The energy for the satellite running around the moon is provided by the power system of solar arrays. The lunar orbital environment has the direct effects on the operations of the solar arrays. The characteristics of the surface of the moon and of the lunar orbit have been analyzed. The research object is a rigid solar array in polar lunar orbit. The method to determine the external heat fluxes received by solar array has been shown detailedly on the basis of fully considering the packing factor and the solar cell conversion efficiency. The process of heat transfer in solar array is treated as 3-D anisotropic transient heat conduction problem without internal heat source. Grid division has been made in the solar array and the fully implicit discrete equations have been acquired. The numerical simulation of solar array in polar lunar orbit has been made and the periodic distributions of the external heat fluxes and the temperature of solar array have been obtained. Comparison between the numerical results in earth orbit and that in lunar orbit shows the characteristics of the periodic distribution for thermal parameters of the solar array in lunar orbit, which will provide powerful references for the design of the solar array and the whole lunar satellite.
Electromagnetic Levitation Force and Loop Structure
Ye Jingwei, Ding Wenyao, Sun Zhibin, Huang Huang, Zhao Qing, Zhai Guangjie
2011, 31(1): 80-86.   doi: 10.11728/cjss2011.01.080
Abstract(2606) [PDF 639KB](47)
Abstract:
Electromagnetic Levitation (EML) is a kind of technology for containerless processing of material. It has a lot of advantages, such as no contamination, processing materials with higher melting point, stronger erodibility and easy concreting nucleus. The important levitation is to produce big levitating force against gravity on the ground, and to compensate the remaining gravity in space. In this paper, the distribution of levitating force produced by loops is calculated. A stable potential well is also studied and produced to capture the sample. The calculation is mainly focused on the relation between the distribution of levitating force and the structure of loops, such as the number of turns, the angle of wimble, the radius of loop, the space and screw-pitch between loops. A series of curves representing the properties of different structures and the theoretical support for actual loop designs have finely been tend.
Statistical Analysis of Multi-spacecraft Observations on CIR Evolution
WANG Jingjing, LUO Bingxian, LIU Siqing, GONG Jiancun
2012, 32(4): 477-487.   doi: 10.11728/cjss2012.04.477
Abstract(2648) [PDF 772KB](82)
Abstract:
STEREO-BEHIND (STB) and STEREO-AHEAD (STA) drifted behind and ahead of ACE around the Sun, with longitudinal separation increasing day by day. CIR driven by high speed solar wind from coronal holes swept STB, ACE, and STA sequentially. Currently, solar wind observations on ACE are the direct basis for Earth space environment forecasting. Based on interplanetary magnetic field and solar wind observations on STB and ACE, assuming high speed stream transmitted uniformly and radially from coronal holes, characteristics of CIR travel time from STB to ACE with their longitudinal separation increased from 0° to 70° was discussed. Statistical variation characteristics of high speed stream parameters were analyzed. The following was found out. Firstly, CIR arrival time on ACE could be predicted by CIR observations on STB. The average and maximum errors of travel time was 0.217d and 0.952d, respectively. 61% of all events reached ACE earlier than theoretical travel time. The maximum errors of travel time increased with longitudinal separation. The errors of travel time was related to observation differences in CIR speed on STB and ACE. The average and maximum errors of travel time were reduced to 0.194d and 0.489d respectively after being corrected by speed variances. Secondly, Linear correlation coefficient of maximum CIR speed on STB and ACE was 0.84. Characteristic parameters of the same CIR on STB and ACE such as speed and proton temperature showed the least difference, while proton density and total pressure showed relatively large difference. The average and maximum range of difference on CIR characteristic parameters observed by STB and ACE, such as maximum speed, maximum proton temperature, maximum total pressure, maximum magnetic field and maximum magnetic southward components, increased with longitudinal separation, while they decreased on maximum proton density. Thirdly, CIR events with larger maximum range and average of observation difference between STB and ACE concentrated in longitude 10°, 25° and 47°, corresponding to CR2059-2060, CR2065-2066, CR2077-2078, which had larger errors on travel time. These results showed that, there was a strong similarity between CIR observations on STB and ACE. Therefore, CIR observations on STB could be used as reference of CIR characteristics on ACE, and provided basis for forecasting of Earth space environment disturbance.
A New Design for Digital Ionosonde
WANG Shun, CHEN Ziwei, ZHANG Feng, GONG Zhaoqian, FANG Guangyou
2014, 34(6): 849-857.   doi: 10.11728/cjss2014.06.849
Abstract(1272) [PDF 3661KB](60)
Abstract:
In this paper a new design for digital ionosonde is presented based on the concept of directly sampling in the RF domain, and the real time digital down-conversion processing is implemented in FPGA device, which improves the signals identity of I and Q, and enhances the dynamic range of the receiver. In addition, since the digital waveform generation in transmitting path, the digital down-conversion processing in receiving path, data pre-processing, and timing control functions of the whole system are integrated in one FPGA chip, which improved the flexibility of the ionosonde. To verify the design, a high quality digital ionosonde called CAS-DIS (Chinese Academy of Sciences, Digital Ionosonde) has been developed. This paper describes the details of CAS-DIS, its main features and testing results in the ionosphere detection, including in Wuhan ionospheric sounding and calibration station and Wuhan-Beijing oblique ionospheric sounding system, and the observations show that performance of the iononsonde using the proposed design is superior, and the ionosonde can operate in both vertical and oblique sounding mode, to meet a variety of applications in ionospheric detection.
New Hybrid Method for High Resolution TEC Measurement With the Tri-band Beacon
Zhao Haisheng, Xu Zhengwen, Wu Jian, Wang Zhange, Liu Kun, Li Na, Chen Jinsong
2011, 31(2): 201-207.   doi: 10.11728/cjss2011.02.201
Abstract(2359) [PDF 684KB](60)
Abstract:
The ionospheric Total Electron Content (TEC) is one of the key parameters of ionospheric sounding results. As the main input parameter, the measurement precision of TEC will directly affect the Computer ionospheric Tomography (CT) imaging result. In the past, the dual-band technique was mainly used for TEC measurement. However, due to the solution of the phase integral constant and error of the system hardware delay, the TEC results cannot satisfy the high accuracy requirement of reconstruction imaging by using the ionospheric CT. The newly developed tri-band technique throws new light on the space-based ionospheric sounding techniques. A new method is proposed for inversing TEC on the basis of combining the propagation delay and phase with the tri-band beacon. By using the fusion of advantages of both detecting random electron density fluctuations and computing phase integral constants with the tri-band beacon, it further improves the measuring resolution of the ionospheric TEC. Simulation results show that the CT resolution is improved by using the three-frequency measurement based on this method.
Solar Extreme Ultraviolet Multichannel Imager
Peng Jilong, Zhu Guang Wu, Wei Fei, Li Baoquan
2009, 29(4): 417-421.   doi: 10.11728/cjss2009.04.417
Abstract(2805) [PDF 549KB](30)
Abstract:
Solar extreme ultraviolet imaging plays an important role in space weather research and forecasting. Many nations have developed such kind of instruments for satellites and obtained valuable data. China has paid more attention to such research in recent years. This solar extreme ultraviolet multichannel imager that this paper presented can photograph corona and chromo sphere at four different radiation lines simultaneously. Comparison and inter-calibration with other similar instruments and more experiments can be done in the future. It takes a few resource of satellites while contributes much observation. Its application in orbit will raise up the level of space weather research and forecasting greatly.
MICRO-DISTRIBUTION PATTERNS OF TRACE ELEMENTS IN NANDAN IRON METEORITE
Li Xue-jun, Chai Zhi-fang, Liu Yong-zhong, Chao Zhi-yu, Xiao Ya-nan, Mao Xue-ying
1992, 12(3): 214-221.   doi: 10.11728/cjss1992.03.214
Abstract(2537) [PDF 702KB](21)
Abstract:
In this paper the micro-distribution patterns of trace elements in the Nandan iron meteorite are studied by a synchrotron radiation X-ray fluorescence micro-scanning method (SRXRFMS).On the basis of our experimental results the classification,origin,evolution and other aspects are discussed.It seems reasonable that the Nandan iron meteorite should be classified to the group IAB.Further,it might be formed from the source matter with the chondritic composition,which experienced the impact and partial melting.
Study and Comparison of Several Passive Positioning Algorithms About
YANG Long, XU Dongmei, ZHANG Shouxin, DONG Xurong
2006, 26(3): 203-208.   doi: 10.11728/cjss2006.03.203
Abstract(2646) [PDF 1804KB](51)
Abstract:
There are only 2 or 3 satellites in the "Beidou" satellite navigation system, so it alone can not meet the demand of passive positioning algorithm. Three kinds of passive positioning algorithms about "Beidou" satellite navigation system are presented and compared: 2 satellites algorithm, 3 satellites 3 unknowns algorithm and 3 satellites 4 unknowns algorithm. The measurable parameters have been increased by adding height measurement and the unknowns have been decreased by modeling the receiver clock error with a 2 order polynomial. The availability of backup satellite of the "Beidou" navigation system is also studied. In addition, a technique named "quasi-differrential" correction scheme has been proposed. The positioning accuracy is improved by this technique. The experiment results show that all the three algorithms can achieve the accuracy of 100 m which can meet the common user's positioning demand.
MORLET TRANSFORM OF SUNSPOT NUMBER AND Ap INDEX
MIAO Juan, TIAN Jianhua, LIN Zhenshan
2004, 24(1): 28-34.  
Abstract(2265) [PDF 627KB](55)
Abstract:
In this paper, Morlet wavelet transformation is applied to analyze the character of sunspot number and Ap index from 1932 to 2000 including solar cycle 17 to the rising phase of solar cycle 23. By the several examples selected during solar maximum and minimum respectively, three conclusion are drawn: (1) Sunspot number and Ap index both have obvious 11-year period and 32-year period, and Ap index also has 6-month period that exist in all phase, 27-day period and 13.9-day period. (2) Compared with the 11-year period of sunspot number, the maximum value of Ap index appears one or two years latter than that of sunspot number. (3) The 27-day period of Ap index is different during solar maximum and solar minimum. During solar minimum, Ap index has stable 27-day period. But during solar maximum, the character of 27-day period disappears or changes. And wavelet transformation could show detailed time when 27-day period vanishes and recurs.
Recent Progresses of Magnetospheric Physics in China: 2010-2011
CAO Jinbin, LIU Zhenxing, PU Zuyin
2012, 32(5): 647-664.   doi: 10.11728/cjss2012.05.647
Abstract(2547) [PDF 204KB](40)
Abstract:
In the past two years, many progresses are made in magnetospheric physics by using either the data of Double Star Program, Cluster and THEMIS missions, or by computer simulations. This paper briefly reviews these works based on papers selected from the 80 publications from April 2010 to April 2011. The subjects covered various sub-branches of magnetospheric physics, including geomagnetic storm, magnetospheric substorm, etc.
Numerical analysis of meteor parameters and height distribution of Meteor
Zhang Yabin, Xu Bin, Xue Kun, Zhao Lei, Chen Jinsong
2011, 31(4): 474-481.   doi: 10.11728/cjss2011.04.474
Abstract(2542) [PDF 728KB](31)
Abstract:
Based on the meteor radar, one can study the radiant distribution and the time variant of meteors, forecast the passage time of meteor showers, and also investigate space, and so on. Based on standard theory, the effects of main factors, such as ambipolar diffusion, the initial trail radius, the finite meteor velocity and the Pulse Repetition Frequency (PRF), on the radar echoes power at different radar frequencies and meteor velocities have been numerical analysis and calculated. The observation data of meteor decay time and the ambipolar diffusion coefficient are consistent with the theories. By analyzing the 571632 meteors observed by Kunming meteor radar, the height distribution of meteors model has been constructed, the result predicted by this model agrees with observation data at different months.
TEC Compensated Inversion Method of Ionospheric Occultation
Liu Zhaolin, Sun Xuejin, Fu Yang
2009, 29(3): 281-286.   doi: 10.11728/cjss2009.03.281
Abstract(2732) [PDF 686KB](18)
Abstract:
A calibrated TEC of Abel inversion method is usually applied in the inversion of ionospheric occultation data, which could cause error for the spherical asymmetry of the real ionosphere. This paper studies a method, TEC compensated inversion method. Combined with background field, this method removes the effect of TEC from the horizontal change of the electron density to improve the applicability of spherical symmetry and inversion accuracy. Then the method is applied in the inversion of simulated data. The result of simulated data inversion validates that TEC compensated inversion method decreases the inversion errors greatly, compared with Abel inversion method. Through the study on background fields obtained by different ways with TEC compensated method, the more close between background and real field, the better inversion result is obtained.
DYNAMIC PROPERTY ANALYSIS FOR SPACECRAFT WITH BEAM-LIKE DEPLOYING APPENDAGES
Zhu Gui-dong, Wang Beng-li, Shao Cheng-xun
1996, 16(4): 326-330.   doi: 10.11728/cjss1996.04.326
Abstract(1856) [PDF 455KB](43)
Abstract:
This paper studies the attitude dynamics and vibration of appendages of spacecraft with deploying appendages. A spacecraft model of a center rigid body with some deployable beams are considered. The governing equations are derived based on characteristic function of bending beam, and the effects of deploying rate and disturbance on system behavior are investigated to find the criteria of the selection of deploying rate. The numerical simulation results are also presented.
Characterization of the Q-factor of resonator for dielectric measurements
Ni Erhu, Luo Ping, Li Dihui
2009, 29(1): 73-77.   doi: 10.11728/cjss2009.01.073
Abstract(3194) [PDF 473KB](54)
Abstract:
The transmission-type measurement of the Q-factor of a reentrant cavity is used to determine unloaded Qu from the measured loaded Ql by the 3 dB three frequencies method together with insertion loss at the maximum output. Also, the one-port reflection technique is used to determine unloaded Qu from the resonant frequency and the bandwidth measured at the xdB point, as well as the magnitudes of the input reflection coefficient measured at both resonant frequency and xdB return loss for the same reentrant cavity. The arithmetic mean Qu was evaluated to be 2519±34 tested under the 40 various couplings at frequency 500 MHz by using transmission and reflection techniques. Finally, these techniques are applied to the realization and tuning of that the input and output couplings are identical to each other for a transmission-mode resonator. Meanwhile, the selection of Q-factor values in measurements of complex permittivity of dielectric materials is discussed.
Component Synthesis Active Vibration Suppression Method of Flexible Spacecraft Based on PWM
Zhang Jiangying, Liu Tun, Zheng Liwei
2010, 30(1): 66-72.   doi: 10.11728/cjss2010.01.066
Abstract(2312) [PDF 574KB](56)
Abstract:
The Component Synthesis active Vibration Suppression method (CSVS) can be applied to suppress the vibrations of flexible systems. In this method, several same or similar time-varying component forces are arranged according to certain rules along the time axis. The resulted synthesized force can be adopted as system input, and it can suppress the arbitrary unwanted vibration harmonics while achieving the desired rigid body motion. For a kind of spacecrafts with constant amplitude reaction jet actuators, the time optimal maneuver control commands corresponded with the roles of CSVS method were converted into form of constant amplitude torque using Pulse Width Modulation (PWM). The time optimal large maneuver control strategies are designed as well. Simulation results verified the availability of this method.
Design of the static calibration test system for Lorentz actuators in space application
Li Peng, Ren Weijia, Li Zongfeng
2013, 33(1): 92-100.   doi: 10.11728/cjss2013.01.092
Abstract(2189) [PDF 887KB](57)
Abstract:
The static calibration test system for Lorentz Actuators of active payload-level vibration isolation system for experiments in space is systematically studied by simulations and tests. In order to meet the demand for real-time changes controller outputs in high quality microgravity vibration isolation system, actuator design parameters should be inspected and the relationship between output force and the input current should be deduced. A test system was designed, and its hardware structure, software model as well as the test program diagram, were introduced. The system hardware contains force sensors, force value shows, three axis displacement control apparatus, motor drive module and data receiving and distribution module. The LabVIEW programming technology was utilized in the system software to realize signal sampling, data displaying and storage. Finally, Matlab was used to process data. The test results provide technical basis for further optimal design of the actuators. By fitting error graphics, the correctness and rationality of the system design were verified, which provides a reliable guarantee for the normal operation of the active vibration isolation system.
Progress of 2014—2016 China's Earth Observation and Earth Science
GUO Huadong, XIAO Han, MA Jianwen
2016, 36(5): 771-780.   doi: 10.11728/cjss2016.05.771
Abstract(802) [PDF 1376KB](47)
Abstract:
The support given by Earth observation data and Earth system science play an increasingly important role in global change, regional sustainable development, extreme events, and the development of social and economic needs. This field is also moving towards systematization, platforms, and standardized development. In December 2015, nearly 200 parties of the United Nations Framework Convention on Climate Change agreed in Paris to make arrangements for global action in response to climate change by 2020. China jointly issued a climate change adaptation strategy for cities in 2016 and then elevated national action to respond to climate change. China's Earth Observation and Earth Science development is facing new challenges as it supports the national civil space infrastructure and high-resolution Earth observation system.
Invariant Modulation of IMF Clock Angle on the Solar Wind Energy Input into the Magnetosphere
Han Jinpeng, Li Hui, Tang Binbin, Wang Chi
2015, 35(6): 673-678.   doi: 10.11728/cjss2015.06.673
Abstract(1081) [PDF 724KB](65)
Abstract:
By use of the global PPMLR Magnetohydrodynamics (MHD) model, a serial of quasisteady- state numerical simulations were conducted to examine the modulation property of the interplanetary magnetic field clock angle θ on the solar wind energy input into the magnetosphere. All the simulations can be divided into seven groups according to different criteria of solar wind conditions. For each group, 37 numerical examples are analyzed, with the clock angle varying from 0° to 360° with an interval of 10°, keeping the other solar wind parameters (such as the solar wind number density, velocity, and the magnetic field magnitude) unchanged. As expected, the solar wind energy input into the magnetosphere is modulated by the IMF clock angle. The axisymmetrical bell-shaped curve peaks at the clock angle of 180°. However, the modulation effect remains invariant with varying other solar wind conditions. The function form of such an invariant modulation is found to be sin(θ/2)2.70 + 0.25.
Disturbance of the Upper Atmospheric Density During August 24, 2005 Severe Geomagnetic Storm Event
SUN Lilin, ZENG Hong, YE Haihua, YANG Xiaochao, CHANG Zheng, LI Hong, LI Jijun, LIN Xianwen, ZHANG Long
2008, 28(2): 137-141.   doi: 10.11728/cjss2008.02.137
Abstract(2643) [PDF 2037KB](45)
Abstract:
During 2005 the Solar activity level was very low, since this year February the monthly mean F10.7<100. At August 24 a severe geomagnetic storm event (Kp=9) occurred with a sudden commencement. This is a good case for the analysis of the influence of a severe geomagnetic storm on the density of the upper atmosphere. In this paper the measured data of the satellite borne atmospheric density detector. From analyzing these measurements the following results were concluded. During this severe geomagnetic storm event, the atmospheric density showed strong disturbances. There are two responses, one is a global thermosphere density enhancement follow the variations of the geomagnetic disturbance, the responding processes were 6 hours late after the geomagnetic disturbance started, the biggest change ratio is 2.5. Another is abnormal density disturbance at high latitude areas during the peak period of geomagnetic disturbances, the biggest change ratio is 5.5, and with an asymmetry feature for the sauthern and northern hemispheres. In situ measurements also show that traveling of the atmospheric density disturbance from high latitude to lower latitude region very fast, the velocity is about 15 º(latitude)/h at middle latitude region.
A Review on the Ionospheric Research: Chinese Works During 2006-2008
WAN Weixing
2008, 28(5): 468-491.   doi: 10.11728/cjss2008.05.468
Abstract(2345) [PDF 313KB](44)
Abstract:
This paper reviews various progresses on the ionospheric studies by the scientists in China during the last two years.The main contents concern the 4 aspects of the ionospheric research:(1)ionospheric weather and coupling with magnetosphere(polar and auroral ionosphere,ionospheric response to substorms,ionospheric storms);(2)mid-and low-latitude ionospheric climatology(ionospheric properties,yearly variations and solar activity dependence,long term variation);(3)ionospheric coupling with neutral atmosphere(gravity waves,tides,planetary waves,background upper atmosphere,and ionospheric response);and(4)ionospheric diagnostics(observation,modeling,and prediction).
Adaptive Mode Method in Inverse Dynamics of a Rotating Flexible Manipulator With High-frequency Excitation
Li Qing, Wang Tianshu
2008, 28(4): 345-349.   doi: 10.11728/cjss2008.04.345
Abstract(2065) [PDF 1347KB](52)
Abstract:
In dynamics and control of space flexible manipulators, high computing speed is always required for solving inverse dynamics. However, when the flexible multibody system suffers from high-frequency excitation such as contact impact, high order modes have to be counted to ensure adequate precisions while the computing speed is lowered down. To increase the computational efficiency of such problems, an adaptive mode method was proposed with an application in inverse dynamic modeling of a rotating flexible manipulator. In the process, the axial displacement caused by transverse deformation of the beam-like model was considered, and high order mode coordinates were reduced gradually as they damped off in the proportion of total energy due to structural damping. The control laws of driving torque for the rotary manipulator articulation were computed to account for its validity. Additionally, the influence of gravity was investigated.
Dust Acoustic Wave in Dusty Plasmas With Streaming Ions Under Ultraviolet Irradiation
REN Liwen, WANG Chi
2012, 32(2): 191-196.   doi: 10.11728/cjss2012.02.191
Abstract(2273) [PDF 164KB](23)
Abstract:
The reductive perturbation method is applied to investigate the dust acoustic soliton in dusty plasmas with streaming ions under ultraviolet irradiation theoretically and numerically. The self-consistent dust charge variation is taken into account. It is shown that the ultraviolet irradiation can significantly lower the magnitude of the dust negative charge, and ion streaming velocity firstly raise the magnitude of the dust negative charge and then lower it. With the growth of (Ultraviolet) UV photo flux or ion streaming velocity, the phase velocity and width of the solitary waves decrease, whereas its amplitude increases.
THE MOVING RADIATION OF COSMIC MAGNETIC MONOPOLE IN ELLIPTIC ORBIT IN PLASMA
Ma Shan-jun, Yang Qian-li, Luo Kai-ji
1996, 16(2): 97-102.   doi: 10.11728/cjss1996.02.097
Abstract(1577) [PDF 356KB](20)
Abstract:
In thes paper, the radiation of the cosmic magnetic monopoles which move in a elliptic orbit in cosmic space are studied. A formula of the radiant spectrum power is de rived. The formula could be used to detect and distinguish the existence of cosmic magne tic monopole.
Study on Actuators of Magnetic Suspension Platform Under Microgravity Environment in Space
CHEN Jinxin, WANG Yu
2008, 28(6): 584-591.   doi: 10.11728/cjss2008.06.584
Abstract(2524) [PDF 1520KB](38)
Abstract:
To fulfill the microgravity level of scientific experiment payloads in space lab, vibration isolation performance of platform with experiment payloads is required. And the actuator of platform under control needs to produce active force timely to restrain the vibration of platform. This paper firstly presents the elementary parameters of actuator. Various structural forms are designed, based on the theory of magnetic suspension. Finite element simulations about magnetic circuit and coil design of the actuator are given based on various forms. To provide basis for the detailed design of actuator, the strong points and shortcomings of each form are concluded through comparisons. The parameters for comparisons mainly involve the mass, the air gap, the maximum force, the current density, the supply power, and the bandwidth of the actuator. The result of comparisons shows that each form is available due to different working conditions and system demands.
ON-LINE MINIMUM VARIANCE TRACKING FILTER FOR THRUST ACCELERATION ESTIMATION
LI Hengnian, LI Jisheng, HUANG Yongxuan
2002, 22(4): 357-362.  
Abstract(2043) [PDF 476KB](77)
Abstract:
The uncertainty of thrust acceleration will cause enormous error to model and track the accelerated motion of maneuvered target during orbit transfer process, an on-line minimum variance tracking filter for thrust acceleration estimation is developed in this paper. The propellant mass-flow rate and exhaust velocity are selected as state variants, which are estimated by employing an integral state model and Expended Kalman Filter. The variation equations for measurement vector to state variants have been established to linearize the discrete-time measurement equations. The algorithm has applied successfully to maneuver process in commanding satellite into geo-stationary orbit. The results show the algorithm developed here can estimate thrust acceleration precisely and quickly during orbit transfer process.
Analysis of Line-of-sight Measurement Error for Satellite-borne Observation Platform
DING Wenzhe, ZHANG Zhanyue, YANG Hong, CHEN Feng
2017, 37(2): 238-248.   doi: 10.11728/cjss2017.02.238
Abstract(1170) [PDF 1398KB](56)
Abstract:
A line-of-sight measurement error modeling and evaluation method based on multi-parameters is studied to analyze the influence of the error sources of the satellite-borne observation platform on the line-of-sight measurement accuracy. Unlike conventional measurement for satellites and space camera, the target imaging model from target position to focal plane and the line-of-sight measurement model for satellite-borne observation platform are constructed on the basis of the satellite, turntable, and camera observation structure. The relationship between the measurement error and the error sources is derived theoretically and a method of error evaluation based on sensitivity analysis is presented. In three axial directions, the influence of the error sources of the satellite-borne observation platform on the line-of-sight measurement accuracy are analyzed. Monte Carlo simulation verified the validity of the theoretical model. The results demonstrate that the line-of-sight measurement accuracy is affected by satellite orbit error, satellite attitude error, load platform angular vibration error, inner frame and outer frame rotation error, image points position quantization error. The method can scientifically evaluate the influence of various error sources on measurement accuracy, and has important application value to the overall design of the satellite-borne observation platform.
Numerical analysis of thermally induced vibration for deployable truss antenna
Yang Yulong, Guan Fuling
2009, 29(4): 432-437.   doi: 10.11728/cjss2009.04.432
Abstract(2449) [PDF 695KB](62)
Abstract:
The thermal equation of a deployable truss parabolic antenna was derived by finite element method, the convergence criteria of real root and thermal steady state root about thermal equation were built according to the features of space deployable truss antenna. The thermal dynamic forces were simulated by model nodes temperature. Typical model node displacement and root mean square of antenna induced by thermal dynamic forces were discussed. The results show that thermally induced vibration occurs at the beginning of thermal dynamic forces great change and stops by damping and right structure type. The dynamic response is mainly structural basic frequency. At the same time, value of root mean square of antenna induced by thermal drastically changes at the beginning.
On Orbit Lifetime of HEO Objects
LIU Lin, TANG Jingshi
2007, 27(4): 327-335.   doi: 10.11728/cjss2007.04.327
Abstract(2684) [PDF 3132KB](54)
Abstract:
The lifetime of the low orbit earth satellite is mainly dominated by atmospheric drag. The satellite loses altitude in the dense atmosphere and eventually falls. However, the lifetime of space objects of HEO type, which goes in a large-eccentricity ellipse with very low perigee altitude and very high apogee altitude, is determined mainly by third-body (Sun and Moon) perturbation, as well as its initial state, which, closely related to RAAN Ω and Argument of Perigee ω, determines the long periodic evolution of the eccentricity. Here examples are taken for Geosynchronous Transfer Orbit debris and the orbit lifetime are estimated for double stars TC-land TC-2, proving that two GTO debris with the same initial elements but 3 hour's difference in entering expected orbits will have distinct destinies, the same conclusion is also valid for TC-1 and TC-2. All the mentioned distinction could be resulted in by third-body perturbation and a difference in initial elements (Ω and ω). This paper would end up with a detailed computation, which accords with previous analysis.
A NUMERICAL SOLUTION OF THE DYNAMO EQUATION FOR THE GLOBAL IONOSPHERE
Xu Wen-yao, Xia Qing, Li Wei-dong
1994, 14(3): 205-209.   doi: 10.11728/cjss1994.03.205
Abstract(2329) [PDF 320KB](86)
Abstract:
The two-dimensional hemispherical dynamo theory is based on the symmetry aboutthe equator, and has certain inherent theoretical shortcomings and limitations in application. In order to extend the dynamo theory to the globe, the assumption of thesymmetry about the equator is removed in present study, the boundary condition atthe north (or south) pole is also removed. In this way the conventional boundaryproblem becomes "boundary--free" one, which describes more reasonably the physicsof the dynamo process and would show some essential characteristics. For instance,this method can be used to study seasonal and UTvariations of the Sq currentsystem, as well as dynamo effects of the non-dipole magnetic field, all of which areasymmetric about the equator. The global current system obtained by using presentmethod for simple symmetric condition is same as that by using hemispheric symmetric dynamo theory. As for asymmetric condition, the current intensity, focus location, current direction and other characteristics show more complicated features, whichcan not be explained by hemispheric dynamo theory.
Calculating Method on Charged Particles Motion in the Near-Earth Region
HUANG Chaoyan, HAN Jianwe
2007, 27(5): 367-373.   doi: 10.11728/cjss2007.05.367
Abstract(1941) [PDF 3404KB](47)
Abstract:
In this paper, based on the theory of magnetospheric particle dynamics, the charged particles motion character and the calculating method appropriate to these different energy particles in the near-earth region (L 〈 10) are discussed in detail, in terms of the single particle approach and dipole filed model. And then, it is analyzed quantitatively how the electric and magnetic field in the magnetosphere determined these particles drift motion. It is shown that, for the electron and proton with energy lower than 10^5 eV and 10^2 eV, respectively, the Guiding-Center Approximation Appoach (GCAA) is recommended; for 10^5 - 10^8 eV electron and 10^2 - 10^8 eV proton, GCAA or trajectory approach with adaptive step can be adopted in some regions. As for GCAA, the electric drift can be ignored when particle energy is higher than 10^5 eV, and the magnetic drift does not need to be taken into account when particle energy is lower than 10^3 eV. So the guiding-center equations are simplified and the efficiency of numerical calculation is improved.
Research on active plasma release experiment in ionosphere
Wang Jindong, Li Lei, Tao Ran, Liu Cheng, Liu Yue, Cheng Bingjun, Xie Lianghai
2014, 34(6): 837-842.   doi: 10.11728/cjss2014.06.837
Abstract(1115) [PDF 4284KB](70)
Abstract:
Barium release is one kind of active experiments for space physics research, which can be used to study the near-earth space environment efficiently. In April 2013, the first barium release experiment of China was successfully implemented by Center for Space Science and Applied Research, Chinese Academy of Sciences, in Hainan Province. Nearly 1 kg barium was released by a sounding rocket at 190 km height in this experiment, which produced a spherical cloud including barium atoms and ions. The evolution process of barium cloud was recorded by ground-based optical observatory, obtaining the whole process of barium cloud brightness, particle density, composition and diffusion range variation with time. Through analysis of barium cloud drift, the neutral wind field characteristics of low-latitude regions of the ionosphere at the point of release are obtained. It is useful for further study of dynamics in low-latitude ionosphere region.
A Carrier Synchronization Algorithm for Autonomous Radio Receiver in Deep Space
Song Qingping, Liu Rongke
2015, 35(3): 343-349.   doi: 10.11728/cjss2015.03.343
Abstract(989) [PDF 586KB](48)
Abstract:
The carrier synchronization algorithm of the autonomous radio for deep space is studied. When the signal modulation is unknown, this paper improves the existing universal carrier synchronization loop for multiple modulations, expands the frequency tracking range of the loop, proposes a Tong detection-based M-ary Phase Shift Keying (M-PSK) signal locking detection algorithm to rapidly and effectively determine whether the current phase discrimination mode matches the modulation mode, so as to independently choose whether to switch the phase discrimination mode. Through theoretical analysis and comparison, it is described that the total detection probability of the algorithm proposed in this paper is significantly higher than the probability of single lock detection. Simulation results show that the algorithm has high detection probability and low computational complexity at a low signal to noise ratio.
The Analysis and Simulation of Co-Frequency Interference in Non-Geostationary Orbit Satellite Network
LI Rui, ZHAO Hongli, ZENG Dexian
2005, 25(4): 280-285.  
Abstract(2130) [PDF 1768KB](68)
Abstract:
With the increasing of non-geostationary orbit satellite systems, the frequency bands allocated to the non-geostationary orbit satellite are getting less, which would bring the co-frequency interference for data transmission in down-link of non-geostationary orbit satellite network. The ratio C/I between the useful received carrier power and the overall contribution at the receiver input of interference power can show the interference situation. This ratio depends on the system characteristics, such as type of orbits, number of satellites in the constellation, antenna radiation patterns, etc. This paper analyses the problem of co-frequency interference, according to the time-varied character of non-geostationary orbit satellite the paper introduces a method to calculate co-frequency interference. The co-frequency interference is simulated and the results is analyzed, then, visualization of the interfering course is realized which can dynamically display the changes of interference-link during the different simulation periods.
Observations of the Ionosphere Effects of the Solar Eclipse on July 22, 2009
HU Xiong, WU Xiaocheng, XU Qingcheng, MA Guanglin, TU Cui, YAN Zhaoai, CHEN Xuxing, XIAO Cunying, ZHAO Mingliang, GONG Jiancun
2011, 31(5): 595-601.   doi: 10.11728/cjss2011.05.595
Abstract(2945) [PDF 579KB](51)
Abstract:
For the first time, Langfang Medium-Frequency (MF) radar was used to simultaneously observe the ionospheric effects due to the solar total eclipse on July 22, 2009, with three GPS/TEC receivers operated at Wuhan, Jiaxing and Langfang respectively. Results show that during the solar eclipse, the D layer electron densities at 78km level observed by the MF radar decreased by 67% and the altitude level of equivalent electron densities of 200cm?3 uprising about 10 km. The ionospheric Total Electron Content (TEC) observed by the GPS/TEC receivers in the above three sites respectively decreased about 1TECU. Their minimum reductions of the D layer electron densities and TEC are synchronous with the solar eclipse maximum phase. After the solar eclipse, a Traveling Ionospheric Disturbance (TID) was revealed with a period of larger than 2 h in the GPS/TEC data.
Development of Azolla Wet Culture Device for Supplying O2
Chen Min, Liu Rundong, Yang Youquan, Deng Sufang, Zhan Jie, Huang Yibin
2010, 30(2): 185-192.   doi: 10.11728/cjss2010.02.185
Abstract(2783) [PDF 762KB](34)
Abstract:
Azolla is an important biological component of the Controlled Ecological Life Support System (CELSS), because it can supply O2 and absorb CO2 from the environment, and can be used as a fresh vegetable by the astronauts. Developing Azolla wet culture device for supplying O2 to set up non-living components on the ground aims to meet the needs of simulation research. The structure characteristics and working principles of the device and its key component are introduced in this paper. By structure and function designation of medium in Azolla wet culture plate, infiltration pipeline of capillary action is set inner store and conserve water stroma layer to keep the overall surface of medium wet but no obvious water always, which creates beneficial conditions for rooting and fixing, nutrient absorption, growth and reproduction. The main technical parameters of water pipe line and intermittent circulatory periods of closed Azolla culture medium transmission and distribution system are determined in the hydraulic pressure test. The results of machine output test show that when the interlayer spacing is 125\,mm, Azolla wet culture area of overall unit is 6.3 m2, using ultra-high brightness white LED as artificial light source, Azolla surface light intensity is 6000~6500 lx, the energy consumption is 152Wm2, Azolla yield, the amount of O2-release and CO2-absorption of overall unit will be increased by a wide margin, and every performance index is in accordance with the design requirement.
Effect of the interplanetary electric field on the magnetopause from global MHD simulations
Huang Zhaohui, Ding Kai, Wang Chi
2012, 32(3): 305-311.   doi: 10.11728/cjss2012.03.305
Abstract(1922) [PDF 182KB](37)
Abstract:
The north-south component Bz of the Interplanetary Magnetic Field (IMF) and solar wind dynamic pressure Pd are generally treated as the two main factors in the solar wind that determine the geometry of the magnetosphere. By using the 3D global MHD simulations, we investigate the effect of the Interplanetary Electric Field (IEF) on the size and shape of magnetopause quantitatively. Our numerical experiments confirm that the geometry of the magnetopause are mainly determined by PdBz, as expected. However, the dawn-dusk IEFs have great impact on the magnetopause erosion because of the magnetic reconnection, thus affecting the size and shape of the magnetopause. Higher solar wind speed with the same Bz will lead to bigger dawn-dusk IEFs, which means the higher reconnection rate, and then results in more magnetic flux removal from the dayside. Consequently, the dayside magnetopause moves inward and flank magnetopause moves outward.
Star Position Correction of Dynamic Star Simulator Based on Distortion Effect
Zou Yangyang, Zhang Guoyu, Sun Gaofei, Zhang Jian, Chen Qimeng
2014, 34(4): 468-473.   doi: 10.11728/cjss2014.04.468
Abstract(1216) [PDF 1931KB](49)
Abstract:
This paper presents the working principle of dynamic star simulator and the calculation of star position error. According to the working principle, a star position correction method was derived based on distortion of star simulator optical system. The correction model is established and the correction formula is deduced through correction principle. By analyzing the optical system, the fitting curve between field of optical system and correction value of star position can be attained with Matlab. After selecting the revise range by means of ascertaining the critical value of field, and revising the star position on display device using the correction formula, the original requirements were met. The proposed correction can lower the requirements of optical system designing and provide an effective method for star position correction of dynamic star simulator.
THE NONLINEAR PROPAGATION OF GRAVITYWAVE PACKETS IN THE SHEARED AMBIENT
ZHANG Shaodong, YI Fan, WANG Jingfang
1999, 19(2): 122-127.   doi: 10.11728/cjss1999.02.122
Abstract(2193) [PDF 410KB](41)
Abstract:
By using a two-dimentional Full-Implicit-Continucus-Eulerian (FICE) scheme,a numerical simulation of nonlinear propagation of a Gaussian gravity-wave-packetin sheared ambient is carried out. The numerical analysis shows that for an initiallygiven upgoing gravity-wave-packet, in absence of a critical layer, although there exists nonlinear interaction during the propagation, the whole wave packet and thewave-associated energy keep moving upward, while the wave front moving downward. Wave-associated perturbation velocity increases with the increasing height,and the vertical wavelength decreases with the increasing height. The propagationpath of wave energy flux coincides well with the ray path predicted by the lineargravity wave theory, but the magnitude of wave energy propagation velocity is evidently smaller than the group velocity derived from the linear gravity wave theory.This indicates that the nonlinear propagation characteristics of gravity wave packetsin sheared ambient are essentially linear.
Application of Atmospheric Disturbances Monitor on Lithosphere-atmosphere-ionosphere Coupling
Hu Xiaoyan, Zhang Donghe, Hao Yongqiang, Xiao Zuo
2014, 34(3): 296-303.   doi: 10.11728/cjss2014.03.296
Abstract(1184) [PDF 4296KB](33)
Abstract:
Gravity waves and infrasonic waves play important roles in the coupling of lithosphere, atmosphere and ionosphere. This paper analyzes the observational data of Atmospheric Disturbances Monitors, which are developed by Institute of Space Physics and Applied Technology, Peking University. The morphological features and spectral structures of the observed gravity waves and infrasonic waves are presented, then their temporal distribution characteristics are summarized. We also have done some case studies about thunderstorms and earthquakes. The disturbances of atmosphere recorded by Atmospheric Disturbances Monitor and the similar observations of ionospheric disturbances during these events are presented. These results reveal that Atmospheric Disturbances Monitor could record the week disturbance of the surface atmosphere, proving which a useful tool for study of Lithosphere-Atmosphere-Ionosphere coupling.
Diurnal Variability Prediction Model of Meteor Burst Communication Channel
Zhang Yabin, Hu Dazhang, Lin Leke, Guo Yuquan
2010, 30(1): 60-65.   doi: 10.11728/cjss2010.01.060
Abstract(2290) [PDF 613KB](41)
Abstract:
Meteor Burst Communication (MBC) is different from traditional communications. It is a low data rate communication with characteristics of burst, discontinuity and unfixed timing. It is necessary to construct prediction model of MBC channel due to its complexities. The Sporadic Meteor Radiant Distribution (SMRD), the usable Meteor Rate (MR) and Duty Cycle (DC) are important factors impacting channel of the MBC links. SMRD varies with seasons and time, therefore it is very crucial to accurately predict the SMRD to change the direction of antennae and improve the data rate. Furthermore, the correct model of MBC channel can be constructed if MR and DC are accurately predicted. By investigating the development of the modeling of meteor radiant distributions, the geometry relationship of the heliocentric and the geocentric space of sporadic meteor is constructed. The theoretic prediction models of Meteor Burst Communication (MBC) channel parameters are derived. These models are applied in MBC links. The results predicted by these models have good agreement with observation data. The prediction models of these channel parameters given herein can be helpful to construct meteor communication system.
Investigation on Es Properties in Representative Region of China
KONG Qingyan, CHEN Yue, LIU Wen, FAN Junmei
2012, 32(4): 506-512.   doi: 10.11728/cjss2012.04.506
Abstract(2478) [PDF 672KB](165)
Abstract:
In this paper, the characteristics of sporadic E layer (Es) is discussed, using data measured from China vertical stations of Haikou (20.02°N, 110.20°E), Lhasa (29.39°N, 91.08°E) and Changchun (43.54°N, 125.19°E) for one solar period between January 1976 and December 1986. The diurnal, seasonal and solar activity variations of Es occurrence probability with critical frequencies greater than several special values (f0Es > 3, 5, 7, 9MHz) are discussed. The obscure property is also analyzed. The results show that: the most significant occurrence probability presented during daytime in summer months, and does not depend significantly on solar activity. The distribution regularity is of great difference with different stations, and in most cases, Lhasa has the biggest occurrence probability. As to the blanketing property, three stations also have different distribution characteristics, except for that the obscure probability in summer is bigger than other seasons and is bigger in solar minimum than solar maximum too.
Size Estimation of Space Object Based on Narrowband Radar
Yu Chunrui, Liang Diannong, Dong Zhen, Yu Anxi
2010, 30(3): 250-254.   doi: 10.11728/cjss2010.03.250
Abstract(2663) [PDF 473KB](61)
Abstract:
Earth orbiting spacecrafts have become an integral part of our everyday lives. A real and growing concern for the safety and reliability of these satellites is the threat from collision with other orbiting objects including space debris. Size estimation of space object is an important task in evaluating its danger of a possible collision with operational spacecraft. RCS (Radar Cross Section) includes much information of space object, and extracting the feature of the object size from the RCS time series of narrowband radar is very helpful to radar target identification. Unfortunately, it is very difficult to get the information of target shape and size from its RCS. In this paper, based on the research of the characteristic of the ellipsoid's RCS, a shape estimation method of space object is proposed, and the problem of size estimation is studied further with a new method of size estimation proposed. The result using real radar data shows that this method is feasible to estimate the shape and two-dimensional sizes of the space object.
Influence of a Streamer Background With Nested Close Magnetic Structures on the Properties of CME Initiated From Its Bottom
YE Zhanyin, WEI Fengsi, WANG Chi, FENG Xueshang, ZHONG Dingkun
2006, 26(6): 409-414.   doi: 10.11728/cjss2006.06.409
Abstract(2282) [PDF 2854KB](38)
Abstract:
The influence of a streamer background with nested close magnetic structures on the properties of CME initiated from its bottom is investigated in a solar meridian plane. In the streamer there contain three small-scale close magnetic field structures with the magnetic direction of the middle one opposite to that of the solar global dipole. A CME triggering model made up of cocircular magnetic field lines is taken to emerge from the solar equator at the inner boundary, where the middle small-scale close magnetic field structure locates, of the computational domain. The magnetic field direction in the front half of the CME triggering model with a radius a = OARs (Rs is solar radius) is opposite to that of the magnetic field line at its emerging position and same to that of the streamer global dipole. It is found from numerical simulation that: the CME triggering model, with a ratio of plasma pressure at its center and that at its edge m ≥ 2, can trigger a CME and can not when m 〈 2. The error for this numerical conclusion is less than 1%.
Structure Analysis of the Hard X-Rays Modulation Telescope (HXMT) Satellite
MA Yi, WANG Sheng, REN Weijia
2007, 27(2): 146-150.   doi: 10.11728/cjss2007.02.146
Abstract(2567) [PDF 1108KB](71)
Abstract:
Based on the HXMT satellite's structure, the finite element model of this satellite is developed, and static analysis, normal modes and frequency responses are investigated. The maximal stress result of every part of the HXMT satellite and the frequencies in 100 Hz are obtained. The results provide data for optimizing design of the HXMT satellite structure and avoiding synchronous vibration occurring. Considering theory analysis and past design experiences, some reasonable suggestions of optimizing the satellite structure are presented.
Radiosonde Observation of Planetary Waves in the Lower Atmosphere Over the Center China
LU Xian, ZHANG Shaodong
2005, 25(6): 529-535.   doi: 10.11728/cjss2005.06.529
Abstract(2568) [PDF 2473KB](83)
Abstract:
Wind data by the radiosonde observation from Wuhan, Yichang, and Enshi Meteorological Stations in the period of 2001-2003 are used to analyze the Planetary Waves (PWs) in the lower atmosphere of the center China. L-S periodgrams show that quasi-16-day PWs and quasi-10-day PWs are dominating planetary wave components in the observed period over three sites. The largeamplitude oscillation of PWs can be observed primarily from 5 km to 15 km. The quasi-16-day PWs propagate westward with a zonal wave number of 2 (the horizontal wave length is 17 324.8 km), and the corresponding phase velocity is estimated to be -12.5 m·s^-1 (positive eastward). The vertical wavelength is estimated to be 25-30 km according to the phase variation with height below 10 km. The phases almost keep unchanged around the tropopause which indicates they may be stationary waves. Quasi-10-day PWs propagate eastward with a wave number of 4 (the horizontal wave length is 8627.3 km) and the corresponding phase velocity is estimated to be 10.0 m·s^-1, the vertical wave length is 22-40 km.
Application of Analog Prediction Method on Ionospheric TEC Short-term Forecast
WENG Libin, FANG Hanxian, XIE Yanqiong, YANG Shenggao
2011, 31(6): 747-753.   doi: 10.11728/cjss2011.06.747
Abstract(2561) [PDF 575KB](65)
Abstract:
Analog Deviation is introduced to evaluate the analog degree between two samples, and tests of Analog Prediction Method for 24 h ahead forecast of ionospheric TEC detected by Xiamen station in 2004 have been conducted in this paper. The results reveal that the relative error has good relationship with the geomagnetic activities, and it will be larger under geomagnetically disturbed conditions than undisturbed ones obviously, reaching 100% indeed; as a whole, the relative error is 18.022%, 44.896% and 11.676% under conditions of geomagnetic disturbances and undisturbed respectively. The cumulative proportions of relative error under 10%, 20%, 30%, 40% are 38.209%, 65.075%, 84.984% and 90.448% respectively. The Analog Prediction Method is based on the autocorrelation method, with the observed ionospheric TEC to predict, but only choosing the 24, 48, 72 h data which will have best analog with the predictions. The result of forecast will be much more better on condition of using ionospheric TEC in mid-latitude or under geomagnetic undisturbed conditions.
A NUMERICAL STUDY ON THE SPATIAL AND TEMPORAL EVOLUTION OF INTERACTIONS OF GRAVITY WAVES PACKETS
ZHU Dan, YI Fan
1998, 18(1): 52-61.   doi: 10.11728/cjss1998.01.052
Abstract(1910) [PDF 659KB](67)
Abstract:
A numerical model for studying the evolution of interactions among coherent gravity wave packets in a two-dimensional space is developed. With this model the complete evolution of interactions caused by the collision between two large-amplitude wave packets is revealed. Numerical results show that downgoing gravity waves can be excited by upgoing gravity waves through interactions. During the evolution process of these interactions, the energy budget of three wave packets and the intensity of interactions are localized. Since the spatial propagation is included, the interaction process is no longer Periodical and then a new characteristic time arises, which has completely different meaning compared with the previous one. This new characteristic time and the final developing level of interactions are determined not only by wave interaction coefficients and the initial amplitudes of wave packets, but also by wave packet spatial scales and the relative magnitude of wave group velocities.
Effect of an Alternating Electric Field on Dust Removal
SUN Zhibin, LIU Xuefeng, WANG Chao, YE Jingwei, JIANG Yu, a, ZHAO Qing, ZHAI Guangjie
2011, 31(6): 808-813.   doi: 10.11728/cjss2011.06.808
Abstract(2092) [PDF 504KB](74)
Abstract:
Dust removal by means of an electric curtain is analyzed theoretically and demonstrated experimentally. A critical “floating” voltage criterion is introduced, above which the effect of the Vander Waals force on dust movement can be overcome. The relationship between critical voltage and frequency of the alternating field is derived. The results of numerical simulation as well as experiments show that the dependence of critical voltage on frequency is different for low and high frequencies. For high frequencies critical voltage is in direct proportion with frequency, while in low frequencies there is a lower limit of critical voltage. The experiment result coincides with our simulation conclusion. This method to remove dust does not abrade the circuit boards and has promising applications in the future exploration of deep space.
Influence of Chip Size on Bubble Dynamic Behavior in Microgravity
QI Baojin, WEI Jinjia, WANG Xueli, ZHAO Jianfu
2017, 37(4): 455-467.   doi: 10.11728/cjss2017.04.455
Abstract(1327) [PDF 4794KB](115)
Abstract:
In order to study the influence of chip size on bubble dynamic behavior in microgravity, the factor of chip size on bubble dynamics under various heat fluxes has been studied by comparison experiments. Typical isolated bubble boiling maintains on both small and large size chips in low heat flux, and the growth and coalescence rates of bubbles are relatively slow. The volume of bubble on large size chip is about 3.4 times that of the bubble on small size chip. The bubble departure could only be observed on the large chip during the experiment. Fully developed nucleate boiling are sustained in the case of moderate heat flux, the coalescence and departure frequency of bubbles is much higher than that in low heat flux, especially on large size chip. Bubbles detach more frequently on large size chip than that on small size chip. Moreover, the wake effect caused by bubble rising reduces the departure diameter of subsequent bubbles, so the formation of dry portions is effectively suppressed. For the high heat flux, obvious film boiling presents on the small size chip and the deterioration of heat transfer is observed. However, stable nucleate boiling still maintains on large size chip in the high heat flux, only the bubbles coalesce and detach more frequently. Therefore, increasing the chip size can effectively promote the bubble departure and improve critical heat flux. Film boiling is also observed as the heat flux on larger size chip is increased beyond the critical heat flux, but the heating surface could not be completely covered by the bubble, just sliding slowly on the slip, which can reduce the rising rate of temperature on chip effectively.
THE MODULATIONAL INSTABILITY OF ALFVEN WAVES
Du Xiao-long, Lu Sheng-zhi
1994, 14(1): 15-22.   doi: 10.11728/cjss1994.01.015
Abstract(1786) [PDF 332KB](50)
Abstract:
Considering the actions of the porderomotive force from both density variations and changes of flow speed, using Karpman's method, the modulational instability of Alfven waves has been investigated. For the two branches of left and right hand circular polarization waves, the coalitions for the existence of wave packet solitons and of anti-wavepacket solitons, the correlations between density fluctuations and wave energy densities, and the nonlinear frequency drifts have been obtained respectively.For the left hand circular polarization Alfven waves with a finite amplitude, the conditions for the occurence of instabilities and it's growth rate have been obtained also.
Surface charging simulation of LEO spacecraft
Yang Fang, Shi Liqin, Liu Siqing, Gong Jiancun
2011, 31(4): 509-513.   doi: 10.11728/cjss2011.04.509
Abstract(2917) [PDF 531KB](63)
Abstract:
The subject of this paper is to investigate surface charging simulation of LEO spacecraft. SPIS was applied to simulate the surface charging of spacecraft in LEO plasma environment. A simple satellite model was made in SPIS with several material assigned as satellite surfaces. This was done with the assumption that solar irradiation is far less than the environment plasma and secondary electron was considered. Result of the numerical simulation has been laid out and compared with the charging theory and in situ observation. It is concluded that charging result can reflect the difference of distinct material, especially the difference between conducting material and non-conducting material. Equilibrium potential and charged time agree with the estimation based on plasma sheath theory and has a good relevance with observation. Simulation result can also provide wake flow structure of moving spacecraft which is hard to obtain analytic solution. Finally, character of LEO spacecraft surface charging simulation made by SPIS has been concluded and is considered as a reasonable result.
A PHYSICAL MODEL FOR IONOSPHERIC VERTICAL PROFILE AND COMPARISON BETWEEN IT AND IRI-90
DENG Yue, WANG Jingsong, XIAO Zuo
2000, 20(2): 103-112.   doi: 10.11728/cjss2000.02.103
Abstract(1755) [PDF 578KB](29)
Abstract:
A physical model for ionospheric vertical profile is established, taking into ac-count four species of ions and electrons in the region of 80-500 km. Neutral windand ions' motion are both involved in the continuity equations for those five species.Ionospheric proflles in different seasons at low and high solar activities are calcu-lated and compared with the results from IRI-90. Results show that E region is atypical Chapman layer and the depth of E-F valley is generally 0.2-0.5 which isdeeper than that given by IRI-90. That the F1 ledge is most obvious in summerat low solar activity is consistent with widely accepted theories, but the F1 ledgeseldom appear in IRI-90. In F2 region, the electron number density at high solaractivity is greater than that at low solar activity, and in winter is greater than thatin summer. rhese all agree with observations rather well.
Research of Earthquake Electromagnetic Satellite Mission Planning System
Wang Hongfei, Liu Yurong, Yan Zhen
2010, 30(6): 620-625.   doi: 10.11728/cjss2010.06.620
Abstract(2393) [PDF 482KB](59)
Abstract:
Earthquake electromagnetic satellite mission planning is the center of satellite management in the orbit. This system's main tasks are 1) to optimize the satellite payload work plan based on the forecasting of regional space characteristics environment in orbit, 2 to get the characteristics space region observational data of the whole track, 3) to arrange observation data downlink. In this paper, the character of Earthquake electromagnetic satellite planning and scheduling system has been investigated. The fundamental principles for the mission planning have been found. The system structure based on the CCSDS standard is proposed. The function requirement and the planning process flow of the system have been analyzed. Then an Earthquake electromagnetic satellite mission planning prototype system is realized to test the feasibility of what we have presented in the paper. Finally, the paper gives the conclusion on the Earthquake electromagnetic satellite mission planning system and points out the system's latest developments trends and application requirement in the future.
Investigating the Geometrical Structure of Magnetic Field Lines in the Magnetosphere
QU Shaojie, SHEN Chao, LIU Zhenxing, TIAN Baoning
2006, 26(6): 427-431.   doi: 10.11728/cjss2006.06.427
Abstract(2263) [PDF 1699KB](52)
Abstract:
The geometrical structure of magnetic field in the magnetosphere is an important issue for discussion in space physics. In this paper an analysis has been made to some regions of magnetosphere, including the Nightside, Cusp and Duskside. By applying the Curvature Radius Method to the magnetic field data measured by four satellites of Cluster, the geometrical structure of Magnetic Field Lines, including the curvature radius, directions of curvature and normal of the osculating planes of the Magnetic Field Lines have been investigated. Then the spacial configuration of Magnetic Field Lines is known ,and consequently the three dimensional structures of the corresponding regions are achieved according to the anterior results. And finally the results testified the validity of the Curvature Radius Method. If more detailed datas are supplied, a three-dimentional model of the whole magnetosphere can be built by extending the method to the other regions in magnetosphere. So the significance of the research is very clear for space science.
2D MHD Simulation of the Lunar Wake
CUI Wei, LI Lei
2008, 28(3): 189-193.   doi: 10.11728/cjss2008.03.189
Abstract(2166) [PDF 1891KB](42)
Abstract:
Two-dimentional ideal MHD simulation of the interaction between the solar wind and the Moon reveals the particle and magnetic field distribution in the lunar wake. The results show that the density of the solar wind falls ramatically and the interplanetary magnetic field increases in the umbra of the Moon. When the interplanetary magnetic field is parallel to the direction of the solar wind velocity, the wake is very long. When the magnetic field is normal to the velocity of the solar wind, the wake is shorter.
The Saturation and Breakdown of the Nonlinear Propagation of Gravity Wave
LIU Xiao, XU JiyaoI MA Ruiping
2006, 26(5): 337-345.   doi: 10.11728/cjss2006.05.337
Abstract(2433) [PDF 2676KB](49)
Abstract:
A time splitting numerical model is developed in this paper, which combined the explicit algorithm in the horizontal direction and the implicit algorithm in the vertical direction, and used to simulate the nonlinear propagation of the gravity wave (GW) in a 2-dimensional compressible atmo- sphere. Numerical simulation of the nonlinear propagation of the small amplitude GW is presented by using this model. The numerical results coincide well with linear theory and indicate that the numerical model is correct. The saturation and breakdown of the nonlinear propagation of the finite amplitude GW is simulated by using the model. The results show that: (1) The overturn appears before the saturation of GW, however, it requires a long time (nearly 1.5 periods of the GW) to induce the GW breakdown. The height (time) of instability predicted by linear saturation theory is higher (latter) than the corresponding results obtained from nonlinear numerical simulation because of the nonlinear wave-wave and wave-flow interaction. (2) The nonlinear wave-flow interaction produces energy transforring from the GW to mean flow prior to instability. The nonlinear wave-wave interaction is induced by the breakdown of GW directly. (3) The direction of the horizontal mean wind acceleration, the jet and the horizontal propagation of GW are consistent and indicate that the nonlinear wave-flow interaction accelerate the formation of horizontal mean wind shear and the development of the instability.
Deployment Experiment of Deployable Truss Antenna
Cheng Liang, Guan Fuling, Zhang Huifeng
2010, 30(1): 79-84.   doi: 10.11728/cjss2010.01.079
Abstract(2132) [PDF 978KB](17)
Abstract:
Experimental study of a proportional deployable truss antenna model is presented. The experimental scheme was discussed. The motioning acceleration of measuring nodes was gathered during movement. Then the experimental result was compared with the analytical result using the program based on the Moore-Penrose generalized inverse matrix theory. The reliability of the generalized inverse matrix theory to analyze this kind of structures was proved.
Scientific progress of combined exploration DSP and Cluster: 2008—2010
Liu Zhenxing, Cao Jinbin, Pu Zuyin
2010, 30(5): 404-421.   doi: 10.11728/cjss2010.05.404
Abstract(2637) [PDF 233KB](60)
Abstract:
The combined observations of Double Star and Cluster missions allow for, for the first time, six-point measurements of the main plasma parameters in the key scientific regions of the near-Earth environment. In the past two years, a great number of works were made based on the data from DSP and Cluster missions, advancing remarkably the research of magnetospheric physics in China. This paper briefly reviews these important scientific results based on 51 selected publications.
Multi-mode Ensemble Visualization Demo System for Space Weather
LI Fangfang, JIANG Xiujie, LIU Cheng, CHEN Zhimin
2012, 32(2): 245-250.   doi: 10.11728/cjss2012.02.245
Abstract(2499) [PDF 508KB](53)
Abstract:
Integration of space weather modes is the basis of operational space weather forecasting. The software system of visualization demo in integration of space weather modes is one of the significant research issues. There are a great deal of space weather modes with diverse elements and complex models, and there are differences in modes’ visualization forms and methods. Combined with characters of current space weather modes in China, the article constructs a multi-mode ensemble visualization demo system with good compatibility and high extensibility, which integrates visualization for most of the current space weather modes. A method of spatial data management is proposed. Based on the OpenGL and Visual C++ software platform, the system fundamentally implements the visualization integration of space weather modes by dynamic loading.
WIND AND WIND SHEAR OBSERVED BY ZN-1 ROCKET AT HAINAN STATION
MA Ruiping
1997, 17(1): 70-74.   doi: 10.11728/cjss1997.01.070
Abstract(1913) [PDF 302KB](59)
Abstract:
Middle atmosphere sounding experiment was taken at HAINAN station in December, l988 using the ZN- l rocket. The principle of wind sounding by rocket as well as the results and the methods of data process is discussed in the paper. The results show that there ekist rather strong wind shears and gravity wave disturbance at the low latitude of the midddle atmosphere. There are distinctive differences between the rocket wind data and the CIRA 1986 or ISO reference atmosphere (ISO 5878-1982 /ADD. 1-1983).
THE INFLUENCE OF QUASI-BIENNIAL OSCILLATION ON THE EQUATORIAL PLANETARY WAVES
Ma Jun, Chen Pei-ren
1994, 14(1): 54-62.   doi: 10.11728/cjss1994.01.054
Abstract(1861) [PDF 562KB](46)
Abstract:
From the theory of the occurrence of Quasi-Biennial Oscillation (QBO), we conclude that Kelvin wave and Rossby-gravity wave should propagate upward alternately during the different phase of the QBO. With the results of the numerical simulation, we conform this conclusion. Further more, we reasonably apply this effect on some other planetary waves, and try to find out the association between the QBO and the solar-terrestrial coupling.
Directional Detection of the Quasi-inertial Satellite GPS Receiver Antenna Installation Angle
WU Huiying, CHEN Hongyu
2012, 32(6): 887-892.   doi: 10.11728/cjss2012.06.887
Abstract(2528) [PDF 539KB](71)
Abstract:
The GPS (Global Positioning System) receiving antenna installation angle on a quasi-inertial orientation of the exploration-satellite is studied. Firstly, according to the mission requirements, the satellite attitude requirements are analyzed. Secondly, theoretical analysis and simulation were conducted according to the attitude requirements of posture on the installation of the GPS receiver antenna installation angle, preferably by the GDOP (Geometric Dilution of Precision) values. Finally, conclusion is drawn based on the simulation results that the GPS receiving antenna axial is near to the ± y axis of body reference frame, viz. the orbital plane normal or negative normal direction.
Global 4D Trajectory Optimization Design for Lunar Vertical Soft Landing
Huang Guoqiang
2014, 34(3): 313-318.   doi: 10.11728/cjss2014.03.313
Abstract(997) [PDF 620KB](51)
Abstract:
A combinatorial algorithm, including dynamic programming and conjugate gradient, was proposed for 4D trajectory global optimization of the lunar probe vertical soft landing. By employing the suboptimum control variable calculated from dynamic programming as the initial control variable of conjugate gradient algorithm, the more precise optimum control variable and flight trajectories were obtained. The lunar probe vertical soft landing trajectory consists of two segments, i.e., the brake and landing segments. The performance index is to minimize fuel consumption of the lunar detector. The 4D trajectory of lunar vertical soft landing is optimized by this combinatorial optimization algorithm. Simulation results showed good accuracy, rapid convergence, and robustness with initial values for this combinatorial algorithm, which promise it to on-line generate a feasible vertical soft landing trajectory on the onboard computer. Meanwhile, the combinatorial algorithm could be extended to other two-point boundary value problems of terminal time uncontrolled type.
Short-term Forecasting of the Ionosphere f0F2 with F10.7
Chen Chun, Wu Zhensen, Sun Shuji, Ding Zonghua, Ban Panpan, Zhao Zhenwei
2009, 29(4): 383-388.   doi: 10.11728/cjss2009.04.383
Abstract(2524) [PDF 540KB](75)
Abstract:
The critical frequency of the ionospheric F layer, f0F2, is of importance to shortwave propagation and ground-space communications. By using regression analysis of the f0F2 observational data and solar radio flux F10.7, a short-term predicting technique of the ionosphere f0F2 is introduced. The solar activity index fc, defined as the moving average of F10.7, is used as the input, and the output is the ionospheric critical frequency f0F2 values three days in advance. Historical data from eight ionospheric stations around China is used to build the method and verify the performance respectively. The results are compared by giving their root-mean-square errors according to different solar activity, season and local time. The results show that the predicting errors at each season and local time are acceptable, which indicate that the method can forecast the f0F2 values effectively. The predicting errors at low latitude are higher than those at middle latitude, which conform the complexity variations of low latitude ionosphere. In addition, this method can also be applied to the short-term forecasting of other ionospheric parameters.
Achievements of Space Scientific Experiments Aboard SJ-8 Satellite
XIE Jingchang, WAN Shixin, ZHANG Pu, LIN Hai, LIU Fang, HU Wenrui
2008, 28(5): 390-394.   doi: 10.11728/cjss2008.05.390
Abstract(2231) [PDF 157KB](58)
Abstract:
As scientific experiment payloads, microgravity experiments of fluid physics, life science,combustion science, physics and accelerator measurement were conducted on board the Chinese recoverable satellite SJ-8 during 18-day orbital flight. The experimental payloads and an experiment support system constituted the microgravity experiment system of the flight mission. This article has presented the briefs of the scientific achievements of these space experiments, the composition and performance of the Microgravity Experimental System (MES) and the general picture of the overall flight mission, respectively.
TYPE Ⅲ BURST SOURCES IN THE CORONA AND COMPARISONS WITH THE INTERPLANETARY MAGNETIC FIELD LINES
Ji Shu-chen, Cao Wen-da, Wei Feng-si
1996, 16(4): 299-304.   doi: 10.11728/cjss1996.04.299
Abstract(1821) [PDF 380KB](40)
Abstract:
In thes paper, some high spacial and temperal resulation data observed with the Nancay Mark Ⅲ Radio heliograph in the period of 1980 March-1981 September are processed. It is found that a great number of Type Ⅲ burst sources in the corona are centralized near the ecliptic. Type Ⅲ burst sonrces located in the north of the ecliptic are larger in number than those in the south; the west are larger in number than the east. For 92.0% Type Ⅲ burst sonrces are located within 40°of the ecliptic. After a comparison with the interplanetary magnetic field lines obtained with the radio spectrograph on board ISEE-3 in the same period, it is discovered that there are clear corresponding relations on latitude distribution between Type Ⅲ burst sonrces in the corona and the interplanetary magnetic field lines. It is evidene that the interplanetary Type Ⅲ burst sources originate from Type Ⅲ burst sources in the corona.
RELATIONSHIP BETWEEN THE METEOR SHOWERS AND THE OCCURRENCE OF SPORADIC E OVER WUHAN
NIU Xiaojuan, XIONG Jiangang, WAN Weixing, NING Baiqi, LIU Libo, YUAN Hong
2004, 24(2): 105-111.  
Abstract(2641) [PDF 651KB](51)
Abstract:
This paper analyzes the relationship between the occurrence of sporadic-E and the meteor numbers during the Perseids, Leonids and Geminids meteor showers in 2002 and Quadrantids meteor shower in 2003 over Wuhan (30°32′N, 114°22′E). The data used here are derived from an all-sky meteor radar and a digital ionosonde at Wuhan. The results show that the meteor number increased during the outburst of meteor showers and that the occurrence frequency of strong Sporadic-E also increases after the outburst of meteor showers. There are two peaks for the mean Cross-correlation function between the meteor number and the occurrence rate of Sporadic-E, one appears around the second day after the outburst of meteor shower and the other appears around the sixth day. It is suggested that the first peak could correspond to the Sporadic-E produced divectely by many meteors ionization during the outburst of meteor shower, the second peak could correspond to the Sporadic-E produced by the subsequent action of wind shear on residual meteor ion concentrations.
THE EFFECT OF POWERFUL HIGH-FREQUENCY RADIO WAVES ON TWO-STREAM INSTABILITY IN THE EQUATORIAL E REGION: THE STUDY OF PIC ELECTROSTATIC PARTICLE SIMULATION
HUANG Wengeng, GU Shifen
2003, 23(2): 102-109.  
Abstract(2117) [PDF 1894KB](43)
Abstract:
Two-stream instability is one of some typical instabilities occurred in ionosphere. It exists in equatorial ionospheric and auroral ionospheric E region. Generally speaking, the two-stream instability appears occasionally due to the presence of a relative strong vertical electric field needed. In recent decades, several powerful High-Frequency (HF) radio wave transmitters were set up successively in the world, which provide us convenience to study the interaction of HF radio waves with plasmas. For example, the parametric process between the powerful HF radio waves (pump waves) and the ionospheric plasma, which will excite the electrostatic waves, and some instabilities may be produced under special conditions. In this paper, one dimension PIC (Particle In Cell) electrostatic particle simulation is used to study the interaction of pump waves with the equatorial ionospheric E region. The simulation results show that pump waves can control the two-stream instability. With different parameters, the instability can be stabilized or destabilized by the pump waves. The results are consistent with the theoretical model qualitatively. The simulation studying provides the probabilities for artificial control the irregularities by very strong radio waves on the ground.
Twenty-four Hour Ahead Prediction of f0F2
Kong Qingyan, Liu Wen, Jiao Peinan, Fan Junmei, Feng Jing, Lu Zhuanxia
2009, 29(4): 377-382.   doi: 10.11728/cjss2009.04.377
Abstract(2534) [PDF 615KB](68)
Abstract:
Using three-layer feed-forward back propagation neural networks, twenty-four hour ahead prediction of the critical parameter of ionospheric F2 layer f0F2 is realized. The prediction model is developed based on 11 years of data (from 1976 to 1986) measured from China vertical station (Haikou, Guangzhou, Chongqing, Lhasa, Lanzhou, Beijing, Urumchi, Changchun, Manchuria). By analyzing time series correlation of f0F2 and solar-terrestrial activity, five input parameters are determined. The same-time training method is selected and the prediction values within 24 hour can be obtained without changing the network frame. By comparing the prediction property of Neural Network (NN) method and the autocorrelation one (named Corr), for quite data the NN method has higher accuracy except for summer data. While for the whole year data set, the Corr is better. In order to improve the applicability of the method for storm-time data, NN is corrected, and using two specified examples to explain the improvement in the article. After such modification, NN is better than Corr for the same test data as that used above.
Progress Report of Space Life Science in China
CHEN Shanguang, LI Yinghui
2008, 28(5): 402-411.   doi: 10.11728/cjss2008.05.402
Abstract(2170) [PDF 363KB](74)
Abstract:
In the past two years, space life sciences research in China is characterized by a tendency toward integration of scientific and engineering resources in preparing and implementing advanced space programs. In the field of operational medicine, we carried out an international cooperated Head-Down Bed Rest (HDBR) experiment and investigated the effects of Chinese herbs compounds on astronaut's physiological functions. The effect of microgravity and its mechanisms were further studied from the level of physiology and biology. At the same time, state-level platform for ground and space experiment was established.
DYNAMIC RESPONSE OF BLOOD FLUX OF VARIOUS ORGANS OF RABBITS UNDER SIMULATED WEIGHTLESSNESS
Xiang Qiu-lu, Shen Xian-yun, Meng Jing-rui, Liu Guang-yuan
1989, 9(2): 148-154.   doi: 10.11728/cjss1989.02.148
Abstract(1638) [PDF 530KB](38)
Abstract:
In this paper an experiment of zoological model with 26 rabbits is reported and the dynamic response curves of blood flux of various organs are given. The relations between the blood flux and the functional state of microvessels of various organs under the simulated weightlessness conditions are also analysed using the method of microcirculation. Finally, the characteristics of the changes of the microcirculatory functions of various organs are discribed, and the mechanism of this changes are primarily discussed.
Forecasting Dst Index With Artificial Neural Network
XUE Bingsen, GONG Jiancun
2006, 26(3): 183-186.   doi: 10.11728/cjss2006.03.183
Abstract(2476) [PDF 990KB](54)
Abstract:
In this work, fully connected neural network, a new kind of artificial network, has been introduced to construct the model for Dst index forecasting, Through studying the mechanism that the geomagnetosphere was affected by the condition of interplanetary media, the geomagnetic disturbance index Dst was found to have close, and complex relationship with both the solar wind parameters and IMF features. By employing the measured parameters from ACE spacecraft, these parameters were the solar wind velocity, the density of solar wind plasma and the southward component of IMF. The most recent measured Dst was also figured to correlate to the Dst several hours ahead. To construct the relationship between interplanetary measured parameters and Dst index, fully connected neural network was introduced. This neural network could demonstrate the complex relationship through building up the internal connection between separate neurons in hidden layer. After a training process with historical data, the forecast model was built during which the neural network will adjust the internal connect weight between units automatically according to the input parameters. The storm time data of 1998 and 1999 was selected in the training process of model construction. The data set during the geomagnetic storm in July 24-29 was used to test the model and the error of the test data was 14.3%.
Analysis of Possibility of Disturbance From Celestial Bodies on Satellite-Carried Optical Sensors
LIU Yanzhu
2006, 26(3): 215-219.   doi: 10.11728/cjss2006.03.215
Abstract(2110) [PDF 1621KB](50)
Abstract:
The satellite-carried optical sensors with various objectives may be possibly disturbed by the entrance of celestial bodies, such as sun, moon and earth into the sensitive area of sensors. In this paper, two kinds of satellite-carried optical sensors are discussed. They are the star sensor with a sensitive axe fixed on the spacecraft, and the satellite-carried astronomical telescope with a sensitive axe fixed in the space. A sensitive sector area of the optical sensor in the ecliptic plane or in the moon's plane is defined as the projective of the sensitive cone of the sensor on these planes. The disturbance occurs when the satellite-sun or satellite-moon vector enters into the sensitive sector area of the star sensor. A disturbance cone of the earth is formed from the satellite-earth vector and the contour of the earch. The disturbance occurs when the disturbance cone intersects the sensitive cone of the telescope. Based on the geometric relationships the conditions of disturbance from celestial bodies on the satellite-carried optical sensors can be determined and some formulas are derived to determine the time of occurrence of disturbance
Collisionless Magnetic Reconnection in Presence of a Guide Field
FU Xiangrong, GUO Jun, WANG Shui
2006, 26(6): 432-439.   doi: 10.11728/cjss2006.06.432
Abstract(2625) [PDF 3136KB](84)
Abstract:
This paper studies the coUisionless magnetic reconnection in the presence of different guide fields using two-and-a-half dimensional full particle simulation. The results show that, a strong guide field with Bz0 〉 0.5B0 will not only strongly alter the motion of electrons but also change the structure of electric field and velocity field around the reconnection region, thus affect the reconnection rate and electron accelerating process. General Ohm's law for two-fluid MHD model is employed to explain the characteristics of these electric field structures. And by tracing beams of electrons near the diffusion region, it is found that in the 2D model, electric field component perpendicular to the simulation plane and located at the center of diffusion region plays the major role in the electron acceleration, while the other two components contribute very little, no matter the guild field is strong or not.
Advance of interplanetary physics study in China: 2008—2010
Zhao Xinhua, Xiang Changqing
2010, 30(5): 427-444.   doi: 10.11728/cjss2010.05.427
Abstract(3013) [PDF 233KB](65)
Abstract:
Interplanetary physics study is an important ingredient in space weather research. Considerable progress this aspect has been achieved by the space physics community of China in recent years. This brief report summarizes the latest advances of the interplanetary physics research in China during the period of 2008--2010. This report includes solar corona and solar wind, interplanetary transients, energetic particles, MHD simulation, space plasma, and prediction methods for physical phenomena originating from both solar corona and interplanetary space.
Study on the Effects of Protons to Spacecraft Internal Charging With Monte Carlo Method
Tian Tian, , Jiao Weixin, Chen Xu, Li Long, Wan Yinghu
2011, 31(1): 93-99.   doi: 10.11728/cjss2011.01.093
Abstract(2202) [PDF 568KB](51)
Abstract:
In this paper, the basic mechanism of spacecraft internal charging was introduced, and proton's effect on internal charging was mainly studied. Monte Carlo method is used to simulate the transporting process of proton in dielectric and the internal charging results in certain flux environment for the case of simple plane dielectric were calculated. Results indicate that the maximum electric field is correlated with the energy of the inject protons, and the electric field reached its maximum value under certain energy; that for the same number of injected particles and the same material parameters, the maximum electric field produced by proton is much higher than that produced by electron. Proton and electron data on 26th July, 2004, the time just before TC-2 satellite's attitude control system becomes invalid were chosen to calculate the internal maximum electric field produced by protons and electrons. The results reveal that the maximum electric field produced by protons is 2~4 magnitudes smaller than that produced by electrons, mainly due to proton's much smaller flux than that of electron.
LSTID Measured by the Technique of the HF Backscattering Sounder
Zhang Xiu-ju, Jiao Pei-nan, Jiang Bing-wu
1988, 8(2): 138-144.   doi: 10.11728/cjss1988.02.138
Abstract(1479) [PDF 744KB](61)
Abstract:
In this paper,large-scale traveling ionospheric disturbances (LSTID) measured by the technique of the pulse Doppler phase array rader are described and a method for the analysis of LSTID are given,which are used to calculate the typical events of LSTID and to obtain their characteristic parameters.In the investigation,some morphological features of LSTID are shown by the corrugated model.
Study of the South China Ionospheric TEC Disturbances During June-July 2009
HUANG Jiang, DENG Baichang, XU Jie, HUANG Linfeng, LIU Weifeng, ZHAO Wenhua
2011, 31(6): 739-746.   doi: 10.11728/cjss2011.06.739
Abstract(2857) [PDF 849KB](59)
Abstract:
There are many origins of ionospheric TEC (Total Electron Content) disturbances during June-July 2009, including several earthquakes and a total solar eclipse. In current study, using the GPS-TEC date observed during June-July 2009 in Guangzhou GPS station and processed by a sliding window with the data of prior 15 days, the characters of South China ionosphere are investigated in spatial and temporal distribution. The results indicate that there are possible relations between the South China ionospheric TEC disturbances and seismic-activities as well as total solar eclipse during June-July 2009. The characters of ionospheric TEC disturbance induced by several earthquakes are commented as follows: positive values before earthquake, positive values or negative values near and after the occurrence of earthquake, even more, that the positive values on the day of total solar eclipse (22 July 2009) may be accounted for magnetic activities, seismic activities and total solar eclipse.
Study of magnetic reconnection between closed loops and open magnetic field driven by horizontal flows on solar surface
Chen Wenlei, He Jiansen, WU S T, Yang Liping, Wang Aihua, Zhang Lei, Tu Chuanyi
2013, 33(3): 231-239.   doi: 10.11728/cjss2013.03.231
Abstract(2444) [PDF 1353KB](85)
Abstract:
Numerous observational events in the solar atmosphere (e.g., solar flares and jets) are attributed to be the energy conversion due to magnetic reconnection. Magnetic reconnection is also involved in a new scenario of solar wind origin to play a crucial role in opening the closed loop and releasing its mass into the open funnel. In the scenario, closed loop are moved towards the supergranular boundary by the supergranular advection, colliding with open magnetic funnel there and triggerring magnetic reconnection between each other. This work aims at studying the occurrence and effect of magnetic reconnection in the scenario in details. Magnetohydrodynamic (MHD) numerical simulation is an important approach to investigate the magnetic reconnection process in the solar atmosphere. A 2D MHD numerical model in supergranular scale is established, which starts from the solar atmosphere with stratified layers of temperature and density. Based on quantitative analysis of the simulation result, the conclusion that the mass flow in the open funnel can be supplied from the closed loop aside through magnetic reconnection as driven by supergranular advection is suggested. Our results lay the foundation for future modeling of solar wind origin.
Gravity Wave Parameters and Their Seasonal Variations Derived from Na LidarObservations at Beijing
Zou Xu, Yang Guotao, Wang Jihong, Gong Shaohua, Cheng Xuewu, Jiao Jing, Yue Chuan, Fu Haichuan, Wang Zishuo, Yang Song, Yang Xianchang, Fu Jun
2015, 35(4): 453-460.   doi: 10.11728/cjss2015.04.453
Abstract(1376) [PDF 833KB](90)
Abstract:
The nightly and seasonal variability of gravity wave activity and spectra in the mesopause over Beijing are studied with 3 years of sodium lidar observations. From the linear layer density response to gravity wave forcing, the lidar data were analyzed to get the atmospheric density perturbations and their spectra. The atmospheric density perturbation, density variance for fluctuations with vertical scales between 2 and 10 km, and amplitudes of density perturbation spectra at m = 2π/8, 2π/4, m = 2π/1.5, m = 2π/1, and ω = 2π/60, ω = 2π/40, 2π/25 all exhibit large nightly variability as well as large seasonal variations, with the semiannual maxima occurring near the solstice. The mean RMS atmospheric density perturbation over Beijing are 5.8%, which are obviously larger in summer than that in winter and the maxima occur near the solstice. The m spectra show power law shapes, and their range of variation is between -1.97 and -3.67 with an annual mean value of -3.02, and ω spectra is between -1.06 and -2.08 with an annual mean value of -1.92, respectively. It is concluded that the reaction of the Qinghai-Tibet Plateau and the background wind may be the main reason of the gravity wave behaviors at Beijing.
Research on the High-Power Microwave Gaussian Beam Air Breakdown
CAO Jinkun, ZHOU Dongfang, NIU Zhongxia, HOU Deting, YANG Jianhong, RAO Yuping
2007, 27(2): 140-145.   doi: 10.11728/cjss2007.02.140
Abstract(2182) [PDF 2824KB](37)
Abstract:
The nonlinear propagation of high-power microwave Gaussian beam in the atmosphere is studied. An appropriate model is presented for calculating the air refractive index when HPM Gaussian beam propagates in the atmosphere. In this model, the cross-section area is treated as a number of concentric annulus, and assuming each has a uniform electric field intensity distribution. Based on the knowledge of air breakdown and the theory of the propagation of Ganssian beam, the air refractive index is calculated for different field intensity, frequency of microwave, width of pulse, pressure, when giving parameters of the Gaussian beam. Then the curves of temporal spatial dispersion are given in the paper. The air breakdown is discussed based on the calculations and some useful results have been obtained.
THE EFFECT OF PLASMA SHEET FAST FLOWS ON SUBSTORMS
SHEN Chao, LIU Zengxing, CAO Jinbin, ZHANG Xiaoxin, WANG Xueyi
2000, 20(3): 216-223.   doi: 10.11728/cjss2000.03.216
Abstract(2029) [PDF 515KB](35)
Abstract:
In this investigation, using a two-dimensional particle code, we have exploredthe influence of the fast flows in plasma sheet on the triggering of substorms. Wehave found that, the local speedy flows in plasma sheet could trigger the magneticreconnection process and cause the fast release of magnetic energy stored in mag-netotail. However, continuing, stable and homogeneous fast convections in plasmasheet may depress the magnetic reconnection processes in magnetotail. The resultsobtained in this study indicate that the local Bursty Bulk Flows(BBFs) can lead tothe onsets of magnetospheric substorms; nevertheless, when the IMF keeps south-ward for a long time, there may be no substorm onset, which has been called SteadyMagnetospheric Convection processes.
DATA RECEIVING AND ALERTING SYSTEM OF FY-2 SATELLITE
GONG Dezhu, SUN Yueqiang, LIU Yiming, LIANG Jinbao, LIN Huaan, ZHU Guangwu, WANG Shijin
2003, 23(2): 142-148.  
Abstract(1951) [PDF 1643KB](53)
Abstract:
FY-2 satellite is a geosynchronous meteorological satellite which is produced and lunched by China. The satellite carries the spatial particle detector and the solar X-ray detector used for detection of solar proton-event in high energy particle environment. The whole data receiving and alerting system of FY-2 consists of three systems: the earth-based system of data receiving and demodulating, the system of data processing and alerting. At first, environment detection data are collected, modulated and transmitted in the onboard system of FY-2 and detectors. Then data signals are magnified, demodulated and sent into the earth-based system of data receiving and demodulating. At last, data is received, processed, stored, displayed and judged to make alarm automatically by telephone for solar proton-events and X-ray flare in the system of data processing and alerting. It is an important way for guaranteeing space vehicle’s safety and enhancing antiradiation’s level.
Seasonal Variation of the Ionospheric Total Electron Content, Maximum Electron Density and Slab Thickness Over Wuhan
XIONG Bo, WAN Weixing, LIU Libo, NING Baiqi, GUO Jianpeng
2007, 27(2): 125-131.   doi: 10.11728/cjss2007.02.125
Abstract(2722) [PDF 4739KB](72)
Abstract:
Half-hourly Total Electron Content (TEC) from Faraday rotation measurement in the EST-Ⅱ satellite and half-hourly foF2 ionosonde data obtained at Wuhan (114.4°E, 30.6°N) from 1980 to 1990 are analyzed to show the seasonal variation of TEC, NmF2 (maximum electron density) and the slab thickness. By analyzing and comparing, the results show that the semiannual anomaly of TEC and NmF2 is obvious in high and low solar activity periods during 1980 and 1990 at Wuhan. The season or winter anomaly of TEC and NmF2 is obvious in high solar activity periods during 1980 and 1990 at Wuhan. The nighttime winter anomaly effect had been observed in the northern hemisphere during solar minimum, which is not observed at Wuhan. The occurrence rate of nighttime enhancements of NmF2 is at maximum in summer during high solar activity periods, but at its minimum during wintertime for low solar activity conditions. The slab thickness is mainly between 200 and 800 kilometers, change of which is small from 0700 LT to 1800 LT and is larger at other time. The observed NmF2 values are used to check the validity of International Reference Ionosphere (IRI) and the single-station model over Wuhan to predict the seasonal variability of this parameter. The effect predicted by the single-station model over Wuhan is better than IRI.[
Gyrosynchrotron Radiation of Interplanetary CMEs
SUN Weiying, WU Ji, WANG Chuanbing, WANG Shui
2012, 32(1): 1-7.   doi: 10.11728/cjss2012.01.001
Abstract(2357) [PDF 202KB](46)
Abstract:
CMEs (Coronal Mass Ejections) are an important means of energy release in the solar corona. Solar Polar Orbit Radio Telescope (SPORT) is a mission being proposed for observing the propagation of interplanetary CMEs from solar polar orbit. The main payload onboard SPORT is a synthetic aperture interferometric radiometer, which receives radio emission of interplanetary CMEs. It is identified that there are mainly three radio emission mechanisms of CMEs, i.e., bremsstrahlung, gyrosynchrotron emission and plasma emission. Among these emission types, bremsstrahlung emission is the main emission mechanism of the high-density plasma clouds of interplanetary CMEs. Gyrosynchrotron emission is the continuous emission generated by high-energy electrons from CMEs, while plasma emission is the main mechanism of transient radio bursts from CMEs. In this paper, the gyrosynchrotron emission of interplanetary CMEs is focused on. Firstly, the mechanism of gyrosynchrotron emission is reviewed. Secondly, a review of the physical parameter models of background solar wind and interplanetary CMEs is presented. After these, the brightness temperature and polarization of gyrosynchrotron emission of interplanetary CMEs are calculated and analyzed. Finally, the detectability of gyrosynchrotron emission of interplanetary CMEs by radio meters is discussed briefly.
Using Back Propagation Neural Network Method to Forecast Daily Indices of Solar Activity F10.7
XIAO Chao, CHENG Guosheng, ZHANG Hua, RONG Zhaojin, SHEN Chao, ZHANG Bo, HU Hui
2017, 37(1): 1-7.   doi: 10.11728/cjss2017.01.001
Abstract(905) [PDF 1078KB](53)
Abstract:
The solar 10.7 cm radio flux,F10.7,a measure of the solar radio flux per unit frequency at a wavelength of 10.7 cm,is a key and serviceable index for monitoring solar activities.The accurate prediction of F10.7 is of significant importance for short-term or long-term space weather forecasting. In this study,we apply Back Propagation (BP) neural network technique to forecast the daily F10.7 based on the trial data set of F10.7 from 1980 to 2001.Results show that this technique is better than the other prediction techniques for short-term forecasting,such as Support Vector Regression method.
The Influences of Solar Flares on Ionospheric Electron Content
Ye Zong-hai, Jiang He-rong
1986, 6(3): 177-183.   doi: 10.11728/cjss1986.03.177
Abstract(1737) [PDF 498KB](66)
Abstract:
This paper provides a statistical study of the disturbance of ionospheric electron content initiated by solar flares over importance one for 1978-1979. It shows the different effects of solar flares grouped by their importance, duration, season and the distance from the solar central meridian. The results show that ionospheric electron content is obviously disturbed by the bright solar flares with duration longer than 1.5 hours. The electron content starts to increase after the occurrence of solar flares and reached its maximum on the fourth-fifth day. The electron content disturbances caused by non-bright flares is smaller than by bright filares. Solar flares with duration <1.5 hours do not disturb the electron content. The flares occurred in the summer seems not to disturb the electron content. Only the flares occurred in the winter obviously disturb the electron content. There is an east-west asymmetry in distribution of flare’s position in causing the electron conten distinct disturbances. Flares occurred on the east 61-90E from the solar central meridian and in winter seasons induce the largest disturbances for the electron content.
Penetration characteristics of VLF wave from atmosphere into the lower ionosphere
Zhao Shufan, Sheng Xuhui, Pan Weiyan, Zhang Xuemin
2011, 31(2): 194-200.   doi: 10.11728/cjss2011.02.194
Abstract(2700) [PDF 557KB](47)
Abstract:
Many papers have indicated that earthquake happens associated with a width frequency band of VLF (Very Low Frequency), ULF (Ultra Low Frequency), ELF (Extremely Low Frequency) electromagnetic radiation, which have been recorded by satellites in the ionosphere and low magnetosphere. In this paper, the reflection and transmission coefficient of the homogeneous half-space ionosphere has been calculated using propagation matrix method. Simultaneously the Booker quartic equation is solved to get the refractive index in the ionosphere. The analysis of the factors which influence the reflection and transmission coefficient of the ionosphere and the propagation characteristics in the ionosphere of VLF wave have been performed, such as wave frequency, incident angle, geomagnetic inclination, electron density and collision frequency in the ionosphere to provide fundamental basis for further studies on numerical calculation of propagation of ULF/VLF waves in the stratified ionosphere and support the study of seismo-ionosphere coupling mechanism. The results show that it is easier for the TE (Traverse Electric) wave radiated by vertical electric dipole to penetrate into the ionosphere, but the TM (Traverse Magnetic) wave radiated by horizontal electric dipole is reflected again and again in the ground-ionosphere waveguide. It is easier to observe the VLF wave anomaly when the electron density is lower or at the high-latitude region. The O wave experiences severer attenuation than X wave, so X wave is a penetration mode whereas O wave is a non penetration mode in the ionosphere. The attenuation of the two characteristic wave decrease as the decrease of the angle between the geomagnetic field and wave vector, that is to say the attenuation is the smallest when longitudinal propagation. When the geomagnetic field is considered, the ULF/VLF wave related with earthquake can penetrate into the ionosphere which is confirmed by the satellite observation. But the further physical mechanism will be delved in the future.
SEVERAL METHODS OF DETERMINING SYNCHRO NIZATION SATELLITE POSITION AND CALCULATION ABOUT PDOP
Sun Hong-wei
1995, 15(3): 245-249.   doi: 10.11728/cjss1995.03.245
Abstract(1859) [PDF 198KB](79)
Abstract:
In this paper,several methods of the synchronization satellite positioning with the second pulse in TV-signals transmmitted by communication satellite are introduced,and calculation methods about PDOP in each positioning model are given.Inaddition, some analysis and calculations for some practical problems are also provided.
Research on the Spatial Density Algorithm of Space Debris
Li Can'an, Pang Baojun
2008, 28(6): 522-530.   doi: 10.11728/cjss2008.06.522
Abstract(3667) [PDF 1124KB](71)
Abstract:
With the development of human's space technology and activities, the space debris environment is getting more and more deteriorated, which results in a great threat to the safety of on-orbit space vehicles. Due to the threat, it's necessary to establish an engineering model for the space debris environment to access space vehicle's impact risk. Since the spatial density is the most important component in an engineering model of space debris environment, this paper is devoted to study the algorithm of the spatial density of space debris. By introducing the orbital parameters, the paper firstly gives the conception and the mathematical definition of spatial density of space debris. According to the definition, construction of the spatial density is carried out. With the aid of probability theory and orbital mechanics, the paper theoretically derives a general analytical expression for the spatial density. Afterwards, simplification of the general expression is discussed by introducing some assumptions, i.e., uniform distribution over right ascension of the ascending node and over the perigee argument, independence of orbital parameters and of spatial coordinates. The result is a more simplified expression of the spatial density, which is suitable for computation. It turns out that the SDPA model's algorithm is just a particular case of the paper's general expression. To enlarge the simplified result's for application, the paper proposes the classification method. To verify the paper's result, application to the Two-line elements is presented, which validates the paper's result. The application also shows that the classification method can help to improve accuracy.
STUDY ON DYNAMICS SIMULATION OF THE STRUCTURAL LOCK OF SPATIAL DOCKING MECHANISM BASED ON THE MULTI-BODY SYSTEMATIC ANALYSIS
WU Yizhong, CHEN Liping, ZHANG Yunqing
2004, 24(2): 152-160.  
Abstract(2088) [PDF 706KB](75)
Abstract:
The paper analyzed the characteristics of structural lock performing mechanism of spatial docking system and the difficulties of solving the model of the mechanism through dynamic analysis software on hand. And them the modeling method of multi-body dynamics is adopted and dynamics equation of the mechanism is established. The solving process considering the special features of the model is also narrated. Finally, the result of dynamics characteristics curves which are obtained from the model proved that the ball bearing lead screw mechanism aided by spring mechanism is feasible as the structural lock performing mechanism.
Numerical Research on Satellite Avoidance Strategy
ZHANG Yao, YANG Xu, LIU Jing, CHENG Haowen, LI Dawei, JIANG Hai, HU Jingjing
2013, 33(4): 448-452.   doi: 10.11728/cjss2013.04.448
Abstract(2786) [PDF 479KB](138)
Abstract:
With the increasing number of space debris, space environment becomes more worsening. Space collisions between two objects take place more frequently which leads to more debris in space. The "active" satellites which carry out their routine tasks will face more collision threat. It's important to establish satellite avoidance strategy in order to prevent satellite from collision. Three contents are researched in this paper. First, foreign process of satellite avoidance is studied. Second, factors including orbital maneuver, orbital propagation and computation of collision probability that affect the estimation of satellite avoidance strategy is analyzed. The third, numerical estimation process of satellite avoidance strategy is established which can be used to provide suggestions for department of satellite management.
Design of YH-1 Satellite Wide FOV Color Camera With its Ground-based Detection
Cao Jianzhong, Guo Wei, Zhu Qing, Wang Weihua, Tang Yao, Wu Li, Zhang Haifeng
2009, 29(5): 480-485.   doi: 10.11728/cjss2009.05.480
Abstract(2389) [PDF 647KB](71)
Abstract:
In this paper, the working principle, specifications, scheme and design result of the Wide FOV Color Camera of the YH-1 satellite are introduced. The static spatial resolution of the camera reaches 180 lp/mm and SNR is 34 dB in the laboratory before launching. According to the user's request, the images are generated by the camera with different manner: in the default working, the first and the second images are completed with the auto exposure algorithm, the others are got with the increased or decreased time of exposure from the second; while in the injected-instruction working, the other images are produced with the appointed time of exposure. For the sake of shooting the bright object in the dark background, experiments are carried out in the dark room and outdoor in night to get images of both a globe and the moon. And the images have been evaluated by the user. The result proved that the camera works well, the data format is correct, the exposure algorithm is successful, the quality of the camera is high, and the data can be collected and sent back correctly. Finally some main technologies applied during the manufacturing process are introduced.
CIRCULAR HOLLOW PLASMA WAVEGUIDE IN AN EXTERNAL MAGNETIC FIELD
HU Binjie, ZHANG Guoji, LAI Shengli
2000, 20(2): 159-164.   doi: 10.11728/cjss2000.02.159
Abstract(1876) [PDF 419KB](66)
Abstract:
The electromagnetic wave propagating along a circular hollow plasma wave-guide immersed in an external magnetic field is presented. Because of the boundaryconditions at all interfaces can be represented by the matrix equations, the char-acteristic equation can be obtained by using the matrix manipulation- The effectsof the plasma thickness of cladding, electron cyclotron frequency, and collision fre-quency on attenuation of the waveguide are investigated.
Application of Solar Photospheric Magnetic Field Properties in SPE Short-term Forecast
Cui Yanmei, Liu Siqing, Wang Huaning
2010, 30(2): 97-104.   doi: 10.11728/cjss2010.02.097
Abstract(2739) [PDF 928KB](61)
Abstract:
Solar Proton Events (SPE) are one kind of the major solar energy release phenomena. The released energies are well known from the magnetic energy. Lots of observations and studies have suggested that solar flares and CME (Coronal Mass Eruptions) are closely correlated to the complexity and non-potentiality of solar magnetic fields. Applying SOHO/MDI full-disk photospheric magnetograms, three magnetic physical properties (the maximum horizontal gradient of longitudinal magnetic field Bz, the length of neutral line with strong gradients L, the number of singular points η) are calculated, which describes the complexity and non-potentiality of solar magnetic fields. In order to verify that solar photospheric magnetic properties are available at forecasting SPE, a simple SPE forecast model that can forecast whether SPE will happen or not in the future 24 hours is set up, which is based on the three physical properties with BP (Back Propagation) neural network. In the consecutive tests for the 2002 and 2003 year samples, the model has very high accuracy rates (90 % for 2002 and 87.54 % for 2003, respectively) and the rather high SPE probabilities of detection (60 % for 2002 and 75 % for 2003, respectively), which supported that solar photospheric magnetic properties are very available in the SPE forecast models.
Influence of Solar Wind Disturbance on Ring Current and Auroral Electrojet Indexes
ZOU Ziming, CAO Jinbin, LI Yi
2012, 32(1): 14-19.   doi: 10.11728/cjss2012.01.014
Abstract(2865) [PDF 484KB](85)
Abstract:
Using the data of solar wind recorded by WIND and geomagnetic activity index, we studied the influence of the variation of solar wind dynamical pressure on ring current index SYM-H and auroral electrojet indexes (AU and AL). The increase and decrease of solar wind dynamical pressure can produce simultaneous or delayed disturbances in geomagnetic activity indexes, which include the transient increase of ring current index SYM-H, increase of eastward electrojet index AU and decrease of westward electrojet index AL. The sudden large increase of solar wind dynamical pressure can trigger super substorm and large geomagnetic storm. The response of geomagnetic activity indexes to solar wind dynamical pressure impulse is complicated and various, indicating the geomagnetic effect of solar wind dynamical pressure impulse not only depends on the strength and duration of solar wind dynamical pressure impulse, but also on the state of magnetosphere. Large geomagnetic storm, which last long and consume more energy, can only be triggered by strong and long impulse of solar wind dynamical pressure.
AN ADDITIONAL APPLICATION OF MSIS-86 AND IRI-86
Shen Chang-shou
1990, 10(1): 50-60.   doi: 10.11728/cjss1990.01.050
Abstract(2202) [PDF 725KB](77)
Abstract:
The purpose of the paper is to give a brief introduction to the atmospheric and ionospheric models of MSIS-86 and IRI-86 and to deduce the thermospheric wind system, the spacial distribution and temporal variation of collision frequencies and ionospheric conductivities, which are important parameters in the research of thermosphere-ionosphere coupling. The model parameters used are different from that of the old models in many cases. For instance, the maximum temperature at 300km altitude is nearly to 80°Nfor winter solstice condition according the MSIS-86 model, while it appears at 23.5°Nin the Jacchia-77 model. Since a lot of new data from DE-Bsatellite flying across polar region are involved in the new model, the temperature distribution presented here is more reliable, especially at high latitudes.The main results from the model calculations given in this paper are the following:1. Generally, the thermospheric wind flows from daylit hemisphere to night side. The air flows longitudewards at noon-midnight meridian (northward at noon and southward at midnight) during the year of sunspot minimum, but is across the longitude at other meridians. At sunspot maximum, however, the wind blowing along a longitude line occurs at 2:00-14:00 LTmeridian, i.e. 30° degree of longitude from the location of maximum heating by solar radiation.2. Strong southward component of the wind velocity appears at high latitudes during magnetic disturbed days as a result of particle precipitation and Joule heating.3. On cursory examination, the conductivity distribution calculated from MISI-86 and IRI-86 is similar to that got by Maeda et al., nevertheless various important details are added. Therefore, recalculation of the conductivity for different special conditions (i.e. time, place, solar and geomagnetic activity etc.) is necessary for the further study of the thermosphere-ionosphere coupling.In brief, this work tries to set up a link between the model based on observations and the study based on theory. Since thte models only present the average situation, the application confined to the macroscopic research and analysis of the phenomena of large scale.
Processing and Arrangement of Atmospheric Observation Data by Earth-based Planet Occultation
Mao Xiaofen, Han Tingting, Li Lei, Zhang Sujun, Hong Zhenjie
2010, 30(6): 554-561.   doi: 10.11728/cjss2010.06.554
Abstract(2200) [PDF 625KB](33)
Abstract:
The technique of planet occultation is one of the most effective methods in detecting Martian atmosphere and ionosphere. Changes in frequency, phase, amplitude and other physical quantities of radio signal from spacecraft, caused by passing through the atmosphere and ionosphere of the planet, were observed in rising and descending planet occultation events. The profiles of the atmosphere, density, temperature and pressure of the neutral atmosphere, and the electron density profile of the ionosphere can be obtained by using some inversion methods. In Chinese YH-1 Mars exploration mission, Earth-based planetary atmosphere occultation is an important scientific research assignment, and observation data arrangement is the first step of the inversion process. This paper presents the data processing of the Earth-based Martian atmosphere occultation processing system, and introduces the structure and function of the observation data arrangement module in detail, including time system transformation, ephemeris interpolation, coordinate system conversion, signal time delay correction and establishing occultation plane. Using our algorithm, some experimental results are generated by using data of MEX Radio Science from NASA Planetary Data System and data of MEX orbit, Earth and Mars ephemeris from MEX SPICE.
Exploring the Plasma Environment of Mars
Li Lei, Zhang Aibing, Kong Linggao, Wang Shijin, Sun Yueqiang, Zhu Guangwu
2009, 29(5): 462-466.   doi: 10.11728/cjss2009.05.462
Abstract(2958) [PDF 507KB](36)
Abstract:
Despite more than 40 years of in situ measurement, we still do not have a complete survey of particles, fields in the near Mars space. The Sino-Russian Joint Mars-Phobos Exploration program provides unique opportunity to investigate the global structure of the solar wind and Mars interaction region. Mars orbiter, YH-1 will explore the Martian space environment, to determine characteristics in different regions and their evolution with solar wind conditions, and to investigate the water escape process related with solar wind forcing. For these purposes, YH-1 will carry a plasma package consisting of two identical ion analyzers, and one electron analyzer, which aim at monitoring the plasma with energy from 0.02 keV up to 10 keV, providing mass analysis of ions in the mass range from 1 to 44\,au with fast time and fine energy resolution. Together with the magnetic field experiment on board YH-1, the plasma package will be the first to give full insight into the local plasma characteristics near the planet, to determine the possible total ion escape rate (particles/s) for the major ion species. The scientific objectives of the plasma experiment, as well as design of the instrument are presented in the paper.
Fast Approach of Doppler Rate Estimation Based on Geometry and SAR Echo Data
Peng Tao, Zhang Hongqun, Wu Yewei, Han Jiawei
2010, 30(3): 270-274.   doi: 10.11728/cjss2010.03.270
Abstract(2265) [PDF 608KB](55)
Abstract:
Doppler frequency rate is one of the key parameters in the azimuth processing of SAR data. Once mismatched, it will cause serious defocusing in azimuth dimension and then result in the degradations of image quality. On the other hand, fast estimation for Doppler frequency rate is necessary for the sake of disaster mitigation. To meet the need of fast estimation of Doppler frequency rate, an approach based on geometry and SAR echo data is put forward in this article, which can simplify the estimation processing according to the relationship between the Doppler frequency rate and range. Besides, the selection strategy for block data used to estimate the Doppler frequency rate is discussed. In the end, corresponding results have been given.
Variation of the Upper Atmospheric Density During the Quiet Period of Solar and Geomagnetic Activity (2007?2009)
LI Yongping, ZHU Guangwu, QIN Guotai
2012, 32(6): 829-833.   doi: 10.11728/cjss2012.06.829
Abstract(2415) [PDF 411KB](54)
Abstract:
The period of low solar activity between solar cycle 23 and 24 last a long time, having low F10.7 and long-term sunspot number record. So it is the time to study the change of upper atmospheric density in this quiet solar and geomagnetic activity conditions, especially for study of the response of upper atmosphere to variations in small geomagnetic disturbance and low solar activity. Atmospheric density detector mounted on the satellite near 650km aims at getting measurement data with the change of geomagnetic and solar flux variability, whose data are available ranging from 2007 to 2009, the results are concluded as follows. Upper atmospheric density obviously responses to the F10.7 variation in condition of low solar activity. When F10.7 decreases from 70 to 65, daily atmospheric density decreases obviously for 4~5 times, which is much larger than the decrease in the model. Upper atmospheric density also obviously responses to the small geomagnetic disturbance. Atmospheric density is increased strongly by 80%~160% when the sum of Kp increases from 23 to 30.
Seasonal Variation of Gravity Wave Spectrum Near the Polar Mesopause
WU Yongfu, XU Jiyao
2005, 25(3): 191-198.  
Abstract(2190) [PDF 2387KB](43)
Abstract:
This paper utilizes horizontal velocity data with a high resolution of 25 m and temperature data with a low resolution of 1 km measured during the MAP/WINE and MAC/SINE campaigns to study seasonal variation of gravity wave spectrum near the polar mesopause. Direct measurement of the temperature allows accurate calculation of the spectral amplitude and Richardson number.Resultsshow that there is considerable variability in the slope and amplitude of the vertical wavenumber spectra of the horizontal velocity near the polar mesopause, which is not consistent with the predictions of various saturation models and the universal vertical wavenumber spectrum. However, the mean vertical wavenumber spectra reveal a significant seasonal variation:the mean spectrum in summer has saturated features, whereas the mean spectrum in winter has unsaturated features. This implies that the saturation processes are present in summer rather than in winter. Enhanced turbulence layer can therefore be expected to occur in summer compared to winter. This result is in rough agreement with the seasonal variation of turbulent energy dissipation rates. Richardson number Ri calculated from Brunt-Väisälä frequency N and horizontal wind shear S also reveals seasonal difference:dynamically unstable regions of Ri smaller than 1/4 are observed in summer, whereas stable regions of Ri larger than 0.4 are observed in winter. These unstable regions are found to associate well with the summer spectrum, whereas stable regions are found to associate well with the winter.
Attitude Control of Micro-Satellite With Only Magnetic Actuators
LIU Haiying, WANG Huinan, CHENG Yuehua
2007, 27(5): 425-429.   doi: 10.11728/cjss2007.05.425
Abstract(2822) [PDF 998KB](51)
Abstract:
This paper researched on the attitude control of Micro-satellite using only magnetic torque for the different control modes including detumbling and attitude acquisition as well as threeaxis stabilization. The satellite model was established relative to orbit frame firstly, then based on the energy considerations and Lyapunov stability analysis methods, the B-dot controller for detumbling was presented, moreover, a new method using global energy control for attitude acquisition and three-axis attitude stabilization was given. At the same time based on the Linearizatlon of the satellite model, a constant gain LQG-controller was designed. Simulating result indicated that the B-dot controller can detumble the satellite's rate effectively; the global energy controller may be used in the large range of attitude capture and stabilization modes; while in small angle range the LQG controller has high precision but the stability properties is not so good compared to the energy controller.
A Statistical Analysis of SITEC Caused by Intense Solar Flares During 1996-2003
CHEN Bin, LIU Libo, WAN Weixing, NING Baiqi, DING Feng
2005, 25(1): 6-16.  
Abstract(2176) [PDF 3183KB](37)
Abstract:
In this paper,the SITEC phenomena is investigated which were caused by the X-class X-ray solar flares occurred from 1996 to 2003.The TEC data which obtained from a global GPS network are used to calculate the TEC increment,ΔTECf,and the variation rate increment,Δ(dTECf/dt),caused by solar flares.It is found that both ΔTECf and Δ(dTECf/dt) are closely related with the flare's maximal X-ray flux and its location on the solar disc.After eliminating the effect of the maximal X-ray fluxes and the locations on solar disc of different flares,results showed that there is a negative relationship between ΔTECf and the distance between the Earth and the Sun.The larger the distance,the smaller is the ΔTECf.Another finding is that Δ(dTECf/dt) correlates with the duration of the flare.Some characteristics of the flares which cause no obvious SITEC are also found.
TIEGCM Ensemble Kalman Filter Assimilation Model Design and Preliminary Results
ZHANG Yanan, WU Xiaocheng, HU Xiong
2017, 37(2): 168-176.   doi: 10.11728/cjss2017.02.168
Abstract(1690) [PDF 1426KB](61)
Abstract:
By using the parameterized ionosphere model TIEGCM as the background model, and based on the COSMIC observations, the global ionospheric electron density assimilation model is established using ensemble Kalman filter. Result shows that this model can effectively assimilate the observations into background model and acquire three-dimensional ionospheric electron density. By comparison to the background, the error between analysis and observations decreases significantly. The Root Mean Square Error (RMSE) of NmF2 decreases by about 60% for observations with assimilation, and 20% for observations without assimilation. The RMSE of hmF2 does not get improvement except for mean error. The results of Simultaneous Assimilation (SA) and Batches Assimilation (BA) are compared for this case. The time that the two methods spend in assimilation is about 6 to 7 minutes, which does not differ very much. SA needs nearly 8GB storage while BA needs less than 2GB. The statistic of electron density error shows that they nearly acquire the same mean error, but the SA gets relative better improvement in RMSE above 250km height.
Formation Constellation States Determination With Carrier Phase Differential GPS and Intra-Satellite Relative Measurement
FAN Guoqing, WANG Wei, XI Xiaoning
2005, 25(3): 218-223.  
Abstract(2165) [PDF 1742KB](67)
Abstract:
This paper presents a mathematical model of determining states of three satellites circular formation constellation, which combines the Carrier Phase Differential GPS (CDGPS) with inter-satellite relative measurement. And then, with the centimeter length constraint to the kilometre baseline inter-satellite which supplied by high accurate inter-satellite relative measurement, the search space of ambiguity is compressed impressively. On this base, the integer ambiguity of single CDGPS inter-satellite was initialized quickly using Bayes Least Square without any satellite movement intentionally. Lastly, the availability was proved by mathematic simulation. Learning from the simulation result, the accuracy of relative positions between satellites reaches 10-2 m and the accuracy of attitude of satellite reaches 10-3 rad.
A NEW KINEMATIC METHOD FOR FLYING-AROUND SATELLITE FORMATION DESIGN
LU Hongwei, XI Xiaoning, YU Qifeng
2004, 24(2): 124-131.  
Abstract(2103) [PDF 593KB](60)
Abstract:
This paper presents a new kinematic design method for satellite formation. First, the kinematic of the relative motion of zero inclination satellite formation is analyzed and orbit design is investigated. And orbit transformation method is proposed for arbitrary inclination satellite formation orbit design. Finally, the simulation results show that the method is effective and feasible.
THE NEW INVERTED ELECTRIC FIELD MILL
LUO Fushan, HE Yuhui, ZHANG Jian, GUO Hu, CHEN Daren
2004, 24(6): 470-474.  
Abstract(1873) [PDF 441KB](53)
Abstract:
The paper introduces a new inverted electric field mill. The electric field mill measures the intensity and polarty of atmospheric electric field to forecast the potential thunderstorm and electric shock in local area. It can be used safely as a monitor of the warning in places where are likely regions for the occurrence of static electricity and thunderstorm, for example, meteorological conditions for space-flight, aviation, oil, electric power, mine and open-air stadium.
Design of Unfolded Mechanical Properties Testing System for Multidimensional Deployment Mechanism of Antenna
WANG Yajun, XU Zhigang, HE Yun, HE Xibin
2016, 36(2): 227-236.   doi: 10.11728/cjss2016.02.227
Abstract(902) [PDF 2386KB](36)
Abstract:
Satellite antenna is a key component for satellite communications. In order to ensure the reliability of antenna deployment mechanism in orbit, its mechanical properties must be tested on the ground. To achieve this goal, this paper presents a mechanical performance testing system of antenna deployable mechanism which is in multidimensional framework style. The deployment process of antenna under high or low temperature and weightless environment of space can be simulated, and a loading test during the process could be carried on. The scheme and working principle of the testing system has been illustrated, as well as the innovative design of the three degrees of freedom mechanical arm and the loading mechanism. In addition, the mathematical model of the loading system has been built and simulated. Analyses show that the error of gravity balance is less than 2% FS (Full Scale) and error of the loading moment is less than 2%, thus the system can meet the test requirements of deployable mechanism. The testing system has made it a reality that the test of deployable mechanism has stepped from theoretical simulation stage across to the full-physical simulation stage, which is of great significance to ensure the satellite reliable communications in orbit.
Design Optimization of Condensers in a CO2 Two-Phase Thermal Control System for Space Detector Application
HUANG Zhencheng, MO Dongchuan, LU Shushen, HE Zhenhui, A. Paul, J.E. Van
2008, 28(1): 44-48.   doi: 10.11728/cjss2008.01.044
Abstract(2939) [PDF 2312KB](56)
Abstract:
The silicon Tracker, a charge particle core detector in the Alpha Magneto- spectrometer, requires a cooling system to provide a working condition. This cooling system must be small in size, strong for its cooling ability and temperature control precision, even in the complex thermal, and microgravity environments on the international space
station. In this paper, the attempt of design optimization of the condenser in the CO$_2$ two-phase thermal control system for such purpose is introduced, by employing thermal simulation analysis with SINDA/FLUINT. Because of the specific radiator, different design of the configurations of condenser inlet are investigated, by contacting the inlet at 1st, 2nd, 5th heat pipe and out of all heat pipes on the radiator. The result shows that with different configurations, the inlet part will have different effect on the heat transfer part of the condenser, which will cause the outlet temperature of the condenser different. It also tells that contacting the inlet at the 2nd heat pipes shows a best result for either reducing the anti-freezing power in cold case or guaranteeing enough subcooling of the pump inlet in the hot case.
OPTIMAL DESIGN FOR STRUCTURAL LOCK OF SPATIAL DOCKING MECHANISM
WU Yizhong, LIU Zhiquan, CHEN Liping, ZHOU Ji
2000, 20(4): 356-365.   doi: 10.11728/cjss2000.04.356
Abstract(2066) [PDF 430KB](48)
Abstract:
Structural lock is an electromechanical equipment that connects rigidly two space shuttles together. In this paper, the eccentric wheel plus cam mechanism scheme is selected. Based on analyzing their advantages and disadvantages, it is pointed out that this structure is simple and self-locking is reliable. Then the parameter of turning and pulling process are optimized. The optimization of structural lock during the pulling process is discusses in view of minimum torsion, minimum power and minimum time. It has been proved that the scheme optimized consumes least energy.
Process Optimization of Space Science Mission Concurrent Design
DENG Li, HAN Chao, CAO Jinbin
2015, 35(4): 511-518.   doi: 10.11728/cjss2015.04.511
Abstract(1420) [PDF 974KB](195)
Abstract:
To optimize the process of space science mission concurrent design, an approach based on the Design Structure Matrix (DSM) modeling and Genetic Algorithm (GA) optimization method is proposed. In this approach, main design activities and dependencies relationship between the activities during the process of space science mission concurrent design are analyzed, and then the DSM model of the process is established. The design activities sequence corresponding to the DSM is treated as the chromosome and is optimized by the GA method. The optimal goal is to reduce the iterative times and to improve the parallel extent. A practical example of space science mission shows that the proposed approach can be applied to modeling and optimization of the process for space science concurrent design.
A STUDY ON LAUNCHING GEOSTATIONARY SATELLITE AT HIGH LATITUDE BY TAKEN ADVANTAGE OF THE MOON'S GRAVITATION
ZENG Guoqiang, XI Xiaoning, REN Xuan
2000, 20(2): 177-184.   doi: 10.11728/cjss2000.02.177
Abstract(1843) [PDF 505KB](38)
Abstract:
A method of make use of Lunar Gravitation (LG) to launch GeostationarySatellite (GS) at high latitude is preselited- At first, preliminary anaJysis of theproblem of launching GS is given using patchedconic technique. Then, preciseanalysis is given in a mathematical model. It is indicated that less energy is neededto launch GS from launch site with latitude higher than 28° using LG method thanthe traditional. The higher the launching site is, the more energy is saved.
CALCULATIONS AND ANALYSES OF VERTICAL GRADIENT OF THE GEOMAGNETIC FIELD IN CHINA AND ADJACENT AREAS
An Zhen-chang, Wang Yue-hua, Xu Yuan-fang
1991, 11(1): 14-23.   doi: 10.11728/cjss1991.01.014
Abstract(2250) [PDF 626KB](57)
Abstract:
In this paper, based on the spherical harmonic model of the geomagnetic field, the spherical harmonic expressions of the vertical gradient of the geomagnetic field are given. The grid values of the geomagnetic field and its vertical gradient at 0.50, 100km above sea level are calculated. The contour maps of the vertical gradient of total intensity, vertical intensity, horizontal intensity and declination are drawn. The geographical distribution and change with height of the vertical gradient of the geomagnetic field are analysed.
Understanding substorms in the magnetotail: early development and recent progress
A. Nishida
2011, 31(3): 269-293.   doi: 10.11728/cjss2011.03.269
Abstract(2146) [PDF 1622KB](25)
Abstract:
This is a concise review of physics of the substorm in the magnetotail. It consists of two parts. The first part summarizes historical developments in the early days of the space age (1960--1975) when the basic concepts such as magnetotail and reconnection were established and the leading model of the substorm was introduced. The second part is an overview of the research conducted in recent years (1995--2010) when very significant advances have been achieved in understanding the substorm physics by virtue of several major satellites missions that addressed the magnetotail physics intensively.
Image quality assessment for Chang'E-1 IIM 2C data
Liu Bin, Ling Zongcheng, Liu Jianzhong, Zhang Guangliang
2012, 32(3): 440-448.   doi: 10.11728/cjss2012.03.440
Abstract(2408) [PDF 800KB](72)
Abstract:
Imaging Interferometer (IIM) onboard Chang'E-1 satellite is the first imaging spectrometer for lunar detection in China. The multi-bands image data of IIM played an important role in lunar minerals and elements retrieval. In this paper, IIM data is evaluated from several aspects including subjective image visual evaluation, objective image quality parameters, geometric precision, data quality change with time, etc. Subjective visual evaluation shows that images of short wavelength bands (band 1, 2, 3, 4, 5) and the last bands (band 31, 32) in image cube had bad qualities, which may not recognize lunar surface very well, while images in the middle of the cube are much better. A phenomenon is found by RGB image that there is an image tone inhomogeneity from left to right, which may be caused by discontinuity of CCD response. IIM data (band 24) is compared with Clementine UV-VIS image data (band 2) by image evaluation parameters such as radiance precision, definition and information content. Results show that IIM data's definition is better than Clementine UV-VIS, but its radiance precision and information content parameters are inferior. IIM data and Clementine UV-VIS data are normalized to the same spatial resolution and IMM's registration precision is compared. The biggest error of control points' registration is only 0.63pixel. Besides, IIM images acquired at different time covering the same district of lunar surface were compared and evaluated through parameters of radiance precision, definition and information content, and the time span is two months. The parameters calculated are very close, illustrating that the instrument worked stably at that period.
PRIMARY APPLICATION OF THE MEMBERSHIP FUNCTIONS IN THE GEOMAGNETIC DISTURBANCE PREDICTIONS
Wei Feng-si, Cai Hong-chang
1990, 10(1): 35-41.   doi: 10.11728/cjss1990.01.035
Abstract(1859) [PDF 472KB](80)
Abstract:
Prediction test for 40 geomagnetic disturbance events caused by the flare-associated interplanetary shock waves, which can be identified by interplanetary scintillation (IPS) observations during 1984-1985, are made based on the membership functions established by using observational data on the solar flares, the interplanetary shock waves and the geomagnetic disturbances during the period of 1966-1982. Main results are: (1) Prediction of the magnetic disturbance onset time-for 50% of all events, the relative error, δT/T≤10%; and for 70%,δT/r≤20%; (2) Prediction of the geomagnetic disturbance amplitudes-for 80% of allevents, the relative error, δ∑Kp/∑Kp≤30% ; and only for 15%, δ∑Kp/∑Kp≥60%. These results show that the method adoption in this paper has some potential prospects for investigating the flare-associated interplanetary shock waves and the geomagnetic disturbance predictions.
One Case Study About the Development of Coronal Hole and the Correlative Earth Effects
MA Donglan, LIU Siqing, GONG Jiancun
2005, 25(2): 86-92.  
Abstract(2577) [PDF 2510KB](57)
Abstract:
The evolutionary features of the coronal hole, the interplanetary and geomagnetic field effects were studied in this paper using the data of a significant coronal hole which recurred between 2003 and 2004, and the data of its correlative solar wind, interplanetary magnetic field (IMF) and geomagnetic field. It is found that the development of the coronal hole can be separated into three phases according to the geomagnetic field effects of coronal hole. That is growth phase, maturation phase and decay phase. There are different characters among these three phases. During maturation phase, the maximum solar wind speed of the high speed stream and the average effect to magnetic field maintain a same level. That means the peak of solar wind speed and the corresponding geomagnetic index (average ∑Kp and maximum ∑Kp) are confined. On the other hand, the structure of this coronal high speed stream and the corresponding recurrent geomagnetic storm are studied. Then it is found that the high speed streams have steady structures on the maturation phase, and the durations of recurrent geomagnetic storms were varied with the high-speed streams. Meanwhile the duration of the high speed is related to the shape and development of the coronal hole, especially to the longitudinal extend of the coronal hole in equator.
Comparison of High Energy Particles Observation Results Between FY-3A Satellite and NOAA Series Satellites
Wang Chunqin, Zhang Xianguo, Wang Shijin, Wang Yue, Liu Chao, Jing Tao
2010, 30(1): 49-54.   doi: 10.11728/cjss2010.01.049
Abstract(2639) [PDF 708KB](51)
Abstract:
FY-3A satellite was launched in June 2008 into solar synchronization orbit (about 800 km altitude). There are detectors that can measure 3~300 MeV high energy proton and 0.15~5.70 MeV high energy electrons on FY-3A satellite to carry out long-time space particles environment measurement. During the period from 2008 to 2009, space environment is very quiet because of low solar activities. The detection results on FY-3A satellite shows that flux of 3$\sim$300\,MeV high energy protons mainly are confined to SAA, whereas flux of electrons are located in SAA and around the north and south poles. The result also shows that the flux of energetic particles is to be highly anisotropic. By combining the detection result from FY-3A satellite with that from NOAA satellites, we can also find there exit differences between the detecting data from the two series of satellites not only in the space distribution of particles but also in the intensity of particles. These show the flux of energetic particles is to be highly anisotropic influenced by different pitch angles. Considering the difference of the particles flux and distribution induced by limits of time and space, even and the different designs between the detectors on the two satellites, we compared the protons and electrons detection results from FY-3A with those from NOAA satellites. A generally good agreement is observed in the flux values and distribution trend of protons and electrons. All the above indicates the detectors on FY-3A satellite have the ability to measure space energy particles. The detection results are now available, so that we can use the data from FY-3A satellite to further study radiation belt particles distribution, origin and transmission.
Global Distribution of Currents in Martian Space
LIU Tongdi, LI Lei, ZHANG Yiteng, XIE Lianghai
2012, 32(6): 765-770.   doi: 10.11728/cjss2012.06.765
Abstract(2645) [PDF 1032KB](81)
Abstract:
Based on the MHD model, distribution of the currents in Martian space is calculated. The results show that there are 4 categories of currents, i.e., the bow-shock current, magnetic pileup boundary current, the ionosphere current and the magnetotail current in Martian space. Currents flow on the surface of the bow-shock independently, which direction are perpendicular to the interplanetary magnetic field direction, with the peak current density located around the subsolar point. At dayside, the magnetic pileup boundary current closes through the ionosphere; while at nightside, magnetic pileup boundary current couples with central current sheet in the magnetotail to form a complete circuit. Magnetotail central currents near Mars within 1.2Rm affected greatly by the ionosphere, would be separated for two or more current slices coupling together. The strength of ionosphere current, flowing from south to north, is the biggest in all, more than 100nA·m-2 in average; and the strength at dayside is bigger compared to that of the nightside.
Research on optical autonomous navigation for approach phase of Mars exploration
Cui Wen, Zhang Shaoyu, Zhang Shuyu, Baoyin Hexi
2013, 33(3): 313-319.   doi: 10.11728/cjss2013.03.313
Abstract(2665) [PDF 551KB](57)
Abstract:
The optical autonomous navigation has recently become one of the key topics in interplanetary space missions. According to the current research literature, most people only focused on the application of optical autonomous navigation for the cruise phase or the approach phase of asteroids exploration. The research for the approach phase of planets is rare. Based on the upcoming Mars exploration program of China, with the research of dynamics model, observation model and filtering algorithm, the process of the optical autonomous navigation during the Mars approach phase is studied. Through the observability analysis of the navigation system, the feasibility of using Mars optical information only for autonomous navigation is proved. Simulation result showed that the total time of the optical autonomous navigation for approach phase is about 40 hours. In the last 5 hours, the filtering results are becoming stable. The overall position error is less than 40km, and the velocity error is 0.25m·s-1. The stability and accuracy of the results can meet the requirement of actual task, and is referencable for Chinese Mars exploration program.
Mid-latitude Planetary Waves Observation from MST Radar Measurements in the Troposphere and Lower Stratosphere
TANG Lei, HUANG Chunming
2016, 36(2): 175-187.   doi: 10.11728/cjss2016.02.175
Abstract(1330) [PDF 3710KB](63)
Abstract:
Characteristics of the Planetary Waves (PW) in the Troposphere and Lower Stratosphere (TLS) were investigated with Mesosphere-Stratosphere-Troposphere (MST) radar wind measurements in Xianghe (116.9°E, 39.8°N) from January 2012 to December 2014. Spectral analyses show that the TLS region is dominated by quasi-16-day and quasi-10-day PW, while the former ones are more significant. In the troposphere regions (above 17km height), the PW with dynamic periods are primarily observed, which last less than three months and don't indicate significant seasonal variation. Meanwhile, the amplitudes of the PW in the zonal direction exceed those in the meridional direction. In the lower stratosphere regions, intense PW mainly occur in the zonal component in winter. The amplitudes in the stratosphere are generally smaller than those in the troposphere. This paper also discusses the propagation characteristics of PW based on MST radar data and MERRA reanalysis data. The result shows that zonal component of the quasi-16-day PW observed in February and March 2014 propagated eastward with a zonal wave number of 2 (the horizontal wave length was about 15324.7km). The corresponding phase velocity was 11.1m·s-1 (positive eastward). The quasi-16-day PW propagated upward vertically with a 64km vertical wave length. In addition, the observation in May 2014 showed that the quasi-10-day PW in the zonal component propagated eastward with a zonal wave number of 1. Its horizontal wave length, phase velocity and vertical wave length were 30649.4km, 35.5m·s-1 and 50km respectively.
Medium and Short Term Forecasting of Ap Related to Coronal Holes
LiuSiqing, Luo Bingxian, Zhong Qiuzhen, Dou Xiankang
2009, 29(6): 545-551.   doi: 10.11728/cjss2009.06.545
Abstract(2707) [PDF 590KB](78)
Abstract:
Ap index is a daily measure of geomagnetic activity. In many reference atmospheric models, geomagnetic storm effects are modeled using Ap index as the driver of global density changes. Ap index is often used in making space mission plans because of the geomagnetic activity effects, and the forecasting of the Ap index plays an important role in space environment prediction. In the present study, the modified autoregressive model is used to forecast the Ap index 27 days ahead. In the modified model, the input data were reconstructed based on the 27-days periodicity of the solar rotation. The average absolute error between the forecasted and observed geomagnetic Ap index is 4.5. For short-term Ap forecasting (3-days ahead in this paper), a new forecasting index Pch derived from the SOHO/EIT EUV images is used. Pch index is a parameter which can reflect both the area and brightness of coronal holes. Because the high speed stream will arrive at the earth orbit and cause geomagnetic disturbances about 3 days later after a coronal hole passes over the center meridian of the solar disk, the parameters of coronal holes can be used to forecast the geomagnetic disturbances. The average absolute error between the forecasted and observed geomagnetic Ap index is 3.7. According to the results of medium term and short term forecasting, the prediction accuracy can be improved by combining the statistical method with the physical analysis above.
Comparison of BBFs observed by single and multi satellites
Cao Jinbin, Cheng Chao, Ma Yuduan, Cai Chunlin
2010, 30(4): 343-348.   doi: 10.11728/cjss2010.04.343
Abstract(2920) [PDF 297KB](210)
Abstract:
This paper, using the data of three Cluster satellites, compares the observations of Bursty Bulk Flow (BBF) by single satellite with those by multi satellites. The results indicate that there exists remarkable difference between observations of BBF by single satellite and multi satellites. The observations of BBF by a single satellite depend on its position relative to the flow channel. The difference is caused by the localization characteristics of fast flows in the plasma sheet, and can lead to diverging views about substorm and causal relations among substorm phenomena.
Numerical Simulation of Thermocapillary Convection in an Evaporating Liquid Layer Under Microgravity Condition
Ji Yan, Liu Qiusheng, Zhu Zhiqiang
2008, 28(4): 350-355.   doi: 10.11728/cjss2008.04.350
Abstract(2967) [PDF 1745KB](59)
Abstract:
A new model of the evaporation of a pure liquid layer underlying its own vapor is proposed and analyzed. The liquid layer is subjected to horizontal temperature gradient under microgravity condition. The thermocapillary convection is coupled with the evaporation, adding complication in the interfacial mass and heat transfer. An analytical expression for temperature distribution is given in pure evaporation case without considering thermocapillarity. For the case of both evaporation and thermocapillary convection, a finite difference algorithm is developed to solve simultaneously the thermal and flow fields in the liquid layer at various evaporation Biot number and Marangoni number until the steady state solution is achieved. The influence of evaporation Biot number and Marangoni number on the interfacial mass and heat transfer has been discussed. Three regimes of the coupling between evaporation and thermocapillary convection are found and explained from our numerical results.
THE CORRELATIONS BETWEEN THE TYPHOON AND THE f0 F2 OF IONOSPHERE
Shen Chang-shou
1982, 2(4): 335-340.   doi: 10.11728/cjss1982.04.335
Abstract(1915) [PDF 502KB](87)
Abstract:
The effect of typhoon on the critical frequency of the F2 region has been studied by using the observations made in 1969,1970,1972,1973.There are 21 observations of typhoon crossing or passing by Hainan chosen to compare with the simultaneous ionospheric data of the same area.It is found that there are evident correlations between the passage of the typhoon and the f0 F2.It is indicated that the f0 F2 decreases in the area right above the centre of the typhoon,but increases in the surrounding area.We suggest that the strong vertical convection in the troposphere caused by typhoon can change the local circulation system in the stratosphere and mesosphere,and this would influence the f0 F2 (e.g.number density of electrons in F2 region) through the change of the height of the turbopause and the change of the ratio of atmospheric composition in the F2 region.The result of this work shows that the study of the effect of the typhoon on the upper atmosphere is an applicable method for the research of the coupling between the upper and lower atmospheres.
Observations of Atmospheric Gravity Waves in Airglow Over Adelaide
JIANG Kui, DING Feng, WAN Weixing, Reid I M, Woithe J M
2007, 27(6): 491-497.   doi: 10.11728/cjss2007.06.491
Abstract(2726) [PDF 2001KB](35)
Abstract:
This paper presents the statistical results of the propagation characteristics of largescale gravity waves observed by OH and OI airglow during the years from 1995 to 2001 in Adelaide, Australia (34.5°S, 138.5°E). The propagation parameters were obtained through the three-channel maximum entropy method. Totally 48 gravity wave events were identified by the OH airglow observation and 29 events were identified by OI. The periods and horizontal phase speeds of these gravity waves peak at about 68 min and 36 m/s, and the gravity waves shows an obvious dominating direction of propagating south-eastward. The mean elevation is 8°- 10°, which shows the nearly horizontal propagation trends. It was also found that an up-going gravity wave event was observed nearly simultaneously by OH and OI. However, in most cases, the gravity waves cannot be observed simultaneously by OH and OI observations, because of the errors of the instruments or the effects of strong wind shears on gravity waves in the mesopause region.
WASTEWATER TREATMENT AND MANAGEMENT IN SPACE STATION
ZHOU Kanghan, LI Junrong, LIU Chengliang, SHEN Liping
2002, 22(2): 169-176.  
Abstract(2313) [PDF 739KB](81)
Abstract:
There need a mount of water in space station during long manned flight. To reduce the maintenance expanditure of flight, wastewater must be recovered and achieve a close loop circulation of water. The key task lies in resolving the problem of wastewater treatment and utilization and constituting a reasonable water circulation system based on the feature of wastewater in space station. In this paper, the wastewater treatment methods in space station are analyzed and compared, a space station integrated water management scheme was designed, and its rationality and feasibility are also discussed and verified from many aspects.
Forecasting geomagnetic activity Kp index of space environment with Hp
Song Dan, Xue Bingsen, Cheng Guosheng
2013, 33(2): 151-157.   doi: 10.11728/cjss2013.02.151
Abstract(2291) [PDF 578KB](73)
Abstract:
Geomagnetic disturbance can cause a series of changes for near-Earth space environment, including the ionosphere and magnetosphere, and Kp index is the important reference index for disturbance of space weather. Hp component data monitored by GOES-8 satellite of geosynchronous orbit was used in this paper. By analyzing statistical relation between Kp index and Hp component width of fluctuation, it is shown that the change of Hp component and Kp index have good correlation. Based on the change of Hp component, Kp index in the same time interval is calculated, and then Kp index forecast model is established by means of regression analysis and RBF neural networks. Monitoring results show that the prediction method has certain validity and practicability especially that Kp index calculated by artificial neural networks is quite consistent with its measured values. By using this method, it is able to forecast geomagnetic disturbance quickly, and to provide reference in time for space weather guarantee not relying on the data from geomagnetic diction. In addition, China is going to launch FY-4 satellite, on which a magnetic field detector will be carried. Hence, this research will provide the foundation for application using FY-4 data in the future.
THE NONLINEAR INTERACTION OF FORCED ROSSBY WAVE PACKETS IN THE MIDDLE ATMOSPHERE I.THEORICAL ANALYSIS
Xiong Jian-gang, Yi Fan, Li Jun
1994, 14(3): 198-204.   doi: 10.11728/cjss1994.03.198
Abstract(2015) [PDF 489KB](68)
Abstract:
The problem of the stability of the forced Rossby wave packets which are nonlinearly interacted resonantly in the middle atmosphere is examined analytically.The expression of the stationary state and the condition of the stability are given.When there is only one forced wave packet, if its lengthscale isn't between that ofthe other two, the forced wave will not translate its energy to the others in thestationary state, the others are exhausted by Rayleigh friction. But if the wavelengthof the forced wave is between the other two, the stationary state bifurcates to another stable one as the intensity of the forcing increasing to some value. After thebifurcation, the amplitude of the forced wave will not vary with the forcing, but itincreases with the atmosphere height, the energy increased is translated to otherwave packets eventually. When there are two forced wave packets, the system willtend to stationary states with nonzero wave amplitudes of all three wave. Moreresults will be given through numerical analysis.
Development of the Microgravity Experimental Device for Pulverized Coal Combustion
YU Qiang, AI Guozhi, WU Le, XU Minghou
2011, 31(5): 635-639.   doi: 10.11728/cjss2011.05.635
Abstract(2431) [PDF 518KB](68)
Abstract:
A facility that can be used for pulverized coal combustion experiment in microgravity is described. It is used to study pulverized coal particles’ pyrolysis, gasification, ignition, volatile release, char combustion and burnout, and other combustion characteristics in microgravity. The pulverized coal is blown into the furnace chamber intermittently. When the temperature reaches the set point, turn on the valve and put pulverized coal into the furnace chamber, and then observe whether pulverized coal can be ignited so as to determine the ignition temperature of pulverized coal. By detecting the coal gases in the combustion, the volatile changes in precipitation of char combustion and the burnout characteristics can be attained. The flame structure and flame temperature distribution can be recorded by CCD image. The structure, the working principle and the experimental results of this facility are introduced. Further improvements of the facility are presented.
Research on Observing and Analyzing Phase Differences of All-sky Meteor Radar
SHEN Jincheng, NING Baiqi, WAN Weixing, HU Lianhuan
2012, 32(1): 75-84.   doi: 10.11728/cjss2012.01.075
Abstract(2381) [PDF 1049KB](61)
Abstract:
A new method is developed on analyzing and estimating phase differences between each antenna of All-sky meteor radar by the mathematical model derived from the distribution of meteors and the antenna configuration. Using the observational data collected from the meteor radar, the temporal-spatial distribution properties of meteors and their effect upon the spatial distribution of meteors, especially the effect upon the variance properties of height distribution result from the phase difference variations of the antennas, are achieved. On this basis a simulation is created to estimate the phase difference variations by the variance of meteors' height distribution. Then this method is applied to analyze data collected from Sanya All-sky meteor radar. The results show that phase difference variations from one antenna or more are able to be estimated by analyzing the observational data without any additional hardware. And the accuracy is less than 2 degree. The calibration to the phase different variations can efficiently improve the measurement precision of the meteors' angles of arrival and the relevant data quality.
Research and Development of an Impact Testing System for Space Docking Mechanism
Han Wei, Huang Yiyong, Zhang Xiang, Chen Xiaoqian
2013, 33(5): 548-553.   doi: 10.11728/cjss2013.05.548
Abstract(1944) [PDF 796KB](90)
Abstract:
In the paper, a new ground based impact experiment system is designed to study the impact phenomenon of probe-cone docking mechanism in the course of spacecraft docking. Firstly, the whole scheme of the system, which includes the composition of the experiment system, experiment process, experimental sample and design of related devices, is given. Then, the frequency characteristic of acceleration and the effect of initial velocity on the impact time are summarized by numerical simulation on the basis of Hertz contact law, and the essential principle to choose the accelerometer for the experiment system is concluded. At last, the experiments of low speed impact are carried out. The experimental results show that the design scheme can meet the demand for measuring the docking impact force.
Properties of New Polyimide Film for Spacecraft
WANG Lei, QING Fengling, FAN Hanlin
2012, 32(6): 869-873.   doi: 10.11728/cjss2012.06.869
Abstract(2348) [PDF 394KB](41)
Abstract:
Atomic oxygen is one of the hazard factors for spacecraft in Low Earth Orbit (LEO). Atomic oxygen interacts with thermal control coatings. The interaction is very aggressive toward coatings properties, especially their thermo-optical properties which are the most important for spacecraft thermal control. Depending on the relationship of conformation and performance, new polyimide film was synthesized to improve the atomic oxygen resistance. The results of atomic oxygen with ground simulation test indicate that the second surface mirrors thermal control coating made by the new polyimide film has better atomic oxygen resistance properties than the coating being in use. Environmental adaptability tests such as ultraviolet irradiation test, proton irradiation test, electron irradiation test were made also. The test results show that the second surface mirrors thermal control coating has very good performance.
Precise Orbit Determination Based on Reduced Dynamic Batch LSQ Estimation Method Using Dual-frequency GPS Observations
WANG Wenbin, LIU Rongfang
2014, 34(4): 460-467.   doi: 10.11728/cjss2014.04.460
Abstract(1179) [PDF 629KB](84)
Abstract:
The dual-frequency GPS carrier phase and pseudorange measurements have become the primary observations for accurately determining the position and velocity of satellites in low Earth orbit (LEO). Reduced dynamic batch least squares (LSQ) technique is used for LEO orbit determination using pseudorange and carrier phase ionosphere-free measurements, which combines the merits of kinematic positioning technique with pure dynamic orbit determination. In order to compensate for any unmodelling or inaccuracy of the employed dynamic model, piece-wise constant accelerations are estimated in consecutive subintervals on the basis of a precise deterministic force model in the batch LSQ method. Particularly, the paper introduces two methods for calculating the sensitive matrix related to empirical accelerations and solving for the inverse of a banded sparse matrix. GRACE-A real flight data has been used to evaluate the positioning performance of the proposed method. Positioning accuracy of less than 5cm in terms of 3D RMS was achieved. The magnitudes of empirical accelerations were all less than 40nm·s-2 in radial, along-track and cross-track directions. The extra dynamic parameters CD and CR were estimated within a reasonable range and the space-borne receiver's clock offset was linear with small periodic fluctuations.
Comparison of the Correlations between the Interplanetary Parameters and Geomagnetic Indexes
Wu Hong-zhong, Du Heng
1986, 6(3): 196-202.   doi: 10.11728/cjss1986.03.196
Abstract(1692) [PDF 493KB](42)
Abstract:
Regression and multiple regression are performed for the data of mean houly values, mean daily values, and daily ranges of interplanetary parameters and geomagnetic indexes in the period of 1966-1975. The correlations between interplanetary parameters and geomagnetic indexes are analysed and compared.
Study of the Response of the Ionosphere Over Sun-Lit Boundary Region to Solar Flare
ZHANG Donghe, LI Qiang, QIN Jiansheng, XIE Shibiao, ZHAO Yingxine YE Jinfenge MO Xiaohua, XIAO Zuo
2006, 26(5): 321-325.   doi: 10.11728/cjss2006.05.321
Abstract(2754) [PDF 1438KB](47)
Abstract:
Using the model of solar irradiance spectrum during large solar flare and MSIS, the electron production rate during flare over sun-lit boundary region is calculated. It is found that during large solar flare the obvious increase of electron production rate over sun-lit boundary region occurs that, in turn cause the sudden increase of total electron content observed in this region. From the profile of electron production rate in different solar zenith angle, it can be seen that the largest electron production rate decreases with the zenith angle increasing and the heights of peak electron production rate increase. Calculation shows that the double peaks exist in the profile of electron production rate when the zenith angle less than 90° that correspond to ionospheric E and F region. Nevertheless, the peak value of electron production rate in F region is more larger than that in E region when zenith angle larger than 90°. Considering the feature of recombination of electron and ion in different ionospheric regions, it can be concluded that the sudden increase of total electron content observed by GPS mainly occurs in F region over sun-lit boundary region.
Auroral electrojet event associated with magnetospheric substorms
Zou Ziming, Cao Jinbin, Li Yi
2010, 30(4): 349-355.   doi: 10.11728/cjss2010.04.349
Abstract(2570) [PDF 214KB](61)
Abstract:
The auroral electrojet index is an important index in monitoring and predicting substorms. A substorms usually includes auroral breakup, auroral electrojet event marked by AE increase, energetic particle injection at geosynchronous orbit, mid-low latitude Pi2, etc. However the question whether an auroral electrojet event corresponds to a substorm remains unanswered. Using the auroral electrojet index in 2004, we analyzed five auroral electrojet events and studied their relation with substorms. The results show that there are three kinds of auroral electrojet events: (1) simultaneous rapid increase of westward auroral electrojet and eastward auroral electrojet; (2) rapid increase of westward auroral electrojet and almost unchangeable eastward auroral electrojet; (3) rapid increase of eastward auroral electrojet and almost unchangeable westward auroral electrojet. Most of auroral electrojet events correspond to substorms. However a few auroral electrojet events are not accompanied by substorms. This situation most often occurs for the auroral electrojet event in which eastward auroral electrojet dominates.
Implementation of adjoint/reverse monte carlo method in the analysis of satellites radiation
Lan Ting, Chen Dong, Chen Shanqiang, Shi Liqin, Liu Siqing
2015, 35(2): 203-210.   doi: 10.11728/cjss2015.02.203
Abstract(1167) [PDF 1177KB](77)
Abstract:
The Reverse Monte Carlo (RMC) method is a powerful biasing technique available in Geant4, also known as the Adjoint Monte Carlo method. In this method, particles are generated on the external boundary of the sensitive part of the geometry and then tracked backward in the geometry till they reach the external source surface, or exceed an energy threshold. By this way the computing time is focused only on particle tracks that are contributing to the tallies. The RMC method is much rapider than the Forward Monte Carlo (FMC) method when the sensitive part of the geometry is smaller compared to the rest of the geometry as well as the external source. Compared with the FMC method, accuracy of the RMC method applied to the radiation dose of the satellite is verified. Comparisons of RMC with the SHIELDOSE2, SSAT show that RMC is the preferred method of high-precision satellite radiation dose.
Satellite Formation Establishing in Near Circular Orbit
MENG Yunhe, DAI Jinhai
2006, 26(2): 148-154.   doi: 10.11728/cjss2006.02.148
Abstract(2202) [PDF 996KB](70)
Abstract:
Based on the assumption of near circular orbit, a method to establish a formation flying with multiple satellites in the same point of orbit-intry was discussed. Firstly, from Gauss' equations and relative motion equations, the relation of control impulse and relative motion was expressed as analysis formulas and simplified based on the near circular condition. By deeply analyzing the mechanism of impulses in each directions (radial, in-track and cross-track directions) effect on relative motion respectively, two maneuvers to establish formation flying are provided: one is to utilize the impulses in radial and cross-track directions, the other is to utilize the impulses in along-track and cross-track directions. Both of the two methods can establish satellite formation flying of any configuration. The method with impulses irradial and cross-track directions needs only 3 impulses, while the method with impulses in along-back and cross-track directions needs 4 impulses. Lastly, by an example of establishing a space-circle formation flying, two maneuvers were compared with each other in the amount of impulses and fuel consuming estimation. Simulations show that the methods are simple and practical, which could solve the establishing problem of satellite formations on near circular orbit easily.
Satellites Separation Method With Eccentricity and Inclination Vector
Li Jiancheng, Zhao Haijun, An Jinwen
2009, 29(6): 605-608.   doi: 10.11728/cjss2009.06.605
Abstract(2276) [PDF 424KB](50)
Abstract:
With the rapid increasing of application of geostationary satellites, the limited geostationary source is becoming run out. Collocating several satellites within the same longitude/latitude window is proved to be a good way. Successful separation with eccentricity vector of two Chinese geostationary satellites was achieved in 2003. To meet the different collocation requirement, and compensate the drawbacks of the eccentricity vector separation, this paper investigates the collocation strategy with eccentricity vector and inclination vector, which largely increases the relative separation of satellites. East-West Station Keeping (EWSK) and North-South Station Keeping (NSSK) procedures are discussed in the paper; and the separation constraints and implementation for two Chinese satellites are also given. The simulated minimum distance between the satellites within a period is more than 10\,km, and these two Chinese geostationary satellites work in orbit with secure operation.
Numerical computation of proton geomagnetic vertical cutoff rigidities on 7-8 November 2004
Zhen Jie, Chu Wei
2013, 33(3): 250-257.   doi: 10.11728/cjss2013.03.250
Abstract(2458) [PDF 883KB](28)
Abstract:
The geomagnetic cut-off rigidity can effectively measure the shielding effect of Earth's magnetic field on cosmic ray particles. In this paper, the single particle orbit theory is used to simulate the movement of cosmic ray protons in the Earth's magnetosphere and the specific location within the magnetic field along the vertical direction to the earth center. Based on the establishment of T04 and IGRF2000, the fourth-order Runge-Kutta method is used to simulate the trajectories of particles. The vertical cutoff rigidities of global cosmic protons around the height of 450km above Earth's surface at two moments in November 2004 are calculated. The value change of geomagnetic vertical cutoff rigidity with the magnetic latitude and magnetic longitude is analysed with the help of 684 calculation results at the same moment. The changes of protons vertical cutoff rigidity with the height from Earth's center, at the position of magnetic latitude of 30°, magnetic longitude of 0°, 45°, 90°, 135°, 180°, 225°, 270°, 315°, are also simulated. Simulation results show that the change of geomagnetic effective vertical cutoff rigidity with the increasing height from the Earth's center is getting more and more slow and slower along the sunny direction to the magnetic tail.
Numerical Research About Interaction Between Two Tube Models Containing Spiral Magnetic Field Lines With a Little Small Length-Scale
YE Zhanyin
2008, 28(3): 194-202.   doi: 10.11728/cjss2008.03.194
Abstract(3036) [PDF 4694KB](36)
Abstract:
After a long time interaction, governed by the magnetohydrodynamic (MHD) equations, between the Parker solar wind flow and a potential magnetic field combined by a dipole and a hexapole, a special streamer background structure in the solar meridian plane is presented. With the background structure, two tube models containing spiral magnetic field lines with a small length-scale can move in the computational domain step by step, interact afterward and trigger a Coronal Mass Ejection (CME) finally. The tube model is approached by a structure made up of two-dimensional co-circular magnetic field lines, with a ratio of the plasma pressure at its center to that at its edge m=2 and with a radius a for two cases: a=0.07 Rs (Rs is the solar radius) and a=0.1 Rs respectively. Corresponding to the two cases, two typical numerical results are obtained. In the case a=0.07 Rs, the two tube models interact with each other, merge into one set of co-circular magnetic field lines in seven solar radii and propagate outward. In the other case a=0.1 Rs, the two tube models do not merge into one and keep two sets of co-circular magnetic field lines exist in the computational domain during their propagation as a whole.
CDGPS Relative Position Determination of Distributed SAR Satellite Formation Based on Dynamic Orbit Model
Gu Defeng, Zhu Shubo, Yi Dongyun
2009, 29(5): 515-521.   doi: 10.11728/cjss2009.05.515
Abstract(2437) [PDF 672KB](47)
Abstract:
To determine the baseline of distributed SAR satellite formation at high accuracy, a CDGPS relative position method of distributed SAR satellite formation based on dynamic orbit model is presented. At first, CDGPS principle is introduced. And then, intersatellite relative position method based on dynamic orbit model is introduced. Based on CDGPS measurement, this method introduces prior restricted information provided by dynamic orbit model, and overcomes the disadvantage that kinematic single point position determination can not be used when observation geometry is bad or observations are not enough. This method can restrain the random errors in measurement, improve relative position accuracy and provide a technology approach to realize intersatellite baseline determination at mm level. At last, simulation computation verifies the efficiency of the dynamic method. Computational results show that the dynamic method can improve the relative position accuracy remarkably. Compared with kinematic method, the fixed solution accuracy of L1 is improved by 68%, and the fixed solution accuracy of ionosphere free combination is improved by 95%.
Forecasting of ionospheric f0F2 in China using neural network
Chen Chun, Wu Zhensen, Sun Shuji, Ding Zonghua, Xu Zhengwen, Ban Panpan
2011, 31(3): 304-310.   doi: 10.11728/cjss2011.03.304
Abstract(2587) [PDF 651KB](33)
Abstract:
By using artificial Neural Network (NN) and considering the effects of the solar and geomagnetic activities on the ionosphere in this paper we brought out a method to forecast the ionospheric critical frequency, f0F2, in China up to 5 hours ahead. The inputs of the NN are time, day of the year, geographical latitude, solar zenith angle, the twelve recent past observations of f0F2 (F-23, F-22, F-21, F-20, F-19, F-18, F-5, F-4, F-3, F-2, F-1, F0) and the 30-day mean moving values of f0F2 (A-24, A-23, A-22, A-4, A-3, A-2, A-1, A0) from the target location. The outputs of the NN are F+1, F+2, F+3, F+4, F+5, representing the values of f0F2 up to 5 h ahead. Data from Wulumqi, Changchun, Chongqing and Guangzhou stations spanning the period 1958---1968 are used for training the NN. Historical data at nine different stations in China are used to checkout the network respectively (Not including the training set). The performance of the NN is measured by calculating the Root-Mean-Square error (RMS) difference between the NN outputs and measured station data. The results indicate that the prediction of NN has good agreement with measured data. Taken into account those temporal and spatial inputs mentioned above, the NN can be applied successfully in the short-term forecasting of the ionospheric f0F2 in China.
Validation of Global VTEC Maps Constructed Using Data Derived From COSMIC Constellation
LEI Xiaolong, FU Yang, XUE Zhengang, DU Xiaoyong, YAN Wei, LU Xu
2011, 31(6): 754-764.   doi: 10.11728/cjss2011.06.754
Abstract(2722) [PDF 770KB](88)
Abstract:
The construction of reliable global maps of vertical total electron content of the Ionosphere (Vertical TEC or VTEC Maps) is a useful but challenging task. A new technological route to construct global VTEC maps has been raised by us that COSMIC RO data points are collected during the past 24 hours in the sun-fixed coordinate system (local time and geomagnetic latitude) and then vertical TEC values within height range from 110km to 750km are calculated by numerical integration of electron density profiles at these RO points after quality control. At last, ordinary Kriging method is adopted to construct Global COSMIC TEC Maps with a grid resolution of MAGLat 2.5°× 2 h. Comparisons during the interval from DOY (Day of Year) 001, 2008 to 181, 2010 between Global COSMIC TEC Maps and IGS GIMs, from DOY 194, 2008, to 181, 2010 between Global COSMIC TEC Maps and OSTM/JASON-2 observations have been made, and differences are calculated for different seasons, local time and geomagnetic latitudes. It proves that COSMIC TEC Maps have good agreements with IGS GIMs and OSTM/JASON-2 observations, so COSMIC TEC Maps are accurate enough to be used to correct the ionospheric delay in GNSS systems. With further improvement on RO theories and commencement of new RO constellations in future, the quality and quantity of ionospheric RO data will be raised greatly with no doubt. Hence, it will be a much promising technology to apply ionospheric RO data to correct the ionospheric delay for GNSS systems.
The Ground-Based Double-Boom Electric Field Detector
Li Yan, Zhuang Hong-chun, Ding Jian-gang, He Yu-hun
1989, 9(1): 33-44.   doi: 10.11728/cjss1989.01.033
Abstract(1670) [PDF 695KB](46)
Abstract:
The principle, structure and property of a kind of ground-based double-boom electric field detector is described here. The atmospheric electric condition represented by the typical recording is analysed. The conception of equipatition of frequency is proposed. The characteristic resistance value is calculated through the analysis of the typical detected data. According to the analysis of the joint measurements with an electric field mill, a method is proposed to distinguish the fluctuation of the local electric condition and the influence from the upper atmospheric electric condition.
Simulation and Validation for CRRES Satellite Internal Charging Effects
LI Xuesheng, JIAO Weixin
2007, 27(4): 309-314.   doi: 10.11728/cjss2007.04.309
Abstract(2188) [PDF 1719KB](33)
Abstract:
Firstly, a method based on the Geant 4 software is introduced. It can calculate the electric field arisen from internal charging effects under the special space environment. Secondly, the space electron environment CRRES satellite was located on was analyzed and used to simulate the internal charging effects. Lastly, the attempt has been made to compare the data from the CRRES IDM space experiment and the data from simulation results. This comparation showed that the calculation method is validated and some basic conclusions about the space environment which causes the internal charging effects are drawn. The calculations show that the high-energy electron flux/energy spectra is the primary cause of discharges. The material characteristics, especially the RIC (Radiation Induced Conductivity) and dose rate factor kp are very important to the steady state electric field. For studying the internal charging effects, need to mensurate these material characteristics accurately in laboratory.
One-step Ahead Prediction of f0F2 Based on Phase Space Reconstruction
Kong Qingyan, Liu Wen, Jiao Peinan, Fan Junmei
2009, 29(2): 208-212.   doi: 10.11728/cjss2009.02.208
Abstract(3502) [PDF 558KB](34)
Abstract:
One-step ahead prediction of critical frequency f0F2 is presented, using samples of about 5856 observations of f0F2 with 15-minute time resolution taken from a station in the low latitude, from March 2005 to April 2005. Based on phase space reconstruction of chaotic time series, and according to the theory that near trajectories have similar characteristics, the k-nearest neighbor method is taken to forecast f0F2 15 minutes ahead. Training method and self-adaptive-select method are attempted to define the neighbor numbers used for prediction, and for these neighbors, averaging method and regression ones are taken to treat them. The forecasting errors for those methods are compared. It is shown that one-step ahead forecasting method based on phase space reconstruction can reach high accuracy. In addition, the method has the advantage of easy to implementing with high processing speed. So it is quite suitable for quasi real-time prediction.
Calibration of Multiband Microwave Radiometer Used for Oceanic Calibration/Validation Site
WANG Zhenzhan, LIU Jingyi, ZHANG Yu, ZHENG Wei, LI Bin
2014, 34(4): 474-482.   doi: 10.11728/cjss2014.04.474
Abstract(1524) [PDF 1815KB](148)
Abstract:
Oceanic Multiband Microwave Radiometer (OMMR) is a five-band and 10-channel remote sensor, which is designed for in-situ calibration and validation of HY-2 satellite's scanning microwave radiometer. It was demanded to satisfy the requirements of providing higher accuracy brightness temperature data than those of microwave radiometer during its one-year lifetime. Due to its special operating condition on the platform and some unexpected interference that might be suffered in this period, an effective calibration method is necessary and critical. In this paper, the principle of OMMR internal calibration was introduced, and attentions were paid on the analyses of calibration result of tests both in laboratory and on the platform. By using these calibration results, the data from in-situ measurements on the platform are given and evaluated.
External Heat Flux of the Solar Array on the Polar Lunar Orbit
SONG Xin, ZHANG Youwei, LIU Zijun, SI Dongbo
2015, 35(3): 362-367.   doi: 10.11728/cjss2015.03.362
Abstract(1408) [PDF 1112KB](95)
Abstract:
Accurate lunar surface temperature distribution model is important for human lunar exploration. But there is a lack of research on how to calculate the temperature distribution of the entire lunar surface. In this paper, an entire lunar surface temperature model has been established which uses Racca model to calculate temperature of the lunar sunny side. For lunar shady side, the lunar surface is divided into several zones along the latitudinal direction whose temperature is solved by one-dimensional non-steady heat conduction equation. According to Chang'E-3 solar array temperature data, parameter values of the heat conduction equation are amended. Thermal analysis results of Chang'E-3 solar array temperature are in good agreement with the measuring data, which preliminary proves that this model is sound and feasible. Based on lunar temperature distribution calculated by this model, heat flux characteristic of the solar array on polar lunar orbit has been researched.
Optimizing the NRLMSISE-00 Model by a New Solar EUV Proxy
XUE Bingsen, CANG Zhongya
2017, 37(3): 291-297.   doi: 10.11728/cjss2017.03.291
Abstract(1444) [PDF 1289KB](50)
Abstract:
Solar EUV radiation is one of the sources for atmospheric density variation in thermosphere. NRLMSISE-00 model is widely used to simulate the density variation in the satellite orbit. However, this model always exhibits large density errors compared with satellite observations.In this work, the model output is compared with CHAMP satellite observation on the same position, and an ideal value of proxy for solar EUV (F*) is chosen through changing the input F10.7. Further investigation shows that F* is closely related to another solar EUV index MgII. By using of neuron network technique, the correspondence relationship between the new proxy of solar EUV (Feuv) and F10.7 and MgII. The target parameter is F*. The new proxy substitutes F10.7, and is input into NRLMSISE-00 model. The results show the difference of thermosphere density between those detected by CHAMP and GRACE-A satellite and that calculated by the NRLMSISE-00 model is dropped significantly.
Three Dimensional Simulation of the Steady Solar Wind in Carrington Rotation 1935
XIANG Changqing, FENG Xueshang, YAO Jiusheng
2006, 26(1): 8-13.   doi: 10.11728/cjss2006.01.008
Abstract(2522) [PDF 2880KB](73)
Abstract:
A three-dimensional MHD simulation is conducted to study the steady solar wind in Carrington Rotation (CR) 1935 by using the three-dimensional numerical magnetohydrodynamic (MHD) model introduced by Feng et al. The numerical results demonstrate that the neutral current sheet has two peaks and two valleys, which is consistent with the result of PFSS model at Wilcox Solar Observatory (WSO). The obtained proton number density at 2.5 Rs is of the same order of magnitude as the result estimated from K-coronal brightness during the CRs 1733-1742 in 1983made by Wei et al. The radial velocity profile along heliocentric distance is consistent with that of low solar wind speed deduced by Sheeley and Wang et al. However, it is not able to reproduce the fast-speed flow in coronal holes and slow solar wind in streamers because of oversimplified energy equation adopted in our model. Future efforts must be made to remedy this deficiency.
Bone-specific Transcription Factor Runx2 on the Role of Antagonistic Bone Loss In Space
GUO Feima, DAI Zhongquan, WU Feng, SHANG Peng, LI Yinghui
2011, 31(5): 627-634.   doi: 10.11728/cjss2011.05.627
Abstract(2572) [PDF 839KB](56)
Abstract:
To construct a stable expression of Runx2 in C2C12, MG63 cells, and primarily investigate the role of Runx2 against bone loss induced by spaceflight. Myoblast C2C12 and pre-osteoblast MG63 was transfected with Runx2 and selected overexpressing cell clone with G418. The stably transfected C2C12, MG63 cell lines with Runx2 were identified by westernblot and named C2C12-Runx2 and MG63-Runx2 respectively. The expression of genes regulated by Runx2 were determined using Real-time Quantitative PCR. The stable cell lines and untransfected cell lines were cultured in clinostat to simulate microgravity condition and detected the expression of Runx2 and its downstream genes by Real-time Quantitative PCR. C2C12-Runx2, MG63-Runx2 cell lines were gained which were overexpressing Runx2. The mRNA expression level of Alkaline Phosphatase (ALP) and Col1a1 increased in C2C12-Runx2 andMG63-Runx2 cells. The mRNA expression of ALP and Col1a1 decreased in the clinorotation group compared with the control group in MG63, C2C12-Runx2 and MG63-Runx2 cells. The decreased degree of ALP, Col1a1 mRNA expression in both transfected cell lines was lower than in untransfected cell lines under simulated microgravity condition. C2C12-Runx2, MG63-Runx2 cell lines were successfully constructed. The data from clinorotation and Real-time Quantitative PCR suggest that Runx2 can partly antagonize the decreased expression of osteogenic specific molecules induced by simulated microgravity.
Three-Dimensional Dynamic Modeling and Simulation of a Beam Attached to a Spatially Moving Base
XIAO Jianqiang, ZHANG Dingguo
2006, 26(3): 227-234.   doi: 10.11728/cjss2006.03.227
Abstract(2191) [PDF 1665KB](61)
Abstract:
The three-dimensional dynamics of a flexible cantilever beam attached to a moving rigid body undergoing an arbitrarily three-dimensional large overall motion is investigated in this paper. A set of dynamic equations for two-dimensional transverse and one-dimensional longitudinal vibrations of the flexible beam is established by using Lagrange's governing equations of motions the coupling effects of dynamic method. In the construction of the the so called transverse deformation-induced longitudinal deformation is included, which leads to the consideration of the dynamic stiffening effects in the obtained dynamic equations. An example is given to show the validity of the method presented in this paper and also the significant effects of the dynamic stiffening terms on the deformation and the dynamic characteristic of the flexible beam, and the difference between the present modeling theory and the traditional vibration theory as well. The traditional vibration theory of flexible beam will produce large error when the flexible beam itself is at higher speed large overall motion. Once the speed reaches at a critical value, the traditional dynamic system will diverge. Whereas the present model has high precision and the dynamic system converges even if the flexible beam undergoes higher speed large overall motion.
Effect of LED on Plant Growth and Development in Space Culture Chamber Simulator
ZHANG Yue, PAN Jing, SUN Weining, ZHENG Huiqiong
2015, 35(4): 473-485.   doi: 10.11728/cjss2015.04.473
Abstract(1397) [PDF 1812KB](95)
Abstract:
The goal of this study is to analyze the influence of LED light on the growth and development of plant in the plant culture chamber simulator for space experiment. The daylight fluorescence lamp was used as control to investigate the advantages and disadvantages of using LED in the plant cultivation, to provide reference data for the experiments of plant culture on board Chinese space lab TG-2 or space station in the near future. This paper focused on the influence of different LED conditions, e.g. spectra component, light intensity, light period and air exchange, on the growth of Arabidopsis thaliana and rice at different developmental stages. The results indicated that higher ratio of red to blue light could induce early flowering and early senescence in Arabidopsis and rice, respectively. The optimum ratio of red to blue light for the growth of Arabidopsis and rice is around 3.9. When the ratio is higher than 16, the growth of both Arabidopsis and rice was suppressed and leaf senescence was induced. In closed container, increased light intensity up to 150μmol·m-2·s-1 could partially release Arabidopsis growth inhibition caused by limited air exchange. When light intensity is higher than 150μmol·m-2·s-1, the growth and development of Arabidopsis were severely inhibited. For rice, the tolerance to high light was higher than Arabidopsis under limited air exchange conditions. Thus, the red to blue ligh ratios, light intensity and limited air exchange in microgravity environment should be considered when LED is used as light source in space plant culture chamber.
Tidal Variability Observed by MF Radar and Comparison with GSWM Model
LIU Xiao, XU Jiyao, YUAN Wei, JIANG Guoying, MA Ruiping
2008, 28(6): 547-554.   doi: 10.11728/cjss2008.06.547
Abstract(3400) [PDF 925KB](50)
Abstract:
The tidal variabilities are studied by using the data from the 14th July to 14th August in 2006, observed by the 3 MHz and narrow beam MF radar located at the Andoya Rocket Range (69.14ºN, 16.02ºE). The results indicate that, the intensity of the zonal and meridinal components of the diurnal and semidiurnal tides has experienced the process of weak to strong and again to weak in the height range 78~94 km. This shows that, the new tides may be produced due to the instability induced by the interactions between tides and other waves during the upward propagation of tides, and again the new tides propagated upward stably. These phenomena may also be caused by the momentum deposition due to the breaking gravity waves or other waves. The tidal amplitude varies not only with increasing height, but also with time evolution. The variability of the diurnal tidal amplitude is very strong and varies by a factor of 3 in some days. Based on the recent results, the gravity waves instability and breaking are one of the causes to induce the tidal variability. Furthermore, The comparative results between the observation and GSWM-00 model shows that, the model can forecast results for the amplitude and phase of the diurnal tide are very good, but it isn't very ideal for the semi-diurnal tide's.
THE ORBITS DISIGNING FOR INTERPLANETARY PROBES AND ARTIFICIAL PLANETARY SATELLITES
Zheng Xue-tang
1991, 11(1): 40-45.   doi: 10.11728/cjss1991.01.040
Abstract(1970) [PDF 412KB](96)
Abstract:
In this paper, the dynamical model, orbital motion and mission time for interplanetary probe and artificial planetary satellite are given. The disign for orbit to cut mission time and save fuel is discussed and the stable region of artificial planetary satellite is also obtained.
Some Properties of X-ray Selected Quasars
Liu Ru-liang, Yang Hao-shou
1985, 5(2): 84-91.   doi: 10.11728/cjss1985.02.084
Abstract(1832) [PDF 557KB](51)
Abstract:
Statistical analysis for 109 X-ray selected quasars as well as 114 radio and optically selected quasars ds carried out in this paper. On the histograms of their redshift, optical luminosity and average optical X-ray spectral index, it is found that X-ray selected quasars are distributed at the low ends of plots of these parameters. On the plot of the monochromatic X-ray luminosity against the monochromatic optical luminosity l0 for all samples, most of the X-ray selected quasars are situated in'optically-faint regions of low luminosity. If we take lglo=31.2erg/s·Hz as a line of demarcation, and divide the optical luminosity into optically-bright and optically-faint regions, it is found that the radio and optically selected quasars have a slope of b=0.64 in the optically-bright region on this plot, and 6=0.95 in the optically-faint region, while the value of b of the X-ray selected quasars is only 0.78, thus implying that they may be a subtype of quasar phenomenon. Finally the factors affecting b are discussed briefly.
CHROMOSPHERIC MAGNETIC FIELDS OBSERVATION FOR QUIET-SUN REGIONS
ZHANG Mei, ZHANG Hongqi
1999, 19(4): 289-294.   doi: 10.11728/cjss1999.04.289
Abstract(2283) [PDF 494KB](65)
Abstract:
Using the solar magnetic field telescope in Huairou Station of Beijing Astronomical Observatory, the solar photospheric and chromospheric magnetic fields forquiet-Sun regions have been observed for the first time. By a study of deep magnetograms of solar photosphere, chromosphere and different levels of chromosphere,it is found that the network magnetic tubes do not diverge a lot from the solarphotosphere to the chromosphere, which is contrary to the popular canopy model'spredication. It is also found that the intranetwork magnetic tubes have reached thesolar chromosphere, which is also contrary to the dynamo model's Predication thatthe intranetwork magnetic tubes will not reach high atmosphere. This observationof solar chromospheric magnetic fields for quiet-Sun regions have challenged twopopular models of solar atmosphere.
Experimental Research and Numerical Simulation on Deep Charging for Spacecraft Dielectrics
Quan Ronghui, Han Jianwei, Zhang Zhenlong, Yan Xiaojuan, Huang Jianguo
2009, 29(6): 609-614.   doi: 10.11728/cjss2009.06.609
Abstract(2632) [PDF 591KB](74)
Abstract:
Deep charging effect caused by high-energy electron irradiation is one of the key factors threatening spacecraft safety under the environment of space radiation. This paper compares the deep charging progress of different thickness polyimide films under different electron beam intensity, simulates the GEO orbit radiation environment with Sr90 radioactive source, and studies the charging progress of Delrin and Teflon under its radiation. This paper also presents a new model, which simulate the experiment results. It also analyzes the deep charging equilibrium potential and time with different electron intensity and dielectrics resistance. It shows that deep charging effect becomes more serious with increasing electron beam intensity and dielectrics resistance, and the time to reach charging equilibrium is mainly affected by dielectrics resistance.
Spacecraft Task Hierarchical Scheduling Analysis Within Fixed Priorities
He Feng, Song Liru, Xiong Huagang
2009, 29(5): 522-528.   doi: 10.11728/cjss2009.05.522
Abstract(2424) [PDF 526KB](103)
Abstract:
In the autonomous control architecture for spacecraft, layered structure style is adopted. It manages all categorical applications through partition management to avoid interaction among them. This paper focuses on the partition schedulablity analysis and the partition design for fixed priorities scheduling model. It introduces a more exact partition task worst-case response time algorithm through observing the actually iterative operator, and addresses a partition designable condition based on the upper limit of the task utilization factor within the fixed priorities. By using the cost function, it also proposes the partition key parameters resolution model and a local optimal algorithm to implement the whole processor partition design. At last, it introduces a practical example to illustrate the validity of the analysis and design methodology.
Parallel Numerical Model for the Simulation of Gravity Wave’s Nonlinear Propagation
Liu Xiao, Xu Jiyao, Li Wenqiang, Gao Hong
2009, 29(3): 296-303.   doi: 10.11728/cjss2009.03.296
Abstract(3488) [PDF 896KB](36)
Abstract:
Based on the idea of MPI (Message Passing Interface) and the domain decomposition, a paralleled numerical model is developed for the simulation of gravity wave's nonlinear propagation. The model is based on the staggered grid system. The domain decomposition technique and data communication between each sub-domain in the staggered grid system are also presented in detail in the paper. The numerical simulation results for the propagation of gravity wave with small amplitude indicate that, the parallel numerical model can reproduce the propagation of small amplitude gravity wave and preserve the energy conservation relation. The parallel efficiency is about 0.65 and can be approximate to its maximum of 1.0 under the perfect conditions. As the comparison with the sequence model, the nonlinear propagation of gravity wave with finite amplitude was simulated by using the sequence and parallel model with different resolutions and the same computational time. The results indicate that, the parallel model can resolve the Kelvin-Helmholtz billows which appear after the time when gravity wave overturns and before the time when the turbulence is excited due to its relative higher resolutions and more processes. But, the sequence model can't resolve the fine phenomena due to its lower resolutions in the same computational time.
Variation Characteristics of Tropopause Temperature and Height
From COSMIC
Yuan Wei, Xu Jiyao, Ma Ruiping
2009, 29(3): 311-318.   doi: 10.11728/cjss2009.03.311
Abstract(3809) [PDF 736KB](36)
Abstract:
The global variation characteristics of tropopause are shown by analyzing the data of temperature profiles from Radio Occultation (RO) observations aboard the satellites of COSMIC. These satellites have excellent explorations with global coverage and vertical resolution. The accurate and high vertical resolution temperature profiles from RO/COSMIC provide a unique opportunity to study the global structure and variability of tropopause. The daily mean temperature data from the day 111 of 2006 to the day 295 of 2007 are chosen for the analysis in this paper. The global distributions of tropopause height and temperature and their temporal variation depending on latitude, by using the method of Lapse Rate Tropopause (LRT), are discussed. These results indicate that the global distributions of tropopause temperature and height are consistent with the investigation by some radiosondes and the reanalyses data of the European Centre for Medium-Range Weather Forecasts (ECMWF). There are three important characteristics in the present study: (1) the obvious seasonal variation of tropopause height and temperature, (2) the reversed phase variability of tropopause height between the equatorial, lower latitude and the higher latitude, and (3) the North-South asymmetry of the annual variation of tropopause temperature and height.
DEPENDENCE OF FIELD-ALIGNED CURRENTS ON THE ORIENTATION OF THE INTERPLANETARY MAGNETIC FIELD
JIAO Weixin, PU Zuyin
2000, 20(2): 144-149.   doi: 10.11728/cjss2000.02.144
Abstract(1866) [PDF 379KB](58)
Abstract:
Field-aligned currents (FACs) measured in the inner magnetosphere by theISEE-1 and -2 spacecraft are investigated as a function of the Interplanetary Mag-netic Field (IMF) orientation and the level of geomagnetic activity, as indicatedby the AL index. It is found that~75% of the FACs observed are associated withsouthward IMF. The remaining 25% occur during the period of IMF turning fromsouthward to northward- Very few are associated with sustained intervals of north-ward IMF. Approximately 75% of the FACs occur when the AL index is < -150 nT.The current intensity and density are higher for both southward IMF and high gecrmagnetic activity. These results show that the occurrence of FACs within the innermagnetosphere is controlled mainly by the IMF, with the actual occurrence being aconsequence of enhanced electrodynamic coupling between. the solar wind and themagnetosphere- ionosphere system.
Precise orbit determination for GEO satellites based on both satellite clock offsets and station clock offsets
Guo Rui, Liu Li, Li Xiaojie, Cheng Yue, Chang Zhiqiao
2012, 32(3): 405-411.   doi: 10.11728/cjss2012.03.405
Abstract(2441) [PDF 491KB](72)
Abstract:
Because of its dynamical features, orbit parameters of the Geostationary satellite (GEO) are strongly correlated with clock offset parameters in Precise Orbit Determination (POD) when using the L-band pseudorange data. In order to solve this problem, clock offsets of the satellite clock as well as the receiver clock are introduced, which are obtained by unattached observation technology. Therefore, the pseudorange data could be converted to ranging data. This paper discussed the GEO POD principle based on pseudorange data with the support of clock offsets, and analyzed the POD accuracy using simulation data from China regional tracking network. Influences from the clock offsets a2 item and errors of the satellite clock offset, stations' clock offsets and systematic errors were analyzed both theoretically and quantitatively.
Primary Study About the Relationships Between Coronal Holes' Parameters and the Correlative Geomagnetic Disturbances
LUO Bingxian, LIU Siqing, ZHONG Qiuzhen, GONG Jiancun
2007, 27(2): 117-124.   doi: 10.11728/cjss2007.02.117
Abstract(2518) [PDF 1812KB](30)
Abstract:
Data from the SOHO EIT284 images are used to analyze the development of coronal holes which existed from 1996 to 2005. In order to investigate the relationship between the coronal hole and earth effect, the correlativity of the coronal hole parameters including coronal holes' area and longitude span, with solar wind parameters and geomagnetic index were examined. Our investigation shows that: The correlation between coronal holes' longitude extend (20°N-20°S) and geomagnetic disturbance duration is very good. For coronal holes that appeared in 2002, the linear-correlation coefficient is 0.91, and for a long-lived recurrent coronal hole that existed for 15 Carrington rotations from 2002 to 2003, the Pearson Coefficient is 0.934. There is poor correlation between coronal holes' areas and maximum solar wind speed in the high speed stream. This result is different from the result that Nolte found in 1976. This might remind us that the solar wind speed in the high speed stream is not only related to the coronal holes' areas. The relationship between the high speed stream and the coronal hole must be much more complex. The correlations between the yearly averaged maximum solar wind speed in CHHSS (Coronal Hole-High Speed Stream) and the yearly averaged corresponding geomagnetic field index, for example, Ap index and Kp index are good, especially for the declining phase of solar activity cycle 23. But to the individual samples, fast velocity does not mean intense geomagnetic disturbance, which means that solar wind velocity is not the only major role that causes earth effect. From the study of a recurrent coronal hole that existed for fifteen Carrington rotations, we found that the daily average velocity maximum v^-max shows somewhat correlation to Kp maximum during the the geomagnetic disturbance. The linear-correlation coefficient is about 0.604.
Derivation of GPS-TEC and Instrumental Biases in the Equatorial Anomaly Region
GAO Wei, MA Guanyi, CHEN Yanhong, SHEN Hua, LI Jinghua, HUANG Wengeng, LI Zheng
2008, 28(6): 541-546.   doi: 10.11728/cjss2008.06.541
Abstract(2997) [PDF 1168KB](48)
Abstract:
Based on least-square technique, this paper presents a method to derive GPS-TEC and instrumental biases of GPS observation in equatorial anomaly region. Applying the method to the data from 4 GPS receivers located at Fuzhou, Xiamen, Guangzhou and Nanning in 2006, the TEC is obtained for 48 meshes with size of 3°× 1° in longitude and latitude covering an area of 20~28°N, 105°~123 °E. The instrumental biases are stable in the whole year. The satellite biases are close to those published by Center for Orbit Determination in Europe. This method can be used to study the ionosphere in equatorial anomaly region.
LIQUID SLOSHING IN SPHERICAL TANK WITH SPACER AT LOW GRAVITY ENVIRONMENT
Wang Zhao-lin, Cheng Xu-duo, Quan Bin
1990, 10(2): 107-119.   doi: 10.11728/cjss1990.02.107
Abstract(1966) [PDF 616KB](75)
Abstract:
In this paper, the sloshing of liquid in a spherical tank with spacer is investigated under low-gravity conditions. Unsing the method which concerning a kind of charateristic functions, expanded into polynominal expressions, the free and forced-sloshing problems are solved. The natural frequencies of liquid sloshing are obtained. The equivalent mechanical models of liquid sloshing are given. The moment and force of liquid acting on tank wall are derived. The numerical results are compared with the ones of spherical tank without spacer, and the advantages of spacer are shown.
Analysis of Solar Activities and Changes
HAO Lisheng, BI Baogui, YAO Xuexiang
2007, 27(4): 265-270.   doi: 10.11728/cjss2007.04.265
Abstract(2473) [PDF 2251KB](29)
Abstract:
Solar activities have obvious effects on earth's climate. Many scientists have studied the relationship between solar activities and climate change, and a lot of papers have been published in this field. The relative sunspot numbers is an important factor in the research of solar activities. Wavelet transform is a fine method to analyze time serials periods. By using different data, the periods are different. In the past time, many scholars had analyzed solar activities by others statistical methods, found that changes of solar activity have periods of 5-6 years, 11 years, 22 years, 80-100 years, and so on. The periods are so disunity that they can't be better used to forecast change trend of solar activities. In this paper, being applied to analysis of solar activities, the wavelet transform method was introduced to analyze periods change, and found some meaningful results. The relative sunspot numbers change with periods of 10.7 year and 101 year. The 10.7 year period is remarkable, and it's amplitude varies with time. In 1935 to 2000, the amplitude of 10.7 year period are especially distinct. The solar activities exist strong or weak phases. Abrupt change occurred in 1950 year, and solar activities became stronger since 1950. It is predicled that the solar activity will be weaker in the near future.
Disturbance of O+ Density Before Major Earthquake Detected by DEMETER Satellite
OUYANG Xinyan, ZHANG Xuemin, SHEN Xuhui, HUANG Jianping, LIU Jing, ZEREN Zhima, ZHAO Shufan
2011, 31(5): 607-617.   doi: 10.11728/cjss2011.05.607
Abstract(2669) [PDF 1631KB](44)
Abstract:
Based on the data observed by French DEMETER satellite, this paper analyzed anomalies which may be caused by Ms7.9 Tonga Islands earthquake (3 May 2006). Perturbations of electric field and plasma parameters above epicenter from observations six days, two days and one day before the earthquake can be seen by visual interpretation of level-2 images. The amplitude and duration of perturbations increased when the earthquake was approaching. Perturbation was also recorded two days after the earthquake and its amplitude was still large. The variation feature of O+ density was more obvious than that of H+ and He+ density, and O+ accounted for about 90% among total H+, He+ and O+ through analyzing the data detected by IAP (Plasma Analyzer Instrument) onboard DEMETER satellite which has a revisiting period of sixteen days. Compared with the revisiting orbits of a half orbit one day before the earthquake from 2006 to 2008, it was found that variations of O+ density can be classified into three types: density in northern hemisphere is higher than that in southern hemisphere in summer; the situation is quite the contrary in winter; and O+ density is almost equal in both southern and northern hemisphere in equinoxes season. This paper presented different effects on O+ density under influence of earthquake and geomagnetic storm. The earthquake affects the distribution of O+ density at an orbit close to the epicenter, while geomagnetic storm affects O+ density at all orbits in a storm day. O+ density increased 20% more at the orbit closest to the epicenter than the other orbits one day before the earthquake, and it increased nearly an order of magnitude referred to the mean of O+ density in May from 2006 to 2008. In addition, we obtained electron density detected simultaneously by ISL onboard DEMETER at the above-mentioned revisiting orbits and discovered that electron density increased synchronously with O+ density. The increment of plasma density may be related to the electric field anomaly which resulted from the earthquake and led to modification of ionospheric structure.
In-flight Experiment of Solar Wind Ion Detectors on Chang'E-1 and the Solar Wind Near the Moon
WANG Xinyue, ZHANG Aibing, KONG Linggao, ZHANG Xianguo, REN Qiongying, WANG Shijin, H. Réme
2013, 33(2): 143-150.   doi: 10.11728/cjss2013.02.143
Abstract(2522) [PDF 746KB](89)
Abstract:
It's the first time for the two scientific instruments of Solar Wind Ion Detectors (SWID-A/B) on Chang'E-1 to explore the plasma environment in the 200km lunar polar orbit. SWIDs are primarily developed for the scientific objectives of measuring the Moon-plasma interactions, and deducing the solar wind bulk speed, density and temperature. SWIDs observe the ions fluxes which include the information of solar wind speed, density and temperature. In this paper, the algorithm of deducing the solar wind bulk speed, density and temperature by the observation results of SWID-A/B is shown. By simulating the solar wind ions injecting to the SWIDs, the algorithm is validated. The characteristics of solar wind near the Moon are studied. During the period of the Sun disturbing comparatively quiet in solar minimum, it is found that the similar trend of variation is maintained when the solar wind go through the interplanetary to the Moon. Whereas the solar wind ions speed and density are the same to those of the upstream interplanetary solar wind, the solar wind temperature near the Moon is 10^3K higher than that of the upstream interplanetary solar wind.
Algorithm of the Capacity of Repetitive Observation of Remote Sensing Satellite Sensors
Li Ziyang, Li Chuanrong, Hu Jian, Gao Cai Xia
2009, 29(6): 615-619.   doi: 10.11728/cjss2009.06.615
Abstract(2390) [PDF 495KB](44)
Abstract:
Capacity of repetitive observation of remote sensing satellite sensors is a key indicator of the system's dynamic monitoring ability. In the paper, the algorithm of orbit computing for realizing repetitive observations was presented based on the analysis of repetitive observation conditions under two imaging modes: nadir and side-looking; selective orbits for repetitive observations in particular areas were also described taking the HJ-1A/1B satellites (the optical satellites of the small satellite constellation for environment and disaster monitoring and forecasting) for example. The work is focused on the orbits of HJ-1A/B satellites. Before computation and analysis of the orbits, the Area of Interest (AOI) should be defined. Considering the optical sensors, in this paper, only the orbits from north to south were computed, yet orbits from south to north were passed over. The capacity of repetitive observation is defined as the overlap of two satellite scenes. By analysis of the nadir imaging and the side-looking imaging mode, the paper draws the conclusion of how to choose the best orbit to realize repetitive observation. Finally, impacts of the satellite constellation consisting of two satellites on the repetitive observations as well as that of latitude were discussed.
OBSERVATION OF IONOSPHERIC DISTURBANCES WITH GPS BEACONS
WAN Weixing, NING Baiqi, YUAN Hong, LI Jingnian, LIANG Jun, LI Libin
1998, 18(3): 247-252.   doi: 10.11728/cjss1998.03.247
Abstract(2150) [PDF 363KB](34)
Abstract:
The GPS method is rarely used in the investigation of ionospheric disturbances because of the movement of the observation point which leads to the mixture of both spatial and temporal changes of the observed total electron content(TEC). The present work proposes a new experiment method to modify the effects of the montion of observation points by the observation of a short baseline array of GPS receivers.The experimental results show that the wave parameters of the ionospheric disturbances derived from the observation of a short baseline GPS array are of high precision and reliable. The main advantage of the new experiment method is that the short baseline GPS array may used to observe ionospheric disturbances in a large range.
Jointly Study on Flux Transfer Events Using the Data Observed by TC-1 and Cluster Near Dayside Magnetopause
YAO Li, LIU Shaoliang, LIU Kai, JIN Shuping, LIU Zhenxing, SHI Jiankui
2007, 27(1): 13-18.   doi: 10.11728/cjss2007.01.013
Abstract(2726) [PDF 1297KB](82)
Abstract:
One of the Double Star satellite TC-1 and Cluster both in the magnetosheath near the dayside magnetopause amount to 25 times from February to April, 2004, when TC-1 in the low latitude and Cluster in the middle or high latitude region. 27 Flux Transfer Events (FTEs) had been detected by these satellite during that interval. This paper analyzed the influence of the transverse component of the Interplanetary Magnetic Field (IMF) on the position at the magnetopause where the reconnection occurs, and searched the evidence of component reconnection. The main results are as follows: (1) when IMF southward component Bz is dominate (|Bz| 〉 |By|), 87.5% of FTEs were detected at low latitude by TC-1, but when IMF |Bz|〈 |By|, most FTEs (about 84.2%) were observed at middle or high latitude by Cluster; (2) there were a few correlative events (the correlative event means a event was observed by TC-1 and Cluster at low- and high-latitude, successively), this imply that most of the FTEs which occurred in lower latitude moved along the sides of the magnetosphere toward the magnetotail, only a few of them over the high-latitude; (3) most FTEs detected at middle latitude were not come from the equator, but burn at that region by the mode of component reconnection.
Adaptive prediction of maximum usable frequency in high-frequency communication
Liu Yanan, Liu Xuecai, Wang Jian, Lin Fajun
2013, 33(3): 286-292.   doi: 10.11728/cjss2013.03.286
Abstract(2894) [PDF 526KB](101)
Abstract:
In order to realize the adaptive prediction of maximum usable frequency in high-frequency communication, Volterra adaptive method is introduced. Based on the oblique sounding data of chain from Qingdao to Xinxiang in March 2007 and 2012, single-step prediction in different solar activity years and short-term prediction of different steps and training samples length are conducted to validate accurateness, adaptability and validity of this method. Results indicate that the super short-term prediction adopting Volterra adaptive method has good agreement with oblique sounding data and this method is suitable for different solar activity periods. When the prediction step is not more than 1/12 period, RMSE is less than 0.79MHz. Comparison with prediction results of Lyapunov exponent method shows that Volterra adaptive method can gain upper precision in the situation of less data, time-varying channel etc., and the practical application is more convenient. The method provides a basis for in-depth study of high frequency prediction technology.
A New INS/VNS Integrated Navigation Method for Planetary Exploration Rover
Xu Yongzhi, Ning Xiaolin
2015, 35(6): 721-729.   doi: 10.11728/cjss2015.06.721
Abstract(1473) [PDF 1956KB](98)
Abstract:
In traditional INS/VNS integrated navigation, the motion errors are usually used as the state vector, and relative motion errors between the inertial and vision navigation are used as the measurement. Since the relative motion is related to both the last and current states, traditional methods augment the position and attitude errors at the last time to the state vector to build the measurement model. The augmented states are considered as constant, and it generates new errors into the state model. Meanwhile, the measurement errors are analyzed based on ideal positions and attitudes at both the last and current time, which results in the measurement relationship with both the last and the current states. In this paper, a new INS/VNS model uses INS error equation as the state model, relative motion errors as the measurement, and attitude errors are described as quaternion error in the measurement model. The analyses of measurement errors are based on the integrated navigation estimation positions and attitudes at the last time, hence it does not need to augment the state, so the measurement only relates to the current state. The lunar surface simulation and experiment on the ground both show that the represented INS/VNS method can achieve high position and attitude estimation accuracy.
Effect of the Heating Flow on the Determination of the Field-aligned Currents
Xu Bin, Wu Jian, Cesar La Hoz, Wu Zhensen, Che Haiiqiin, Xue Kun
2009, 29(6): 573-579.   doi: 10.11728/cjss2009.06.573
Abstract(2420) [PDF 508KB](72)
Abstract:
The detection of the filed-aligned currents is an important scientific subject for the Europe Incoherent SCATter radar association (EISCAT). Using the different channels, the ion line and the plasma line can be observed synchronously by the incoherent scatter radar, which can be used to deduce the resonance frequency of the ions and electrons, and the filed-aligned current can be determined by these frequencies. The method is reasonable for the plasma with the Maxwellian distribution. However, the heat flow can be caused by the drift velocity in the velocity phase space. The 16-moment distribution function is used to describe the heat flow effect. On this basis, the solutions of the dielectric function and dispersion relation with a complex frequency are presented for an arbitrary velocity distribution, and the results are compared with those of Maxwellian distribution. The effects of the heating flow on the electron velocity distribution function, the real and imaginary parts of dielectric function, the resonance frequency and damping rate of ions and electrons, are discussed. With a positive electron drift velocity, the filed-aligned currents will be overestimated by the measurement of upshifted plasma line, and with a minus electron drift velocity, the filed-aligned currents will be underestimated. For the case that both upshifted and downshifted plasma lines are measured, the filed-aligned currents will be overestimated.
WARNING OF SOLAR PROTON EVENTS
HU Xiong, HUANG Zerong, ZHANG Xunxie, GONG Jiancun, XUE Bingsen, YE Zonghai
1998, 18(4): 323-328.   doi: 10.11728/cjss1998.04.323
Abstract(2857) [PDF 364KB](121)
Abstract:
A new warning scheme of solar proton events was proposed in this paper. In this scheme, five parameters including the solar flare position in the sun, the peak flux of X ray radiations and its rise bine, the half integrated fluxes of microwave fadiations of 2695MHz and 8800MHz, were used to give a warning of the occurences of solar proton events and their peak flux and time with an ANN (Artificial Neural Network) method. A simple discription of ANN was given. Some historical data of solar flares and solar proton events were provided for ANN's training and test repectively. Results showed that the presented scheme has a prediction accuracy of 93.75%.
SPACE DEBRIS COLLISION PREDICTION RESEARCH
LIU Jing, WANG Ronglan, ZHANG Hongbo, XIAO Zuo
2004, 24(6): 462-469.  
Abstract(2247) [PDF 713KB](61)
Abstract:
The population of orbital debris is increasing and these debris has serious hazards to spacecrafts in the earth orbit so to form an impact to human’s space activities. In recent decades, researches on space debris and its applications have attracted more and more attentions as a branch of space environmental study. In this paper, the issue of Space Debris Collision Prediction key techniques were studied, there after, the prediction method was established and tested. With large numbers of debris orbital data collected, this method and codes were verified by two collision and avoidance examples so to prove their validity. The conclusion was deduced that developing the collision avoidance technique and applying it into practice is feasible.
Theoretical Analysis of Surface Error for Deployable Truss Antenna
Yang Yulong, Guan Fuling
2009, 29(5): 529-533.   doi: 10.11728/cjss2009.05.529
Abstract(2779) [PDF 463KB](36)
Abstract:
Aimed at the characteristics of large deployable truss antenna with many trusses and joints, surface error and repetitive deployable precision of antenna with tolerances of trusses and joints clearances were studied. Considered the randomicity of tolerances of trusses and joints clearances, a stochastic finite element model of deployable truss antenna used Monte-Carlo method was developed to simulate the root mean square of surface error. It is shown that the value of root mean square of surface error caused by joints clearances is much larger than that from tolerances of trusses, and the repetitive deployable precision error of antenna can not be neglected.
Effect of Solar Cycle Activity on High Energy Proton of Inner Radiation Belt in the Low Altitude Region
SHI Liqin, LIN Ruilin, LIU Siqing, ZHENG Huinan
2012, 32(6): 804-811.   doi: 10.11728/cjss2012.06.804
Abstract(2717) [PDF 702KB](44)
Abstract:
The NOAA-15 high energy proton observation from 1998 to 2011 is used to analyze the effect of solar cycle activity on high energy proton flux. The statistic research indicates that there is an inverse correlative relationship between the proton flux in inner radiation belt and solar activity. This anti-correlation is related to geomagnetic coordinates L and B, and more significant with the increasing of L and decreasing of B. There is also a phase lag between the solar activity and the proton flux. This hysteresis effect is more obvious in the region with smaller L or larger B. The lag can reach one year in some regions. This hysteresis effect means it takes a long time to reach the dynamic balance between the source and the loss for the proton of inner radiation belt in the low altitude region. The unbalance between the source and loss is the reason why the intensity of proton flux at the same solar activity is different. The comparison with the result of AP8 model indicates the energetic proton flux from AP8 is higher than the satellite's observation in the region with large B, which suggests that the AP8 model may overstate the proton flux enhancement at inner radiation belt in the low altitude region if only the long-term variation of magnetic field is considered.
Research on Sloar Proton Event Warning With Observation Data of ACE Satellite
XIONG Senlin, CUI Yanmei, LIU Siqing
2013, 33(4): 387-395.   doi: 10.11728/cjss2013.04.387
Abstract(2737) [PDF 605KB](127)
Abstract:
Solar Proton Event (SPE) can bring significant radiation hazards to astronauts and spacecrafts in space. An accuracy SPE warning model is meaningful since some effective actions on basis of the warning results could be done to reduce the abundant radiation from which astronauts and spacecrafts would suffer. Therefore, a number of researchers try to build reliable SPE warning models, and some of the results are quite satisfactory. Five-minute- average real-time integral energetic solar protons flux data (mainly above 10MeV) from ACE satellite and GOES in Solar Proton Event periods were analyzed. Besides, correlation coefficients between two kinds of data were calculated. The optimal correlation coefficients were satisfactory, and they showed that the flux data from GOES have tens of minutes up to several hours lag time compared with that from ACE. This paper tries to use the ACE satellite data described above to build a new SPE onset warning method. Furthermore, five-minute- average real time integral energetic proton flux on GOES from Aug. 7, 2001 to Feb. 20, 2012 were utilized to check the new method's validity. This new method has low false probabilities (14.7%) and fairly good detection probabilities (76.3%) in SPE onset warning. Moreover, it has a prior time from tens of minutes up to couple hours. The results were compared with SPE warning results of SWPC, which shows this new method is superior to the latter in some extent.
Experimental Study on the Coupling of Thermocapillary Convection and Evaporation Effect in a Liquid Layer
Zhu Zhiqiang, Ji Yan, Liu Qiusheng, Yan Jiaping, Xie Jingchang
2008, 28(1): 12-16.   doi: 10.11728/cjss2008.01.012
Abstract(2305) [PDF 2373KB](41)
Abstract:
There has been a variety of applications for therm ocapillary convection and evaporation,such as t1iin-film evaporators, boiling teclinologies and heat pipes. And the stab ilities of therm ocapillary convection in a fluid layer subjected to a liorizontal temperature gradient have been experimentally and nulnerically analyzed by many scientists. While tlie inter I : acia I flow with evaporation,whic1i is a classical physical phenomenon, is absent of comp re1iensive understanding. Recently, many theoretical and experimental researcbes have found that evaporation plays a very important role inthe instabilities of therm ocapilllary convection. In our experiment, we study the coupling of the omcapillary convection and evaporation effect Ilor 0.65 cst Silicone Oil as the experimental liquid in a recta ngitlar cavity which has the I engtli of 0.08 m and width of 0.04 m. The temperature gradientalong the liquid layer, which induces t1ie therm ocapillary convection, is the dominate parameter. The temperature at the interface and the evaporating rate are measured by a thermocouple and a laser co focal displacement meter, respectively. The PIV metbod is applied for flow visualization, and the flow pattern transforms from a steady unicellular flow to a steady multicellular fiow, to a turbulent flow ultimately with the temperature difference along the interface increases from 2o C to l4o C . For discussion, the experimental results are compared wit1i linear stability analysis.
Application of DC/DC Converter in Secondary Power for Spacecraft
WANG Xiaopeng, YU Ping, LI Dongjing, QI Xinda
2011, 31(6): 814-820.   doi: 10.11728/cjss2011.06.814
Abstract(2559) [PDF 660KB](60)
Abstract:
In aerospace engineering, it is demanded to design a power system of high-reliability, high performance and strong anti-interference ability, to ensure the life of the spacecraft and its reliable operation. The DC/DC converter has been widely used in the secondary power supply in aerospace engineering attributing to its reliability, high integration, small size, high efficiency. But in the DC conversion process, it is easy to introduce various forms of interference and noise, which directly affects the quality of power supply, and consequently affects the spacecraft's technical performance. To solve the interference problem and improve the reliability of the secondary power supply, a number of key techniques have been discussed on the DC/DC design applications, including: soft-start, filter, Electromagnetic Compatibility (EMC), reliability. After taking corresponding measures, reliability of the secondary power supply has been greatly improved, with surge current being reduced to 1/20 of the original level, and the output ripple being reduced to 1/4 of the original level. The measured data of the CE (Conduction emission) and RE (Radiation emission) tests in the EMC were under the limitation of GJB 151A-97. Results of the experiments and actual application show that the anti-interference design is effective.
Effect of Acoustic Gravity Waves Excited by Anomalous Electric Field on Ionosphere Before Strong Earthquakes
XU Tong, HU Yanli, WANG Min, WU Jian, WU Zhensen, SUO Yucheng
2013, 33(4): 436-440.   doi: 10.11728/cjss2013.04.436
Abstract(2878) [PDF 439KB](153)
Abstract:
The study of the ionospheric disturbances prior to the occurrence of large earthquakes has attracted much attention for many years. However, until recently, the physical mechanism of seismo-ionospheric coupling is not fully understood. A strong perturbation of vertical electric field may take place within the epicentral zone a few days before strong earthquakes, which can penetrate into ionosphere through atmospheric conductivity. Acoustic gravity waves may be resulted from the non-stationary Joule heating of a local region above the epicentral zone of an imminent earthquake due to the anomalous electric field. Based on this mechanism and one-dimensional time physical model of ionosphere, the effect of acoustic gravity waves on ionosphere was calculated, which showed that the disturbance of horizontal neutral speed was too weak to have obvious effect on the ionosphere. This mechanism can not well interpret the ionospheric phenomena prior to strong earthquakes. Nevertheless, the electric field might modify ionospheric dynamic and electron density distribution through the effect of E×B.
Response of the Ionospheric F2-region Over Irkutsk and Hainan to Strong Geomagnetic Storms
E B Romanova, G A Zherebtsov, K G Ratovsky, N M Polekh, J K Shi, X Wang, G J Wang
2013, 33(5): 494-500.   doi: 10.11728/cjss2013.05.494
Abstract(2029) [PDF 1269KB](29)
Abstract:
The ionospheric responses to two strong storms on 17-19 August 2003 and 22-23 January 2004 are studied, using the data from Irkutsk (52.5°N, 104°E) and Hainan (19.5°N, 109°E) ionospheric stations. The analysis of variations in relative deviations of the critical frequency Δf0F2 revealed that at middle latitudes (Irkutsk) negative disturbances were observed in the summer ionosphere; positive and negative ones, in the winter ionosphere during the main and recovery phases respectively. At low latitudes (Hainan), the disturbances were positive in all the cases considered. Mechanisms of the disturbances were analyzed with the aid of empirical models of the neutral atmosphere NRLMSISE-00 and thermospheric wind HWM07. The main factors determining Δf0F2 variations at middle latitudes during the storms were demonstrated to be the disturbed equatorward thermospheric wind transporting the disturbed atmospheric composition, the increase in the atomic oxygen concentration, and the passage of internal gravity waves. At low latitudes, the effects associated with neutral composition variations are less significant than those of the thermospheric wind and electric fields.
CROSS-EQUATOR IPROPAGATION OF PLANETARY WAVES IN MIDDLE ATMOSPHERE
Ma Rui-ping
1995, 15(3): 207-214.   doi: 10.11728/cjss1995.03.207
Abstract(1950) [PDF 537KB](15)
Abstract:
A semi-spectral model of global primitive equation is used to simulate the cross-equator propagation of quasi-stationary planetary waves.The results show that the amplitude fluctuation and phase variation of the quasi-stationary planetary waves at the tropopause in winter can cause the cross-equator propagation of the planetary waves in the middle atmosphere and create the transient planetary waves in the summer hemisphere.A new mechanism that the cross-equator propagation of the planetary waves in the middle atmosphere and the source of the planetary waves in summer hemisphere and the coupling between northern and southern hemispheres was advanced by the simulation.
A STUDY ON SPACECRAFT INTERNAL CHARGING WITH MONTE CARLO METHOD
GAO Bingrong, HAO Yongqiang, JIAO Weixin
2004, 24(4): 289-294.  
Abstract(1961) [PDF 561KB](68)
Abstract:
Dielectric internal charging caused by energetic electrons will cause anomalies in Geosynchronous satellites, so it is an important problem faced by satellite designer. In recent years, many statistical studies have been conducted in this area. In this paper, Monte Carlo method has been used to simulate the charge deposition in the dielectric caused by energetic electrons. The electric field in the dielectric was calculated as the function of injected electron energy, thickness of shielding and dielectric. It is found that the electric field induced by the deposited charges in the dielectric has significant correlation with these three factors.
Research on the Application of Single-antenna GPS Measurement System on Guided Rocket
Ding Chuanbing, Wang Liangming, Zheng Cuicui
2010, 30(6): 607-611.   doi: 10.11728/cjss2010.06.607
Abstract(2136) [PDF 531KB](40)
Abstract:
In order to improve the attitude determination accuracy of the guided rocket which transverse size is not enough for fixing multiple antennae, a single-antenna GPS aiding attitude determination method was proposed. The pseudo attitude was introduced, using which the concrete algorithm for obtaining the altitude is analyzed. And the model of the single-antenna GPS aiding attitude is established. The Kalman filtering is adopted to filter the state vector model. And the relative velocity and acceleration is obtained. According to the relationship between ordinary and pseudo attitude, the ordinary attitude of guided rocket is obtained. Throughout the simulation research, the feasibility and effectiveness of the application of single-antenna GPS system on rocket projectiles is demonstrated.
TLE accuracy analysis and conjunction prediction
Li Dawei, Liu Jing, Zhang Yao
2012, 32(3): 398-404.   doi: 10.11728/cjss2012.03.398
Abstract(2618) [PDF 470KB](79)
Abstract:
Two Lines Elements (TLE) were widely used for on-orbit conjunction prediction. The accuracy of TLE data had great impact on conjunction prediction results, and was one of the necessary parameters for collision probability calculation. Only if the predicted position accuracy of TLE data were calculated exactly, the value of collision probability is reliable. In the research, the TLE position accuracy was calculated based on two kinds of criterion data, including updated TLE data and Consolidated Prediction Format (CPF) data, whose predicted position was more accurate than TLE data. The TLE position accuracy based on CPF data was used for true TLE position accuracy. Besides, both CPF data and TLE data were used for calculating conjunctions of satellites. CPF data was used for validating the conjunction results calculated based on TLE. The results of the research showed that the position accuracy based on updated TLE data was a little smaller than the true value. So in general cases, the collision probabilities were a little higher, which could be one reason for why conjunction predictions based on TLE were contained of a lot of fake results. With TLE data position accuracy based on CPF instead of updated TLE data, the conjunction results calculated with TLE data might be more reasonable.
Numerical Simulation of Liquid-Vapor Interface Tracking in Tank of Spacecraft
LI Zhangguo, LIU Qiusheng, JI Yan, HOU Hui
2008, 28(1): 69-73.   doi: 10.11728/cjss2008.01.069
Abstract(2381) [PDF 2394KB](69)
Abstract:
This paper presents a comprehensive analysis of the transport processes of propellant in tank of spacecraft in different gravity. The motion of the liquid-vapor interface of propellant in the tank of on-orbit spacecraft is investigated numerically by solving the incompressible Navier-Stokes equations using the VOF method coupled with the surface tension effect under micro-gravity environment. The objectives of this study are to examine the robust method of controlling the interface transformation of the two phase flow by comparing and analyzing the effects of gravity and contact angle as the typical parameters. Results show that, the gravity effect plays a dominant role in determining the shape of gas-liquid interface and the relative location of the gas-liquid phase in the tank at large Bond number; when the Bond number is small enough, the wettability effect exert a great influence.
Shear Rate Determination of Flow Near Magnetopause
Li Linghan, Chen Tao
2008, 28(4): 273-282.   doi: 10.11728/cjss2008.04.273
Abstract(2340) [PDF 4147KB](56)
Abstract:
Shear rate of flow near magnetopause is related to the degree of energy transfer near magnetopause. Many numerical simulations near magnetopause have to use shear rate of flow as an important input parameter. However, up to now it is still hypothetical and not realistic. By simultaneous multipoint observations of Cluster, using methods of linear interpolation and barycentric coordinates, we have determined shear rate of flow near magnetopause, an observational spatial parameter that can not be obtained until Cluster. Observational spatial distribution of shear rate of flow at dawn side and dusk side of magnetopause, magnetosphere and magnetosheath nearby has been analysed. Data analysis demonstrates that shear rate of flow as large as velocity difference of 330\,km/s over the distance of 100 km can exist near magnetopause sometimes even under quiet solar wind and geomagnetic conditions. Under many circumstances shear rate of flow near magnetopause is small, with the spatial velocity difference of dozens of km/s over the distance of 1000 km. The method we have adopted here can be used widely to determine shear rate of flow at any location.
Dynamic Prediction Model of Relativistic Electron Differential Fluxes at the Geosynchronous Orbit
LI Sheng, HUANG Wengeng, LIU Siqing, ZHONG Qiuzhen
2017, 37(3): 298-311.   doi: 10.11728/cjss2017.03.298
Abstract(1045) [PDF 9420KB](45)
Abstract:
The Empirical Orthogonal Function (EOF) analysis is applied to develop an empirical model to predict relativistic electron fluxes at the geostationary orbit. This model uses the solar wind parameters and geomagnetic index to forecast the EOF-coefficient, and then gives the 5min prediction results of relativistic electron differential fluxes during the coming day according to the EOF base function. By comparing with the original relativistic electron data obtained by GOES 10 from January 2003 to June 2006, it is found that the model is capable of approximately reconstructing the real changes of relativistic electron fluxes and of effectively forecasting their 5min variations. The mean prediction efficiency of this model is 67%.
SEMIANNUAL VARIATION OF GEOMAGNETIC Z COMPONENT AT LOW LATITUDE
MA Ruiping, XU Jiyao, JI Qiao
2004, 24(5): 340-345.  
Abstract(2468) [PDF 583KB](45)
Abstract:
Using the data collected in 4 geomagnetic stations located separately at Wuhan, Guangzhou, Quanzhou and Qiongzhong in the low latitude, the difference of geomagnetic Z component (Dz) between the diurnal average value and the average value of 1100-1300 LT at 5 quiet-day in every month have calculated. The amplitude and phase of semiannual variation in every year have obtained by analyzing the 12 Dz with multiple regression method. The result shows that Dz of 4 stations all have semiannual variation in every year. The amplitude of semiannual variation is related to the solar activity, and in general, the amplitude of semiannual variation of Dz in solar maximum is obviously greater than that in solar minimum. The semiannual variation of solar activity modulates the amplitude of semiannual variation of Dz obviously. The phase of semiannual variation of Dz is in March- April (or September-October), so the maximum of Dz appears in Equinox. The semiannual variation of geomagnetic Z component at low latitude indicates that the equato-rial electrojet have semiannual variation as well. The semiannual variation of the equatorial electrojet causes the f0F2 of ionosphere to appear semiannual variation by fountain effect. And this is a reasonable mechanism to produce semiannual variation of f0F2.
THE BLAST WAVE PROPAGATING IN A MOVING MEDIUM WITH VARIABLE DENSITY
Wei Feng-si
1982, 2(1): 63-72.   doi: 10.11728/cjss1982.01.063
Abstract(1951) [PDF 786KB](67)
Abstract:
The blast wave propagating from a point source in a moving medium with variable density has been treated.On the basis of the analytical solutions obtained by the paper some important characteristics of the flare-generated shock waves propagating in the Solar wind are discussed.It is found that the 1AUregion is just a transitional region of various important effects of the flare-generated shock waves; the equivalent power of the deceleration of Shock wave (D=K(uo,Es)R-t(uo,Es,R) is the function of Selar wind velocity uo,Shock wave energy Es and Shock's propagation distance R,usually i<1/2 and the convection effect of Solar wind is very important when R>1AU,due to this effect a stronger Shock wave could propagate to the 10-20 AU beyond,it consists with the recent observations of the space-crafts Pioneer 10 and 11.
Flow field prediction of an orbiter entering the Mars atmosphere
LÜ Junming, Cheng Xiaoli, Wang Qiang
2013, 33(2): 129-134.   doi: 10.11728/cjss2013.02.129
Abstract(2161) [PDF 1167KB](42)
Abstract:
Based on the hypersonic entry in the Entry-Descending-Landing procedure, the three-dimensional Navier-Stokes equations are solved by a parallel code to analyze the flow field structures, aerodynamic characteristics and their variation patterns of the Mars Science Laboratory entering the Martian atmosphere with and without the chemical reaction models. The analysis shows that parameters of the thermal dynamics and the transportation have an effect on the position and intensity of the shock wave. As a result of the chemical non-equilibrium effect, the shock layer is strongly compressed, the stagnation pressure decreases and the maximum temperature behind the shock is highly reduced where large number of CO2 is dissociated. Results of the streamlines on symmetric plane and in space reflect the complicated three-dimensional separation flows in the wake.
NUMERICAL SIMULATION OF IONOSPHERIC STRUCTURE BELOW F2 PEAK
Zhang Shun-rong, Huang Xin-yu
1994, 14(2): 116-124.   doi: 10.11728/cjss1994.02.116
Abstract(1743) [PDF 2824KB](70)
Abstract:
Taking account of the photo-chemical reactions and the transport processes induced by diffusion and neutral wind, a one-dimensional and time-dependent numerical model for the ionospheric profile is established, in which stable and metastable atomic ions [O+(4S), O+(2D) and O+(2P)]and molecular ions (O2+, NO+ and N2+) are involved. Based on the model, the ionospheric morphology and related processes at WUCHANG (30.5°N, 114.4°E) in the region below the F2 peak, especially. within the E/F and F1/F2 valleys, are discussed, and the main results are summarized as follows:(1) With respect to atomic ions, the chemical reactions and the transport process for O+(4S) only are responsible for a shallow F1/F2 valley; the O+(2D)Patticipated reactions are more favourable to form a deep one conversely, O+(2P), when present, is an unfavourable factor for ie valley formation. As for molecular ions, the transport induced by neutral wind is also beneficial for a deep valley. (2) The atomic-molecular ions transit level is located at about 180-190 km with a larger value for morning and evening hours only above which the linear assumption of the loss rate is valid in the traditional continuity epuation with respect to electrons.(3) The widest F1/F2 valley occurs at 11h (LT), and the deepest Due at local noon. The E/F valley width is generally about 20-30km for low solar activity and 25-45km for high one, and the morning and evening values are 10-20km larger. (4) O2+ with a double-peak profile is the most important composition in for ining Eand F1 ledges. Its low peak forms E-layer, while the upper one, in combination with NO+ contribution, makes up F1-Layer.Good agreements are found between the simulated and the observational results as a whole. The present model exhibits great potentiality for the study of ionospheric profiles, such as its mathematical description, the ionogram inversion techniques. and also the morphological and related mechanical research for a particular geophysical event.
Numerical Simulation on Single Bubble Pool Boiling in Different Gravity Conditions
ZHAO Jianfu, LI Zhendong, ZHANG Liang
2012, 32(4): 537-543.   doi: 10.11728/cjss2012.04.537
Abstract(2188) [PDF 592KB](64)
Abstract:
In this paper, the growth processes of a single bubble on a fixed single site and the relative heat transfer under different gravity are numerically investigated for saturated water at 0.1MPa. A simplified lubrication theory is used to predict the contribution from the micro-wedge area underneath the growing bubble, while vapor and liquid phases in other macro-area are treated as one fluid by using the continuum interface model. The Level Set Method and constant superficial contact angle are used to capture the interface between the vapor and liquid phases and the motion of contact line on the heating wall, respectively. The numerical results indicate that the equivalent diameter is proportional to about (1/3~1/2)-power of the growing time in spite of whatever gravity levels. But gravity has great influences on both the departure diameter and the growing time. The bubble departure diameter is proportional inversely to about 1/3-power of gravity, while the growing time is proportional inversely to about 4/5-power of gravity. The area-averaged heat fluxes are approximately proportional to the 3/2-power of the wall superheat when the number density of active nucleation sites fixes. Furthermore, this trend has no change with the decrease of gravity.
Gas-liquid Like Phase Transition in Granular Gases Under Zero Gravity
HOU Meiying, LIU Rui
2008, 28(1): 1-5.   doi: 10.11728/cjss2008.01.001
Abstract(2397) [PDF 1494KB](44)
Abstract:
Granular systems are intrinsically far from equilibrium for their many-body and dissipative nature.Driven by external foroes,they can behave like that of solids,liquids,or gases.In dilute granular gases,clusters usually form due to dissipation,which leads to inhomogeneous density distributions.Such a local condensation shows spontaneous symmetry-breaking instability and negative compressibility,just sa droplets form in vapor.In this paper,a three-dimensional model for granular gases under zero gravity is investigated,and calculations predict such a gas-liquid like phace transition.Molecular dynamics simulations show good agreements with the theoretical results.The numerical results shall provide detailed experimental parameters for the further related space exteriments.
Forecasting of Ionospheric Critical Frequency Using Neural Networks
CHEN Yanhong, XUE Bingsen, LI Libin
2005, 25(2): 99-103.  
Abstract(2740) [PDF 1368KB](73)
Abstract:
The use of feed-forward back propagation neural networks to predict ionospheric F2 layer critical frequency, f0F2, 24 h ahead, have been examined. The data we used are from Wuhan ionospheric station, China, and Hobart ionospheric station, Australia. The data period is from 1970 to 1990 at Wuhan and from 1962 to 1990 at Hobart. The five day's measurements of f0F2 before the day that need forecast are reduced to five coefficients. The inputs used for the BP neural network are the coefficients, the solar 10.7cm flux index, and the outputs are the day's 24 h observed f0F2 data. The trained net then can forecast f0F2 24 h advance. The result indicates the predicted f0F2 using NN has good agreement with observed data. Comparison with IRI model suggests that NN method is more accurate than IRI. In addition, the error analysis indicates that predicted f0F2's Root-Mean-Square Error (RMSE) is smaller in Hobart than in Wuhan, smaller in low solar activity than in high solar activity, smaller in winter and summer than in spring and autumn. In conclusion, using neural network to predict ionospheric parameters is a feasible method.
Effect of Interplanetary Magnetic Field on the Field-aligned Currents Occurrence in the Magnetotail
CHENG Zhengwei, SHI Jiankui, ZHANG Ziying, LIU Zhenxing
2013, 33(4): 396-402.   doi: 10.11728/cjss2013.04.396
Abstract(2438) [PDF 836KB](149)
Abstract:
Using the magnetic field and plasma data from Cluster spacecraft, the effect of Interplanetary Magnetic Field (IMF) clock angle Φ and cone angle θ on the Field-Aligned Currents (FAC) occurrence rate at the Plasma Sheet Boundary layer (PSBL) in the magnetotail is investigated. There were more FAC cases occurred when IMF was within the 0°< Φ< 180° clock angle range comparing with the range of -180°< Φ<0°. It indicated that FAC occurrences were associated with duskward IMF (IMF By>0). Also, there were more FAC cases occurred when the IMF was within the 90° < |Φ|< 180° clock angle range. It supported that FAC occurrences were associated with southward IMF (IMF Bz<0). Most of the FAC cases occurred when IMF was within the θ>30° cone angle. In addition, A few of FAC cases occurred when the IMF clock angle was in the θ<30° range regardless of the value of Φ. The occurrence rate of FAC was the largest when θ> 30° and 140°< Φ<160°.
THE COMPRESSION CODING OF SECONDARY PLANET INTERFERENTIAL SUPERSPECTRICAL IMAGE SERIES
XIAO Jiang, WU Chengke, DENG Jiaxian, YANG Yadong
2004, 24(3): 211-218.  
Abstract(2105) [PDF 1887KB](18)
Abstract:
A new second planet superspectrical image series compression coding algorithm is proposed in the paper. The algorithm adopts the still image compression method EBCOT (Embedded Block Coding with Optimized Truncation) as the coding engine, but it can efficiently reduce the redundancy among the frames. In the most documents on multispectral or superspectral images compression, the redundancy among the frames were usually reduced by 3 dimensional compression algorithm, such as 3 dimensional SPIHT, which in general based on 3 dimensional transform. Therefore, the huge memory is necessary when the transform is done, but the hardware system on the second planet must be lightest and with the lowest power consumption, and 3 dimensional compression algorithms are difficult to be used on the remote-sensing second planet. The novelty of the proposed compression coding method is that the interferential imaging characteristic of progressive scan is utilized to do the matching operation in the wavelet domain, when the relative shift between the two successive images is detected by the match method, the difference (error) image of the two images is encoded in stead of the origin image. Therefore the whole coding efficient is improved and the fidelity of the images can be improved by 3—4 dB. Since the complexity and memory is similar to the 2 dimensional compression algorithm, the algorithm is easier than the one based on 3 dimensional wavelet transform to be implemented on the second planet, and the disadvantage of large memory requirement and long encoding delay is overcome also. Numerical experiments on the 512-frame superspectrum image series show that the reconstructed images after using the proposed algorithm exhibit a comparative or even better effect at the same compression ratio than the 3 dimensional methods.
Lidar Study of the Background Na Layer Over Wuhan: Long Term and Nighttime Variations
PENG Caihua, YI Fan, ZHANG Shaodong
2006, 26(1): 28-34.   doi: 10.11728/cjss2006.01.028
Abstract(2493) [PDF 3523KB](64)
Abstract:
Based on the lidar observations from April 2001 to December 2004 over Wuhan, the long term (time scale longer than one year) and nighttime variations of background Na layer are presented, and their possible causes are also discussed. The observation results of long term variation show that Na abundance has a maximum value in November, which is approximately 2 times of the minimum value (1.6 × 10^9 cm^-2) in May; Na centroid height reaches a maximum value in August, which is about 1.4 km higher than the yearly average value (91.2 km); the average value of rms width is 4.5 km, and its maximum and minimum values occur in December and March, respectively; Both of the Monthly averaged centroid height and rms width show a quasi-semiannual variation, but with contrary phase variations. Except the long term variations, the background Na layer also exhibits obvious nighttime variation: Na abundance increase with the nighttime except a short duration near the dawn time with a maximum value of 2.9 ×10^9 cm^-2 at 0540 LT; the height of peak value decreases with the nighttime; the centroid height of Na layer increases slowly with the nighttime until the time of 0520 LT, then it decreases rapidly to the value at the time of 2000 LT; the magnitudes of the fluctuations for the averaged Na layer abundance, height of peak, centroid height and rms width in the nighttime are 1.2 × 10^9 cm^-2, 3km, 0.3km and 0.8km, respectively.
On fault-tolerance of IEEE1394 PHY/Link interface
Zhou Qingrui, Sun Huixian
2009, 29(1): 107-111.   doi: 10.11728/cjss2009.01.107
Abstract(2290) [PDF 588KB](27)
Abstract:
IEEE1394 bus is a high performance commercial bus standard. Today, it is gradually used in avionics. So it is necessary to study the fault tolerance of IEEE1394 to meet the avionics reliability and performance requirements. In this paper, the study is focused on the fault tolerance of PHY/link interface. All kinds of fault possibly presented in the interface signals between physical layer and link layer under PHY control, were analyzed. The techniques of how to
avoid these faults for serious damage to avionics were provided.
On the Expansion of Coronal Funnels in the Quiet Sun
Tan Bo, Tian Hui, He Jiansen
2009, 29(4): 353-358.   doi: 10.11728/cjss2009.04.353
Abstract(2912) [PDF 618KB](51)
Abstract:
Coronal funnels originated from chromospheric networks are key regions of solar wind origin and mass supply to large coronal loops. However, due to the lack of observational coronal magnetic field data, the geometrical and physical properties of coronal funnels can not be obtained through direct observations. Through applying force-free magnetic field extrapolation to a rectangular quiet-Sun region based on the observational MDI magnetogram, the coronal magnetic field up to 40 Mm above the photosphere can be reconstructed. Below 20 Mm, there are over 10 small funnels originating from magnetic networks and expanding with height. The small funnels merge into two big funnels above 20 Mm. For the first time, the height variations of the funnels' cross section areas in the quiet Sun are studied using observational data. The result reveals that coronal funnels expand almost linearly with height above the photosphere in the quiet Sun region. The expansion factor is larger in the lower part of the solar atmosphere than in the upper part. This result has been discussed with regard to 2D modeling of solar wind origin and mass flows in coronal loops. It is also found that the number of closed magnetic field lines decreases exponentially with height.
Influence of the Storm on the Ionospheric Spread-F in Hainan Region
Luo Zhixian, Shi Jiankui, Gao Taichang, Wang Guojun, Shang Sheping, Wang Xiao, Fang Hanxian, Wang Zhao, G A Zherebtsov
2010, 30(1): 23-28.   doi: 10.11728/cjss2010.01.023
Abstract(3338) [PDF 476KB](110)
Abstract:
Using the data observed with DPS-4 ionosonde from February 2002 to December 2007, influence of geomagnetic storm on the ionospheric Spread-F (SF) in Hainan region is statistically studied. The result shows that the occurrence of spread-F as a whole is suppressed by the storm. But for the different type of SF, influences of the storm are different. During storm time, FSF is motivated in 2002 and 2003, and suppressed during 2004---2007; RSF is suppressed during 2002---2005, and motivated in 2006 and 2007; MSF is suppressed in 2002, motivated in 2003 and 2004, and suppressed again during 2005---2007; SSF is suppressed during 2002---2004, motivated in 2005 and 2006, and weakly suppressed in 2007. These results are important to study the mechanism for different type of ionospheric SF during the storm time in the low latitude region.
Model Research of 10.7 cm Solar Radio Flux 27-day Forecast
Wen Jing, Zhong Qiuzhen, Liu Siqing
2010, 30(3): 198-204.   doi: 10.11728/cjss2010.03.198
Abstract(2965) [PDF 620KB](133)
Abstract:
The mid-term forecast of daily solar active index is always complex and difficult in space environment forecasting operation. A new 27-day forecast model of 10.7 cm solar radio flux F10.7 index) based on the observation and general evolution of the solar active regions has been built to improve the Auto-Regress (AR) method. The area and longitude of an active region has been used as control parameters in the new model. The sunspot decay rate suggests a simple way to forecast the area of active region in next solar rotation. The new model is tested in the following two cases: (1) F10.7 index is much larger than usual as unexpected solar active regions appear on the disk; (2) F10.7 index becomes quite peaceful because the dominant solar activity regions disappear. The result indicates that the relative errors of the new model were mainly 5%~9 % smaller than those of AR model under these two conditions. That means it is possible to improve the operational forecast model of solar index using the information of solar active regions.
A STUDY OF THE IONOSPHERIC DYNAMO BY USING EMPIRICAL MODEL PARAMETERS
Shen Chang-shou, Li Qing, Jiao Wei-xin, Zi Min-yun
1992, 12(2): 102-110.   doi: 10.11728/cjss1992.02.102
Abstract(1975) [PDF 805KB](54)
Abstract:
The empirical parameters of MSIS-86 and IRI-86 are used to deduce the three dimensional distribution of ionospheric conductivity and thermospheric wind system.Furthermore,the distribution and variation of the electrostatic potential and layer ionospheric current density at the Northern Hemisphere are calculated by the dynamo theory.The work combines the theoritical research of the ionosphere and thermosphere and the parameters of empirical model based on vast amount of data.The thermospheric wind system,height-integrated conductivity,electrostatic potential and ionospheric current density are compared with observed data and the results deduced from model calculations.There is a good agreement between them.The general significance of the method engaged is discussed too.
CHANGES OF THE ATMOSPHERIC DENSITY AT SZ-3 ORBIT ALTITUDE
QIN Guotai, QIU Shiyan, HE Aiqing, ZHU Yiqiang, SUN Lilin, LIN Xianwen, LI Hong, XU Xuepei, YE Haihua
2004, 24(4): 269-274.  
Abstract(2639) [PDF 540KB](87)
Abstract:
Atmospheric density detector was on board spacecraft SZ-3 launched on March 2002. At SZ-3 orbit altitude (330--410 km) atmospheric density data were collected near half year. The results show that in the rather quiet period of solar and geomagnetic activity, the difference of the atmospheric density between the sunshine and shade area is one of the principal change of thermosphere density, the highest ratio of atmospheric density in the sunshine to the density in the shade reaches about 3.0, and correlate with solar and geomagnetic activity; During 2002-04-17 and 2002-04-19 two strong geomagnetic disturbance events, the globe thermosphere density obviously increases and amplitude of the increase reached about 60%, and shows a positive correlation with a delay of about 6—7 h; The abnormal disturbance of atmospheric density were observed in the 30°N—40°N during these strong geomagnetic disturbance events; The thermospheric density changes with the value of F10.7 which represents the solar activity level and exhibits a obvious correlation.
Identification Method to Improve Disturbance Model Parameters of Reaction Wheel
SUN Jie, ZHAO Yang, TIAN Hao
2006, 26(1): 70-74.   doi: 10.11728/cjss2006.01.070
Abstract(1995) [PDF 1836KB](58)
Abstract:
Reaction wheel is one of the main disturbance sources that affect the precision of attitude control system of spacecraft. The purpose of setting up a disturbance model of reaction wheel is to predict the effects of the disturbance on the spacecraft, and then adopt corresponding control methods and isolation systems to restrain them. This paper presents the experimental disturbance model of reaction wheel. By analyzing the experimental data of reaction wheel, the parameters of the disturbance model, harmonic numbers and amplitude coefficients are determined. The energy compensation method is then given. The simulation results show that the identification accuracy of harmonic numbers does not exceed 0.04%. When adopting the amplitude spectrum method to compute the amplitude coefficients, the error is high up to 15.5%, however the error not over 1.1% when adopting energy compensation method. It indicates that the energy compensation method improves the identification accuracy of amplitude coefficients. This paper aims at providing a certain basis for improving the attitude control precision and stabilization of the spacecraft.
THE OBSERVATION AND THEORETICAL MODELING OF SODIUM DISTRIBUTION OVER WUHAN, CHINA
LI Hongjun, ZHENG Wengang, YANG Guotao, GONG Shunsheng
1999, 19(1): 54-60.   doi: 10.11728/cjss1999.01.054
Abstract(2101) [PDF 455KB](63)
Abstract:
The WIPM sodium resonance lidar and the inversion method of observationdata are introduced, the modeling calculation of the sodium density profile overWuhan, China and the comparative research between calculation and observationresult are reported, and some factors that may influence the density distribution ofsodium layer are discussed.
Solving the Near-far Problem for Positioning the High Earth Orbital Satellite With GPS
Liang Minmin, Qin Honglei, Li Feng
2010, 30(3): 255-262.   doi: 10.11728/cjss2010.03.255
Abstract(2313) [PDF 576KB](63)
Abstract:
Cross correlations caused by the limited dynamic range of the GPS Gold codes represent a significant ``near-far'' problem when GPS is used for positioning of High Earth Orbital (HEO) satellite. The power differences among signals received by High Earth Orbital satellite from different GPS satellites will be up to tens of dB since the lobe amplitude of GPS satellite transmit antenna and transmission distance are both different. Based on the requirement of positioning of HEO satellite using GPS, a Maximum Likelihood (ML) estimator algorithm is used to resolve the near-far problem introduced by the sub-optimal sliding correlator solution. The GPS maximum likelihood estimator acquisition algorithm performs a simultaneous, two-dimensional search of both the Doppler frequencies and GPS Gold codes. At first, simple cross correlator is used to detect the strong code signal. Then, a fine acquisition will be done to estimate the parameters of the strong code signal accurately. The maximum likelihood algorithm is used to cancel the strong code signal. As the near-far problem has been dealt with by canceling the strong code signal, the acquisition of the weak code signal can still be completed. In order to show the good performance of the estimator, GPS signal received by HEO satellite is analyzed to generate a simulated signal. Also, simulations have been done to compare the performance of the maximum likelihood estimator and the Simple Correlator (SC) algorithm. The result shows that the maximum likelihood estimator can improve the two-dimensional searching performance and decrease the interference arising from near-far problem.
Research of Circuit System in CCD Ultraviolet Sensor for Probing Moon
GONG Dezhu, JIA Jinzhong, LIU Yang
2006, 26(2): 132-141.   doi: 10.11728/cjss2006.02.132
Abstract(2576) [PDF 4775KB](40)
Abstract:
The research and development of CCD circuit, including both hardware and software are introduced in this paper. This circuit will be employed in the Ultraviolet Sensor (UVS) system of CE1 satellite, which is one of Chinese projects of detecting the moon. UV CCD sensor is made of optical structures, CCD and its processing circuit, Data Process Unit (DPU) and its software. The light of incidence goes iuto CCD, reflected by ichnographic mirror and thrilling through lens, and is transformed to digital signal by video processing circuit. The digital image signal is stored in data memory, and is analyzed by DPU. The calculated moon center is transformed to the attitude angle of detector to moon finally. UVS CCD circuit system includes CCD circuit, timing circuit, driver circuit, video process circuit and power circuit. The key device (CCD) is CCD48-20 from E2V company. It is detailedly introduced about CCD's timing and driving, smear problem, and so on.
Statistical Analysis of Geomagnetic Disturbances and Ionospheric Scintillations Over Guangzhou Region During Solar Minimum
HUANG Linfeng, DENG Baichang, HUANG Jiang, XU Jie, LIU Weifeng, LIU Zuolian, QUAN Hongjun
2012, 32(1): 25-32.   doi: 10.11728/cjss2012.01.025
Abstract(3134) [PDF 714KB](36)
Abstract:
The correlations between geomagnetic disturbance and GPS ionospheric scintillations are studied here using geomagnetic monitoring data of Zhaoqing geomagnetic station and the ionospheric scintillations observed by GPS monitoring network of South China, which is established by Guangzhou meteorological satellite ground stations. With the use of geomagnetic K values converted from the variation of geomagnetic horizontal component H at Zhaoqing to represent geomagnetic disturbance over Guangzhou region, the relationships between the geomagnetic disturbance and amplitude scintillation index (S4) over Guangzhou region during solar minimum are statistically analyzed.
Analysis indicates that most storms/strong magnetic disturbances of the year did not trigger the scintillation occurrence, that the ionosphere scintillation occurrence is mainly confined to the periods of lower K values, and that the ionosphere scintillation occurrence declined for periods of higher K values (K ≥ 4). Occurrence rate of ionosphere scintillations is changed with seasons and the geomagnetic activities. The scintillations occurrence rate is obviously correlated with the variation of geomagnetic activity K index, i.e., as the index K is raised, scintillation occurrence rate of above medium at night and weak in spring, as well as scintillations above medium in summer decreases. But there is no obvious relationship between occurrence rate of ionosphere scintillation and K values in autumn and winter. In addition, comprehensive analyses for the effects of geomagnetic and solar activity on ionosphere activity show that there are more ionosphere scintillations over Guangzhou region during geomagnetic quiet and low solar activity periods.
Lunar Soft-landing Trajectory Design Based on Evolutionary Strategy
LUO Zongfu, MENG Yunhe, TANG Guojian
2012, 32(1): 92-98.   doi: 10.11728/cjss2012.01.092
Abstract(3025) [PDF 735KB](49)
Abstract:
Lunar soft-landing trajectory design methods using evolutionary strategies and differential correction are investigated. According to the launch site and vehicle of the Chinese Lunar Exploration Program, the general constraints and objectives of lunar soft-landing missions are given. The primary trajectory is calculated by evolutionary strategies based on patched conic model. Then the differential correction method is adopted to modify the error introduced by the inaccurate model. The trajectories of cislunar and lunar orbiter phase before the soft-landing are also simulated by the commercial software STK, and the feasibility of the methods delivered in this paper is confirmed by the comparison of results. The difference of parameters between the preliminary and accurate model indicates that the design based on evolutionary strategies gives a proper value for the differential correction. This approach will be significant for the lunar soft-landing trajectory design of Chinese Chang'E Mission.
Methods for Extracting Backscatter Ionogram Leading Edges
FENG Jing, LI Xue, QI Dongyu
2012, 32(4): 524-531.   doi: 10.11728/cjss2012.04.524
Abstract(2479) [PDF 2688KB](119)
Abstract:
Algorithms for automatic backscatter ionogram scaling are established. The algorithms are used in the backscatter sounding system developed by China Research Institute of Radiowave Propagation (CRIRP) and show good results. The autoscaling system has been developed in two overall stages. The first stage is the automatic cleaning of a raw ionogram, which filters the raw ionogram to remove the interferences and noises. The second stage is to extract features from the clean ionogram, such as the propagation modes, the leading edges, etc., and this paper describes part of this work. Methods for extracting backscatter ionogram leading edges are presented. For a single layer or the lower one of two layers, the leading edge is extracted by edge identification algorithm on the ionogram with interferences and noises removed. For the upper one of two layers, the leading edge is extracted by power and gradient algorithm based on Gaussian-fashion weights on the ionogram just after interference suppression. The methods given in this paper have high accuracy and are easy to implement. They are applied successfully in several projects.
Adaptive Fitting of Colored Noises and Corresponding Covariance Matrices in Navigation
CUI Xianqiang, YANG Yuanxi, ZHANG Xiaodong
2012, 32(4): 592-597.   doi: 10.11728/cjss2012.04.592
Abstract(2770) [PDF 460KB](60)
Abstract:
To use Kalman filtering for kinematic navigation and positioning, we have to deal with function model and stochastic model. The precision and reliability of kinematic Kalman filtering are affected remarkably from the function model and stochastic model errors. Adaptive fitting of both colored noise and covariance matrices by using moving windows are presented based on the assumption that the observation and dynamic model noises mainly include the colored noises with first order self-correlation character. The expressions to calculate the colored noise estimators and covariance matrices of the modified observations and predicted states are obtained. Feasibility and practicability of the model and algorithm are tested by an example. It is shown that the Kalman filtering, based on the adaptive fittings of the colored noises and covariance matrices, can be effective in resisting the influence of the colored noises on the navigation results.
THE MEASUREMENTS OF MESOPAUSE TEMPERATURE BY THE SYNTHETIC SPECTRA METHOD
WANG Yongmei, WANG Yingiian
1997, 17(4): 348-352.   doi: 10.11728/cjss1997.04.348
Abstract(1804) [PDF 333KB](54)
Abstract:
Amethod of calculating the synthetic spectra by using the comb function isproposed. By using a weighted leastsquare method to fit the synthetic spectra withthe observed spectra of OH(9,4) nightglow at Beijing suburb, the rotationaltemperature of mesopause is derived. The variations of the nightglow intensity andthe rotahonal temperature with time are analyzed.
Initial Application of Unequal Step Grid and Explicit Method in the Simulation of Nonlinear Propagation of Gravity Wave
LIU Xiao, XU Jiyao, MA Ruiping
2007, 27(2): 132-139.   doi: 10.11728/cjss2007.02.132
Abstract(2382) [PDF 3501KB](53)
Abstract:
An unequal step grid and explicit numerical model is developed in this paper by using the 3rd order TVD explicit time integration method, which is used to simulate the nonlinear propagation of the gravity wave in a 2-dimensional compressible atmosphere. The model can simulate the small-scale complex wave with high resolution while the computer cost doesn't increase. It can be used to simulate the nonlinear propagation of gravity waves breaking into small-scale complex wave from the middle-scale wave. The simulation results for the propagation of small amplitude gravity wave indicate that, the model can reproduce the propagation of small amplitude gravity wave and preserve the energy conservation relation and the phase difference between different perturbation variable. The numerical results coincide well with linear gravity wave theory. The simulation results for the nonlinear propagation of finite amplitude gravity wave show that, compared with the equal grid system with the same grid number, the unequal step grid system can simulate the evolution of gravity wave from instable to breakdown with higher resolution. The simulation results in the equal grid system with the grid number increasing one time are same as that for the unequal grid system indicate that, the simulation results in the unequal grid system is correct, and the computer cost is saved greatly. The advantages of explicit method are also preserved in this model, such as, needn't iterative method to solve the solution and extend to 3-dimensional easily.
Image Data Processing of Spaceborne Fabry-Perot Interferometer Prototype
HAN Weihua, , LÜJiangong, WANG Yongmei
2011, 31(6): 784-788.   doi: 10.11728/cjss2011.06.784
Abstract(2609) [PDF 570KB](44)
Abstract:
Fabry-Perot Interferometer (FPI) is one of the best detectors to explore the middle and upper atmosphere wind. A spaceborne FPI prototype with a large diameter telescope was designed and constructed and the image of interference fringe was acquired. This paper introduces the principle of FPI and a feasible inversion algorithm of the wind velocity in the middle and upper atmosphere. A technique for F-P interference fringe auto-processing is developed. The technique includes filtering, segmentation, thinning, and extracting of interferogram characteristic data. Filtering is composed of median filtering and background compensation. Binary fringe is obtained through selecting the area mean gray scale as threshold for segmentation. Mathematical morphology is fitting for restoring rupture and burr. As thinning is essential for the accuracy of inverting middle and upper atmosphere wind, thinning is discussed in details. Skeletonization thinning is put into practice. At last, characteristic data such as center of circle and radius are extracted. Visual C++ is adopted to develop the FPI interference fringe image process software, and the technique mentioned above has good performance in experimental practice.
Effects of microgravity on the characteristics of single bubble growth
Yang Yan, Pan Liangming, Wei Jinghua
2012, 32(3): 376-382.   doi: 10.11728/cjss2012.03.376
Abstract(2476) [PDF 773KB](107)
Abstract:
Based on the previous experiment and the VOF (Volume of Fluid) multiphase model, the growth characteristics of a single bubble was numerically investigated, on the condition of micro-gravity, for the section size of 10mm × 10mm × 25mm rectangular channel of pool boiling. The transportation of mass and energy during the phase change is implemented by adding source term to the mass and energy equations with User Defined Function (UDF). The results show that under the microgravity condition, the streamline and the temperature field distribution around the bubble have difference; due to surface tension, the bubble under microgravity and normal gravity are different from the bubble detachment; under the condition of microgravity, the change of bubble diameter is more complex, and the heat transfer coefficient fluctuate, the increase of microgravity will enlarge the amplitude of fluctuations.
Preliminary Studies on Collagen Fibrosis and Hydroxyapatite Crystallization under Microgravity
WANG Jing, LAN Ding, WANG Yuren, DAI Guoliang, KONG Liming
2015, 35(3): 330-335.   doi: 10.11728/cjss2015.03.330
Abstract(973) [PDF 1977KB](49)
Abstract:
Bone loss during long-term space flight is a serious problem. Collagen fibrils in bones are a key factor of Hydroxyapatite (HAP) crystal growth in its crystallization process, which is a main constituent of bones. In this paper, the changes of collagen fibrosis process under simulated microgravity and normal gravity conditions were studied, and the morphologies of HAP crystals grown on the surface of collagen fibrils were observed. Results showed that the amount and the size of pores inside collagen fibers formed under simulated microgravity condition and different concentrations of collagen were significantly larger than that under normal gravity condition and different concentrations of collagen. The distribution of the porosity under simulated microgravity condition was different with that under normal gravity condition. The morphology of HAP crystals under simulated microgravity condition was mainly cube-shaped. However, under normal gravity condition, HAP crystals were mainly plate-liked. These preliminary results will help to clarify the mechanism of bone loss in space in future.
Measurement and Analysis of Ionospheric Virtual Height With High Precision
ZHU Zhengping, NING Baiqi, WAN Weixing
2007, 27(3): 204-210.   doi: 10.11728/cjss2007.03.204
Abstract(2090) [PDF 2335KB](44)
Abstract:
In order to improve the spacial resolution of ionospheric virtual height in vertical ionospheric sounding, a high precision virtual height measurement experiment are carried out by means of ionospheric echo's phase measurement and corresponding data analysis processing arithmetic with modern digital ionosonde. When two radio frequency pulse signals, the frequency difference of which is a fixed value are transmitted and the echo's phase difference is measured, the ionospheric virtual height with high precision can be acquired. According to this ionospheric virtual height sounding principle, the observation mode of ionospheric virtual height with high precision is realized. In this mode, the measured height resolution of the ionospheric virtual height is increased by more than ten times, that is, from 6 km to about 200 m, which can entirely satisfy the observation research demand of the ionospheric fine structure and small scale disturbances. Through a series of virtual height measurement experiments by using combinational pulses control and echo's phase measurement analysis based on CADI ionosonde, some meaningful results are obtained and some comparisons are made with TOA (Time Of Arrival) method. Experimental results reveal that the height resolution of ionospheric virtual height measurement with echo's phase method is ten times higher than that of virtual height measurement with TOA method. This is very important in that electron density profile under ionospheric peak can be accurately inversed and ionospheric fine structure can be carefully studied.
Adaptive Neural Network Control of Free-floating Space Manipulator With an Attitude Controlled Base
GUO Yishen, CHEN Li
2008, 28(2): 173-179.   doi: 10.11728/cjss2008.02.173
Abstract(2404) [PDF 1523KB](65)
Abstract:
The control problem of coordinated motion of free-floating space manipulator with an attitude controlled base is
discussed. Firstly, with the Lagrangian formulation and the relationship of the system linear momentum conversation, the dynamic equation of system is derived. Based on the above results and the RBF neural network technique, the Ge-Lee (GL) matrix and its product operator, the dynamics of free-floating space manipulator is approximated. And then with all unknown inertial parameters of the manipulator, the adaptive neural network control scheme of coordinated motion between the base's attitude and the manipulator's joints of free-floating space manipulator is developed. It need neither linearly parameterize the dynamic equation of system, nor know any actual inertial parameters. And the neural network need not do training and learning online too. Therefore, the control scheme is prone to real-time application. Lastly, a planar free-floating space manipulator is simulated to verify the proposed control scheme.
Constellation Design for Geosynchronous Belt Surveillance System Based on the SBV Sensor
TANG Yi, ZHONG Wenan, SHOU Junming, LI Shuang
2015, 35(1): 94-103.   doi: 10.11728/cjss2015.01.094
Abstract(1480) [PDF 4557KB](65)
Abstract:
The constellation configuration of the surveillance system was analyzed and designed, under the background of monitoring the entire geosynchronous belt using the Space-Based Visible (SBV) sensor. Firstly, the optimal observation model was extracted based on summarizing the merits and weak points of the three observation models. Secondly, relationship between the orbit altitude of the surveillance satellite and parameters of the search fence was deduced, and the numeric area of orbit altitude was derived. Thirdly, the principle of distribution of optimal observation period and imaging time for SBV sensor were extracted, based on analyzing the influence factors. Finally, the principle of selection for the satellite number of surveillance system and the size of the search fence, and the numeric area of orbit altitude of two-satellite surveillance system which satisfied the requirement of regressive orbit characteristic were extracted, based on analyzing the percentage of coverage and observational frequency for the single-satellite and two-satellite surveillance system. The results indicate that the ability of coverage for geosynchronous object which has a large inclination is improved when the surveillance satellite crossing the celestial pole and using pinch points observation model. The orbit of surveillance satellite is sun-synchronous circle orbit which local time of descending node at 06:00LT or 18:00LT, altitude from 615km to 850km, and around this range there are 6 piece regressive orbits.
CHARGING PROCESS OF SPACE DUST AND ITS DEPENDENCE UPON PLASMA PARAMETERS
LI Jiawei, LI Zhongyuan
2004, 24(5): 321-325.  
Abstract(2149) [PDF 427KB](20)
Abstract:
Dust grains immersed in plasma will be charged of various charging currents, this paper considers three main currents due to the relative velocity between the dust grains and the plasma: the primary ions, the primary electrons, and the sec-ondary electrons. The surface potentials of silicate and carbon dusts grains in H+ and H2O+ plasma environments are calculated using universal plasma parameters, these plasma conditions are common in space environments, such as comets, plan-etary rings, and interplanetary media. A conclusion is found that the equilibrium potential of dust grains have close correlation with the plasma temperature. At low temperatures, the surface potential will become lower while the temperature rises. The dust can reach a positive potential when the temperature is high enough. The potential of carbon grains is lower than that of silicate grains. The component of plasma may affect the potential, too. For both silicate and carbon grains, potential in H+ plasma is higher than that in H2O+ plasma.
Causes of Martian Magnetic Field and the Distribution
Tong Dongsheng, Chen Chuxin
2010, 30(3): 193-197.   doi: 10.11728/cjss2010.03.193
Abstract(3456) [PDF 507KB](78)
Abstract:
A model of currents around Mars is proposed, upon which the distribution of magnetic field in Martian equatorial plane is calculated. In this model, there exist currents in the Martian magnetopause, the Martian ionosphere and the current sheet in the Martian magnetotail based on the observational data from satellite and appropriate assumptions. According to the continuity of the current, these currents satisfy the relation that the total current in the Martian magnetopause is equal to the summation of the total current in the Martian ionosphere and the total current in the Martian magnetotail. Superposition of the magnetic field generated by these currents and solar wind magnetic field constitutes magnetic field in the Martian equatorial plane. Results obtained through the model of Martian currents are consistent with observational results through satellite and those gained by other methods.
A New Autonomous Celestial Navigation Method for Deep Space Probe and Its Observability Analysis
NING Xiaolin, FANG Jiancheng
2005, 25(4): 286-292.  
Abstract(2087) [PDF 2103KB](41)
Abstract:
Celestial navigation method is a kind of important autonomous navigation method for deep space probing. Now it is widely used in many situations, especially in deep space exploration for its special characteristics. There are two kinds of celestial navigation methods. One is to use the geometric technique, in which the navigation information is obtained from the geometric relation between the celestial bodies and explorer. The other is an optimal estimate technique, which uses the celestial measurement as observation directly and employs the extended Kalman filter to estimate the position of explorer. A new autonomous celestial navigation for lunar explorer is developed and investigated in this paper, which combines both these two techniques. At first using the geometric technique to calculate the position of satellite and then reestimate the original position determination results using orbit dynamical equations and Multiple Model (MM) Kalman filter to get a better navigation result. The simulation result shows the high precision of this new method. Finally, the superiority and effectiveness based on the observability and the degree of observability analysis of this method are demonstrated by the simulation result simultaneously.
REDUCTION OF SOLAR IRRADIANCE BY THE PRESENCE OF EFFECTIVE SUNSPOTS AND VARIABILITY OF SOLAR IRRADIANCE BY THE PRESENCE OF EFFECTIVE PHOTOSPHERIC ACTIVE FEATURES
Li Zai-kun
1982, 2(4): 275-280.   doi: 10.11728/cjss1982.04.275
Abstract(1829) [PDF 595KB](44)
Abstract:
This paper presents a new idea by modelling the reduction of solar irradiance by the presence of effective sunspots.Based on the author's personal conservative measurement of the sunspot pictures of April 1 through July 16,1980,a comparison between the theoretical solar irradiance and the total solar irradiance measured by SMMspacecraft has been made,which shows a reasonably good agreement and high correlation (r=0.78).Moreover,the author presents further an improved model of solar irradiance variability by the presence of effective active features on the photospherie disk,which is as follows.here Au,Apu,Af and A,denote the areas of umbrae,penumbrae,faculae and the visible solar disk,respectively;θu,θpu,θf are the umbral,penumbral and facular contrast values;θfh represents the limb darkening that depends on the helioeentric-angle θ.The author also sets forth several problems that need further investigations.
New regional geomagnetic activity index based on multi-station observation
Wang Chuqin, Du Dan, Zhang Xiaoxin, Zhao Mingxian, Jiang Yong
2015, 35(1): 26-39.   doi: 10.11728/cjss2015.01.026
Abstract(1234) [PDF 2896KB](59)
Abstract:
With the data of 14 geomagnetic observatories in China and 23 geomagnetic observatories abroad, both temporal and spatial variation characteristics of rH index are analyzed. And the 14 geomagnetic observatories in China are divided into 7 regions by using K-means clustering algorithm based on the similarity measurement, and the residual index (Ra) of rH index between each two observatories. Then the regional rH index (Rr) of each region is calculated by linear weighted sum method. The results show that rH has a periodic change in 27 days, which is the solar rotation cycle. Although no significant seasonal variation is found in rH, it is also shown that the average of rH in spring and autumn is greater than in summer and winter. For spatial variations, rH increases with the latitude. There are some obvious difference in amplitude and morphology of rH during geomagnetic storms, and the feature of dusk-dawn asymmetry is found. Comparison with the observational data of H component and other Global geomagnetic activity indices, such as Dst, SYM-H and Kp, indicate that Rr can reflect the regional geomagnetic disturbance effectively.
Atmospheric density calibration using the real-time satellite observation
Miao Juan, Liu Siqing, Li Zhitao, Qin Guotai, Tang Geshi
2011, 31(4): 459-466.   doi: 10.11728/cjss2011.04.459
Abstract(2705) [PDF 708KB](70)
Abstract:
For low Earth satellites, thermospheric density models are widely used in orbit determination and prediction. However, typical models often show density errors of 15 %~30 % under normal condition and the errors may be much greater during unusually solar and geomagnetic period. Density errors can be translated into orbit errors and effect mission plan, re-entry operations and precise orbit determination. In this paper, on the basis of detected data of Shenzhou, a kind of model calibration is expected to be developed on real-time detected data. By analyzing and comparing the character of density error for the national atmosphere model NRLMSISE-00, a kind of average calibration method is developed for relative quiet geomagnetic field (Ap≤30). During the quiet geomagnetic field, the errors of model at the same local time and latitude are considered approximately identical, so the error may be substituted by average error at the same station. The results of model are tested based on Shenzhou 4 data by two means and both are improved in accuracy. The errors of 20 % decreased to 6 % by real-time error calibration. The errors of one day in advance decreased to 7.8 %, two days in advance decreased to 9.4 % and three days in advance decreased to 10.5 %.
Space Environment Background Calculation for HXMT
LI Gang, WU Mei, ZHANG Shu, JIN Yingkang
2008, 28(6): 531-540.   doi: 10.11728/cjss2008.06.531
Abstract(3388) [PDF 2283KB](73)
Abstract:
The Hard X-ray Modulation Telescope (HXMT) is a broad band X-ray (1~250 keV) astronomical satellite. Its core payload, High Energy X-ray Telescope (hereafter HE), operates in the hard X-ray (20~250 keV) range. HXMT/HE will perform an all-sky hard X-ray survey and focused observations with the highest sensitivity. To achieve a high sensitivity, it is important to reduce the background that caused by the interactions between the satellite and the space particles. With reference of documents and up-to-date observation data which describe the background of near earth space, a suit of self-consistent data and formulas related to background particle of near earth space are sorted out. The background of HXMT and its variation with time and orbit are also given through simulation calculation with software Geant 4.
ABUNDANCES AND DISTRIBUTION OF ELEMENTS ON THE LUNAR SURFACE
XU Tao, LI Chunlai
2001, 21(4): 332-340.  
Abstract(2216) [PDF 1003KB](123)
Abstract:
Recently USA launched two Moon probes which are "Clementine" and "Lunar Prospector". They carried some newly developed or innovated instruments to map the elements abundances on the moon, such as gamma-ray spectrometer, neutron spectrometer and UV-VIS imager. Based on the data of high quality those instruments gained, new progress have been made about the quantification of lunar elements.
This paper summarizes those up to date progress in two ways. First the instruments used by Lunar Prospector and Clementine to map the elements abundances will be introduced, then the progress achieved in the theory of elements quantification will be discussed in detail, especially about the quantification of iron, titanium and Ree.
THE IMPACT OF TROPOPAUSE VARIATION ON OZONE DISTRIBUTION IN UPPER TROPOSPHERE/LOWER STRATOSPHERE
LI Guohui, LU, Daren
2003, 23(4): 269-277.  
Abstract(2629) [PDF 801KB](60)
Abstract:
The upper troposphere/lower stratosphere (UT/LS), as a special region, lies between 8 and 25 km altitude. Because most of ozone column resides in the lower stratosphere, small change in ozone abundance could have a large impact on climate and the surface UV flux. The tropopause, as an interface or transition zone between the well mixed, ozone-poor upper troposphere and the stratified, ozone rich lower stratosphere, has its seasonal and long-term variation trends which in turn could lead to a direct and evident effect on the distribution of atmospheric ozone and its column abundance. This work simulated the impact of tropopause variation on the distribution of ozone in UT/LS with a two-dimensional model named SOCRATES (Simulation Of Chemistry, Radiation, And Transport of Environmentally important Species). The model, developed in the Division of Atmospheric Chemistry of NCAR, is one coupling chemical, radiative, and dynamical processes. Its domain and resolution are 0-120 km and 1 km in vertical and 85S-85N and 5?in horizontal. Model simulation results show that the annual cycle of the tropopause height has remarkable impact on the ozone distribution in the UT/LS. The local change of ozone can be more than 10%. When the tropopause is increased by 1 km in winter in middle latitudes of Northern Hemisphere, the impact on ozone distribution is evident and the local change of ozone can be more than 6%. However the impact on total ozone is relatively small, less than 5 Dobson units. This is much less than the statistic results between tropopause height and total ozone from data analysis.
Predicting the Shock Arrival Time Using 1D-MHD CE/SE Solar Wind Model
Zhang Ying, Feng Xueshang, Yang Liping
2010, 30(2): 105-112.   doi: 10.11728/cjss2010.02.105
Abstract(2569) [PDF 658KB](54)
Abstract:
A 1D-MHD shock propagation model (1D-MHD (CE/SE) model) is established to predict the arrival time of interplanetary shocks at 1AU, using the space-time Conservation Element and Solution Element (CE/SE) method. Applying this model to 137 solar events during the period of February 1997 to August 2002, it is found that our model could be practically equivalent to the STOA, ISPM, HAFv.2 and SPM models in forecasting the shock arrival time. The absolute error in the transit time from 1D-MHD (CE/SE) model is not larger than those of the other four models for the same sample events. Also, the prediction test shows that the relative error of our model is ≤10% for 25.6% of all events, ≤30% for 69.3%, and ≤50% for 87.6%, which is comparable to the relative errors of the other models. These results might demonstrate a potential capability of our model in terms of real-time forecasting.
DYNAMIC CHARACTERISTICS ONDIFFERENTIAL CUSHION DAMPING ANDTRANSMISSION SYSTEM OF SPACE DOCKINGMECHANISM
ZHAO Yang, CAO Xibin, WANG Xinggui, SHAO Chengxun
1999, 19(2): 173-180.   doi: 10.11728/cjss1999.02.173
Abstract(2018) [PDF 411KB](51)
Abstract:
The model of a differential cushion damping and transmission system is oneof the main fields of spacecraft docking dynamics. The dynamic characteristics ofthe differential cushion damping and transmission system are researched based onthe analysis of system kinematics relationship. A new applied dynamic modeling isgiven for docking dynamic simulation.
Destriping for TDI-CCD Remote Sensing Images
ZHAO Bianhong, HE Bin, YANG Lihong, TAO Minghui, REN Jianyue
2012, 32(2): 298-304.   doi: 10.11728/cjss2012.02.298
Abstract(2648) [PDF 804KB](75)
Abstract:
Based on the characteristic of striping noise in TDI-CCD images, a new destriping noise technique which combines FFT with wavelet transform to search the frequency point of the striping noise is presented. The improved notch filter is selected to eliminate the striping noise. In addition, an improved threshold function based on lifting wavelet transform is used to eliminate the stripes. Experiment shows that the method of improved notch filter is superior to the improved threshold function while the improved threshold function is superior to the hard and the soft threshold function. After destriping using the improved notch filter, the quality of image is enhanced. The PSNR of the destriping image processed by improved notch filter is increased to 46.4181dB and the NMSE is decreased to 0.00007. Compared to the methods of threshold function based on lifting wavelet transform, the PSNR of destriped image is improved by 3~4dB and the NMSE is reduced by 0.00007~0.00011. The method of improved notch filter which combined FFT with wavelet transform and the methods of threshold function based on lifting wavelet transform can eliminate the striping noise while preserve the characteristic of the original image, so the several methods are of feasibility.
Effects of Simulated Weightlessness on Rabbit's Ear Microcirculation
Shen Xian-yun, Xiang Qiu-lu, Meng Jing-rui
1988, 8(3): 223-232.   doi: 10.11728/cjss1988.03.223
Abstract(1474) [PDF 935KB](33)
Abstract:
Experiments in two groups of rabbits (supine and head-down 20°) were done to observe the effects of cephalad redistribution of body fluid during simulated weightlessness on rabbit's ear microcirculation.Results showed that cephalad redistribution of body fluid can induce certain changes in microcirculation,i.e.increase of bore of capillaries and veinles,decrease of flow speed and blood pooling in veins,aggregetion of blood cells,patechae in the ears,and changes of regulative function of the microvessels during orthostasis.The indexes of blood rheology also had relative changes.The cause of certain changes were analysed,and some new ideas were postulated.A kind of specially designed rabbit cage and the method of observation of microcirculation through intact rabbit ears were also introduced.
Reflector and Thermal Analysis of Plan-parabolic Membrane Antenna
Xu Yan, Guan Fuling, Wang Hongjian
2009, 29(5): 534-539.   doi: 10.11728/cjss2009.05.534
Abstract(2345) [PDF 516KB](44)
Abstract:
To solve the problem between limited volume of the rocket mantles and large caliber requirement of antenna and the problem between carrying capacity of rocket and large weight of antenna, the inflatable antenna structure technology is one of the best choices. Afterward, to obtain high precision of inflatable reflector, one of figuration theories which is titled as plan-parabolic reflector, was investigated. The elastic theory analysis was carried out and the relationship between reflector shape and inflatable pressure, material, boundary condition is obtained. There is M shape error between reflector shape and parabolic. Based on these works, the influence that temperature variety affects on the reflector precision on orbit was studied and methods to eliminate this effect are discussed. The analyze result from ANSYS software is compared with the result from this paper and the validity of analysis method is clarified.
NUMERICAL INVESTIGATIONS OF A SMALL THRUSTER PLUME AT HIGH ALTITUDE
CHENG Xiaoli, MAO Mingfang, YAN Xiqin
2002, 22(3): 261-267.  
Abstract(1874) [PDF 638KB](47)
Abstract:
A small thruster plume flow of nitrogen at high altitude is numerically investigated by using a DSMC method. A hard sphere model is employed to simulate nitrogen molecule. The collision frequency is calculated through using the random sampling frequency method for each cell. An axisymmetrc model based on a two-dimensional modification is introduced to model the flow field. To raise the computation efficiency of the DSMC method, both a grid domain decomposition method and a local grid clustering technique are enforced. An inner flow numerical result is considered as the outflow conditions of the thruster, a escaping boundary condition is implemented at far-field boundary, and a perfect scatter reflection model is chosen as the solid wall boundary condition. Moreover, molecule rotation energy included in inner energy is considered besides translation energy. The reliability of the numerical method is demonstrated by comparing with the relevant experimental results. Both the properties of plume flow at high altitude and the nonequilibrium effect related to rarefied gases are analyzed.Resultsshow that the DSMC method coupled with a fine grid technique is an effective approach for high altitude plume simulations, and that the nonequilibrium effect of gases must be numerically dealt with. Moreover, pitot pressures are given numerially in good agreement with measured data.
Design and Implementation of Full-link Simulation System of Space-to-ground Optical Communication
CUI Minglu, WANG Zhiqiang, LIU Wei
2012, 32(2): 257-264.   doi: 10.11728/cjss2012.02.257
Abstract(2512) [PDF 682KB](46)
Abstract:
The existing designs of space-to-ground single-photon communication have the defect that the system-level parameters are difficult to be given, due to the adoption of the analysis based on subsystems. For the purpose of combining all subsystems and key system-level parameters’ influence, full-link simulation method is introduced. A space-to-ground optical communication full-link simulation system based on OMNeT++ is constructed to perform the APT (Aiming, Pointing, Tracking) and single-photon communication experimentation by Monte-Carlo method. The simulation system has the abilities of simulating correlations between subsystems, reflecting the key parameters’ influence on the whole system, and estimating the performance of a true system due to its full-link character. The simulation system is significant to design and optimize true space-to-ground optical communication systems.
THE STUDY OF THE CHEMICAL COMPOSITIONS OF THE NINGQIANG CARBONACEOUS CHONDRITE MATRIX AND DARK RIM
Fang Hong, Feng Xi-zhang, Chai Zhi-fang
1992, 12(1): 63-70.   doi: 10.11728/cjss1992.01.063
Abstract(2152) [PDF 712KB](70)
Abstract:
The chemical compositions of the Ningqiang carbonaceous chondrite matrix and a dark rim are analysed with instrumental neutron activation method.The results indicate that there are more abundant light REE and chalcophile elements in the matrix of Ningqiang than in the whole rock sample of Ningqiang,and it roughly exhibits a similarity of REE model between the Ningqiang and Allende matrices.The difference between the dark rim and Ningqiang matrix is that the former has richer FeO and poorer refractory elements.It is deduced that the meteorite matrix and the dark rim came from different source material regions of the solar nebula.The event related to the formation of the dark rim might ever have taken place many times in the different regions of the solar nebula.
Investigation on Properties of Ionospheric Es Layer in Hainan Region
GONG Yu, SHI Jiankui, WANG Guojun
2007, 27(3): 198-203.   doi: 10.11728/cjss2007.03.198
Abstract(2834) [PDF 1910KB](54)
Abstract:
Using the observation data (Mar. 2002-Feb. 2005) from DPS-4 at Hainan ionospheric station, a statistic analysis for sporadic-E (Es) occurrence frequency in Hainan region in the descending phase of solar cycle has been performed. The seasonal variation and annual variation of occurrence of Es are mainly studied. The results show that, in the three years, Es occurrence in Hainan region is increasing with year. Esl and Esq occurs most frequently, next is Esr, then, Esc and Esf occurs lesser, ESh occurs least. Es occurs most frequently in Summer, secondly in Autumn and Winter, and most infrequently in Spring. Different type of Es has different properties, such as Es1 and Esq occurs almost every season, next is Esr, then, Esc, Esf and ESh occurs infrequently in any season, particularly, Esf almost disappears in Autumn. These results provide observation evidence for studying the physics mechanism of the ionospheric irregularity, it is also important to establish space weather predicting model on ionosphere.
Study on the Detectability of Typhoon-Generated Acoustic-Gravity Waves
XIAO Saiguan, ZHANG Donghe, XIAO Zuo
2007, 27(1): 35-40.   doi: 10.11728/cjss2007.01.035
Abstract(3147) [PDF 392KB](80)
Abstract:
In this paper, the detectability of the ionospheric response to the typhoon-generated acoustic-gravity waves was studied through the statistical analysis of the HF Doppler shift records which come from the corresponding observation station at Peking University (39.4°N, 116.2°E) and a comparison with corresponding typhoon data. It is shown that the HF Doppler frequency sounding can be an effective tool for detecting the acoustic-gravity waves excited by typhoon, and the detectability is as high as up to 22 out of 24 for the present study. The detailed analysis of the HF Doppler records at different stages of the typhoon influenced period was made under the quiet conditions. Then, a comparison was made with the results of Huang (2 out of 12) and the possible causes of the differences between these two studies were analyzed. The non-linear propagation process of the main disturbances is reappeared by the method of numerical simulation, and the simulation results are in good agreement with observation results and the linear theory of acoustic-gravity waves propagated in the atmosphere. This confirmed that the detectability should be high in general. Also it is shown that the differences of detectability may be due to the fact that the detectability keeps a close correlation with the difference of relative locations of the source of typhoon and Doppler observation sites, and the propagation pattern of the medium-scale TIDs in the ionosphere.
Modeling and simulation of visible light scattering properties of spatial object using STK
Li Yanjie, Jin Guang, Zhong Xing
2013, 33(2): 188-193.   doi: 10.11728/cjss2013.02.188
Abstract(2273) [PDF 564KB](72)
Abstract:
For supplying the space-based optical observation system designer with referenced data, equivalent magnitude model of spatial object is established using STK. First, the visible light scatting characteristics of spatial object surface cell is analyzed by using BRDF five-parameter model. Second, combined with the characteristics of object shape and material property, the configuration model of space target is built, and formulation of equivalent magnitude computing model of space object is carried out by analyzing every single surface cell. Last, Satellite Tool Kit (STK) was used to provide relationship among sun, space object and observation satellite to simplify the solving of the formulation, and then, a new magnitude computing model based on STK is established. It was verified with one example and some analyses. The result displays that the new model is much more precise than the diffuse one. Besides, the results show that the best observing time and the corresponding magnitude can be easily solved with STK.
Phenomena excited by ionospheric heating observed on DEMETER satellite
ZHANG Xuemin, FROLOV V L, SHEN Xuhui, RUZHIN Y, ZHAO Shufan, ZEREN Zhima, XU Weidong, QIAN Geng
2016, 36(1): 25-39.   doi: 10.11728/cjss2016.01.025
Abstract(1362) [PDF 6694KB](54)
Abstract:
The phenomena of ionospheric perturbations during the experiments between SURA and HAARP heating facilities with DEMETER satellite have been summarized, and the main disturbed electromagnetic signals have been found, including the radiated HF pump wave and sideband pump wave, enhanced VLF transmitter signals and extended frequency band, modulated ULF/ELF/VLF wave, ELF electromagnetic emissions, ULF resonant wave, perturbations in plasma parameters and precipitation of high energy particles. Then the occurrence frequency of each kind of phenomenon is studied, in which the radiated pump waves were with high occurrence probability of larger than 68%, while other disturbances detected by satellite were with low probability of smaller than 40%, and some even occurred occasionally under specific condition, owing to the effects of local ionosphere background and modulated mode, etc. Finally, combined with the orbit design and payload installation on China Seismo-Electromagnetic Satellite (CSES), some suggestions have been provided on future experiments between ionospheric heating facility with CSES on the basis of the statistical results, in order to avoid the problems and improve the successful experimental probability as much as possible.
A Spectral Numerical Solution of Navier-Stokes Equations in a 3-Dimensional Spherical Coordinate System
HUANG Chunming, YI Fan, ZHANG Shaodong
2005, 25(1): 37-43.  
Abstract(2057) [PDF 1695KB](61)
Abstract:
Aiming at numerically studying the global nonlinear propagation of atmospheric tides,a new fully nonlinear numerical model in a three dimensional spherical coordinates is established.In the construction of the numerical model,the spectral allocation method was used to numerically resolve the Navier-Stokes equations,which was taking as the governing equations.In the specification of the boundary conditions,periodic and projected characteristic line boundaries are chosen as the zonal and vertical boundaries,respectively;moreover,the polar boundary are also carefully specified.For the purpose of examining our newly established model,the global nonlinear propagation of a gravity-wave packet with large scales is simulated and compared with a previou simulation.The calculation result exhibits the essential characteristics of the nonlinear propagation of a gravity-wave packet in atmosphere:the whole wave packet propagates upward and the wave-associated disturbance velocity increases with the increasing height,which is quantitatively consistent with the previous simulation.These suggested that our numerical model and the nonlinear simulation are reliable.
CESE Method for Resistive Magnetohydrodynamics
Liu Yuanxin, Ji Zhen, Feng Xueshang, Zhou Yufen
2010, 30(3): 211-220.   doi: 10.11728/cjss2010.03.211
Abstract(2735) [PDF 669KB](49)
Abstract:
In this paper, the 2.5-dimensional resistive Magnetohydrodynamics (MHD) equations were solved to simulate two magnetic reconnection problems in single current sheet by applying the space-time Conservation Element and Solution Element (CESE) method. Three different versions of CESE method are employed: (1) the original CESE method, (2) the Courant Number Insensitive Scheme (CNIS) CESE method, (3) the high order CESE method. The numerical results obtained from the above-mentioned approaches are discussed in the aspect of the divergence of the magnetic field. The numerical results indicate that no obvious differences exist among the three approaches in the configuration of the magnetic field. However, for the divergence of the magnetic field, the results obtained from the three approaches differ from each other. In respect to keeping the divergence of the magnetic field small, the CNIS method is better than the others. It is hoped that these conclusions might be helpful for the design of algorithm where the magnetic reconnection problems should be included, since the controlling of the divergence of the magnetic field is one of the key issues in MHD simulation.
Statistical Analysis of Chemical Components of Moon and Terrestrial Planets
Xu Dao-yi
1985, 5(1): 59-64.   doi: 10.11728/cjss1985.01.059
Abstract(1780) [PDF 399KB](63)
Abstract:
Materials of model chemical analysis of Moon and terrestrial planets are examined by some multivariate statistical analyses (cluster analysis and discriminant analysis). The results show that the Moon's constituents are more closely related to those of the Mars and asteroids than other terrestrial planets including the Earth. Therefore, it is suggested that the Moon possibly came from the region located at the outer side of Earth's formation region.
SPE short-term forecast with the photospheric magnetic field properties and traditional forecast factors
Cui Yanmei, Li Rong, Liu Siqing
2011, 31(4): 436-440.   doi: 10.11728/cjss2011.04.436
Abstract(3069) [PDF 463KB](69)
Abstract:
In Ref.[1] a simple Solar Proton Events (SPE) short-term forecast model is built with three solar photospheric magnetic physical properties (the maximum horizontal gradient of longitudinal magnetic field |▽hBz |m, the length of neutral line with strong gradients L, and the number of singular points η), which suggested magnetic physical properties are effective in forecasting SPE. The traditional SPE forecasting models, which have not used magnetic physical properties as input parameters, often have low Probably of Detections (POD) or high False Alarm Rates (FAR) for SPE. This paper built a more effective SPE short-term forecasting model with the traditional SPE forecasting parameters and magnetic physical properties by BP neural network. Model A uses only the traditional SPE forecasting parameters and Model B uses the traditional SPE forecasting parameters as well as those three magnetic physical parameters. In testing 973 samples during 2002--2003, Model A and B have the same POD while Model B has a lower FAR than Model A. It further testified that magnetic physical properties are effective for forecasting SPE. And the most important thing is that it will largely improve our practical ability in forecasting SPE.
Theory of Penetration of Hydromagnetic Wave into Cylindrical Model of Equatorial Ionoshere
ZHANG Dayue
2005, 25(3): 181-184.  
Abstract(2023) [PDF 811KB](48)
Abstract:
This paper presents a theory of penetration of fast mode hydromagnetic plane wave into the cylindrically stratified equatorial ionosphere and atmosphere. The fast mode hydromagnetic plane wave is decomposed into cylindrical wave modes. Then the propagation of cylindrical wave modes in cylindrically stratified ionosphere and atmosphere are solved as a two-point boundary value problem. The governing equations are from Maxwell equations. They are a system of four complex first order differential equations. The lower boundary of the solved region is the ground.The upper boundary is the plane of 500km altitude. Above the upper boundary, the wave electric field component along the magnetic field is zero. The wave magnetic field component along the ambient magnetic field satisfy the Bessel equation. Therefore the wave magnetic field component can be decomposed into cylindrical Bessel functions. The wave magnetic field component at the upper boundary are formed by the summation of inward going wave component and outward going wave component. The wave magnetic field is differentiated with respect to r. Then the inward going wave component is expressed in terms of the Bessel function solution and its differentiation. Through the continuation of the electric and magnetic field along the boundary, the boundary conditions are therefore formed. The cylindrical wave modes are composed to give the spatial distribution of the electromagnetic wave fields.
A COMPARISON OF THE MAIN IONOSPHERIC PARAMETERSOVER CHINA WITH IRI
Liang Shang-qi
1990, 10(2): 135-140.   doi: 10.11728/cjss1990.02.135
Abstract(1923) [PDF 266KB](63)
Abstract:
By using the ionosonde data observed at several observation stations in China, the observed values of f0F2, f0F1 are compared with that of IRI-86. The study showed that there exist a systematical and obvious deviations between them. The deviations for E- and F-region are somewhat small. However, the deviation for F2-region is considerably large, even being up to 60% in some cases. The deviations show clearly diurnal, seasonal and solar activity variations. In general, the relative deviations for f0F2 in the night time, summer and active solar zear. Moreover, the deviations become larger with decreasing latitude, and the values calculated from IRIare usually larger than the observed ones.
Extended Research of the Geometric Dilution of Position in Pseudo-distance Navigation System
Huang Ying
2009, 29(5): 540-544.   doi: 10.11728/cjss2009.05.540
Abstract(2344) [PDF 354KB](57)
Abstract:
The GDOP is an important parameter in the navigation system. Yet, along with the development of navigation system from single mode to integrated modes, different systems were integrated into a composed mode system, which resulted in difficult definition and calculation of GDOP and restricted its applications. Based on numerical computation of GDOP, the paper converts the calculation into resolution of different linear equations. The different systems are considered as different restricted conditions. This new method successfully resolved the problem, which could improve the application of the GDOP.
On the Prediction of Geomagnetic Storm Following the Eruptive Event on the Solar Disk
XUE Bingsen
2007, 27(6): 453-458.   doi: 10.11728/cjss2007.06.453
Abstract(2843) [PDF 993KB](75)
Abstract:
Solar flares are well-known events on the solar disk while most of them being non-geoeffective. The key factors that makes them geo-effective are weather they have CME accompanied and the features of CME as well. But among the hundreds of CME, only few of them could cause significant geomagnetic disturbances, which mainly depends on whether they are towards to the earth. In this work, the relationship between the geomagnetic disturbances and the energetic proton flux (ACE-EPAM) data, together with the parameter of the solar flares that related to the CME was carefully investigated. The preliminary result is that, more than 90% of the enhancement of the particle flux followed by shock could be measured by ACE. But the correlation between flux of the particles and magnitudes of the geomagnetic disturbances was not much clear. Other factors that related to the characteristics of the CME have also to be taken into consideration. The position of the flare, which may affect the direction of the CME, the flare scale, which may decide the velocity, and the duration, which could relate to the magnetic field strength. But through statistical work, it was found that the relationship between the magnitudes of the geomagnetic disturbance Ap index and all those parameters mentioned above was non-liner, so neural network method was introduced to simulate the relation automatically. After the neural work being trained with the historical data range from 1986 to 2002, a model to predict the geomagnetic storms after the solar eruptive events was constructed. Test result showed that the error of the model comparing with the measurement was less than 20%.
COMPOSITE ADAPTIVE CONTROL OF SPACE MANIPULATOR SYSTEM WITH PRISMATIC JOINT
CHEN Li
2003, 23(1): 60-67.  
Abstract(1963) [PDF 666KB](37)
Abstract:
In this paper, the control problem of free-floating space manipulator system with prismatic joint was studied. It is shown that the Jacobian matrix and the dynamic equations of the system could not easily be linearly parameterized, if we deduced it by use of the conservation relationship of the momentum and the angular momentum of the system. With the augmentation approach, we got the augmented generalized Jacobi matrix and the dynamic equation of the system that could be linearly dependent on a group of inertial parameters. Based on the results, the composite adaptive control scheme for free-floating space manipulator system with prismatic joint and unknown inertial parameters to track the desired trajectory in inertia space is proposed. The advantages of the control scheme proposed are that it needs not to measure the position, velocity and acceleration of the base. A two-link planar space manipulator system is simulated to verify the proposed control scheme.
Research of Blue/Red Reflecting for Space Silicon Solar Cell
LEI Gang, SHEN Zhenjue, CAO Jiaye
2012, 32(1): 136-140.   doi: 10.11728/cjss2012.01.136
Abstract(2089) [PDF 483KB](58)
Abstract:
The non-reflective silicon cells could increase cell efficiency in comparison to cells with smooth surface, while they would also increase the operational temperature as IR and UV energy is efficiently absorbed. This temperature increase completely offsets the initial efficiency gain when the non-reflective silicon cells were used in space. A Blue/Red Reflecting (BRR) for space silicon solar cell has been developed to improve the performance of silicon solar cell. The BRR consists of UVR on the front surface of the coverglass and the IRR on the rear surface produced in method of electron-beam gun evaporation with ion-assisted deposition. The operating temperature reduction between 6℃ and 12℃ and the in-orbit efficiency gains between 1.8% and 4.1% for silicon solar cell with BRR have been predicted. The potential benefits of the BRR are greatest for the non-reflective silicon cells.
Scientific Objectives and Payloads of Chang'E-4 Missionormalsize
JIA Yingzhuo, ZOU Yongliao, XUE Changbin, PING Jinsong, YAN Jun, NING Yuanming
2018, 38(1): 118-130.   doi: 10.11728/cjss2018.01.118
Abstract(2750) [PDF 3118KB](167)
Abstract:
The Chang'E-4 lunar explorer is composed of a communication relay satellite, a lander and a rover. The latter two are the backup of Chang'E-3. It is estimated that the Chang'E-4 explorer will be launched by the end of 2018, which is scheduled to land at the South Pole Aitken (SPA) basin, and carry out in-situ detection and reconnaissance at the farside of the moon with the communication support of the relay satellite. Chang'E-4 mission has been planned to install six scientific payloads to complete the corresponding tasks. Three payloads are installed on the lander, including the Landing Camera (LCAM), the Terrain Camera (TCAM), and the Low Frequency Spectrometer (LFS); and the other three payloads are installed on the rover, including the Panoramic Camera (PCAM), the Lunar Penetrating Radar (LPR), and the Visible and Near-Infrared Imaging Spectrometer (VNIS). The LFS is newly developed for Chang'E-4 lander, and the other five payloads are inherited instruments from Chang'E-3. Besides the above six payloads, there are also three international joint collaboration payloads to be installed on Chang'E-4 explorer, which are the Lunar Lander Neutrons and Dosimetry (LND) on the lander, the Advanced Small Analyzer for Neutrals(ASAN) on the rover, and Netherlands-China Low-Frequency Explorer (NCLE) on the relay satellite. In this paper, the scientific objectives, landing area overview, payload configurations and system designs, and the task for each payload with its main technology index of Chang'E-4 mission are mainly discussed.
THE CALCULATION OF LOWER IONOSPHERIC TEC ENHANCEMENT DURING INITIAL FLARE BURST USING HF DOPPLER RECORDS
ZHANG Donghe, XIAO Zuo, GAO Yufen, WANG Jialong
1999, 19(4): 315-320.   doi: 10.11728/cjss1999.04.315
Abstract(2005) [PDF 420KB](50)
Abstract:
By analyzing the change of electron density in different ionospheric regionsduring flare bursts, a new method is introduced, by which the TEC enhancement inthe lower ionosphere during the initial phase of a flare burst can be calculated using HF Doppler records. Some TEC enhancements caused by flare bursts from Marchto June in 1990 are calculated using this method. The results of TECenhancementare compared with the maximum fluxes of the soft X--ray of the corresponding flares.The correlation between the calculated TEC enhancement and maximum fluxes ofthe soft X-ray radiation of solar flares are fairly good in general, except very intenseflares.
On a Tracking and Data Relay Satellite (TDRS) Tracking a Lunar satellite
LI Yuheng, ZHENG Jun, YI Kechu
2007, 27(3): 227-232.   doi: 10.11728/cjss2007.03.227
Abstract(2443) [PDF 1324KB](69)
Abstract:
China has implemented its change engineering. The first lunar satellite will be lunched in 2007. When it is on orbit and tracked and controlled by a ground-based TTC station, the zone of exclusion caused by the earth's rotation is about 50%. Although the coverage can be improved by scattered more earth stations along the longitude, the improvement effect is limited with the restriction of Chinese territory. Obviously, an on-orbit tracking and data relay satellite can enlarge the coverage. Based on the orbital elements, an algorithm to calculate the terms for a TDRS tracking a lunar satellite is presented here. Then the space coverage of a lunar satellite tracked by an earth station or a TDRS is computed. Their results show that compared with the tracking coverage of 32% or 50% made by an earth station, a TDRS can cover a lunar satellite by 61% with lunar exclusion or 90% without lunar exclusion. When a lunar satellite is tracked by a TDRS rather than an earth satellite, some extra requirements are added to the TDRS' antenna movement. These requirements are beyond the capability of the current on-orbit TDRS, which is designed for tracking low earth satellites. Finally, with the help of an earth station and a careful scheduler, a proposal is presented to further enlarge the tracking coverage for a current on-orbit TDRS tracking a lunar satellite.
Simulation on the Penetration of Energetic Particles Into the Magnetosphere
Tang Pengju, Xu Ronglan, Wang Chi
2008, 28(4): 283-287.   doi: 10.11728/cjss2008.04.283
Abstract(2420) [PDF 1910KB](56)
Abstract:
The study on the penetration of interplanetary energetic particles into the magnetosphere, is one of the key problems in magnetospheric and space weather study. Most of the previous works concentrated on the statistical investigation of the penetration of energetic particles into magnetosphere under different interplanetary conditions. In this paper, the new-developed code is used to calculate the trajectories of energetic particles' penetration into the magnetosphere based on T89 model with different energies and pitch angles. The preliminary results show that only those particles moving along the magnetic field lines can penetrate and reach the earth's surface. The particles will be reflected earlier with larger deviation angle with respect to the magnetic field lines. The particles with higher energies can penetrate into the magnetosphere with larger distribution of the pitch angle, but only those with directions along the magnetic field lines can reach the ground. All these results are in consistent with theoretical predictions.
IN-FLIGHT RADIOMETRIC CALIBRATION FOR THERMAL CHANNELS OF FY-1C AND FY-2B METEOROLOGICAL SATELLITE SENSORS USING QINGHAI LAKE
HU Xiuqing, RONG Zhiguo, QIU Kangmu, ZHANG Yuxiang, ZHANG Guangshun, HUANG Yibing
2001, 21(4): 370-380.  
Abstract(2754) [PDF 1016KB](142)
Abstract:
This Paper describe the in-flight radiometric calibration for thermal channels of FY-1C and FY-2B meteorological satellite sensors using Qinghai lake, water surface radiometric calibration site. The radiance of water surface measured by CE312, and then performed atmosphere correct including gas absorption and path radiance which computed by radiance transfer code MODTRAN37, predict the radiance in the satellite sensor entrance pupil. At the same time the spectral response of Satellite sensor and that of ground-based sensor are coupled. At last the apparent radiance of sensor spectral channels are compared to the digital count of satellite's output to give the calibration coefficient. Several calibration is conducted for the satellite thermal sensors of FY serial satellites. The result show the difference between in-flight and on-board calibration is about 5%, equivalent to a brightness temperature of 3 K.
Measurements of the HF Backscatter Echo Spectra
Jiao Pei-nan, Zhang Xiu-ju
1985, 5(3): 191-198.   doi: 10.11728/cjss1985.03.191
Abstract(1659) [PDF 542KB](63)
Abstract:
In this paper, the HPbackscatter echo spectra measured by the technique of the pulse Doppler radar. The Doppler spectra are displayed in 3-dimensonal (time delay-power-Doppler frequency) spectrograms, i.e. the scatter function of the HPbackscatter propagation channal. The typical spectrograms are studied and the vertical motion velocity of the equivalent reflection height of the ionosphere are infered from the Doppler spectra. The values of the velocity are in accord with that infered from the vertical sounding data.
Research of EASM decadal variation characteristics based on the EMD method and the relationship with solar activity
Jiang Qiongfei, Guo Shengli, Liang Haowen, Wu Shanwei, Su Yucheng
2015, 35(1): 50-55.   doi: 10.11728/cjss2015.01.050
Abstract(1246) [PDF 963KB](144)
Abstract:
By application of normalization of the SLP data from Hadley and NCEP/NCAR, the East Asian Summer Monsoon (EASM) index from 1850 to 2011 are obtained. EMD method is adopted to analyze the periodic characteristics and get the EASM index cycles on various time scales. With three times analyses, the 11-year cycle component is obvious and has the highest correlation with the original data. Both the sunspot activity and the EASM activity have the same cycle component of 11-year and 80-year, especially the 11-year cycle component is obvious. With comparison between 11-year cycle component of sunspot number and that of EASM index, both of the fluctuation amplitude changes are basically identical.
Research of combined effect of small space debris and atomic oxygen
Li Hongwei, Cai Minghui, Han Jianwei, Huang Jianguo, Li Xiaoyin, Yu Jinxiang, Gao Zhuxiu, Liu Danqiu
2011, 31(4): 503-508.   doi: 10.11728/cjss2011.04.503
Abstract(2733) [PDF 787KB](144)
Abstract:
Using plasma drag particulate accelerator and atomic oxygen device based on PIG ion source, the first experiment was carried out about the combined effect of small debris and atomic oxygen on both the standard Kapton and Kapton with aluminum film. The result indicates that hypervelocity impact by particulate can accelerate the erosion effect of atomic oxygen on both Kapton and Kapton with aluminum film. The combined effect of hypervelocity impact and atomic oxygen is more important on Kapton with aluminum film than Kapton without film. This is because the impact by hypervelocity particles can destroy the aluminum film which prevents the atomic oxygen from eroding Kapton. So when consider the atomic oxygen effect on Kapton with aluminum film, the combined effect of hypervelocity impact by space debris and atomic oxygen should not be neglected. As a result, this effect is a threat to the life-span and credibility of spacecraft, which will restrict the development of high credibility and long life spacecraft.
OH MASERS IN W33B
Zheng Xing-wu
1991, 11(1): 1-8.   doi: 10.11728/cjss1991.01.001
Abstract(2065) [PDF 474KB](58)
Abstract:
The polarization observations are carried out towards OH masers in W33B with the 23/2, J = 3/2, F=1→1, and F = 2→2 transitions. The magnetic strength of 5 mGis inferred by the Zeeman splitting between right and left circular polarization spectra. The hydrogen density of the protostellar matter, n(H2) =3×107cm-3, in the active massing region is estimated by considering a spherical maser with the fully saturation and the homogeneous pumping.
Current Sheet Structure and Motion Observed by Cluster on September 15, 2001
LEI Jinnguo, LU Li, LI Zhongyuan, LIU Zhenxing, A. Balogh, H. Réme
2006, 26(1): 21-27.   doi: 10.11728/cjss2006.01.021
Abstract(2353) [PDF 5786KB](53)
Abstract:
Multiple crossings of the neutral sheet were observed by the Fltax Gate Magnetometer (FGM) and the Cluster Ion Spectrometry experiment (CIS) onboard the Cluster li at (-19, 4,-1) Re from 0430 UT to 0515 UT on September 15, 2001. The high-speed proton flow, which reversed from tailward to Earthward, was detected during the multi-crossings. Using a linear gradient/curl estimator technique the cross-tail current was obtained. The peak of the current density reached 28 nA/m^2. A large-scale wave propagating duskward and the thin current sheet flapping in the vertical direction were investigated, the thickness of the current sheet ranged from 0.3 Re to 0.2 Re, and had a tendency of being thinner. The velocity of the proton bulk flow in the x direction exceeded 1000 km/s during the magnetic field reconnection. By using the multi-point timing analysis and Minimum Variance Analysis, the structure and motion of the magnetotail current sheet were estimated.
Multiband Microwave Radiometer Design and Development for HY-2 Oceanic Calibration/Validation Site
Liu Jingyi, Wang Zhenzhan, Zhang Yu, Zheng Wei, Li Bin
2014, 34(3): 352-359.   doi: 10.11728/cjss2014.03.352
Abstract(1409) [PDF 1991KB](67)
Abstract:
Oceanic Multiband Microwave Radiometer (OMMR) with five frequencies and ten channels is designed for the calibration and validation of HY-2 satellite's scanning microwave radiometer. The development of this remote sensor is challenged with harsh working environment as well as long-term stable continuous 360° observation. In this paper, it is focused on the radiometer's system constitution, design and implementation of technical indicators. OMMR system includes eight functional units, i.e., antenna, receiver, scanner, calibration unit, temperature measurement, data sample and system control unit, power source and structure. The process of system indicators test and calibration is described. Testing results showed that the radiometer can meet the design requirements.
Advances in the Study of Transionospheric Propagation of VLF Waves
LIAO Li, ZHAO Shufan, ZHANG Xuemin
2017, 37(3): 277-283.   doi: 10.11728/cjss2017.03.277
Abstract(1227) [PDF 1021KB](42)
Abstract:
Very Low Frequency (VLF) electromagnetic wave (3~30kHz) mainly radiated by lightening and ground-based VLF transmitters, which plays a very important role on controlling the distribution of high energy particles in the magnetosphere. VLF radiation can penetrate into the ionosphere, and propagate in whistler mode in the ionosphere, and interact with high energy particles in the magnetosphere. In this paper, the development of the calculation model of VLF wave penetrating into the ionosphere, the validation of the model and the application of the model in the study of the ionospheric phenomena are reviewed, and a preliminary outlook for future work has also been made.
Observations of the Global Ionospheric Response During the January 2009 Stratospheric Sudden Warming Event
LEI Xiaolong, FU Yang, XUE Zhengang, DU Xiaoyong
2012, 32(4): 513-523.   doi: 10.11728/cjss2012.04.513
Abstract(2313) [PDF 1183KB](16)
Abstract:
A major Stratospheric Sudden Warming (SSW) in January 2009 was the strongest and most prolonged on record. In the period of this warming event, the solar activity and geomagnetic disturbance are extremely low. Hence it provides a good opportunity to investigate the response of the ionosphere to SSW event. The Kriging method is adopted to construct map of NmF2, hmF2, and integrated Vertical TEC (VTEC) within height ranging from 110km to 750km with data derived form COSMIC radio occultation system. And global TEC maps in the Sun-fixed coordinate are also withdrawn from IGS GIMs. By comparing these maps, it can be found that NmF2, hmF2 and TEC increase in the morning hours and decrease in the afternoon and night. Under fixed location and local time bins, cases during SSW and non-SSW days from global COSMIC observations are compared, which shows that NmF2, hmF2, and VTEC during SSW days, on average, increase 17%, 12%, 10km in the morning , decrease 10%, 15%, 16km in the afternoon, and decrease 19%, 23%, 11km in the afternoon respectively. According to the results of comparison of IGS GIMs during SSW and no SSW days, the main difference occurs in the middle and low latitude region, moves along with UT time and corresponds to the position of ionospheric anomaly. It also can be found that increase of TEC (VTEC and IGS TEC) is stronger in the northern hemisphere than in the southern hemisphere during the morning time. Furthermore, the phenomenon that NmF2, hmF2 and TEC (VTEC and IGS TEC) are decreased in the night hours has never been mentioned by previous studies. So altimeter observations by the OSTM/JASON-2 satellite are used for further verification and the phenomenon is validated at last.
THE EFFECTS OF NITRIC OXIDE ON ELECTRON DENSITY
Xu Xiu-juan
1995, 15(1): 14-18.   doi: 10.11728/cjss1995.01.014
Abstract(2653) [PDF 257KB](76)
Abstract:
In this paper,The effects of Nitric Oxide on electron density content in the 100-200km region at mid-low latitudes is studied by using the model of ionospheric electron density. It is found that the correlation of Nitric Oxide with electron density can be either negative or positive.The positive correlation occurs as the NO + hv → NO+ + e is the dominant production source of NO+.
There is Seasonal Abnormal Phenomenon in Night Time f0F2
Suo Yu-chang, Li Yong-sheng, Wei Min-jun
1989, 9(1): 64-69.   doi: 10.11728/cjss1989.01.064
Abstract(1852) [PDF 398KB](92)
Abstract:
Using data of nine ionospheric stations of China during Dec., 1975-Dec., 1986, it is presented that under the conditions of certain latitudes and solar activity, night time f0F2 shows a seasonal anomaly similar to that of the daytime foFz. This anomaly obviously shows two features: it only occurs in low latitudes; the higher solar activity is, the larger exlent of the degree of the anomaly is to. The night time seasonal abnormal phenomenon is the continuation of daytime seasonal abnormal phenomenon. The promary mechanism of the phenomenon is the seasonal variation of neutral air (O, O2, N2) concentration ratio O/O2 and O/N2, caused by the summer hemispher to winter hemisphere air flow. It is analysed why the night time seasonal abnormal phenomenon is limited in low latitudes and why the abnormal degree changes with solar activity.
Nonlinear Propagation of Finite-Amplitude Gravity Wave Packet in an Isothermal Compressible Atmosphere
YUE Xianchang, YI Fan, LI Fang
2005, 25(1): 29-36.  
Abstract(2110) [PDF 2558KB](69)
Abstract:
By using the Alternative-Direction-Implicit(ADI) scheme,a fully nonlinear,compressible and two-dimensional model is developed to numerically study the nonlinear propagations of gravity-wave-packets with different initial amplitude.The simulations show that the nonlinear effects depend strongly on the wave amplitude.The nonlinearity will damp the wave amplitude growth significantly,change the vertical wave numbers,and alter obviously the vertical velocity of energy transmission.The mean flows are accelerated extensively and greatly in the nonlinear propagation of a gravity wave packet with large amplitude.
EFFECTS OF ELECTRON RING-BEAM ON THE SATELLITE SURFACE POTENTIAL AND PLASMASHEATH
CAO Jinbin, ZHOU Guocheng, WANG Deju, CAI Chunlin
2000, 20(1): 16-22.   doi: 10.11728/cjss2000.01.016
Abstract(1819) [PDF 458KB](15)
Abstract:
The effects of electron ring-beam on the satellite surface potential and plasmasheath in magnetized plasma of low earth orbit are studied by means of 21/2-Delectrostatic code. The simulation results show that the satellite is charged negatively when there exists electron beam, and the increase of the density and velocityof electron beams increase the absolute value of satellite negative potential. Whenelectron ring-beams are injected in an oblique angle with respected to the magneticfield, the effects of electron ring-beams decrease when the oblique injection angleincreases from 0° to 90°. The plasma sheath becomes wider when there is electronring-beam and its shape changes from "tear drop" to "fan".
MF RADAR OBSERVATIONS OF TIDES AND THEIR INTERACTIONS OVER WUHAN (30°N, 114°E)
ZHANG Shaodong, YI Fan, HU Xiong
2003, 23(6): 430-435.  
Abstract(2411) [PDF 580KB](69)
Abstract:
Data obtained from the medium-frequency (MF) radar at Wuhan (30°N, 114°E) from 11 to 25 February and from 28 February to 13 March have been used to study the tidal oscillations and their interactions at mesopause (80-98km) region over Wuhan in winter. A dynamic spectral variation of disturbance amplitude illustrates a prominent peak at a period of 24 hours at all heights and almost uninterrupted, and there are occasionally slightly strong semidiurnal and weak terdiurnal tidal disturbances. These indicate that in the mid-latitude regions, the diurnal tide is the dominant tidal disturbance at mesopause in winter. A detailed analysis of tidal amplitudes and their wave kinematical energies implies that there may be significant resonant interaction among the diurnal, semidiurnal and terdiurnal tides. The phase profiles of the diurnal tides show obvious increase trend with the increasing heights in both the zonal and meridional directions, which indicate that the observed diurnal tides are propagating upward. The mean vertical wavelengths of the diurnal tides obtained from the zonal and meridional phases are 45km and 47km, respectively, and the corresponding downward phase velocities are 1.88km/h and 1.97km/h, respectively.
Study of sodium layer density over Haikou by Lidar during the night of 4 May 2010
Zhang Tiemin, Wang Jihong, Fu Jun, Guan Sai, Zhang Fuheng, Shen Zhenjiang, Yang Guotao
2013, 33(1): 48-52.   doi: 10.11728/cjss2013.01.048
Abstract(2566) [PDF 417KB](104)
Abstract:
The basic characters of the sodium layer density at a low-latitude location (Haikou, China, 20°N, 110°E) are described from analysis of sodium lidar observation data. A Nd:YAG laser pumped dye laser is used to generate the probing beam. The wavelength of the dye laser is set to 589nm by a sodium fluorescence cell. The energy and divergence of the beam are about 42mJ and 1mrad, respectively. The repetition rate of Nd:YAG laser is 30Hz. The backscattered fluorescence photons from the sodium layer are collected by a telescope with a 1000mm diameter primary mirror. A sodium layer density profile of upper atmosphere is derived from lidar files collected during the night of 4 May 2010 in Haikou, China. In this paper, the relative density and the absolute one for the sodium layer profile are studied. This result, shows a good correlation with that reported by Beatty at Arecibo, Puerto Rico (18°N, 67°W). A sporadic sodium layer is observed and lasted 12 minutes.
Influence of fluxgate magnetometer on the evenness of feedback magnetic field
Liu Nannan, Zhou Bin
2015, 35(2): 211-216.   doi: 10.11728/cjss2015.02.211
Abstract(1041) [PDF 1544KB](76)
Abstract:
Effects of the nonuniform feedback magnetic field on the fluxgate sensor is studied, and several typical types of the sensor are analyzed and compared mutually. It is required that the drive cores of fluxgate sensor should work in a uniform magnetic field in principle. When the magnetic field is nonuniform, error signal will be caused. Resultingly, the nonuniformity of the feedback magnetic field will lead to the change of fluxgate sensor's linear coefficient. Typical types of fluxgate sensors which work for space magnetic exploration include discrete form, Helmholtz form and Compacted Spherical Configuration (CSC) form, etc. The nonuniformity of the three feedback coils are analyzed as well as the performance of the fluxgate sensor when the feedback magnetic field is nonuniform. Compared to the simulation results, uniformity and stability of CSC sensor are much better than that of the discrete sensor, and CSC sensor is more conducive to the space magnetic field detection.
A NUMERICAL STUDY ON THE ENERGY PROPAGATION AND CONVERSION OF GRAVITY-WAVE PACKETS EXCITED BY WAVE-LIKE DISTERBANCE IN THE MESOSPHERE
HUANG Chunming, ZHANG Shaodong, YI Fan
2003, 23(2): 110-117.  
Abstract(2057) [PDF 1769KB](51)
Abstract:
By using the spectral allocation method, the characteristics of the energy propagation and conversion in the excitation of gravity wave by an initially given Gaussian wave-like disturbance is numerically studied. The simulation results show that any single wave-like disturbance component (horizontal wind, vertical wind, density or temperature) can independently excite two gravity-wave packets, one propagates upward and another propagates downward. With the same wave parameters, the energy propagation paths of the packets under the above mentioned four kinds of disturbances are almost identical with each other and slightly different from the ray paths derived by the linear theory. A further numerical analysis indicates that the characteristic time of the energy conversion from a disturbance to a wave is almost identical for those different disturbances, equal to two times of wave period. However, the energy conversion efficiencies for different disturbances depart significantly from each other.
Empirical Orthogonal Function (EOF) Analysis on the Thermospheric Total Mass Density Retrieved From CHAMP Observation
Zhou Xu, Wan Weixing, Zhao Biqiang, Yue Xin'an, Ren Zhipeng
2010, 30(3): 228-234.   doi: 10.11728/cjss2010.03.228
Abstract(2874) [PDF 583KB](60)
Abstract:
The Empirical Orthogonal Function (EOF) analysis was applied to study the thermospheric total mass density at the altitude of 400 km with the data obtained from German CHAMP satellite during the interval from 2003 to 2007, when the solar activity is in declining period. The solar cycle and yearly variations of the thermospheric total mass density ρ are obtained. It is found that the total mass density ρ was obviously affected by the solar activity, the correlation coefficient between solar cycle variation component of ρ and F10.7 index can reach 94.5%. At the mid- and high-latitudes, the amplitude of solar cycle variation is larger in the south hemisphere than in the north. The amplitude of the solar cycle variation is decreased as the latitudes change from low to high. At low latitudes there exists a structure of double crests which is recently known as the Equatorial Mass density Anomaly (EMA). In the yearly variation of the total mass density, there is a seasonal variation that the density is larger in summer than in winter. The amplitude of the yearly variation of density ρ increases with solar F10.7 index as well as the absolute latitude. Comparing the result of CHAMP data with the output of NRLMSISE00 model under the input of the same condition of observation, it is found that both the solar cycle and the yearly variations of thermospheric total mass density are in good agreement. Even though, the latitude difference of the solar cycle variation of ρ is a little bigger from NRLMSISE00 than CHAMP data and there is no EMA structure in NRLMSISE00 model. Furthermore, there is an obvious semiannual variation component while analyzing the NRLMSISE00 data without 130-day-wide sliding window. Thus it is considered that, with the restriction of CHAMP orbit, the 130-day-wide sliding window may smooth out the semiannual component, as well as the higher. It is concluded that the present results are meaningful in the study of the thermospheric climatology.
Calculation Analysis of Ionospheric Irregularity Zonal Drift Velocity in Guangzhou Based on GPS Measurements
LIU Weifeng, HUANG Jiang, DENG Baichang, XU Jie, QUAN Hongjun, HUANG Linfeng, LIU Miao
2012, 32(1): 48-54.   doi: 10.11728/cjss2012.01.048
Abstract(2540) [PDF 649KB](58)
Abstract:
Using data observed by two GPS ionospheric scintillation monitors located near each other at Guangzhou station, the amplitude scintillation was measured, and the zonal drift velocity of the ionospheric irregularities was studied by choosing three scintillation events, with methods of signal intensity power spectrum and cross-correlation technology. The results show that each of the scintillation registered in two receiver monitors occurs at the same time and induced by the same ionospheric irregularity. The zonal drift velocity is about 50m/s to 160m/s, on average about 120m/s from the two calculating methods, varies significantly at the beginning of the scintillation, decreased with time and eastward. The characteristics of the zonal drift velocity in Guangzhou are consistent with the observation at other stations in the low latitude region, which indicate that the two calculating methods are feasible and effective.
THE FORMATION AND EVOLUTION OF ASYMMETRICAL HIGH DENSITY CLOUD AND NON-LINEAR WAVE IN A CORONAL MASS EJECTION EVENT
Zhang Gong-liang
1995, 15(3): 169-178.   doi: 10.11728/cjss1995.03.169
Abstract(1829) [PDF 712KB](54)
Abstract:
The SMM observation of the 18 August 1980 coronal mass ejection is analyzed thoroughly and quantitatively,using the function fitting and digital filtering tech niques.It is shown that the formation of an asymmetrical high density cloud is something related to the deviation in the location of eruptive prominence with respect to the asymmetrical axis of the streamer.The evolution of the asymmetrical structure and its influence on the development of the event are discussed.The dark cavity is proved to be an expanding structure with strong magnetic field. From the radial brightness profiles,the first observational evidence for the front steepening of a non-linear coronal wave during its evolution is found with the time and height for shock formation estimated.The results of the present study are in favor of the event driven by an expanding strong magnetic field structure,rather than by a thermal impulse.
Analysis of single-event effects rate of K6R4016V1D chips applied in low Earth orbit
Han Jianwei, Feng Guoqiang, Yu Yongtao, Ma Yingqi, Shangguan Shipeng, Chen Rui, Zhu Xiang
2015, 35(1): 64-68.   doi: 10.11728/cjss2015.01.064
Abstract(1144) [PDF 1291KB](62)
Abstract:
Russia's Mars probe Phobos-Grunt together with China's first Mars probe Yinghuo-1 were launched into Low Earth Orbit (LEO) on November 9, 2011. Unfortunately, the main probe failed to fire its thrusters and transfer its orbit as planned after 159 minutes, eventually the trip to Mars was terminated. The most likely cause of the accident investigated by Russian Space Agency (RSA) was that RAM chips in onboard control computers worked wrong when hit by cosmic heavy charged particles, which sequently led to the two computers restart and eventually disturbed the probe totally. However experts on satellite radiation hardness casted lot of doubt on the statement that LEO probe can be effected by Single-Event Effects (SEE) resulting from space radiation particles in so short period of time. Based on information of the victim RAM components disclosed by RSA, experiment tests and calculations were performed for K6R4016V1D chip to predict SEE rate when applied in LEO. Finally, possibility for SEE to cause the failure of Phobos-Grunt probe was discussed.
Detecting Energetic Neutral Atoms in and out of the Heliosphere
K C Hsieh
2015, 35(3): 253-292.   doi: 10.11728/cjss2015.03.253
Abstract(1579) [PDF 15415KB](69)
Abstract:
By Energetic Neutral Atoms (ENA), we mean atoms having kinetic energies >0.1keV found in and out of the heliosphere. In the regions lacking any neutral gas of temperatures >106K, while abundant in ions of kinetic energies >0.1keV, surely an ENA has to be the product of charge exchange between an ion and an atom or molecule B of the local gas, i.e. A++BA+B+. Because energy exchange is minute during charge exchange, the newly formed ENA A and ion B+ can be considered keeping their respective original kinetic energies. Instantly, ion B+ is trapped by the local magnetic field, but ENA A is liberated and flies yonder, to be a sample of its originating plasma in mass and energy, thus providing a precious medium for remote sensing the parent plasma. The recent success of NASA's IBEX (Interstellar Boundary EXplorer) Mission in directly detecting ENA coming from the local interstellar medium greatly expanded the scope of ENA remote sensing. Here, we review the discovery of ENA in high altitudes, the basic concept and existing examples of remote sensing of ENA, recent results, and the designs and development of the necessary instruments, and also offer a prospective on ENA-sensing in the near future.
Seed Point Selection through Equal Line Integral of Magnetic Field Intensity Algorithm for Visualization of Geomagnetic Field
GAO Guangda, HU Xiaoyan, ZHONG Jia, ZOU Ziming
2016, 36(2): 147-152.   doi: 10.11728/cjss2016.02.147
Abstract(1530) [PDF 1101KB](75)
Abstract:
Drawing the magnetic lines as streamlines is a general method of visualizing geomagnetic field. A key factor to evaluate the effect of the geomagnetic field visualization is whether the space distribution of geomagnetic field lines is consistent with that of magnetic field intensity, while the distribution of geomagnetic field lines is determined by seed point selection. The traditional algorithms that select seed points with uniform angles on magnetic meridian circles cannot objectively reflect the space distributions of magnetic field intensity. This paper proposes an algorithm of selecting seed points with equal line integral of magnetic field intensity. The algorithm is applied to draw the geomagnetic field lines with the data from T96 model and IGRF model. The redundant magnetic field lines existing in the result are removed. Statistical analysis and comparison between the space distribution of magnetic field lines and the geomagnetic field intensity reveals that this algorithm can effectively visualize the geomagnetic field.
Prediction Method of CME Associated Geomagnetic Disturbances Based on Fuzzy Mathematics
WANG Jing, FENG Xueshang
2007, 27(6): 459-466.   doi: 10.11728/cjss2007.06.459
Abstract(2655) [PDF 2593KB](61)
Abstract:
Based on the 73 geomagnetic disturbance events caused by coronal mass ejection (CME) associated with interplanetary shock waves and using fuzzy mathematics, here is presented a prediction method for geomagnetic disturbances. According to the solar location of CME, the transit time of the interplanetary disturbance, the geomagnetic disturbance magnitude and the velocity jump observed by IPS at the disturbed front, five membership functions μθ,μT,μM,μ△v are constituted. Based on the five membership functions and fuzzy mathematics, prediction tests for the 73 CME associated geomagnetic disturbance events during 1996--2004 are made by considering the influence of CME velocity on the onset time of geomagnetic disturbances. Main results are: (1) For the prediction of the magnetic disturbance onset time, 91.78% is within the range of relative error △Tpre/Tos≤30% and 12.33% within △Tpre/Tos≤30%; (2) For the prediction of the geomagnetic disturbance amolitudes, 60.27% is within the range of relative error △∑Kp/∑Kpobs≤30% and 12.33% within △∑Kp/∑Kpobs≤50%. These results show that the prediction method has good feasibility for geomagnetic disturbance prediction.
LET DISTRIBUTION AND ABSORBED DOSE IN SZ-3 RECOVERER
JING Guiru, REN Guoxiao
2004, 24(2): 112-118.  
Abstract(2082) [PDF 586KB](54)
Abstract:
In order to measure the absorbed dose and the dose equivalent induced by heavy ions which enter the space capsule inside, a solid state nuclear track detector is installed in the inner wall of SZ-3 recoverer. This detector is composed by the sandwich of CR-39 sheets and aliminium sheets. The flight time of the detector on board of SZ-3 is about 162 h. After the chemical etching for recoverd CR-39 sheets, we scaned and measured the ion track spots on the CR-39 sheets. Refering to the calibration value for different ions provided by heavy ion accelerator experiment and subtracting the background provided by the contrast samples on the ground, the linear energy transfer (LET) distribution in recoverer are obtained. When the linear energy transfer (LET) is larger than the threshold of the detector, the integral intensity is (4.667±0.071)×10-5cm-2·s-1·sr-1. For LET > 12.6keV/μm (H2O), the total absorbed dose and the total dose equivalent are (23.50±0.46)μGy and (355.6±9.7)μSv, respectively. The relationship between the total dose equivalent and the thickness of shield are obtained.
F2-LAYER RESPONSE TO GEOMAGNETIC DISTURBANCES
MA Ruiping, XU Jiyao, WU Mingliang, JI Qiao
2003, 23(2): 118-126.  
Abstract(2107) [PDF 2020KB](35)
Abstract:
Using the data observed in 37 ionosonde stations during 1974-1986 and adopting the correlation analysis method for the deviation of the daily f0F2 value from its monthly median to ap index, the geomagnetic latitude distribution of the F2-layer response to geomagnetic disturbance is obtained for the first time in every year of one solar activity cycle in the East Asia-Australia sector, Europe-Africa sector and America-East Pacific Ocean sector. The results showed that the negative response appeared at the high and middle geomagnetic latitude, the positive response appeared at the low latitude and geomagnetic equator, the response sign changes at the geomagnetic latitude of about ±30°, the maximum positive response appeared at geomagnetic equator and maximum negative response appeared at the geomagnetic latitude of about ±50°, and the amplitude of maximum negative response is larger than the amplitude of maximum positive response. The responses have obvious longitude dependence and the asymmetry between the Southern hemisphere and the Northern hemisphere. The geomagnetic latitude distribution of the response is symmetrical between the Northern and Southern Hemispheres in the East Asia-Australia sector. But in the Europe-Africa sector and America-East Pacific Ocean sector, the asymmetry between the Northern and Southern Hemispheres is obvious, the amplitude of maximum negative response is larger in the Northern Hemispheres than in the Southern Hemispheres.
INFLUENCE OF CHARGE FLUCTUATION ON DUST MAGNETOACOUSTIC WAVE IN SPACE DUST PLASMA
SHI Zhidong, LI Zhongyuan
1997, 17(4): 303-308.   doi: 10.11728/cjss1997.04.303
Abstract(2379) [PDF 359KB](206)
Abstract:
Charging processes of dust gndns in plasma are analyzed. Aset of self-consistenttaewflulds equahons are given for dust Plasma. From these equaons, fluctuation ofcharge on dust grain is stUdied and dispersion relations are derived for dustmagnetoacoustic waves in magnehzed dust plasma The influence of charge fluctuationon dust waves is discussed for some dust plasma in space.
Location Algorithm and Error Analysis for Earth Object Using TDOA, FDOA by Dual-Satellite and Aided Height Information
LIN Xueyuan, HE You, SHI Pei
2006, 26(4): 277-281.   doi: 10.11728/cjss2006.04.277
Abstract(2424) [PDF 1490KB](51)
Abstract:
Determining the position of an object on Earth's surface has many applications, such as in navigation and in remote sensing. The location system generally consists of a number of spatially well separated receivers that capture the radiated or reflected signal from the object. The satellite positioning systems has the advantage of long-distance and wide coverage compared with ground positioning systems and airplane positioning systems. When satellite positioning systems locates an object on earth's surface, TDOA (Time Difference Of Arrival) measurements, but when there are relative motions between object and satellite, the FDOA (Frequency Difference Of Arrival) can also be measured. When the altitude from sea-level of object is known, WGS-84 ellipsoid earth model can be used as the precise location model. This paper puts forwards the location algorithm for emitter on Earth using the TDOA and FDOA measurements of two low-orbit satellite, and studies in detail this algorithm, at the same time provides the error distributions model of location accuracy.
Precision Analysis and Shape Adjustment of Inflatable Antenna
XU Yan, GUAN Fuling, GUAN Yu
2006, 26(4): 292-297.   doi: 10.11728/cjss2006.04.292
Abstract(1964) [PDF 2287KB](61)
Abstract:
Inflatable antenna structures made of flexible membrane materials have many benefits over machine deployable antenna: low in mass and can be packaged into small volumes and are easy to control the deploy process. A kind of ground demonstration model of lenticular membrane antenna was designed in this paper, and nonlinear finite-element analyz model of inflatable structures is built. Precision analyses of inflatable reflector were conducted, and all important design parameters such as inflation pressure, membrane thickness, material characteristics and antenna focal length are investigated. The parametric study results were then used to design a 2-meter ground demonstration model of lenticular membrane antenna. The demonstration antenna reflector model was assembled by twelve gores from 0.18-mm-thick Mylar films. Gravity influence in the reflector was compared under three postures and one of them is chosen as final experiment posture. For this antenna structure, a new feasible shape adjustment measure was improved based on surface accuracy test of the membrane antenna reflector. Analysis and experiment results indicate that this method can improve the inflatable reflector precision effectively.
Feasibility of Geosynchronous ATV Navigation Based on GPS
Fan Litao, Tang Jianguo, Wu Jie
2008, 28(4): 311-315.   doi: 10.11728/cjss2008.04.311
Abstract(2621) [PDF 1522KB](130)
Abstract:
The GPS is used to determine the orbit of Geosynchronous Autonomous Transfer Vehicle (GATV). The visibility of the GPS satellites relative to the vehicle is analyzed in this paper. Moreover, inertial error, pseudorange and delta pesudorange models are established in the earth centered inertial coordinate system. The adaptive kalman filter with a fading factor is applied for the vehicle orbit determination. Simulation results show that even slope-lobe signal is used, GPS satellite visibility becomes lower as the vehicle flies higher. Usually, the visibility can not be improved effectively by increasing the receiver antenna gain and direct orbit determination is infeasible with only one epoch GPS observation. It is indicated that by using kalman filter, in the conditions of 1 km initial position deviation, 1 m/s initial velocity deviation, 10 m pseudorange mean square error and 0.05 m/s delta pseudorange mean square error, the final position deviation is smaller than 50 m while the velocity deviation is smaller than 0.02 m/s.
Field-Aligned Currents Distribution Deduced From the Global Electric Field Model
Song Xiao-ting, Wu Lei, Zhu Gang-kun
1985, 5(4): 245-253.   doi: 10.11728/cjss1985.04.245
Abstract(1584) [PDF 556KB](51)
Abstract:
In this paper the expressions of the Volland, s model of large-scale convection electric field revised by using the experimental data measured on board the satellite GEOS-2 and other sounders are summarized, and with this model the field-aligned currents are calculated. The expressions for the calculated field-aligned currents from the electric potential function are applied to the case of weakly disturbed conditions. The results of calculation are consistent with the observations by the satellite Triad (Iijima and Potemra, 1978). This means that the revised Volland, s model is reasonable and hence the magnetospheric dynamical characteristics derived from GEOS-2 are reliable.
Dimension less Jump Conditions for the Magnetohydrodynamics Shock Wave
Wei Feng-si
1984, 4(1): 22-33.   doi: 10.11728/cjss1984.01.022
Abstract(1775) [PDF 655KB](38)
Abstract:
The jump equations of the magnetohydrodynamics shock wave are transformed to the dimensionless form, so that their solutions become very simple and straightforward. An obligue, a perpendicular, a parallel shock wave as well as the unitized form for the aerodynamic and the magnetohydrodynamics shock wave are discussed in this paper respectively.
Physics of Wind-blown Sand and the Threshold Wind Speed of Dust Storms on Mars
CAI Huangbing, CHEN Chuxin
2013, 33(4): 374-380.   doi: 10.11728/cjss2013.04.374
Abstract(2916) [PDF 525KB](36)
Abstract:
The planet Mars is most closely related to Earth in its size and character. From the comparative planetology point of view, what happens on the Mars is of importance to our human being on the Earth. There exist dust storms on both Earth and Mars. The dust storm on Mars is different from that on Earth in its scale. However, in some aspects, they are similar on these two planets, like the mechanism for the generation of dust storm. In this paper, a model of wind-blown sand at the surface of sanded ground is constructed, and the threshold wind speed for dust storms to start on Mars is calculated based on the wind profile of atmospheric turbulent boundary layer. It is concluded that the wind speed of 28.7 meters per second at 2 meters height is needed for a dust storm to start on Mars, and the suspended dust particles' diameter is less than 30 micron when wind speed is at the threshold value. It is also found that sands need to roll a distance of one particle's diameter before saltation.
Observation of OSCAR-3 Satellite Radar Cross Section Using the Tristatic Radar
JIN Wang, WU Jian, WU Zhensen, LIU Yongjun, SUN Mingguo, LI Hui
2013, 33(4): 453-457.   doi: 10.11728/cjss2013.04.453
Abstract(2498) [PDF 471KB](85)
Abstract:
This is the first space debris observation experiment using 930MHz Europe Incoherent Scatter (EISCAT) UHF Radar in China. For the purpose of analyzing the discrepancy of tristatic RCS (Radar Cross Section), taking observation satellite named OSCAR-3 as an example, the standard European Incoherent Scatter (EISCAT) ionospheric radar experiment model is used. The results showed that the RCS precision from Sodanky radar is five times higher than that from Tromso radar; according to the forecast debris model of National Astronomical Observatories of Chinese Academy of Sciences and the theoretical antenna pattern, the revised RCS is referential when the U.S. Space Surveillance Network does not provide RCS results. Results of the present work confirm that the tristatic radar could provide higher precision RCS than monostatic.
RECURRENT LAW OF THE ACTIVE REGIONS OF PROTON FLARES
Zhou Shu-rong, Wu Ming-chan, Ni Xiang-bin
1996, 16(4): 293-298.   doi: 10.11728/cjss1996.04.293
Abstract(2030) [PDF 475KB](98)
Abstract:
Recurrent law of the active regions for proton flares are studied in this paper. The results indicate that on the sun there are "active volcanos" of the motion along longitude, that is active reviviscent bodies of the proton flares. In 22th solar activity cycle, there are two stronger active reviviscent edes of the proton flares on the sun, they are in two latitude bands of 26°- 35°N and 20°30°S. The proton flares with peak fluses≥100pfu and ≥1000pfu produced by these reviviscent bodies are about 70.7% and 83.3% of those on the solar disk. Long periods of the revivifications for active reviviscent bodies are about 8- 11.6 years, short periods are 1-2.6 years. Due to long and short periods of the revivification for the reviviscent bodies consist with 11 years periods of the solar activity cycle and time interval of the peak years, therefore, the periodic revivifications of the active reviviscent bodies can be important cause of the 11 years periodic variation of the solar activity cycle and intensive eruptions of the flares during solar active maximum.
Marangoni Effect in Subcooled Nucleate Pool Boiling
ZHAO Jianfu, LU Yanghui, LI Zhendong, LI Jing
2008, 28(2): 159-163.   doi: 10.11728/cjss2008.02.159
Abstract(2705) [PDF 914KB](29)
Abstract:
The lateral motion of bubbles attached to the heater surface during nucleate pool boiling of subcooled liquids is studied in the present paper. It is assumed that there exists the Marangoni convection surrounding a discrete vapor bubble due to the temperature difference acting on the interface between vapor and liquid. The mutual entrainment of adjacent bubbles in the Marangoni convection might drive bubbles toward each other during nucleate boiling of a subcooled liquid. This kind of motion promotes coalescence of adjacent bubbles. A scaling analysis on such flow is presented. The characteristic velocity of the lateral motion is obtained approximately. Furthermore, an approximate equation for estimating the observability of such motion is also presented. The predictions are consistent with the experimental observations. Moreover, it is predicted that the intensity of the Marangoni convection may be very high for fine bubbles initiated at some active cavities on the heater surface, which will result in the micro-jet at the top of the bubble. The effect would be especially important in cases where the bubble release rate is low such as boiling on horizontal down-facing surfaces and boiling in microgravity.
DELTA-SUNSPOTS AND X CLASS FLARES IN SOLAR CYCLE 22
Shi Zhong-xian, Wang Jing-xiu
1994, 14(1): 1-7.   doi: 10.11728/cjss1994.01.001
Abstract(2212) [PDF 583KB](48)
Abstract:
Asample of 221 active region with magnetic configurations from 1986 to 1991 in solar cycle 22 is used to investigate the characteristics of δ-sunspots and the relationship between the δ-sunspots and Xclass X-ray flares.(1) The previous findings from Tang (1983), Zirin and Liggett (1987) are confirmed that all δ-sunspots form from penetration of leading and following sunspots from two dipolar regions, and have strong sheared transverse field on the polarity inversion line. However, unlike that concluded by Zirin (1987), examples of separation of δ-sunspots have been identified in this study. The separation is caused by individual proper motions of each dipole.(2) The δ-sunspots tend to have an imbalanced flux in opposite polarities. For 35 δ-sunspots with available sunspot data and Huairou magnetograms at hand, which produce 104 Xclase X-ray flares, the average ratio of flux in majority polarity to minority polarity is about 5.3; and in all highly flare productive regions, such as AR5395, 5629, 6555, 6659 and 6891, the a ratio is≥5.(3) There are relationship intimately between lifetime of δ-sunspots and productivety of Xclass X-ray flares.
THE DETERMINATION OF TRAVLING DIRECTION OF SEVERAL CMEs CAUSING SEVERE GEOMAGNETIC STORM
LE Guiming, YE Zonghai
2004, 24(1): 15-21.  
Abstract(2080) [PDF 713KB](58)
Abstract:
Coronal Mass Ejections (CMEs) are important factors for the space weather. The geomagnetic storms with sudden commencement are caused by CMEs. CMEs with the south direction of Bz > 10 nT and high traveling speed can often cause intensive magnetic storm. But many problems keep unsolved on the relationship between a CME and the intensity of the relative geomagnetic storm. In this paper, the traveling directions of several coronal mass ejections causing severe geomagnetic storm are investigated by using the galactic cosmic ray data observed at McMurdo and Thule neutron monitor. If a CME’s traveling direction straightly towards to magnetopause, then the variation in galactic cosmic ray intensity observed at the two stations should be almost the same. Several selected CME events are analyzed. The results show that the direction of the CME related to the geomagnetic storm on Dec.19, 1980 was almost dead against magnetopause, the situation was the same for the CMEs related to the geomagnetic storms on Jul.13, 1982, Nov.6, 2001 and Mar.31, 2001. The traveling direction of the CME related to the geomagnetic storm on Jul.15, 2000 is slightly directed to south of the earth. By comparing the intensity of the geomagnetic storm on March 31, 2001 and July 15, 2000 and comparing the disturbed solar wind driven by corresponding CME, it is thought that the traveling direction of a CME is a factor having impact on the intensity of the geomagnetic storm caused by the CME. For a CME, the more deflection of its traveling direction towards the magnetopause, the weaker the geomagnetic storm caused by it.
Fluid Loops in General-purpose Space Science Experimental Platform
He Chongchao, Zhang Hanxun
2010, 30(2): 165-169.   doi: 10.11728/cjss2010.02.165
Abstract(2256) [PDF 831KB](40)
Abstract:
Space Science Experimental Platform (SSEP) is a multi-function experimental platform being developed as an alternative for traditional single-function experimental apparatus. This paper introduces the designs of heat transfer fluid loops in SSEP, and related design methods for some major equipment, including Avionics Air Assembly (AAA) fan, gas-liquid heat exchanger and cold plates. Suggestions for working fluid selection are also listed with the considerations of heat transfer efficiency and system safety. Preliminary analysis results, as well as the successful application of such designs in similar platforms developed by ESA and NASA, proved that fluid loop heat transfer technology, combined with complementary active and passive thermal control measures, can maintain the multi-function experimental platform and its payloads within their required temperature limits.
Application of Singular Spectrum Analysis to Solar 10.7cm Radio Flux 27-day Forecast
ZHONG Qiuzhen, LIU Siqing, HE Juanxiong, GONG Jiancun
2005, 25(3): 199-203.  
Abstract(2455) [PDF 1485KB](45)
Abstract:
In this paper, singular spectrum analysis (SSA) method was applied to 27-day solar 10.7cm radio flux forecast for the first time. In order to focus on the F10.7 prediction during the period of the low level solar activity, the test prediction range was chosen from April 30 to May 30, 2004 within the cycle 23 descendent phase. To ensure there were enough data to construct the sample series, both real time data and partial data in the cycle 20 descendent periods following the rule of similar cycle method were chosen, in this way sampling number increased and at the same time, effects of high solar activity are kept away so to get more precise F10.7 forecast during the low solar activity. The forecasted results of these 31 days show that they mainly coincided with the general tendency of F10.7 vaviations. The averaged relative error of each 27-day forecast was about 10%. The total average relative error of the 31 days was 10.5%. The minimum average relative error was 4.8% and the maximum was 16.7% during the test forecast period. Comparing with American Air Force (AAF) forecast in the same periods, the total average relative error of SSA is less than AAF, the former was 11.3% and the latter was 14.6%. Furthermore, each average relative error of SSA was less than AAF except two days. But to the short-term forecast within one day to 12 days, the result of AAF was superior to SSA.
Applications of Surface Plasmon Resonance Biosensor in Microbial Detection
LIU Xueyong, BAI Yanqiang, XIONG Jianghui, WANG Chunyan, LI Yinghui
2006, 26(4): 264-267.   doi: 10.11728/cjss2006.04.264
Abstract(2740) [PDF 817KB](60)
Abstract:
There are a variety of microbes in the environment of the Earth and spaceflight. The proliferation of these microbes especially the pathogenetic microbes in the spacecraft will threaten astronauts' health even lives, so rapid and accurate detection of these microorganisms is put on schedule. Among so many detection methods, surface plasmon resonance biosensor developed rapidly in recent years by merit of its rapidness and high sensitivity. The SPR phenomenon occurs when an incident beam of p-polarized light of a given wavelength strikes the surface at a given angle through a prism, the biosensors based on SPR principle are used to monitor the changes of refractive index of ultrathin organic films at metal surfaces and are widely applied in the interaction of antigen-antibody, DNA-DNA and so on, but the harsh conditions of space bring forward more demands for the sensor. Because the detection of SPR sensor is independent of the gravity and it can resist the interference of electromagnetic, sound and so on, the SPR sensor has great advantages in the application of space. This article summarizes the application of SPR biosensor in the microbial detection, aiming at providing reference to microbial monitoring of earth and spaceflight.
THE NONSTEADY AND NONLINEAR INTERACTION BETWEEN PLASMA WITH THE FIELD IN WAKE REGION OF A MOVING BODY IN SPACE
MA Shanjun, WAN Guoxiang, XU Xuexiang
2004, 24(6): 434-440.  
Abstract(1861) [PDF 770KB](44)
Abstract:
The interaction between a body in space and its plasma environment is one of the basic problems in space plasma physics. Based on a set of the coupled equations that describe the non-steady and non-linear interactions between plasma and the electromagnetic field in the wake region of a moving body in space, using the method of numerical simulation, the evolutions of the density distributions of charged particles and collapses of electric field are obtained. Considering the property of axial symmetry of field quantity, the initial conditions of two dimensions with three field components and the method of limited differencial, FTCS (time forward-differencial and space central-differencial method), have been used. The initial condition must satisfy the condition of transverse wave ▽·Êȓ,τ=0)=0 and the basic parameters in numerical calculation are V0 = 106cm/s, Te = 2780 K, ne0 = 1 × 105 cm-3, R0 = 100 cm, Ê0 = 0.15. It is noticeable that we take into account the effect of time derivative on the density disturbance and field distribution, which is not considered in previous researches. The results of numerical calculations show that the density cavitons and potential solitons are formed due to the modulational instability. Comparing with the previous works[5]-[7], the velocity of the collapse is faster relatively. By detecting the distribution of density catiton, the moving body can be traced out by means of the change of the density caviton, although the body may be a stealth vehicle which can not be detected by the radar.
Finite Element Analysis of Actuator for Active Vibration Isolation System
Jin Darong, Yu Qiang, Yu Chun
2010, 30(1): 73-78.   doi: 10.11728/cjss2010.01.073
Abstract(2003) [PDF 741KB](38)
Abstract:
Active vibration isolation system applied to microgravity vibration isolation has utilized Lorentz force electromagnetic actuator to realize the levitation of isolated platform in the space. The Dynamic Analysis of the Electromagnetic Actuator (DAEA) is the basis of design and experiments. In this study, a structure of the actuator was presented, the finite element analysis of the permanent magnet part was implemented and the mechanical feature was validated. With the establishment of electromagnetic actuator model, the finite element analyses have been conducted, which includes static force feature analysis, implement modal analysis, transient analysis, harmonic response analysis and spectrum analysis as well. These analyses have paved the way for system structure optimization and actuator size reduction as to decrease the development cost, shorten the designing period and promote the product quality.
Robust Control for Space-based Robot With External Disturbances and Uncertain Parameters in Joint Space
Chen Zhiyong, Chen Li
2010, 30(3): 275-282.   doi: 10.11728/cjss2010.03.275
Abstract(2257) [PDF 595KB](44)
Abstract:
The robust control problems were discussed for space-based robot system whose base was not controlled. The under-actuated dynamic equations of the system were derived through the Lagrange method and linear momentum conservation of the system. It was shown that the dynamic equations mentioned above can be linearly dependent on a group of inertial parameters. Based on the results and with the augmentation approach, a robust control scheme was developed for space-based robot system with uncertain payload parameters and external disturbances to track the desired trajectory in joint space. The control scheme proposed doesn't require measuring the position, velocity and acceleration of the base with respect to the orbit due to an effective exploitation of the system dynamics. Besides, it is computationally simple, because the controller is always robust to the uncertain parameters and external disturbances rather than explicitly estimating them online. Therefore, the control scheme is prone to real-time and on-line applications in space-based robot system. A two-link planar space-based robot system was simulated to verify the proposed control scheme.
ew Method to Analyse the Orbital Abnormal of LEO Satellite Using TLE Data
Yang Xu, Liu Jing, Wu Xiangbin, Wang Ronglan, Yu Youcheng, Wang Rendong, Zhang Yao, Li Dawei
2011, 31(2): 223-228.   doi: 10.11728/cjss2011.02.223
Abstract(2973) [PDF 486KB](58)
Abstract:
Finding the orbital abnormal of orbiting satellite accurately and in time has great meanings. The presented method can find the orbital abnormal of debris or spacecraft effectively, which provide data supports to analyse and verify the collision event computed by space debris collision avoidance system. The orbital abnormal also includes the orbit maneuver and other orbit change. This paper discussed how to analyse the orbital abnormal of LEO satellites using TLE data. Then, a method of using the satellite adjacent elements plus compositive criterion are presented. The basic idea of compositive criterion method is to get each sub criterion and turnover rate using a certain period data of satellites, and each satellite has its own criterion instead of using an settled criterion to all satellites. Analysis showed that compared to using a single element threshold method, the compositive criterion method decreases the missing discrimination and also has a high accuracy of right discrimination. This paper also briefly analyzed other kinds of orbit using the same method.
DYNAMICS OF DEPLOYMENT AND LIBRATION OF TETHERED SATELLITE SYSTEMS
GU Xiaoqin
2002, 22(2): 154-162.  
Abstract(2006) [PDF 602KB](69)
Abstract:
The three-dimension dynamic equations of tethered satellite systems, with the mass of the tether considered, are formulated. The tension control rules and the optical relieving speed of the tether are derived by Pontryagin's method. A libra-tional motion of deployed system about the local vertical is studied. The movement couple between the center of mass and the attitude of tethered satellite systems is discussed, when the center of mass moves along Keplerian orbit. The numerical simulation results are included.
Application of satellite remote sensing technology in monitoring underground nuclear test
Yan Weidong, Zhao Yigong, Ni Weiping, Sun Bin, Wang Peizhong
2011, 31(3): 378-383.   doi: 10.11728/cjss2011.03.378
Abstract(3125) [PDF 910KB](70)
Abstract:
Satellite remote sensing technology plays an irreplaceable particular function in discovering, monitoring, identifying, locating, and analyzing the underground nuclear test, and makes it possible to deter the nuclear explosive test beforehand. Surveillance and verification of the Comprehensive Test Ban Treaty (CTBT) by satellite is a highly complex all-around decision-making process. Several effective remote sensing techniques were presented with examples in this paper, such as serial image analysis, image fusion, change detection, K-L transform, D-InSAR, DEM, GIS database. The limitation of the satellite remote sensing technology is also indicated, that is, it is unable to determine the underground nuclear explosion in physics term, and therefore false and missed alarms can not be avoided effectively.
Capacity of One-dimensional and Two-dimensional Modulation Under AWGN Channels
XIA Guojiang, XIONG Weiming, SUN Huixian
2008, 28(2): 180-184.   doi: 10.11728/cjss2008.02.180
Abstract(2746) [PDF 1181KB](73)
Abstract:
Satellite and deep space communication channels are regarded approximately as white Gaussian noise channels approximately, so it's significant to study on channel capacities using usual modulation schemes under this channel. Starting from Shannon's information theory, this paper develops the channel capacities of one-dimensional and two-dimensional modulation schemes. Based on above, it explains that special modulation schemes ought to be adopted according to different signal to noise ratio. For example, BPSK modulation schemes is used in deep space communication because of very low signal to noise ratio. It also explains the essential of coding gain with the same spectral efficiency applying coded modulation. For instance, a rate R=2/3 convolutional code can be combined with 8-PSK modulation which can be compared with uncoded QPSK modulation, since they both have the same spectral efficiency of η=2 bit/symbol. The Shannon's limit of AM and PSK without bandwidth constraint and the asymptotic capacity of PSK with high signal to ratio are discussed at the end of this paper.
Energetic Neutral Atom Imaging of the Earth Ring Current During Magnetic Storms—Comparison Between Simulation Results and Observation
CHEN Zhiqing, SHEN Chao, LU Li, S. McKenna-Lawlor, LIU Zhenxing
2012, 32(2): 182-190.   doi: 10.11728/cjss2012.02.182
Abstract(2851) [PDF 1330KB](35)
Abstract:
Based on an analytical ion model for the ring current, in conjunction with the Chamberlain exosphere density model, Energetic Neutral Atom (ENA) images were calculated for the magnetic storm occurred in November 2004. It was shown that the simulated ENA images differ from images recorded by the Energetic Neutral Atom Detector Unit (NUADU) instrument aboard TC-2 of Double Star mission in terms of azimuth/magnetic Local Time (MLT) distribution, altitude/latitude distribution and energy spectral distribution. If the determiner of asymmetry of the ring current and azimuth of flux maximum can be selected according to evolvement of storms, and more emphasis be placed on density of low altitude exosphere or neutral atoms other than H be taken into account, the ion model is hopeful to produce more precise ring current ion distributions and ENA images. In addition, the ion spectrum at the injection region is expected to be revised and change of ratio of different ion species should be taken into account in order to get better simulation results.
Fluctuations of high-energy electron fluxes in Earth's radiation belt and its applications for geomagnetic storm alert
Huang Wengeng, Shen Hua, Liu Siqing, Zhong Qiuzhen, Chen Yanhong
2015, 35(1): 18-25.   doi: 10.11728/cjss2015.01.018
Abstract(1280) [PDF 5327KB](69)
Abstract:
The outer radiation belt consists mainly of high energy electrons trapped by the Earth's magnetic field. The disturbance of the geomagnetic field caused by the Coronal Mass Ejection (CME) or the Co-rotating Interaction Region (CIR) can result in electron radiation belt variations. According to the variation feature of high energy electron flux in the outer radiation belt during magnetic storms, a novel index referred to as high electron flux fluctuation index was evaluated by using the 5-min resolution sampled electron flux data provided by GOES, and its correlation with geomagnetic Kp index was analyzed. It is found that high electron flux fluctuation index has a good correlation with geomagnetic Kp index, and the new index can be used as an indicator of geomagnetic storm occurrence. In comparison with 3-hour Kp index, which is wildly used in space environment operation prediction system, the suggested index in this paper can alert geomagnetic storm occurrence earlier.
Study on Dynamics Property of Smoke Particles in Vacuum and Microgravity
CHEN Ning, PAN Gongpei, CHEN Houhe, GUAN Hua, XUE Feng
2006, 26(1): 43-47.   doi: 10.11728/cjss2006.01.043
Abstract(1997) [PDF 1692KB](34)
Abstract:
The dynamics of smoke particles can be effectively described by the Stokes sedimentation theory and diffusion coefficient expression in normal conditions; but in vacuum and microgravity, the forementioned principles are not applied any longer. In order to study the applicability of the IR smoke in outer space, by analyzing the vacuum and microgravity effects of the smoke particles, we can simulate approximately the dynamics property of smoke particles using molecule dynamics theory. On the basis of correlative theory, the force between particles is related to the space between them. When the space is less than ten times balance space, the force is large enough to form steady smoke, otherwise, the force is too small, smoke particles cannot form steady smoke. According to the Maxwellian distribution function, a function model of space between particles is established. Based on the model, the effects of smoke materials radius r, consistency ρ and the moving time of particles t on the space between smoke particles are discussed by Mathematica method. The results show that the space reduces with the increasing of the r and ρ, the smoke screen stability will increase gradually; the more long t is, the more the space is large, the smoke screen stability will decrease.
Effect of Tailward Flows From the Ionosphere on the Near-Earth Magnetic Field
ZHANG Lingqian, LIU Zhenxing, WANG Jiye, PU Zhuyin, MA Zhiwei, SHEN Chao
2007, 27(3): 192-197.   doi: 10.11728/cjss2007.03.192
Abstract(2125) [PDF 1274KB](49)
Abstract:
Tailward flows are often observed in the near-Earth magnetotail by TC-1 satellite during quiet time and substorm active period. The statistical studies show that the perpendicular component of the tailward flow will leads to stretching of magnetic field lines. Due to the tailward flow, the Bx component of the magnetic field distinctly increases or the magnetic field geometry becomes tail-like from dipolar-like. The magnetic field is recovered and back to dipole-like structure when plasma flow is reversed. Along with magnetic field stretch, it is found that both temperature anisotropy and ion temperature decrease at the same time. During the period of the magnetic field recovering dipolar- like, the ion temperature rapidly increases and the temperature becomes anisotropy associated with the release of the magnetic energy. From the observations, it is also shown that the tailward flow causes an enhancement of By component. The results from the TC-1 satellite indicate that the tailward flow from the ionosphere has an important effect on the near-earth magnetotail.
MF Radar Observations of Nonlinear Interactions Between Tides in the Mid-latitude Winter Lower Thermosphere
LIU Renqiang, LU Daren
2008, 28(2): 142-151.   doi: 10.11728/cjss2008.02.142
Abstract(2215) [PDF 4716KB](15)
Abstract:
Data obtained from Wuhan MF radar in winter of 2001 are used to study the quadratic nonlinear interactions between tides in lower thermosphere. It is observed that diurnal, semidiurnal and terdiurnal tides are the prominent perturbations in the meridional wind component near mid-latitude winter mesopause region, and the 6 h tide is clear. By bicoherence spectrum analysis, it is revealed that most prominent bicoherence peaks stand for phase correlation between tidal harmonics or self-coherence of a single tidal wave. By examining the vertical wavelength time variations, a significant correlation is found between the vertical wavelength of the observed 8 h tide and that of the supposed nonlinearly generated one by the interaction between 12 and 24 h tides. In the interval of 94.0~98.0 km, there exist not only a certain phase correlation and vertical wavenumber correlation but also a strong amplitude correlation of the oscillatory amplitudes equivalent and oscillatory phases synchronous or reversed between the prominent tides, indicating a wave-wave quadratic interaction has occurred. However, below 94.0 km, the various correlations between tides grow weaker and weaker with descending height and hence the tidal quadratic interaction is more likely a local and temporary phenomenon.
Ionospheric Responses to IMF Southward Turnings in Mid- and Low-latitudes
Sun Shuji, Chen Chun, Ding Zonghua, Ban Panpan, Xi Dilong
2009, 29(3): 268-274.   doi: 10.11728/cjss2009.03.268
Abstract(2798) [PDF 677KB](58)
Abstract:
Using the historical data from ionosonde stations and satellite, the response of ionospheric f0F2 to major Interplanetary magnetic Field (IMF) southward turnings in mid- and low-latitudes is studied. It shows that the IMF southward turnings can cause disturbing response in the ionosphere, which depends on latitude, season and local time when the turning occurs. In mid-latitude, the ionospheric response to southward turnings in summer and equinox and by night is stronger, which fades out with latitude decreases. During the recovery phase the irregular fluctuation in the ionosphere comes forth. In low-latitude, the disturbance caused by the turnings is strong in summer and equinox and weak in winter, although it tends to be immersing into the background disturbances. It is also found that the maximal negative responses of the ionosphere is well related with the maximal negative Bz after the southward turnings linearly.
AUTONOMOUS CONTROL FOR SPACECRAFT
DAI Shuwu, SUN Huixian
2002, 22(2): 147-153.  
Abstract(1913) [PDF 655KB](37)
Abstract:
A distributed multi-agents autonomous control system that satisfies the control needs of spacecraft is designed. The planning and scheduling subsystem that is composed of an abstract scheduling and a precise scheduling, is discussed in the paper. At last, a layered architecture is chosen for agent structure. Layered architecture allows integrating reactivity and deliberation together, which are all necessary for spacecraft control.
Attenuation of Alfven Waves in Weakly Ionized Near Earth Atmosphere
Liu Yuantao, Zhao Hua, Li Lei, Wang Jindong, Zhou Bin, Feng Yongyong
2011, 31(3): 299-303.   doi: 10.11728/cjss2011.03.299
Abstract(2337) [PDF 489KB](46)
Abstract:
Alfven waves, produced on the ground by artificial or by soundstorm, propagating to the near-earth space along the geomagnetic field lines, would decay greatly with distance. A dipole geomagnetic field model in near earth space, plasma density and conductivity models derived from observational data are used in this study to investigate the attenuation of Alfven waves below 1000 km altitude by numerical simulation methods. The frequency that would be detected by magnetometer carried by satellite was also found. The result showed that: Alfven waves will decay sharply in the height of less than 50 km for the much weak electrical conductivity in this region; it is 0.4 Hz Alfven waves, when transmitted to 1000 km, that becomes about one-thousandth of the original, so Alfven waves below 0.4 Hz can be detected by LEO satellites.
Analysis of Surface Wave Plasma Drag Reduction Properties in Near Space
Cai Honghua, Nie Wansheng, Feng Songjiang
2014, 34(3): 304-312.   doi: 10.11728/cjss2014.03.304
Abstract(1156) [PDF 2679KB](90)
Abstract:
In order to investigate the drag reduction effect of surface wave plasma in near space, this paper analyzes the surface wave plasma flow control mechanism based on basic characteristics of the fluid control macro model, simulates its flow field in the 0 degree angle of attack based on the airship model. The drag reduction effect of different actuator control program is compared, and the plasma flow control effect on the airship tail is studied. Results show that the surface wave plasma can increase the airship lift and reduce its flight resistance. The airship lift can be increased through the unilateral control scheme, while the symmetrical control scheme is invalid for the airship lift because of the airship force balance in the vertical direction. The maximum drag reduction effect of unilateral control scheme is about 7 percent, and the symmetrical control scheme is better than unilateral one with its maximum drag reduction effect up to about 32 percent. The surface wave plasma has good elimination and inhibition of flow separation in the airship tail.
Research on Formation Initialization Control for Elliptic Reference Orbit
LEI Bochi, ZHENG Jianhua, LI Mingtao
2015, 35(1): 86-93.   doi: 10.11728/cjss2015.01.086
Abstract(1048) [PDF 2009KB](37)
Abstract:
Formation initialization for elliptic reference orbit is studied in this paper, and three formation initialization strategies for planner formation configuration are derived. Firstly, two impulsive initialization strategy is derived using the state transition matrix. Secondly, three and four in-track impulsive initialization strategies are studied using the Gauss perturbation equations with the principle of minimal fuel consumption. Finally, numerical simulations of three initialization strategies are carried out, and the sequence quadratic programming and genetic algorithm are proposed to optimize the numerical results. Simulation results show that three in-track impulsive initialization strategy requires about 41% less velocity increment compared with two impulsive initialization strategy, and four in-track impulsive initialization strategy requires almost equal velocity increment compared with three in-track impulsive initialization strategy.
THE EVOLUTION OF THE FILAMENT IF THE REGION AR2522 AND THE ERUPTION OF THE FLARE
Wu Gui-ping, Xu Ao-ao
1996, 16(1): 56-61.   doi: 10.11728/cjss1996.01.056
Abstract(1757) [PDF 470KB](43)
Abstract:
With observational data in several bands in region AR2522, the relationshipbetween the evolution of the filament and the eruption of 1B/M4 two-ribbon flareis analysed. It is shown that: (1) the shearing movement of the filament footpointleads to the increase of the current intensity and the stored energy for the flareeruption; (2) the ascending motion and twisting of the filament are the results ofthe increasing current intensity and the stored energy of the flare, (3 ) Martens Kuin model is applicable to illustrate eruptive phenomena of the two-ribbon flarerelated to the filament with rapid motion.
Reverting the Distribution of Space Protons and Ions From the Ground Cosmic Ray Neutrons Intensity
LAI Zhijuan, XUE Bingsen
2007, 27(6): 474-480.   doi: 10.11728/cjss2007.06.474
Abstract(2664) [PDF 3334KB](52)
Abstract:
By using the method of linear regress, the relation between the cosmic ray intensity of the OULU neutron monitor and the differential fluxes of space energetic proton and ion during quiet time has been studied. The differential spectrum of interplanetary particles with high energy is also calculated through the intensity of neutron at the ground level. On the basis of the energy spectra of proton and ion, a new calculation of the differential fluxes of proton and ion with' high energy is suggested by combining the intensity of the neutron measured by OULU neutron monitor. For particular discussion, four channels (350-420 MeV, 420-510 MeV, 510-700 MeV, 〉700 MeV) on the GOES satellite and the element C on the ACE satellite are chosen as examples. Through comparison, it is concluded that the result is well consistent with the measurements. In order to prove the practicability of the method mentioned above in description of the space radiant condition,the differential As a result, it proton fluxes are is concluded that from the intensity of the ground calculated during November and December in 2006 by the method. the differential fluxes of space proton and ion may be well rebuilt neutron with this method.
Status and perspectives of dark matter searches in China
Chang Jin
2010, 30(5): 422-423.   doi: 10.11728/cjss2010.05.422
Abstract(2400) [PDF 60KB](73)
Abstract:
In this paper, we give a review of direct detection searches reported by the DAMA (China as a Co-I), and indirect detection searches reported by the ATIC (China as a Co-I). We also outline the future plans of dark matter search in China.
Method on Calculation of Lunar Soil Particles Trajectories Considering Collision Effect
ZHENG Gang, CUI Yuhong, YU Wei, REN Depeng, YE Qing, GENG Dongliang
2015, 35(4): 486-494.   doi: 10.11728/cjss2015.04.486
Abstract(1261) [PDF 2292KB](58)
Abstract:
Regarding to the trajectory and mass distribution of lunar soil particles which are lifted by the lunar lander during the descending stage, a method considering the particles' collision effect is proposed. Based on the law of mass and energy conservation, the speed of regolith particles after collision is determined, and through the iterative calculations of fluid-structure interactions, the mass distribution caused both by collision effect and lunar lander effect on the lunar soil particles is presented. Through the measured data from the US Apollo 11 descending and landing on the lunar surface, the method are tested and verified by the numerical simulation. The analysis result shows that after the regolith particles colliding with each other having been considered, their trajectories have a more obvious tendency to spread. Furthermore, after the collision energy loss having been considered, the tendency to spread of regolith particles is weakened. And the smaller the coefficient of restitution is, the lower the raising height of the lunar soil particle will be.
Meteorological rocket sonde of meridian project and its detection results
Shi Dongbo, Wei Feng, Zhang Yu, Wang Lianzhong, Jiang Xiujie, Liu Bo
2011, 31(4): 492-497.   doi: 10.11728/cjss2011.04.492
Abstract(2860) [PDF 600KB](36)
Abstract:
A meteorological rocket sonde based on GPS system is developed, which is composed of a microminiature bead form thermistor temperature sensor with rapid response and negative temperature coefficient, a piezoresistive silicon pressure transducer and a GPS-Receiver. Compared with meteorological rocket sondes flight before, this new sonde can make higher accuracy measurement of meteorological parameters on temperature, pressure, density and wind field, and its telemetry receiving equipment is more portable. Besides, simple prelaunch preparation work and high system reliability are two other advantages of it. The launching test of the sonde has been successfully conducted in the Meridian Project, and satisfactory detection results have been obtained.
Double-Satellite Formation Constellation States Determination With GPS and
HU Limin, WANG Wei, XI Xiaoning
2006, 26(3): 197-202.   doi: 10.11728/cjss2006.03.197
Abstract(2648) [PDF 758KB](53)
Abstract:
The states determination of formation constellation is an important research task. CPS is a chief means, which uses two observational signals: pseudo-range with an accuracy of 10 m, and carrier phase with an accuracy of 10^-3 m. Benefiting from AFF (Autonomous Formation Flying) technology, an assistant means "CPS-like" ranging technology is introduced to improve the states results, which can provide more accurate relative measurement information that are owed to shorter pseudo-code length and wavelength of carrier phase comparing to that of CPS technology. The states determination problem with double-satellite formation constellation for the earth-observation purpose is dicussed. The mathematical model combines "CPS-like" ranging technology with CPS is developed. Single GPS inter-satellite integer ambiguity and single "GPS-like" intra-satellite integer ambiguity are quickly and simultaneously initialized. Finally, these models above mentioned are simulated. The results of our tests indicate the formation states are improved significantly, with the accuracy of relative position reaching 10^-3 m and the accuracies of absolute attitudes reaching 10^-4 rad. The method proves to be valid through simulation.
Characteristic Study on the Porous Reservoir of Liquid Lubricant in Space
WANG Yang, LIU Qiusheng, YAN Jiaping
2008, 28(6): 592-596.   doi: 10.11728/cjss2008.06.592
Abstract(2184) [PDF 879KB](76)
Abstract:
Many moving mechanical assemblies for space mechanisms rely on liquid lubricants to provide performance. However, the loss of lubricant due to space environment may results in some moving mechanical assemblies don't work before the end of mission. So lifetime, many methods are applied to supply lubricant, one of these is porous reservoir. Porous reservoirs are widely used in small space mechanisms for their small volume, simple structure and low cost. They are desirable to maintain film thickness levels and oil distribution, so many researchers paid more attention to them. Centrifuging and heating can come into being lubricant transportation in reservoir. In this paper, the rule of lubricant transportation is analyzed on the influence of centrifuging and heating. Two experimental fixtures are designed to study the rule of lubricant transportation in porous reservoir.
PERFORMANCE ANALYSIS FOR REGIONAL SATELLITE POSITIONING SYSTEM BASED UPON GEO/HEO HYBRID CONSTELLATION
LIU Huijie, ZHANG Naitong
2001, 21(4): 351-358.  
Abstract(2216) [PDF 654KB](81)
Abstract:
As for satellite positioning system, selection of constellation type would greatly influence the performance.of positioning. Connected with Archimedes plan among constellation schemes for GNSS-2, this paper presents a GEO/HEO hybrid positioning constellation by using three HEO satellites and three GEO satellites, here the objective region is chosen as our country. Firstly, the parameters for GEO and HEO satellites are optimized from regional visibility. Secondly, positioning performance analysis for the given hybrid constellation are provided in certain region measured by GDOP and PDOP. Simulation results show that we can expect similar accuracy with GPS in certain region by the hybrid constellation put forward here.
Study of Spacecraft Attitude Tracking Using Variable Speed Control Moment Gyros
JIA Feilei, XU Wei, LI Hengnian, HOU Liqiang, ZHANG Zhibin
2012, 32(1): 106-112.   doi: 10.11728/cjss2012.01.106
Abstract(2432) [PDF 502KB](52)
Abstract:
The attitude tracking problem of spacecraft using VSCMG (Variable Speed Control Moment Gyros) as actuators is studied. The attitude dynamic model of spacecraft with VSCMG attached is built, and an angular velocity filter state governed through the stable liner differential equation is introduced. Based on the Lyapunov stability theory, the adaptive control law is designed. In order to determine the attitude control vector of the VSCMG, a weighted minimum norm solution is applied. A new singularity measurement is constructed which describes the configuration singularity. The null motion of the VSCMG, is designed using the gradient method based on the singularity measurement, and is employed to avoid the singularity, as well as to make the rotary speed of rotors to tend to their expected values. In the end, the VSCMG with four-pyramid configuration is applied in the simulation, and the simulation results validate the feasibility and efficiency of the VSCMG systems on the spacecraft attitude tracking.
Validation Study of FY-3A-TOU Total Ozone Using Ground-based Data
LIU Li, ZHENG Xiangdong, CHEN Shu, WANG Weihe, SHE Yong
2015, 35(6): 696-706.   doi: 10.11728/cjss2015.06.696
Abstract(1119) [PDF 2602KB](38)
Abstract:
Total ozone from July 2009 to December 2013 measured by Total Ozone Unit (TOU) borne on the FY-3A meteorological satellite is validated with the ground-based observations over the global five latitudinal bands, the north pole (north to 63.5°N), middle north of hemisphere (23.5°N~63.5°N), tropic zone (23.5°N~23.5°S), middle of south hemisphere (23.5°S~63.5°S) and South Pole (south to 63.5°S). The results show that the linear correlated coefficient between TOU and the ground-based data is more than 0.95. The globally average TOU Relative Difference (RD) from the ground-based data is (-0.16±4.3)%, with the respective of (0.6±3.8)%, (-0.5±3.9)%, (1.8±3.1)%, (-0.6±3.7)% and (-0.1±3.9)% over the 5 north-southward bands. The sensitivity tests suggest that TOU RD over the tropical zone evidently rises with the growth of the ground-based total ozone. The global TOU ozone RD reduces as the Solar Zenith Angle (SZA) is greater than 70° and the RD may reach from -4% to -10% as SZA from 75° to 85°. The TOU ozone RD is insensitive to the variability of cloud amounts and altitudes: the RD ranges within ±2% as the cloud amount changes from 0 to 100% or the cloud altitude changes from 1 to 15km. The TOU ozone RD is sensitive to the absorptive aerosol characterized by the positive Aerosol Index (AI), and it may decrease from -2% to -5% over the middle of south hemisphere as the AI from 1 to more than 2. The globally respective RD of TOU ozone to Dobson, Brewer and SAOZ observations is (0.6±0.17)%, (0.05±0.2)% and (0.04±0.01)%. TOU RD is generally negative as the Dobson or SAOZ total ozone is lower than 200DU, while it generally 2%~6% as SAOZ total ozone is 430~500DU. The respective RD of TOU to Dobson, Brewer and SAOZ is also insensitive to variations of SZA (less than 70°) or the cloud amounts, however, the RD of TOU respective to Brewer and SAOZ may behavior some small trend with the occurrence of high cloud or positive AI.
Hierarchical Mathematic Model and Hierarchical Routing Algorithm
GAO Lijuan, ZHAO Hongli, JIANG Taijie
2007, 27(5): 430-434.   doi: 10.11728/cjss2007.05.430
Abstract(2194) [PDF 2069KB](49)
Abstract:
A hierarchical mathematic model of multi-layers satellite network is built in this paper.Based on the research of the mathematic model, a new hierarchical routing algorithm is proposed for multi-layers satellite network. The simulation results show that it has faster computing rate and has better performance in time delay. The routing performance of the multi-layers satellite network is effectively improved.
THE TEC VARIATIONS DURING SUDDEN MAGNETIC STORM IN WUHAN
Li Li-bin, Wu Zhen-hua, Wang Bing-kang
1996, 16(2): 133-139.   doi: 10.11728/cjss1996.02.133
Abstract(1870) [PDF 2595KB](65)
Abstract:
In this paper, 136 sets of Faraday rotation data obtained by observation of Japanese Geostationary satellite ETS--Ⅱ radio beacon during April 1980 to December 1990 at Wuhan are analysed to study the response of TEC to SC Geomagnetic storm. It was found that TEC generally enhances during geomagnetic storm. The behavior of △TEC shows much disparity from that observed at mid--and high--latitude. Another interesting fact was that if SC starts in daytime, △TEC will get maximum 36 hours later. Otherwise, no maximum of △TEC appears. This fact exists all the time regardless of sunspot number or season.
SHORT WAVE RAY TRACING IN THE IONOSPHERE
Suo Yu-cheng
1993, 13(4): 306-312.   doi: 10.11728/cjss1993.04.306
Abstract(2382) [PDF 428KB](79)
Abstract:
In accordance with the requirement of ground communication system of remote distance for short wave band, on the basis of the model calculation of the mean background of ionospheric parameters, a method is presented for calculating the trace of short wave ray in ionosphere. The work is mainly concentrated on two aspects. First of all, bacause the frequency of short wave is relatively higher, the magnetic and collision effects in refractive index are neglected, so that general ray equations are simplified. In the second place, a method of calculatitng he first-order partial derivative of ionospheric plasma parameter is presented. The calculation of the partial derivative is on the basis of model result of parameters of each ionospheric layer, that is, on the basis of mean background of ionospheric parameters.It can be used in HFcommunication system, and other short wave system such as target position system of HFradar, etc.
Study on the Simulation Strategy of Lunar Dust/Regolith Environment Effects
SHI Xiaobo, LI Yunze, HUANG Yong, WANG Jun
2007, 27(1): 66-71.   doi: 10.11728/cjss2007.01.066
Abstract(2482) [PDF 1367KB](90)
Abstract:
Lunar regolith grains and dust was found to adhere to all surfaces it came into contact with, including radiators, solar cells, space suits and hand tools. Dust coating and contamination may cause more severe problems such as components overheating, clogging of mechanisms, seal failures, material abrasion, and so on. In this paper, study results on the nature of lunar dust, the interaction mechanism between lunar dust and lunar exploration systems, lunar dust environment simulation strategy are reviewed. A conceptual design of small lunar dust environment simulation system is performed accordingly. The system is a necessary tool to experimentally study the nature of lunar dust, and may serve for the test facility of lunar exploration system material chosen tests, mechanical system reliability tests and dust protection strategy verification tests.
Analysis and Simulation of Characteristics of Space Objects for Space-borne Optical Sensor
ZENG Dexian, DU Xiaoping
2008, 28(6): 560-566.   doi: 10.11728/cjss2008.06.560
Abstract(2651) [PDF 998KB](47)
Abstract:
The characteristics of space objects are very important for the space-borne optical sensor. This paper analyzes the characteristics of distribution and geometry of the space objects, and summarizes the reflectivity of major materials used by satellite. Visible light scattering characteristic of the space objects are discussed specially. Firstly, solar radiation is calculated. Secondly, radiation luminescence calculation models of the two basic diffuse reflection surfaces of satellites are established. The simulation program of optical characteristic of space object is proposed. The simulation system of visible light scattering characteristic of space objects is set up. The simulation system can change the observation distance, photometric magnitude and the sun light phase at real time. Then two validate methods are derived for it is difficult to get real observation data. These validate methods are preferable methods for analyzing space-borne optical sensors. At last, the characteristics of space objects observed by space-borne optical sensor is depicted. This paper provides an effective reference to space-based observation system design.
Inversion Algorithms and Precision Analysis of ROPP
WANG Dazhao, BAI Weihua, SUN Yueqiang, MENG Xiangguang, WANG Dongwei, LI Wei
2015, 35(3): 350-355.   doi: 10.11728/cjss2015.03.350
Abstract(1239) [PDF 1861KB](82)
Abstract:
The unique combination of global coverage, high precision, high vertical resolution, long-term stability and all-weather viewing of radio occultation will enhance the data sets of numerical weather prediction and improve the precision of Numeric Weather Prediction (NWP). And data assimilation requires preprocessing of the raw radio signals into the bending angles and refractivity. Then the atmospheric parameters such as temperature, pressure and humidity can be retrieved through data variational assimilation. The procedures for processing of radio occultation data, especially several important steps are introduced. And comparative analysis between these results and those from CDAAC shows that below the altitude of 30km, the relative errors of refractivity, pressure and humidity are within 2% and the deviation of temperature is below 2K. The results are also compared with the data from ERA-interim model of ECMWF and similar conclusion is obtained.
FINITE ELEMENT SOLUTION OF THE HYDRO-ELASTIC VIBRATION IN THE COMPLICATE STORAGE TANK
YUE Baozeng, WANG Zhaolin, KUANG Jinlu, LI junfeng
1997, 17(3): 274-281.   doi: 10.11728/cjss1997.03.274
Abstract(1797) [PDF 420KB](32)
Abstract:
Semi-analytical finite element method is applied to reduce the hydroclashc problemof the fluid filled spherical tank with damping spherical shell to two dimensionalproblem, the Gaerkin method and Hamilton principle is used respectively to productthe system equation of flind and dampng spherical shell. Annular triangular element isused in fluld domain, the conical frustum element is used in damping spherical shell.
Study on Deorbit of Satellites of LEO and Constellation
XIAO Yelun, LI Chenguang, CHEN Shaolong
2006, 26(2): 155-160.   doi: 10.11728/cjss2006.02.155
Abstract(2709) [PDF 1256KB](33)
Abstract:
One of the measures of Space Debris Mitigation is to execute a deorbit maneuver after the mission of LEO completed, and the satellites die out gradually by the drag of atmosphere in 25 years. Some fuels are needed in deorbit maneuver, so deorbit maneuver must be considered in the phase of satellite overall design. The relations of orbital parameters of LEO, cost of deorbit maneuver and existent lifetime must be studied deeply. The theories and methods of solving deorbit maneuver are explained. A highly effective method of calculating orbit lifetime is introduced: method of differential-integral, and its correctness and validity are validated. The relation of aftermission orbit lifetime and expense of deorbit maneuver is studied. The positive question and the contrary question are presented and solved. The infections of other factors such as F10.7 and s acting on those relations are studied, and estimate values are provided. Some computing results are provided, and are analyzed and summarized. An applied method dealing with question of deorbit maneuver is provided for the design of LEO.
Orbit Design for Approaching Multiple Spacecrafts Repeatedly
Fu Xiaofeng, Wang Wei, Xi Xiaoning
2010, 30(6): 524-531.   doi: 10.11728/cjss2010.06.524
Abstract(2294) [PDF 565KB](86)
Abstract:
The orbit design for single spacecraft approaching multiple spacecrafts more than one time is discussed in the paper, based on the result of orbit design for single approaching multiple spacecrafts once. The technique of determining approaching domain, which is established from the two-body approaching orbit, and the approach extent evaluation, which can be used to orbit design of approaching multiple spacecrafts repeatedly, are presented in the paper. Based on three types of orbit adjustment, three operators with different computation complexity are constructed to generate the new approaching orbits, and the scale of their corresponding approaching domain and the distribution of the optimal approaching orbit are analyzed. The improved simulated annealing algorithm is employed in the paper to solve the optimal approaching orbit. At last, the simulation experiment demonstrates the validity of the orbit design algorithm.
In-orbit calibration of Haiyang-2 scatterometer using natural land-extended targets
Zhu Jintai, Dong Xiaolong, Wang Lei
2015, 35(2): 244-252.   doi: 10.11728/cjss2015.02.244
Abstract(1294) [PDF 1423KB](114)
Abstract:
The scatterometer onboard Haiyang-2 satellite (HY-2 SCAT) is a rotating pencil-beam scatteromter. It provides 4 times of radar cross-section (σ0) measurements at different azimuth/incidence angles over a wind vector cell, in order to determine the near-surface wind field using the Geophysical Model Function (GMF). To achieve the required wind vector accuracy, radar cross-section measurements must be calibrated within a few tenths of a decibel (within 0.5dB). In this paper, HY-2 SCAT is calibrated using natural land-extended targets over different regions and is compared with OSCAT. σ0 errors over different azimuth angles are eliminated. The error sources of the measurements are analyzed and the pointing errors are compared with that estimated from measurements of Altimeter onboard HY-2 satellite.
A class of quasi-cyclic LDPC codes and encoding
Xia Guojiang, Qi Jianzhong, Sun Huixian, Xiong Weiming
2009, 29(4): 443-447.   doi: 10.11728/cjss2009.04.443
Abstract(2312) [PDF 502KB](75)
Abstract:
Firstly, based on the characters of space communication, this study improves a class of regular quasi-cyclic LDPC codes which is based on circulant matrices and obtains a kind of irregular quasi-cyclic LDPC codes. Compared with original codes, the parity check matrix called H of this irregular LDPC ensemble has three characters: 1. $\pmb H$ is row full rank; 2. H is lower triangulation; 3. $\pmb H$ contains degree one variable nodes. With the first two characters, the encoding complexity of computation and architecture of this kind of LDPC are proportion to the length of check symbols, so encoders implemented with software and hardware are quite simple. This feature is very important to deep space communication because the resource on board is constrained. The third character makes the iterative decoding threshold lower than the original codes. Moreover, the computer simulation has proved this result. Secondly, the proof for the condition of girth not shorter than 6 is simplifed compared to the original ones. Last, the computing formula is derived for parity check symbols of systemic codes. Based on this formula, the encoding circuit has been investigated using shift registers.
KINETIC ALFVEN SHOCK IN THE SOLAR WIND
LU Xianhe, SONG Liting, WEI Fengsi
1997, 17(1): 14-19.   doi: 10.11728/cjss1997.01.014
Abstract(2015) [PDF 370KB](64)
Abstract:
In this paper, a theory of kinetic Alfvenic shock wave in the solar wind is presented. There ekist nonlinear interaction and dispersion in the kinetic Alfven wave regime. Thus, theoretically the kinetic Alfven shock wave can occur. Based on this idea, a two fluld model combined with the abnormal damping of ion acoustic wave is considered, and then the inunediate shock structure is obtained by numerical simulation.
Application in predicting the geomagnetic storm with variation characteristics of cosmic ray
Zhu Xiaolu, Xue Bingsen, Cheng Guosheng, Cang Zhongya
2015, 35(2): 185-191.   doi: 10.11728/cjss2015.02.185
Abstract(1078) [PDF 1701KB](92)
Abstract:
An algorithm is introduced to use the cosmic ray neutron detector data to predict great geomagnetic storms. The connection between cosmic ray and great geomagnetic storms and the relationship between cosmic ray stations are qualitatively analyzed. The neutron detector data from Irkutsk and Oulu stations are employed and wavelet denoising technology is used to improve the stability of the data. It is found that under the same conditions of universal time the correlation of the two stations is higher than quiet days during geomagnetic disturbances, while it is contrary under the same local time. Thus the variation in disturbed time and quiet time can be used to predict geomagnetic storms. The algorithm is specifically used to analyze the geomagnetic storm events in July 2004. It is found that before geomagnetic storm, relative fluxes of cosmic rays of Irkutsk and Oulu station became different. It can be used as a precursor of strong geomagnetic storms. Statistics with all relative events during March 2001 to May 2005 support an appropriate threshold related to the relative difference of cosmic ray about strong geomagnetic storms. It is tested with all events during September 2005 to December 2011 with the threshold. The result turned out to be encouraging with the accuracy rate reaching 87.5% (7 out of 8) and false forecast rate reaching 35.7% (5 out of 14).
NUMERICAL SIMULATION OF A CYLINDRICAL ELECTROSTATIC ANALYZER
YU Dejiang
1999, 19(1): 61-68.   doi: 10.11728/cjss1999.01.061
Abstract(1814) [PDF 478KB](50)
Abstract:
Numerical simulation is made to SSJ/460°cylindrical electron detector boardedon DMSPsatellites. The potential distribution in the analyzer is found from solvingLaplace equation by means of SORiteration procedure. Based on the numericalsolutions of path equation, the responses of the detector are computed by using MontCarlo method. The appropriate choice of time and energy scale in the simulationleads to simple scaling laws of the response functions and the geometrical factor.
Research on the Solar Proton Fluence Model
Li Tingting, Shi Liqin, Liu Siqing
2010, 30(3): 205-210.   doi: 10.11728/cjss2010.03.205
Abstract(2788) [PDF 551KB](46)
Abstract:
Solar Proton Event (SPE) has great influence on the human space activities. Establishing prediction model for total fluence of solar protons accumulated during a mission and taking protective measures are of vital significance for the security of the spacecraft and astronauts. Based on a data set of proton events from the last four solar cycles, a new statistical model is designed to predict the proton fluence for space mission analysis. The energy ranges considered are E>10 MeV and E>30 MeV, respectively. Because of the quasi-random nature of the occurrences, and spectra of SPE, solar proton mission fluence must be treated statistically. The purpose of this analysis is to derive the probability of exceeding various proton fluence as a function of proton energy and mission duration. Compared with commonly used JPL model, solar activity levels are taken into account to obtain the occurrence probability of proton events. The new model can access proton fluence in different phase, and is more consistent with the distribution of proton events.
Image Feedback Control System in the Space Drop Evaporation Experiment
YU Qiang, NING Qiao, ZHU Zhiqiang, YUAN Zhangfu
2008, 28(1): 64-68.   doi: 10.11728/cjss2008.01.064
Abstract(2407) [PDF 1865KB](16)
Abstract:
In this paper, a method to measure the drop evaporation velocity by image feedback control system is presented. The system is constituted of 3 parts: image acquisition, image processing, and feedback control. Analyzing drop pictures from the CCD camera, the physical features of the drop could be obtained, and evaporating volume could be calculated
from the geometry differences between two pictures. To maintain the drop volume, drive the injector to inject dynamically. The evaporation velocity could be calculated by the evaporating volume per unit time. In order to determine the accurate contour of the dynamically changed drop, the contour approach principle is investigated and some numerical algorithms such as Laplace equation, Newton-Raphson method and Runge-Kutta method are introduced. Based on the drop contour determined from the contour approach, the volume and the surface area of drop could be calculated by numerical integral. The software structure and hardware structure of the system are described, an experiment result is given finally. The system is developed for the liquid experiment in SJ-10 recoverable satellite.

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bimonthly Founded in 1981

Sponsor:CAS

Sponsored by:NSSC, CAS; CSSR

Publisher:Science Press

ISSN:ISSN 0254-6124

CN:CN 11-1783/V

Editor chief:WU Ji

Counselor:Gu YiDong

Deputy-chief-editor:

CAO Jinbin

FALANGA Maurizio (Switzerland)

FU Suiyan   KANG Qi
LIN Baojun   LIN Yangting 

SHI Jiancheng   YANG Huigen
YANG Zhen   ZHANG Shuangnan

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