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Study on service performance of single frequency SBAS in Algerian satellite-based augmentation system
PAN Lijing, WANG Ling, JIN Biao, WANG Leilei, LIU Ningning, ZHAO Liqian, WANG Shaoxian, JING Hui
, Available online  , doi: 10.11728/cjss2025.04.2024-0078
Abstract(219) FullText HTML (21) PDF 3095KB(11)
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The Algerian Satellite-based Augmentation System (ALG-SBAS) is a satellite-based augmentation system (SBAS) based on the Algerian Communications Satellite 1 (Alcomsat-1), which is already in its official operational phase. In order to deeply understand the system service type and performance, this paper first introduces the system, and then evaluates the stability of the broadcast message of the geosynchronous orbit (GEO) satellite、Ionospheric delay correction accuracy、positioning accuracy and integrity. The results show that ALG-SBAS GEO satellite has strong stability. The ionospheric delay correction percentage is better than 87%. The positioning accuracy of The positioning accuracy of ALG-SBAS is significantly improved than that of GPS positioning, and the average positioning accuracy is increased by more than 39%. The average SBAS PPP 3D positioning accuracy of all stations is better than 0.45m. The positioning accuracy is compared with EGONS, and the results show that ALG-SBAS is slightly worse than EGONS. At the same time, the integrity of the station positioning results was analyzed, and no integrity risk events occurred in ALG-SBAS during the evaluation period. ALG-SBAS had an average availability of 99.9% at all stations in the Approach with Vertical Guidance-I(APV-I) phase. The service performance of the satellite-based augmentation system meets the single frequency service index and can provide single frequency SBAS service.
Analysis and Evaluation of Data from Near Space Meteorological Rocket Detection in Northwest Area
HE Yang, Chen Tailong, HUANG Jiangping
, Available online  , doi: 10.11728/cjss2025.04.2024-0074
Abstract(144) FullText HTML (17) PDF 1344KB(8)
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Meteorological rocket is an important in-situ detection method to obtain the fine structure of vertical distribution of atmospheric environment in near space, the detection results should have higher accuracy than ground-based or space-based remote sensing detection. Objective evaluation of the data quality is an important prerequisite for the effective use of the data. In this paper, the atmospheric temperature, wind field, density, and pressure in the altitude range of 20～60 km are obtained by using a meteorological sounding rocket launched in Qinghai in winter of 2023. The error correction of the temperature measured by thermistors is carried out. The detection results are compared with the data of remote sensing detection, empirical prediction model and reanalysis data. The results show that the rocket wind field results are in good agreement with the MERRA2 data, and the HWM empirical forecast model cannot accurately describe the atmospheric environment in the corresponding region. The measured temperature error of the rocket is gradually prominent when it is over 40 km, and the main error terms are current heating term, temperature hysteresis term and pneumatic heating term. The corrected temperature is in good agreement with the reference data, and the main difference of temperature data from different sources is that the height of the temperature inflection point in the stratosphere is different. The deviation of pressure and density results increases with altitude. The analysis believes that the quality of the rocket's detection data is good and the accuracy is high. Through the analysis and evaluation of the data, the effectiveness and reliability of the mathematical model of atmospheric element inversion are verified.
Design, Flow Field Simulation and Launching Cost Evaluation of a Space Laundry Platform
YANG Zhaoshu, LI Sen, ZHU Guangya, YANG Songlin, DING Pengbo, SUN Minzheng, CAO Shiyi
, Available online  , doi: 10.11728/cjss2025.03.2024-0058
Abstract(234) FullText HTML (46) PDF 5909KB(27)
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The urgent request for micro-gravity laundry technologies should be satisfied, especially for long-term on-orbit habitats for astronauts. However, the traditional, ground-based laundry techniques could not operate properly in microgravity environments. In this paper, a laundry platform based on atomization and ozone-sterilization technologies was proposed. The platform uses ultrasonic arrays to atomize liquid water and facilitate better immersion of clothing in microgravity environments; the ultraviolet lights were implemented to generate ozone for disinfection. Simulations based on finite element method were applied to study the changes in relative humidity and ozone concentration during the laundering process. Parameters studies were conducted and the pre-fogging time and ozone lamp configuration were determined. Subsequently, the resource cost of the proposed laundry platform was evaluated using the equivalent system mass method. It was found that the resource cost of running the platform for one year in orbit was only 15.7% of that of the commercial laundry technology. By using the on-orbit laundry platform and recycling the clothes, a total amount of 61.9% of the equivalent system mass could be saved compared to disposing all the clothes. Through the analysis of the benefit-balancing time of on-orbit laundry technology and the cost of transporting consumable clothes, it is shown that in future deep space exploration missions, developing on-orbit laundry technology is a more cost-effective option than transporting clothes as consumables, as long as the mission duration is longer than 2.5 months for space station missions, and 2.5 months for deep space exploration missions. The work of this paper could set a milestone for the development of the microgravity laundry platform for our country.
Monthly Variations Characteristics of Sodium Layer over Mid-low Latitudes Based on Lidar
CHAI Weiwei, ZHANG Tiemin, HE Shimin, ZHANG Yimin, YANG Dali, PENG Hongyan, WANG Jihong
, Available online  , doi: 10.11728/cjss2025.03.2024-0064
Abstract(266) FullText HTML (36) PDF 5720KB(13)
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In 2020, the same equipment and the same laser parameters of sodium fluorescence lidar were used to simultaneously observe the sodium layer over different latitudes. This paper systematically explores the monthly characteristics of the overall sodium layer in two regions in 2020 through the sodium layer echo photon data obtained from the observation, and inverts and analyses the raw data to reveal the geographic differences of the sodium layer at different latitudes. It is found that except August, the average monthly column abundance in Beijing (40.5°N, 116.0°E) at mid-latitude is higher than that in Haikou (20.0°N, 110.3°E) at low latitude. According to the statistics of special events in 2020, the probability of Sporadic Sodium Layer (SSL) events in Beijing and Haikou is 5.3% and 44.9% respectively, and the probability of Double Sodium Layer (DSL) events is 5.3% and 4.3% respectively; the peak altitude of SSL events in Beijing is located at a higher height throughout the year, and strength factor of SSL reaches the maximum value of 10.6 throughout the year. By comparing the ionosphere data by an ionosonde operated at Danzhou, China (19.5°N, 109.1°E), it is found that SSL events above 96.0 km in Haikou have a high correlation with Sporadic E layer (Es). Monthly average peak value of the SSL events in Haikou is higher than that in Beijing, and the peak altitude is the opposite. Comparison between two regions shows that without excluding the special events, the monthly trend of sodium layer in Beijing is more regular than that in Haikou. SSL events in Haikou are more frequent, DSL events are more concentrated in Beijing, and they are extremely frequent in May, which may be the result of the modulation of Es and other factors. The average peak altitude of the secondary sodium layer of DSL events in both regions are located near 110 km. This work can further refine our understanding of the behavioral characteristics of sodium layers, providing reference data and conclusions for future research on sodium layers.
Integrated Software Design and Implementation for SDGSAT-1 Satellite Mission Planning and Command Generation
CAI Jiji, YU Yeluo, YANG Shujie, CHEN Yujun, LI Wei, ZHOU Da
, Available online  , doi: 10.11728/cjss2025.03.2024-0059
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The SDGSAT-1 satellite was launched at 10:19 Beijing time on 5 November 2021, using the Long March 6 carrier rocket at the Taiyuan Satellite Launch Center in China. The satellite carries three payloads: thermal infrared, low-light and multi-spectral imagers. Through the coordinated observation of the three payloads all day, it aims to achieve a detailed portrayal of the “traces of human activities”, which will provide data support for the study of indicators that characterize the interaction between humans and nature and the monitoring, evaluation and scientific research of the realization of global sustainable development goals. This paper aims to provide an efficient mission planning and instruction generation technology for the multi-payload system of the SDGSAT-1 satellite. First, the three payloads of the SDGSAT-1 satellite are analyzed in detail to determine their power-on options in different working modes. These modes include single-payload independent operation and dual-payload combined operation to adapt to different observation needs and task priorities. In order to ensure the efficient execution of the observation task, a set of algorithms is designed to optimize the observation time of the payload. The algorithm takes into account a variety of constraints, including but not limited to: payload data rate, lighting conditions, working area, data transmission time, downlink rate, etc. Based on these constraints, an integrated mission planning and command generation system is implemented. The system can automatically generate payload control plans and data reception plans that meet the usage constraints of the satellite and its payload. Through precise mission planning, we can ensure that the observation mission of the satellite during its orbit is efficiently executed while maximizing the efficiency of payload usage. In order to further improve the efficiency of data transmission, the satellite’s data transmission process is deeply analyzed, and an innovative dual-station relay transmission mode is introduced. This mode allows satellites to transmit data between different ground stations, and effectively increases the amount of satellite data transmitted through relay, especially when the communication between the satellite and the ground station is restricted. This paper develops an efficient, flexible and reliable mission planning and command generation technology by comprehensively considering the multi-payload characteristics and multiple constraints of the SDGSAT-1 satellite. The successful implementation of this technology not only improves the efficiency of satellite data acquisition and transmission, but also provides strong data support for achieving sustainable development goals.
Enhanced Ion Sampling Techniques for In-situ Neutral Gas and Low-energy Ions Exploration of Main-belt Comet
WANG Xinyue, ZHANG Aibing, SU Bin, DAN Du, KONG Linggao, TIAN Zheng, ZHENG Xiangzhi
, Available online  , doi: 10.11728/cjss2025.03.2024-0124
Abstract(128) FullText HTML (27) PDF 2540KB(12)
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One of the detection objectives of the Chinese Asteroid Exploration mission is to investigate the space environment near the Main-belt Comet (MBC, Active Asteroid) 311P/PANSTARRS. This paper outlines the scientific objectives, measurement targets, and measurement requirements for the proposed Gas and Ion Analyzer (GIA). The GIA is designed for in-situ mass spectrometry of neutral gases and low-energy ions, such as hydrogen, carbon, and oxygen, in the vicinity of 311P. Ion sampling techniques are essential for the GIA’s Time-of-Flight (TOF) mass analysis capabilities. In this paper, we present an enhanced ion sampling technique through the development of an ion attraction model and an ion source model. The ion attraction model demonstrates that adjusting attraction grid voltage can enhance the detection efficiency of low-energy ions and mitigate the repulsive force of ions during sampling, which is influenced by the satellite’s surface positive charging. The ion source model simulates the processes of gas ionization and ion multiplication. Simulation results indicate that the GIA can achieve a lower pressure limit below 10–13 Pa and possess a dynamic range exceeding 109. These performances ensure the generation of ions with stable and consistent current, which is crucial for high-resolution and broad dynamic range mass spectrometer analysis. Preliminary testing experiments have verified GIA’s capability to detect gas compositions such as H2O and N2. In-situ measurements near 311P using GIA are expected to significantly contribute to our understanding of asteroid activity mechanisms, the evolution of the atmospheric and ionized environments of main-belt comets, the interactions with solar wind, and the origin of Earth's water.
Impact of Ionospheric Model Corrections in Different Seasons of China on the SPP of GPS Systems
ZHANG Chun, WANG Ge, ZHANG Minjian, ZHU Yilong, WANG Sisi
, Available online  , doi: 10.11728/cjss2025.03.2024-0073
Abstract(150) FullText HTML (22) PDF 8392KB(4)
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For GNSS satellite signals traveling from the satellite to the ground, the ionosphere is an unavoidable path. At the same time, the ionosphere is also a major error source in GNSS PNT applications. At present, both BDS and GPS broadcast ionospheric error correction model parameters to users via navigation information. The BDS broadcasts the BDGIM model with 9 parameters, while the GPS use the Klobuchar model with 8 parameters. A systematic analysis of the impact of different ionospheric models or products on the accuracy of standard Single Point Positioning (SPP) can serve as a valuable reference for global single-frequency satellite navigation users in selecting suitable ionospheric error correction methods. This paper focuses on the Chinese region and evaluates SPP performance at different latitude stations using the Klobuchar model, BDGIM model, IGS ionospheric grid products, and regionally modeled CHNION products in March, June, September, and December 2022. By comparing SPP accuracy, the correction performance of various ionospheric models and products in China is analyzed. The results show that the Klobuchar model provides the lowest SPP accuracy in China. The BDGIM model improves the average positioning accuracy by 20% across four stations. For mid-latitude and low-latitude stations BJF1, ZLTG, and HKSL, using the CHINON product for ionospheric correction results in a monthly average precision is 1.65, 1.27, 3.2, and 2.87 m, respectively. with the IGS final product, the monthly average positioning precision is 1.6, 1.37, 3.1, and 2.73 m.
Recognition Method of Auroral Kilometric Radiation Based on Fusion of VGG16 and Self-attention Mechanism
WANG Heye, GUO Xuedou, ZHANG Sai, HUANG Yangyang, LIU Tianle, ZHAO Shuya
, Available online  , doi: 10.11728/cjss2025.03.2024-0043
Abstract(216) FullText HTML (63) PDF 6301KB(42)
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An enhanced image recognition algorithm for Auroral Kilometric Radiation (AKR) detection is presented by integrating a self-attention mechanism into the VGG16 Convolutional Neural Network (CNN) architecture. The primary goal is to improve the flexibility and detection accuracy of AKR identification, which is crucial for understanding the dynamic changes in Earth’s radiation belts and the associated energetic particle variations. The methodology begins with employing the VGG16 CNN as the foundational model to extract local features from raw data that are instrumental in AKR recognition. Subsequently, a custom Self-Attention Mechanism (SAM-V) is embedded in the VGG network. The Self-Attention Mechanism (SAM), originally designed for sequential data processing, is adapted to work with the VGG16 network. Traditional integration of SAM with VGG16 could potentially increase the model’s complexity and computational cost, leading to potential feature sparsity issues. However, the proposed custom SAM-V generates queries, keys, and values through defined convolutional layers, offering more control over feature input and output. This customization implies shared parameters, reducing the number of model parameters, thereby mitigating the risk of overfitting and enhancing the model’s generalization capabilities. This approach is particularly adept at capturing correlations in power spectral density across different time points or frequencies, minimizing the impact of noise and improving recognition accuracy. Additionally, a linear learning rate warm-up and dynamic decay strategy are employed to accelerate model convergence and enhance generalization. The experimental results demonstrate that the improved model achieves an average recognition accuracy of approximately 93%, which represents a 3.3% increase compared to the original VGG16 model. Furthermore, other performance metrics such as recall rate and precision have also seen significant improvements. In conclusion, the integration of a custom self-attention mechanism into the VGG16 network has yielded a more efficient and accurate model for AKR detection. This advancement not only bolsters the study of auroral kilometric radiation but also has broader implications for the analysis of Earth’s radiation belt dynamics and energetic particle behavior. The model’s enhanced generalization capabilities and improved accuracy underscore the potential for applying similar techniques to other image recognition tasks within the field of space physics and beyond.
Machine Identification Method of Auroral Substorm Onset Time
JIANG Jianan, ZOU Ziming, LU Yang
, Available online  , doi: 10.11728/cjss2025.03.2024-0039
Abstract(245) FullText HTML (35) PDF 1305KB(15)
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Auroral substorm is a geomagnetic disturbance resulting from the interaction between Earth’s magnetic field and the solar wind. The accurate identification of the onset times is crucial for a deep understanding of the underlying physical mechanisms. The existing machine methods for auroral substorm identification differ from manual identification standards and typically require complex image preprocessing and parameter tuning by manual. To achieve a machine model consistent with manual identification standards, this paper designs two identification strategies aimed at addressing the issue of variable image sequence lengths encountered in replicating manual standards. Based on deep learning methods, this paper proposes an EfficientNet model featuring CBAM attention as a key component for model construction. The model is trained using ultraviolet auroral images from the Polar satellite between 1996 and 1998 and tested on image data from 1999 to 2000. The model achieves an identification accuracy of up to 0.98 and an efficiency of 36.93 frames per second. This model not only eliminates the reliance on image preprocessing present in existing models but also adapts to real-world observations with unequal image sequence lengths and extreme imbalances in the number of samples between substorm and non-substorm sequences, demonstrating its high practicality.
Dawn-dusk Asymmetry Distribution of Kelvin-Helmholtz Instability at the Magnetopause of the Mid-magnetotail
FENG Jingyi, ZHOU Yue, LU Jianyong, WANG Ming, ZHANG He
, Available online  , doi: 10.11728/cjss2025.03.2024-0038
Abstract(280) FullText HTML (56) PDF 4357KB(24)
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The Kelvin-Helmholtz (K-H) instability is an unstable phenomenon that occurs in the boundary layer between two different fluids with velocity shear, and plays an important role in particle, momentum, and energy transport from the solar wind to the magnetosphere. At the Earth’s magnetopause, the magnetosheath plasma flows rapidly along the magnetopause and creates a velocity shear with the stationary magnetospheric plasma, providing favorable conditions for the occurrence of the K-H instability. Our investigation selects the magnetopause crossings at the mid-magnetotail region (X ≈ –60 Re) from 2015 to 2020 using the observation data from the Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun (ARTEMIS) satellite and, in conjunction with the 51 K-H instability events that also take place in the mid-magnetotail, conducts a statistical analysis of the dawn-dusk asymmetric distribution of K-H instability at the mid-magnetotail magnetopause. The findings suggest that the occurrence rate of K-H instability is relatively high on the dawn side of the magnetopause in the mid-magnetotail region. Under northward Interplanetary Magnetic Field (IMF) condition, the occurrence rate of the K-H instability events on the dawn side significantly surpasses that on the evening side; when the Parker-spiral IMF dominates, there are more K-H instability events on the duskside. The varying parameters of the solar wind also significantly influence the distribution of K-H vortices at dawnside and duskside of the mid-magnetotail magnetopause. Under conditions of low magnetoacoustic Mach number, the occurrence rate is higher on the dawnside. For slow solar winds, K-H vortices are significantly more frequent on the dawnside compared to the duskside. And the occurrence rate peak on the dawnside is pronounced under low dynamic pressure, while the occurrence rate at duskside is slightly higher than at dawnside for increased dynamic pressure. The K-H waves in the magnetotail region may contribute to the asymmetrical distribution of plasma in the magnetotail plasma sheet.
Dst Index Prediction Method Based on LSTM Neural Network
LI Shaowen, NIU Jun, MEI Bing, YAO Lizhu, LI Yanbin
, Available online  , doi: 10.11728/cjss2025.03.2024-0045
Abstract(464) FullText HTML (105) PDF 4619KB(47)
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The Dst index is one of the widely used hourly geomagnetic indices to reflect geomagnetic storm processes, and forecasting the Dst index constitutes a primary concern in modern space weather studies. This study leverages Long Short-Term Memory (LSTM) neural network methodology alongside solar wind parameters and Dst index data spanning from 2008 to 2022 to construct a predictive model for the Dst index. Two models are established: the LSTM model, modeling the entire temporal domain, and the Storm model, modeling solely data from storm periods. Employing the LSTM model for rolling forecasts of Dst index during 2001 to 2002 yields a correlation coefficient exceeding 0.94 and a root mean square error within 11 nT for forecasts ranging from 1 to 6 hours in advance. The Storm model effectively addresses the issue of pronounced forecast errors during storm periods, particularly during the main phase of intense storms (Dst < –100 nT), showcasing improved forecast accuracy. Forecasting experiments conducted on 23 strong storm events occurring during 2001―2002 demonstrate an enhancement in the correlation coefficient for forecasts made 6 hours in advance during storm periods, increasing from 0.902 with the LSTM model to 0.948 with the Storm model. Integration of both forecasting models into the LSTM-Storm model yields correlation coefficients above 0.95 and root mean square errors within 9 nT for Dst index forecasts, presenting a marked improvement in forecasting accuracy compared to the standalone LSTM model.
A Comparative Simulation Study of Graphene and Carbon Foils in Satellite-borne TOF System
XU Penghui, KONG Linggao, ZHANG Aibing, MA Jijie
, Available online  , doi: 10.11728/cjss2025.03.2024-0156
Abstract(150) FullText HTML (38) PDF 6252KB(7)
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Recently, graphene foils are considered a promising material for space detection applications due to their minimal thickness. For comparing the specific performance of graphene and carbon foils in film-type Time-of-Flight (TOF) systems, a detailed computer simulation in a definite TOF system is conducted by integrating SRIM, the particle transmission simulation software, with SIMION, the particle optical simulation software. TOF simulation results focused on various aspects of TOF system performance are obtained, such as TOF spectra, scattering distribution, scattering angle, and detection efficiency. These parameters of the TOF system provide reference to the ability of mass spectrometric differentiation and simulation results show that graphene foils applied to the satellite-borne TOF system have higher spectral resolution, shorter scattering radius, lower scattering angle, and higher detection efficiency compared to carbon foils. Graphene’s better performance is derived from its lower thickness, which causes less scattering during ion transmission into graphene. These findings indicate that using graphene foils instead of carbon foils can improve the performance of film-type TOF systems. Further validation of this conclusion requires corresponding experimental test data and results. The conclusion can be referred to the practical testing of graphene foils and other related research, which can make progress for the final practical facilitation of graphene on in-flight TOF systems.
Orbit Determination of Asteroid 2016HO3 and Analysis of Detection of Yarkovsky Effect Force
CAO Jianfeng, MAN Haijun, LIU Shanhong, HUANG Hao, ZHANG Yu
, Available online  , doi: 10.11728/cjss2025.03.2025-0007
Abstract(162) FullText HTML (48) PDF 4802KB(26)
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To address the requirement for high-precision ephemerides in autonomous asteroid exploration missions, data processing and analysis were conducted on asteroid 2016HO3. Initially, a high-precision dynamical model for the asteroid was established. After a 40-year integration, the resulting ephemerides exhibited a deviation of less than 400 m compared to those from the JPL Horizons system. Subsequently, orbit determination calculations were performed using observational data released by the Minor Planet Center (MPC). The impact of two weighting strategies on the orbit determination results was analyzed, revealing that, despite highly consistent residuals, the orbital deviation approached 100 km. Furthermore, an attempt was made to detect the Yarkovsky effect through orbital solutions, which verified the effectiveness of the detection method. The orbital evolution analysis demonstrated that, due to the fixed-month observations of the asteroid by ground-based facilities, the orbital deviation was most stable during that specific month, whereas the orbital evolution diverged significantly in other months. This study provides references and theoretical support for subsequent data processing in autonomous asteroid exploration missions.
Rotational Characteristics and Surface Thermal Environment of Asteroid (469219) Kamo‘oalewa: Target of the Tianwen-2 Mission
YING Jiajun, JI Jianghui, JIANG Haoxuan, TAN Dongjie, HU Shoucun, BAO Gang
, Available online  , doi: 10.11728/cjss2025.03.2025-yg04
Abstract(194) FullText HTML (55) PDF 4855KB(32)
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This paper provides a comprehensive analysis of the orbital characteristics, rotation parameters, and relative motion with Earth of the near-Earth asteroid 2016 HO3 (Kamo‘oalewa). Through fitting the asteroid observed light curve, we preliminarily determined the orientation of its rotation axis as $ \lambda =67. 9°\pm {3. 1}^{\circ },\;\beta =-46. 0°\pm {10. 6}^{\circ } $. By simulating the forthcoming Tianwen-2 space mission, we predicted changes in the apparent magnitude of the asteroid as observed by the spacecraft during its approach phase. Using the Advanced Thermophysical Model (ATPM), we performed a detailed analysis of the surface temperature distribution of asteroid 2016 HO3, revealing detailed temperature distribution features under varying thermal inertia conditions. Finally, this paper outlines future research directions, highlighting the significant potential for improved accuracy in determining the asteroid rotational parameters and orbital properties through higher-resolution observations and longer-term data accumulation. The successful implementation of the Tianwen-2 mission will provide crucial data, further advancing our understanding of the origins and evolutionary histories of asteroids.
Advances in the Study of the Musculoskeletal Multi-rigid-body Dynamic Modeling in Manned Space Flight
ZHANG Jing, ZHOU Biyun, NIE Jiachen, DONG Xianpeng, DING Li
, Available online  , doi: 10.11728/cjss2025.03.2024-0163
Abstract(126) FullText HTML (34) PDF 3385KB(9)
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With the advancement of China’s manned space program from near-Earth space to deep space exploration, the protection of astronauts against musculoskeletal injuries during long-duration space missions and their adaptation to low-gravity environments during extraterrestrial exploration have become critical issues concerning astronaut health and safety. To address the limitations of ground-based experiments in studying human motion and musculoskeletal system responses in microgravity/low-gravity environments, musculoskeletal system modeling and simulation technologies, based on biomechanical principles and computer-aided design, have emerged as novel methods and tools for evaluating astronaut exercise regimens and analyzing the kinematics and dynamics of microgravity/low-gravity environments. This paper introduces the principles of musculoskeletal system multi-rigid-body dynamics modeling in space environments, including forward dynamics-driven and inverse dynamics analysis methods. Taking OpenSim software as an instance, this paper elaborates on the procedure of constructing human-device-environment models in microgravity/low-gravity environments and the solution of muscle forces and joint torques via inverse kinematics and inverse dynamics algorithms. Furthermore, to assess the credibility of musculoskeletal modeling and simulation methods for manned spaceflight research, the relationship between experiments and modeling/simulation is analyzed. Based on existing literature, credibility assessment is conducted from eight factors: data pedigrees, input pedigrees, code verification, solution verification, conceptual validation, reference validation, results uncertainty, and results robustness. On this basis, the application of musculoskeletal system dynamics modeling and simulation methods in three key areas is reviewed as follows: assisting astronauts in space exercise by comparing the advantages and disadvantages of different exercise regimens and designing space station-compatible exercise equipment; optimizing extravehicular spacesuit design by calculating joint reaction torques through human-spacesuit coupling biomechanical models and improving spacesuit design to enhance comfort and work performance; and supporting extraterrestrial exploration by focusing on research into human motion characteristics in low-gravity environments and the development of human-spacesuit-exoskeleton systems to confirm the effectiveness of exoskeleton systems in planetary exploration. Finally, the limitations of musculoskeletal system multi-rigid-body modeling and simulation methods are analyzed, and new perspectives on future research directions and application prospects are proposed.
New Denoising Method based on the Contribution Value Parameters of the Medium Frequency Radar Antenna
ZOU Zhanzhuo, WANG Liming, WEI Junfeng, TANG Zhongcai, SONG Xiaoyuan, ZHU Jinpeng, CHEN Jinsong, LI Na
, Available online  , doi: 10.11728/cjss2025.03.2024-0197
Abstract(65) FullText HTML (20) PDF 4824KB(9)
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The wind field of the Mesosphere and Lower Thermosphere (MLT) is an important parameter for studying the dynamics of the middle and upper atmosphere. Medium Frequency Radar (MF Radar) is one of the important techniques for observing the atmospheric wind field in the MLT region. Full Correlation Analysis (FCA) is a commonly used inversion algorithm for MF radar wind fields, but it is highly sensitive to noise. Effective noise processing can significantly enhance the accuracy of the FCA method in MF radar wind field inversion. Currently, the polynomial fitting denoising method widely used in MF radar exhibits inconsistent performance in different noise environments, leading to a reduction in the amount of valid wind field data that MF radar can observe, which restricts its application prospects for wind field observation in the MLT region. To address this challenge, this study introduces the antenna contribution parameter into MF radar for the first time and proposes the MF-AH algorithm, which uses the antenna contribution parameter as the evaluation criterion to effectively reduce noise in the correlation functions generated from MF radar signals. Compared with the conventional polynomial fitting method, the MF-AH algorithm, validated by both simulation and experimental data, reduces zonal and meridional wind speed errors by approximately 20% under low Signal-to-Noise Ratio (SNR) conditions. Moreover, the algorithm eliminates reliance on noise as the primary evaluation metric, significantly enhancing the effectiveness and richness of wind field data.
Design and Verification of Temperature Measurement Bridge Excitation Source in the Taiji Program
YAN Lihui, LIU Heshan, BIAN Xing, LUO Ziren
, Available online  , doi: 10.11728/cjss2025.03.2024-0040
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Thermal disturbance is one of the most important sources of interference for spatial gravitational wave detection. To meet the needs of the Taiji program for spatial gravitational wave detection, it is necessary to ensure that the temperature fluctuation in the area where the detector's optical interference platform is located is better than 10 μK·Hz–1/2 at frequencies between 0.1 mHz and 1 Hz. This requires μK·Hz–1/2 temperature measurement technology. In response to the need for high-resolution temperature measurement technology in spatial gravitational wave detection, this paper has developed an experimental setup for a temperature measurement bridge with multiple excitation sources based on the Wheatstone bridge. The design of the excitation sources and other components of the temperature measurement bridge is discussed, and experimental verification of the noise floor of the temperature measurement bridge under excitation from constant voltage sources, constant current sources, and alternating current sources is conducted. The experimental results show that when the bridge is excited by the three excitation sources, the alternating current source combined with phase-locked readout technology can achieve lower background noise compared to the other two excitation sources. The noise is better than 10 μK·Hz–1/2 in the frequency range of 30 mHz to 1 Hz, basically meeting the requirements of the Taiji Pathfinder. This provides an important reference for the subsequent development of the μK·Hz–1/2-level temperature measurement system for the Taiji program.
Knowledge Base Construction and Payload Configuration in the Field of Deep Space Exploration
YANG Song, NIU Wenlong, PENG Xiaodong, LI Siqi, LIU Jincheng, YANG Zhen
, Available online  , doi: 10.11728/cjss2025.03.2024-0054
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A method is proposed to address the strategic needs of national mission planning and demonstration in the field of deep space exploration, focusing on challenges such as the diversity and complexity of missions, the large scale of data, and difficulties in direct data utilization. The construction of an ontology model for the deep space exploration domain is carried out using a hybrid approach that combines top-down and bottom-up methodologies. In the top-down process, domain knowledge is analyzed and expert input is incorporated to build the ontology model. On this basis, a bottom-up ontology updating strategy is introduced, leveraging N-gram analysis and text semantic clustering to dynamically update the ontology through semantic recognition and processing of textual data related to deep space exploration. Structured, semi-structured, and unstructured data are integrated to build a comprehensive knowledge base for the domain, comprising 2140 entity nodes, 4608 relationships, and 9079 attributes. Based on this knowledge base, a payload configuration method is proposed to recommend payloads that meet specific scientific goals. This is achieved through correlation analysis of scientific target data within the knowledge base, combining a knowledge extraction model with a semantic similarity model to synthesize exploration object information and historical payload data. The effectiveness of this approach is validated using the Tianwen-1 mission, demonstrating its capability in supporting payload planning, scientific target analysis, and mission configuration in the field of deep space exploration.
Simulation Study of 1 bit Sigma-Delta Digital Fluxgate Magnetometer
LV Shang, WANG Jindong, ZHANG Yiteng
, Available online  , doi: 10.11728/cjss2025.03.2024-0061
Abstract(248) FullText HTML (40) PDF 1076KB(6)
Abstract:
A high-resolution digital fluxgate magnetometer is designed based on the 1 bit sigma-delta modulation technique with 24 bits measurement resolution. By using Matlab Simulink tool kits, the digital fluxgate magnetometer system was simulated and analyzed, the performance parameters of the system in terms of noise, linearity, dynamic response speed and frequency response are obtained. The simulation result shows that, in the range of ±1000 nT, the magnetometer system has a noise floor of 0.17 pT˙Hz–1/2 at 1 Hz, a maximum linearity error of 1.04 pT, a dynamic response speed of 1.07×103 nT˙s–1, and a -3 dB bandwidth of more than 30 Hz. The use of a 1 bit Sigma Delta modulator, significantly improves the conversion accuracy of the DAC (digital-to-analog converter), reduces the noise level and non-linearity of the magnetometer system, and significantly improves the overall performance of digital fluxgate magnetometer. This system is able to meet the requirements of long life, high precision and high reliability of space magnetic field exploration tasks, provides a high-precision and high-reliability detection means for the field of space magnetic field detection, showing its wide application prospects in the field of deep space exploration and space science.
Detection of Tonga Volcanic Ash Using Middle and Upper Atmospheric Lidar
WANG Wei, WANG Jiqing, JI kaijun, CHENG Xuewu, LIN Xin, YANG Yong, LI Faquan
, Available online  , doi: 10.11728/cjss2025.03.2024-0046
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Abstract:
This study presents the first report of detecting Tonga volcanic ash over Wuhan (30.5°N, 114.3°E) using a middle and upper atmospheric lidar system. The research analyzes the intensity variations of Tonga volcanic ash as it spread over Wuhan from March to July 2022, and also examines the volcanic ash's Aerosol Index (AI). The findings reveal that from March 8 to 7 April 2022, the detected volcanic ash signals were relatively weak. However, starting on April 10, 2022, the lidar detected a sudden increase in the strength of the volcanic ash return signals, which remained consistently strong between altitudes of 20～25 km over the following months. This phenomenon suggests a significant change in the volcanic ash's propagation during this period, which may be closely related to atmospheric flow patterns. Further analysis of the detected volcanic ash heights revealed an uneven, layered structure in the stratosphere, indicating a distinct distribution of volcanic ash at different altitudes. This provides important insights into the mechanisms of volcanic ash propagation in the atmosphere and its environmental impact. Additionally, the lidar data analysis from April to July 2022 shows a weak correlation between the detected volcanic ash altitude and the particle size. This suggests that the movement and settling behavior of volcanic ash particles are likely influenced by various complex factors, rather than being governed solely by their size.
Evaluation Methods for Intelligent Synthesis Technology of Aerospace Control Software
WANG Heran, ZHAO Ming, DONG Xiaogang, GU Bin, LI Xiaofeng, ZHONG Ruiming
, Available online  , doi: 10.11728/cjss2025.03.2024-0041
Abstract(295) FullText HTML (53) PDF 3534KB(19)
Abstract:
Program synthesis is a technique for automatically generating programs, which derives corresponding program code from given specifications or requirements. With the successful application of artificial intelligence in the field of program synthesis, intelligent program synthesis technology has become a new paradigm for software development. Although there are some evaluation methods for intelligent program synthesis technology, there are still many challenges that need further improvement and refinement. This paper summarizes and refines evaluation indicators for intelligent program synthesis technology by investigating the evaluation criteria used in intelligent program synthesis technology and analyzing the mainstream evaluation methods of intelligent program synthesis technology. Combined with the characteristics of aerospace embedded software, a hierarchical evaluation indicator system for intelligent synthesis of aerospace embedded software is constructed, and a comprehensive evaluation method for intelligent synthesis technology of aerospace control software mainly based on dynamic and static combination is designed. By calculating the Pearson correlation coefficient with ChatGPT3.5 simulating human scores, it is found that the proposed combined dynamic and static evaluation method can obtain a higher correlation coefficient than either dynamic or static evaluation methods alone, and can reflect the improvement of performance after model iteration.
Design of Finite Frequency Domain Disturbance Rejection Controller for the Drag-free Spacecraft in Space-borne Gravitational Wave Detection
XU Qianjiao, CUI Bing, WANG Pengcheng, XIA Yuanqing, ZHANG Yonghe
, Available online  , doi: 10.11728/cjss2024.05.2024-0022
Abstract(558) FullText HTML (151) PDF 5881KB(58)
Abstract:
In space-borne gravitational wave detection, there are technical challenges in designing the controller for the drag-free spacecraft with dual test masses. These difficulties arise from constraints within the limited measurement frequency domain and the necessity for a high-precision control index. In this paper, a design method of disturbance rejection controller in the finite frequency domain based on the generalized Kalman-Yakubovich-Popov (GKYP) lemma is proposed. Firstly, to address the performance constraints within the designated frequency band of the detection mission, a finite frequency domain control performance index in the form of a frequency response function is constructed. This index is meticulously developed by amalgamating the sensitivity and complementary sensitivity control indexes. Then, a control structure with fixed-order characteristics for output feedback is proposed, and a method for selecting controller parameters based on the GKYP lemma is established. By this, a finite frequency domain disturbance-resistant controller design method is constructed. In contrast to current drag-free controller design methods, the proposed approach significantly diminishes the conservatism in the control index. This realizes the precise design of the controller in the specified frequency band, ultimately resulting in a reduction in the order of the controller. Finally, numerical simulations demonstrate that the proposed method successfully meets the control performance index for each loop of the drag-free system even in the presence of complex disturbances and noises.

Journal Introduction

ISSN 0254-6124       CN 11-1783/V

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