Optical Observations and Its Application on Orbit Determination for 2016HO3 Exploration

Since an upcoming Chinese asteroid mission will target a near Earth asteroid Kamo`oalewa (2016HO3) and a main-belt comets 311P/PANSTARRS, a full simulation analysis has been made on the spacecraft optical navigation based on three types of optical observations collected by on-board cameras. The observations include the elevation and azimuth angle relative to the camera body coordinate system, the right ascension and declination in the celestial reference system, the angle between asteroid and the planets relative to the spacecraft. The dynamical model of the asteroid exploration mission was firstly built and then the celestial bodies could be observed during the mission for the third model was selected, which helped to determine the observation scheme and the pointing direction of the camera. Based on such setting, the observation was simulated which error is about one arcsecond and then the spacecraft orbit determination was calculated. The results indicated that when the observation time reaches 100 h, the 3D position accuracy of the spacecraft could reach 50 km, thus technically meeting the navigation requirement. However, the position and velocity in x and y direction are strongly autocorrelated, which means that the spacecraft position in xy plane cannot be easily constrained using only these optical observations. Meanwhile, the results also shown that the orbit determination accuracy based on single observation type data is 3~4 orders of magnitude lower than that of joint observations. The third-type observations make a much more significant contribution with respect to another two kinds of observations which indicates that the precise position of the solar system bodies is helpful when constraining the position of a spacecraft for 2016HO3 exploration.