Research On Orbit Determination Of Probe Around Earth-Moon Libration L2 Point Based On Solar Pressure Correction Model

Before the Chang’E-4 relay satellite entered the Earth-Moon L2 halo orbit,there were only two Earth-Moon L2 missions worldwide,one was the ARTEMIS mission in the United States,and the other was the expansion mission of China’s "Chang’E-5 reentry and return test mission".The actual mission samples are few and the accumulated experience is limited.Based on the Chang’E-4 relay satellite mission,the precise orbit determination technology of detector around the earth moon L2 point is studied in this paper.The precise orbit determination theory of probe around the Earth-Moon L2 point is studied.The process of precise orbit determination and the space-time coordinate system are systematically sorted out.The Earth-Moon L2 rotation coordinate system and its transformation to the Earth/Moon inertial coordinate system are discussed in detail.In addition,the observation model and the force model is analyzed.Through simulation analysis,the solar pressure is the most important factor besides the gravity of the sun,the earth and the moon.The unique configuration of the relay satellite with a box and dish antenna makes it difficult to estimate the equivalent area of solar pressure under the cannon-ball solar radiation pressure model,which will significantly affect the orbit determination accuracy.In order to improve the orbit determination accuracy of relay satellites in Halo orbit,a multi-feature surface solar radiation pressure model based on real-time attitude of relay satellites is proposed in this paper.After simulation analysis and verification of measured data,compared with cannon-ball model,the orbit determination accuracy can be effectively improved.Under overlapping arc strategy,the position accuracy can be increased by about 1 km,and the speed accuracy can be improved by about 6 mm/s.In view of the frequent maneuvers of relay satellites such as unloading and orbit maintenance in Halo orbit,this paper carries out the analysis of rapid orbit reconstruction after maneuvering.The analysis results show that the rapid orbit reconstruction can be completed through 2-day data.With the support of VLBI,1-day data can also complete orbit reconstruction.We found that the accuracy of orbit determination is obviously different when the + Z axis directs or non-direct to the sun.It is important reference value for the adjustment of relay satellite’s + Z axis during long-term management.