Real-time orbit determination for transfer orbit and lunar orbit of the CE-5T1 probe

Abstract

In order to meet the needs of autonomous capability for the lunar exploration, an analysis of real-time orbit determination is proposed in this paper for the CE-5T1 probe by using extended Kalman filter. For the lunar-Earth transfer orbit, compared with the least squares method, the accuracy of orbit determination result using 2.5 h satellite-based GNSS data is about 30 m in position, and 1 cm/s in velocity by using EKF method, as well as the velocity of convergence is better than 1 h. For the lunar orbit, the result shows that the EKF method is able to achieve the same level accuracy to the least squares method, furthermore, through a better orbit forecast algorithm design, the Earth-based observation gap caused by the shelter of the moon has little influence to the filter accuracy of the following observation arc.