The Effect of Wheel Off-Loading on the Orbit of Tianwen-1

Abstract

In view of the disturbance of the frequent Wheel Off-Loading(WOL) of Tianwen-1, firstly, this paper analysed the perturbation magnitude of WOL and the effect on the orbit in its relay and remote sensing orbits. Secondly, a uniform acceleration model in RTN coordinate system was established to describe the acceleration produced by WOL events, several strategies were proposed to analyze the orbit of the relay and remote sensing orbit respectively, and finally orbital accuracy was assessed by overlap comparison. The results show that WOL events are the main error, affecting orbital accuracy. The position accuracy of the relay orbit is about 150 m, and in the remote sensing orbit where the unloading events are more frequent, the position accuracy decreases to 700 m.

Keywords

Tianwen-1 / wheel off-loading / orbit determination / precision analysis