A Decentralized Method for BeiDou Satellite Autonomous Orbit Determination Based on Schmidt-Kalman Filter

Abstract

For current GNSS, most of the data processing relies on the operation of ground stations. But when the station is not available out of some adverse conditions such as earthquake, electronic jamming or military precise attack, all the calculation process need to be executed on satellite. But limited by the capacity of on-board computer and communication load, obviously single satellite could not afford such a large amount of calculation. So the calculation need to be decentralized to every single satellite, which means each satellite only need to predict the orbit of itself in order to reduce the calculated amount. Based on Kalman Filter theory, this paper puts forward a decentralized method of autonomous orbit determination applicable for BeiDou. Firstly, satellite Tool Kit (STK) software is used to generate the BeiDou constellation scenario, in which the satellite tracks are regarded as datum orbits. Secondly, this paper developed an advanced satellite-choose strategy to obtain an ideal Geometric Dilution of Precision (GDOP) value. Finally, this paper presents the orbit error curves by the comparison of estimated orbit and reference orbit and then give an analysis of orbit determination accuracy as well as position accuracy. Preliminary simulation shows that, for BeiDou constellation, the precision of orbit determination by using such method could keep up effectively, basically within 5m. And by using the advanced satellite-choose strategy, inter-satellite GDOP value could constantly be maintained under 10. Besides, this paper uses Beijing as the location of positioning receiver to analyze the position performance. Results shows that when we leave out the influence of other environmental factors, such method could achieve a position accuracy under 10m within 24 hours.