Research on Multipath Mitigation Based on the Variable Length Reduced Sigma Point Kalman Filter

In the modernized GNSS systems, multipath has become the major limitation to the application of high precision positioning and the performance of all sorts of receivers. Moreover, the characteristics of multipath of different satellites are different in the combined constellation. Towards the aim of multipath mitigation for the monitoring stations in Beidou navigation satellite system (BDS), this paper analyzes the characteristics of multipath of combined constellation in BDS system first, and an algorithm of multipath mitigation based on the variable length Reduced Sigma Point Kalman Filter (RSPKF) is put forward subsequently, which can be employed in the multipath mitigation for different kinds of satellites in the combined constellation. The results of field experiments implied that, the standard deviation of multipath residuals for all frequencies and all kinds of satellites were reduced more than 27 % by the proposed algorithm while compared with the multipath mitigation method based on the fixed data length RSPKF.