Characterization and Mitigation of BeiDou Triple-Frequency Code Multipath Bias

摘要

Regarding the problem of systematic multipath bias on BeiDou navigation system code observations, ten days BeiDou triple-frequency observations of multi-stations were collected, the relationships between the characteristic of multipath bias and the type of the satellite, the signal frequency and the satellite elevation angle were analyse d. In order to solve this problem, a modified sidereal filtering based on zero-phase filter was proposed to mitigate the multipath bias on GEO and IGSO satellites code observations, and elevation-angle correction method was introduced to decrease the multipath bias of IGSO and MEO satellite code observations. The experimental results show that the modified sidereal filtering can decrease the multipath bias of Bl, B2 and B3 frequencies code observations for GEO and IGSO satellites over 17.0, 18.6 and 10.5%, respectively, and the elevation-angle correction method can reduce the multipath bias of IGSO and MEO satellite Bl, B2 and B3 frequencies code measurements by 5.0, 6.8, and 4.1%, respectively. After mitigating the multipath bias of BeiDou code observations, the precision of single point position for east, north and up directions can be improved about 34, 45 and 51%, respectively.