The BDS Multipath Hemispherical Map Based on Double Difference Residuals and Its Application Analysis

Abstract

Sidereal filtering is effective to mitigate multipath errors from observations or coordinates by taking advantage of the sidereal repeatability of GPS multipath signals. However, the characteristics of BDS multipath effect are different from that of GPS because the constellation and orbit of BDS are more complicated than that of GPS. According to the repeatability of BDS multipath signals, the multipath hemispherical map (MHM) is established for each satellite pair based on double difference residuals, and then the validity of the model is tested using real field observation data. The results show that the BDS MHM can reduce the root mean square (RMS) of double difference residuals by 83.6 % on average and improve the coordinate accuracy by 20.0, 52.2, and 16.5 % in E, N, and U directions, respectively. While observation sidereal filtering method improves the coordinate accuracy by 17.5, 50.0, and 13.0 %, and coordinate sidereal filtering method only improves the coordinate accuracy by 12.5, 42.2, and 7.8 % since it does not consider the repeat periods of MEO satellites multipath signals, which are about 7 days. Compared to the sidereal filtering methods, MHM is not only more effective to multipath mitigation, but also easier to implement in real-time applications since it can avoid calculating the accurate repeat period of multipath signals for each satellite.