Analysis of Multipath Error Characteristics of BeiDou Navigation Signal

Pseudorange multipath error is one of the main error sources of BeiDou Navigation Satellite System (BDS), all precise applications which use code measurements are severely affected. In view of the current situation that BDS lacks comprehensive assessment of multipath error characteristics, this paper analyzes time and frequency domain characteristics of multipath error and its relationship with elevation angle, following with its performance under different signal modulation systems, correlator intervals and RF bandwidths. By way of tri-frequency pseudorange and carrier phase combination method, the results demonstrate that three types (MEO, GEO, IGSO) of satellites’ multipath error all reflect low frequency characteristics, and the multipath error elevation-dependence of BDS-3 MEO satellites is significantly lower than that of BDS-2. Compared with signal B1I with 4 M modulating bandwidth, the multipath error fluctuation of B2I, B3I and B2a (single sideband reception) with 10 M bandwidth are smaller. For the new system broadband modulation system, signal using TMBOC(6, 1, 4/33) modulating method has better anti-multipath performance than BOC(1, 1). In addition, increasing RF bandwidth or reducing correlator interval can both impair multipath error. The research results would have certain guiding significance for the performance evaluation of the new Beidou navigation signal system and the system design for Beidou navigation receiver.