The analysis and evaluation of the multipath error of the BDS marine measurement

Abstract

Marine measurements are generally with more multipath effects than land measurements. The characteristics of the multipath error from the different antennas and different types of signals are also worthy of investigation, and the new signals delivered by BDS-3 (the 3rd generation BeiDou system) have the better feature. Especially, the performance of new signals, B1C and B2a, for anti-multipath needs to be further investigated. The experiments with the same type of receivers connected to different antennas in the oceanic environment were conducted. The signal power and the multipath of the different signals are compared. Moreover, to explore the correlation between the multipath of the code and carrier, the normalization principle is firstly executed to archive the uniform variable, and correlation coefficients are counted after that. The research results show that in the same observation scene, the B1I signal power of the Multipath Suppression Antenna (MSA) is bigger than that of the Normal Geodesy Antenna (NGA), whereas the other signals, such as B3I, is contrary. It reflects weighting only by C/N0 in the positioning is not accurate. The B1C and B2a have a prominent difference in the aspect of the signal power, and this difference is not obvious between the legacy signals. On the other hand, the MSA has a prominent effect on the BDS-3 new signals in the aspect of the anti-multipath. Concerning the correlation, though the code is modulated on the carrier, the multipath of the code and phase are uncorrelated from the statistics, and the different codes are weakly correlated.