Comparative Analysis of Beidou Single and Dual Frequency Positioning Accuracy Evaluation

Aiming at the situation that the BeiDou Navigation Satellite System’s (BDS) single-frequency positioning accuracy is better than dual-frequency positioning found in the daily monitoring and evaluation of the International GNSS Monitoring and Assessment System iGMAS, the observation data of iGMAS overseas stations and domestic station receivers in the same time period are selected for comprehensive analysis. The sequence analysis of different satellite B1I/B3I dual-frequency UERE by different types of monitoring receivers shows that the fluctuation of dual-frequency UERE sequence is larger than that of single-frequency UERE sequence, which is caused by the ionospheric combination amplifying the pseudo-range multipath error; However, dual-frequency UERE of different types of receivers has different mean values, which are caused by group delay parameter errors,this error is indirectly caused by the deviation of the pseudorange measurement constant caused by the non-ideal characteristics of the downlink navigation signal. The pseudorange multipath error can be eliminated by phase smoothing pseudorange, but the analysis shows that the group delay parameter error is mainly caused by the satellite downlink navigation signal distortion, that is, the downlink signal quality is the key to restricting Beidou dual-frequency positioning accuracy. This paper proposes the following research directions for the optimization and improvement of dual-frequency positioning accuracy during the smooth transition period and the Beidou-3 separate service period, and the user receiver configuration parameter design, which lays the foundation for better use of dual-frequency to achieve higher-precision positioning.