The benefit of B1C/B2a signals for BDS-3 wide-area decimeter-level and centimeter-level point positioning with observable-specific signal bias

Abstract

In addition to the legacy of B1I and B3I signals, the BeiDou Global Navigation Satellite System (BDS-3) also broadcasts the new navigation signals B1C and B2a, which brings new challenges and opportunities for multi-frequency precise point positioning (PPP) ambiguity resolution. The observable-specific signal biases (OSBs) provide flexible frequency choice for multi-frequency ambiguity resolution. This work implemented an approach of BDS-3 quad-frequency OSBs estimation, making the generated OSBs suitable for ambiguity resolution using any frequency combinations. Besides, the benefits of B1C and B2a signals for wide-area decimeter-level and centimeter-level point positioning with ambiguity resolution are also investigated in depth. The BDS-3 B1C/B1I/B2a/B3I measurement data of 110 stations over one month were used to estimate the quad-frequency phase OSBs, and 20 different stations were selected for PPP verification. The results indicate that the BDS-3 quad-frequency phase OSBs are relatively stable, with a standard deviation of less than 0.06 cycle. The B1C/B2a/B3I combination achieved the highest positioning accuracy for instantaneous triple-frequency PPP wide-lane ambiguity resolution, with root-mean-square of 0.15 m, 0.17 m and 0.51 m in the east, north and up directions, respectively. Moreover, the use of B1C/B2a instead of the traditional frequency B1I/B3I as the WL combination improved the single-epoch PPP accuracy. Furthermore, after solving the narrow-lane ambiguity, the median convergence time of B1C/B2a for the kinematic and static mode was 26.5 min and 14.5 min, which was shortened by 29.3 % and 27.5 % compared to the results of the B1I/B3I combination, respectively.