BDS-3 Triple-Frequency Timing Group Delay/Differential Code Bias and Its Effect on Positioning

BeiDou Global Navigation Satellite System (BDS-3) broadcasts multifrequency signals that offer more choices of frequencies and signal combinations for positioning. This paper analyzes the effect timing group delay (TGD) differential code bias (DCB) BDS-3 on corresponding triple-frequency The observation models are summarized DCB correction derived four different frequency ionospheric-free (IF) combination (IF123), two dual-frequency IF (IF1213) uncombined (UC123) positioning modes. Standard point (SPP) precise (PPP) experiments were conducted using 30 days observations from 25 multi-GNSS experiment (MGEX) stations. results show TGD/DCB has a significant impact accuracy SPP. IF123 IF1213 improved by about 73~90% after TGD correction, in comparison to 27~30% improvement achieved UC123 model. In addition, is slightly better than TGD. significantly improves initial epoch PPP, which helps convergence filtering reduces time. average times IF123, 26.1, 26.9 38.3 min, respectively, reduced 6.79, 2.54 8.59% with correction. pseudorange residuals closer zero-mean random noise Furthermore, affects evaluation inter-frequency (IFB), ionospheric floating ambiguity parameters. However, tropospheric almost unaffected DCB.