Triple-frequency PPP Ambiguity Resolution with BDS-2 and BDS-3 Observations

Abstract

The availability of multi-frequency signals from BeiDou navigation satellite system (BDS) brings great opportunities for improving precise point positioning (PPP) ambiguity resolution (AR). In this contribution, we investigate the triple-frequency PPP AR with B1, B2 and B3 observations from BDS-2 satellites and evaluate the performance of the triple-frequency PPP AR with mixed BDS-2 and BDS-3 satellites. The uncalibrated phase delay (UPD) products are estimated based on triple-frequency observations of BDS-2 and BDS-3 satellites and the quality of UPD products in terms of temporal stability and residual distributions are evaluated. Data recorded from 9 International GNSS Monitoring and Assessment System (iGMAS) stations, 17 Crustal Movement Observation Network of China (CMONOC) stations and 83 Multi-GNSS Experiment (MGEX) stations for a 60-day period were used to validate the effectiveness of BDS UPD products and triple-frequency PPP AR method. Our results show that the wide-lane (WL) and narrow-lane (NL) UPDs with a standard deviation (STD) of less than 0.1 cycles can be achieved for BDS-2 satellites after the code bias correction while a STD within 0.1 cycles can also be achieved for BDS-3 satellites. With the precise UPD products, the triple-frequency BDS PPP AR with BDS-2 and BDS-3 observations can be implemented. Numerous results showed that the performance in terms of positioning accuracy and convergence time can be obviously improved by ambiguity resolution. The triple-frequency PPP AR achieved the best performance with the time to first fix (TTFF) of 30.95 min, a 11.6% improvement compared to dual-frequency fixed solution and 18.5% improvement compared to triple-frequency float solution. With respect to the triple-frequency float solution, the positioning accuracy is improved by 32.23%, 17.04% and 13.70% by PPP ambiguity resolution.