Modeling of BDS-2/BDS-3 single-frequency PPP with B1I and B1C signals and positioning performance analysis

Abstract

On June 23, 2020, the BDS-3 constellation was fully operational and started providing global positioning navigation and timing services. In the future, BDS-2 will continue to provide services and so it is of great importance to study the combination method of BDS-2 and BDS-3 for BDS precise positioning. Compared with BDS-2, BDS-3 is added new signals B1C, B2a and B2b, and the key is how to handle the signal biases between BDS-2 and BDS-3 in BDS-2/BDS-3 combination processing. With consideration of the signal biases between BDS-2 and BDS-3, we present the BDS-2/BDS-3 single-frequency precise point positioning (PPP) model and study the contribution of BDS-2/BDS-3 combination to BDS precise positioning by using one week data of 36 globally distributed stations from multi-GNSS experiment (MGEX) and international GNSS monitoring and assessment system (iGMAS). It is found that the receiver signal biases between BDS-2 and BDS-3 should be carefully considered no matter B1I or B1C signals are used when BDS-2 and BDS-3 are combined. By comparing the positioning performance of BDS-3 single-frequency PPP (SF-PPP) with B1I and B1C observations, it is noted that the positioning performance is related with the receivers of different networks. The positioning performance with B1I is better than that with B1C at iGMAS stations, while it is opposite at MGEX stations. In addition, the contribution of BDS-2/BDS-3 combination is validated. The convergence performance of BDS-2/BDS-3 SF-PPP is better than that of BDS-2 and BDS-3 SF-PPP. Compared with BDS-3 SF-PPP, the vertical convergence performance of BDS-2/BDS-3 SF-PPP improves by about 43.6% at the 68% confidence level. For the positioning accuracy, BDS-3 and BDS-2/BDS-3 SF-PPP are nearly the same, and improves by about 60% compared with BDS-2 SF-PPP.