Calibration of inconsistent receiver-dependent pseudorange bias and its impact on wide-lane ambiguity fixing

The prerequisite for achieving highly reliable Wide-Lane (WL) ambiguity resolution (AR) is the accurate determination of phase fractional cycle biases (FCB) on both the receiver and satellite side. It is generally assumed that the observation signal biases on the receiver side are stable, and receiver FCBs can be expressed using a single parameter over a period. However, due to the influence of satellite signal distortion and multipath errors, the receiver-dependent pseudorange biases (RDPB) may be inconsistent for different observed satellites at a certain receiver, which is called inconsistent RDPB (IRDPB) in this study. To improve the WL AR performance in GNSS network processing, we propose an optimized FCB estimation method with IRDPB corrected by the receiver individual. Utilizing data from 490 stations with four receiver types, the effect of the proposed WL FCB is verified in terms of ambiguity residual distribution and ambiguity fixed rate by comparing it with the original FCB and FCB with IRDPB corrected by receiver type. The proposed method improves the proportions of WL residuals within +/- 0.1 cycles by 13.7%-20.5% for GPS, BDS-2 and BDS-3 compared to the original FCB. Compared to FCB corrected with receiver-type IRDPB, the number of stations with the proportions of residuals within +/- 0.1 cycles in the percentage range (80,100] are improved by more than 130 for GPS, BDS-2 and BDS-3. Using the proposed FCB, the GNSS stations can obtain reliable real-time WL fixing solution. The result also shows that the influence of IRDPB varied with receiver types and GNSS systems. Galileo was less affected by IRDPB than GPS and BDS-2/3, and Trimble Alloy receivers suffer more significant IRDPB than the other three types of receivers.