Pseudorange Bias Correction for BDSBAS Single Frequency Service

BDSBAS broadcasts SBAS corrections and integrity information via BDSBAS-B1C signals of BeiDou-3 GEO satellites to improve the accuracy and integrity for GPS L1CA single-frequency users in BDSBAS service area. However, if the GPS receiver type and technical status of BDSBAS reference station is quite different from the receiver of GPS ground operational control system and the BDSBAS receivers do not fully refer to the receivers of GPS ground operational control system to adjust the correlator spacing and front-end bandwidth, there will be inevitable relative pseudorange bias between the BDSBAS receivers and GPS ground operational control system receivers. Pseudorange bias is an important factor restricting the performance of BDSBAS single-frequency service. This contribution analyzes the impact of GPS satellite pseudorange bias on the accuracy of BDSBAS single-frequency service, and then proposes a pseudorange bias correction method based on the Timing Group Delay (TGD) parameters, which can eliminate the impact of pseudorange bias on the GPS L1CA SBAS positioning accuracy and improve the single-frequency service performance of BDSBAS. Six stations in the BDSBAS service area are used to carry out GPS L1CA SBAS positioning experiment, the experiment results reveal that the average 95% positioning accuracy has a significant improvement after using the mentioned method to correct the pseudorange bias. The positioning errors are reduced from 1.70 m to 1.38 m and from 2.83 m to 2.29 m in the horizontal and vertical directions, respectively.