Research on performance improvement method of BDSBAS multi-GNSS service with DFMC protocol

Abstract

BDSBAS refers to the DFMC protocol to broadcast long-term corrections and integrity messages in real-time to meet the high integrity requirements of civil aviation users. Based on the measured data of the BDSBAS monitoring station, the long-term corrections and integrity messages of BDS/GPS/GAL are calculated, and from the user's perspective verifies the service capability of the above information which mainly including positioning accuracy, pseudorange bias and Protection Level (PL). The test results show that the accuracy of multi-GNSS long-term corrections is better than 0.14 m; when the user uses the long-term corrections, the positioning accuracy can be improved by 27% in the horizontal direction and 31% in the vertical direction compared with the level of the single BDS. In addition, the results show that the BDSBAS DFMC service can satisfy the LPV-200 availability contour in Mainland China except western China and satisfy the Cat-I availability contour only in the central region of China depend on only BDS constellation. When all the messages of BDSBAS DFMC service based on BDS/GPS/GAL constellations are used, it can reach the availability of 100% which satisfy the LPV-200 index in China and surrounding areas, and the availability of 99.4% which satisfy the Cat-I index in Mainland China. Finally, the effect of pseudorange bias errors on positioning accuracy of different types of receivers are analyzed. Results show that pesudorange bias of BDS and GPS is about 0.2 m ∼ 0.3 m, and for Galileo is about 0.05 m. With multi-GNSS corrections and integrity information, the level of service availability and coverage for LPV-200 and CAT-I of BDSBAS DFMC service could be effectively improved.