Research on BDSBAS Service Coverage Area Assessment Methodology

On July 31st, 2020, the construction of the BeiDou Satellite-Based Augmentation System (BDSBAS) was completed, which can provide two service signals, single frequency augmentation and dual frequency dual constellation augmentation, and is currently carrying out civil aviation testing and certification of single frequency augmentation services. When conducting service coverage area assessment, domestic scholars generally use the grid point evaluation method used by the US Wide Area Augmentation System (WAAS), which uses the premise that WAAS has passed civil aviation test certification and verified the reliability of pseudodistance integrity in the entire service area. However, BDSBAS has not yet completed the test certification, so this method is debatable for the evaluation of BDSBAS service coverage areas. Therefore, this paper proposes a service coverage area evaluation method and process applicable to BDSBAS, which realizes the accurate evaluation of ionospheric grid coverage area and positioning service coverage area through the national multi-station dense networking monitoring. In this paper, the observation data of the Chinese monitoring station of the Crustal Movement Observation Network of China (CMON) in August and O4ctober 2021 are evaluated, and the results show that the BDSBAS single frequency service area in northern China can achieve 99% coverage of APV-I level availability, while most BDSBAS single frequency service areas in southern China are below 99% availability. Compared with the grid point evaluation method, it is obvious that the availability of single frequency enhanced services in the southern region is poor due to ionospheric anomalies, which verifies the effectiveness and correctness of this method. This method can effectively support BDSBAS civil aviation testing and certification work in the future.