Improvement of ionospheric availability for BeiDou satellite-based augmentation system based on SHAKING method

The BeiDou Satellite-Based Augmentation System (BDSBAS) provides ionospheric correction and integrity monitoring services for users in China and surrounding regions through domestic monitoring stations. Therefore, it demands high availability of ionospheric algorithms. This paper utilizes the adjusted spherical harmonics adding Kriging (SHAKING) method to calculate ionospheric parameter information for BDSBAS. Performance analysis of existing Satellite-Based Augmentation System (SBAS) ionospheric models reveals that some SBAS systems broadcast delay correction information marked as unmonitored points. Demand analysis of regional SBAS grid points in China shows that when the satellite elevation angle is set as 15°, SHAKING provides 189 usable points and 3 unusable points. Combined with clock and orbit correction information provided by BDSBAS, SHAKING improves the availability range of approaches with vertical guidance by approximately 30% compared to the inverse distance weighting (IDW) method.