Study on China regional ionosphere modeling based on BeiDou ground-based augmentation system

For GNSS navigation and positioning, ionospheric delay is one of the main error sources, and its influence can reach to several meters or even hundreds of meters. Therefore, it is necessary to study high-precision ionospheric model, especially regional ionospheric model establishment. In this study, a regional ionospheric model based on BeiDou foundation strengthening system is studied. By calculating the observation data of the three systems (GPS／BDS／GLONASS) of BeiDou foundation strengthening system and combining with the polynomial function model for modeling, the ionosphere model in China is obtained. The model precision was evaluated by direct comparison with CODG and indirect single frequency precision single point positioning results. The validations show that the accuracy of the regional ionospheric model based on the BeiDou foundation strengthening system is higher than of the ionospheric grid model published by CODG, and more consistent with the actual ionospheric spatial distribution.