On the Design and Performance Analysis of BDS3 Ground Based Augmentation System Service

With the fast development of BDS3, the global service of BDS3 now is opened. During the past few years, more than ten thousand of BDS reference stations are established over the whole country. In this paper, firstly a BDS3-GBAS (Ground Based Augmentation System) is completed and tested with self-built nationwide CORS (Continuous Operation Reference Station) tracking network. More than 10 thousands of users can be served simultaneously with this this BDS3-GBAS service software. Besides, performance and positioning accuracy of the BDS3-GBAS service are analyzed with six different strategies, namely, BDS2-only, BDS3-only, BDS3_n-Only, BDS2+BDS3_n, GPS and GNSS-All. As demonstrated by the filed test results, all the strategies except BDS2 almost show a similar accuracy in horizontal direction, while the accuracy in vertical direction varies a lot. The vertical positioning accuracy of the above six strategies is 0.0405 m/0.0259 m/0.0213 m/0.0210 m/0.0215 m/0.0183 m in southern China, respectively. While, the vertical positioning accuracy is much more improved in northern China, and the accuracy is 0.0405 m/0.0259 m/0.0213 m/0.0210 m/0.0215 m/0.0183 m in southern China, respectively. Furthermore, the results also show that BDS3-only can achieve equivalent results to GPS-only in China. Moreover, different methods of ionospheric correction interpolation are also addressed in this paper. As the results shown, the LIM (Linear interpolate model) with residual correction performs the best while the LSM (Liner Surface Model) performs the poorest. And the performance is improved by 13.9% and 14.8% when compared with LSC (Least Squares Collocation) interpolation model and LIM (Linear Interpolation Model) interpolation model, respectively.