Comparative analysis of broadcast ephemeris accuracy before and after the opening of BDS-3 system

BeiDou-3 Navigation Satellite System (BDS-3) has been in operation for more than one year. By studying the BeiDou Navigation Satellite System (BDS) broadcast ephemeris data from August 2019 to August 2021, the orbit, clock error and signal-inspace ranging error (SISRE) of BeiDou Navigation Satellite (regional) System (BDS-2) and BDS-3 satellites are analyzed by using the post precision ephemeris. The results show that after the BDS-3 system is opened, the satellite orbit accuracy is significantly higher than that of BDS-2. The radial error root mean square (RMS) value is improved from about 0.87 m to better than 0.23 m, the accuracy is improved by about 74%, and the 3D error RMS value is improved from less than 1.63 m to better than 0.75 m, the accuracy is improved by about 54%; The accuracy of hydrogen atomic clock and rubidium atomic clock is the same. The accuracy improvement of RMS value of BDS-3 clock error is basically the same as that of BDS-2, with an accuracy improvement of about 1 ns; In SISRE accuracy comparison, the RMS value of BDS-2 SISRE is increased from 0.9 m to 0.7 m, and BDS-3 SISRE is increased from 0.8 m to 0.5 m. through comprehensive comparison, the performance of BDS-3 system is greatly improved