北斗三号系统开通前后广播星历精度对比分析

北斗三号卫星导航系统(BDS-3)开通已一年有余，通过研究2019-08—2021-08共2 a的北斗卫星导航系统(BDS)广播星历数据，采用事后精密星历对北斗二号卫星导航系统(BDS-2)和BDS-3卫星的轨道、钟差和空间信号测距误差(SISRE)进行分析. 结果表明:BDS-3系统开通后，卫星轨道精度比BDS-2提升明显，径向(R)误差均方根(RMS)值从0.87 m左右提升至优于0.23 m，精度提升约74%，3D误差RMS值从1.63 m以内提升到优于0.75 m，精度提升约54%；氢原子钟和铷原子钟精度相当，BDS-3钟差误差RMS值精度提升与BDS-2提升基本相同，精度提升约1 ns；SISRE精度比对中，BDS-2 SISRE的RMS值从0.9 m提升到0.7 m，BDS-3从0.8 m提升到0.5 m. 综合比较，BDS-3系统性能提升较大. 

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