BDS-3 PPP-B2b实时精密时间同步方法探讨

Discussion on real-time precision time synchronization method for PPP-B2b of BDS-3

针对传统实时精密单点定位(PPP)时间同步方法需要连接互联网,以及对北斗三号全球卫星导航系统(BDS-3)精密单点定位服务信号(PPP-B2b)用于长基线实时时间同步的研究较少的问题,提出一种将PPP-B2b信号用于PPP时间同步的实时时间同步方法:将高精度铷原子钟作为全球卫星导航系统(GNSS)接收机外频标输入,通过GNSS接收机实时接收PPP-B2b改正数,解算接收机钟差并实时调整铷原子钟,输出与时间基准同步的秒脉冲(1PPS)信号,较之传统GNSS接收机输出1PPS有更佳的频率稳定性;设计PPP-B2b时间同步硬件测试平台对提出的PPP-B2b时间同步方法进行测试。结果表明,通过PPP-B2b时间同步方法进行时间传递的精度优于0.2 ns;短基线实测实时时间同步精度优于0.95 ns;卫星模拟器仿短基线精度优于0.87 ns,仿长基线精度优于0.9 ns。

Aiming at the problems that the traditional real-time precise point positioning(PPP)time synchronization method needs to be connected to the internet and few studies have been conducted on the use of BeiDou-3 global navigation satellite system(BDS-3)PPP service signal(PPP-B2b)for real-time time synchronization of long baselines,the paper proposed a real-time time synchronization method for PPP time synchronization using the BDS-3 PPP-B2b signal:the high-precision rubidium atomic clock was used as the external frequency standard input of the global navigation satellite system(GNSS)receiver,and the PPP-B2b corrections were received in real time through the GNSS receiver;then,the receiver clock offset was calculated,the rubidium atomic clock was adjusted in real time,and the output of pulse per second(1PPS)signal was synchronized with the time reference,which had better frequency stability than the 1PPS signal output by the traditional GNSS receiver;finally,a PPP-B2b time synchronization hardware testing platform was designed to test the performance of PPP-B2b time synchronization method.Results showed that the accuracy of time transfer through PPP-B2b time synchronization method would be better than 0.2 ns,the real-time time synchronization accuracy of the short baseline measured would be better than 0.95 ns,and the accuracy of the satellite simulator's simulated short baseline and long baseline would be better than 0.87 and 0.9 ns,respectively.