光纤Round-Trip法授时的误差分析

Error Analysis of Fiber Time Service Using Round-Trip Method

现有天基时间同步网络的精度限制和光钟的出现,使得光纤授时成为高精度时间同步的主要方案之一。介绍了利用密集波分复用(DWDM)技术实现单纤双向传输的Round-Trip法授时方案,该方案抑制了利用光纤业务授时而导致的双向信道延时不对称问题。利用光纤授时系统中各模块的典型参数和信道特征分析了授时偏差和随机误差,提出了相应的补偿偏差和抑制误差的方法。理论分析表明,该方案在现有光纤中继距离上的授时精度可以达到亚纳秒量级。利用时间间隔计数器测量了50km光纤授时系统中主要模块的时延及其时延波动范围,实验验证了理论分析的结果。

The emergence of optical clock and the precision limits of the existing time synchronization space-based make fiber one of the major high-precision time service systems.A Round-Trip method that uses dense wave length division multiplexing（DWDM） technology in a single fiber and achieves bidirectional time information transfer is introduced.This method restrains the delay time asymmetry of the optical time service using fiber business channel.The time deviation and random error are analysed by using typical parameters of various modules and the character of the fiber channel in the system,and the corresponding suppression of deviation and compensation of random error methods are brought forward.Theoretical analysis shows that the method can satisfy time-precision of nanosecond order of magnitude in the existing fiber distance relay.Taking advantage of the time interval,the delay time and the time stability of the major modules in the 50 km fiber time service system are measured,verifying the theoretical analysis.