卫星双向时间频率传递的误差研究

A Research on Errors in Two-way Satellite Time and Frequency Transfer

卫星双向时间频率传递（TwSTFT）是目前世界上最准确的远距离时间比对技术之一，其时间比对准确度和频率稳定度分别优于1ns和10^（-14）d^（-1）．TwsTFT两站间信号传播路径近似对称使各种路径时延误差的影响大部分被抵消，这是TWSTFT技术获得高精度时间比对的原因．但随着TWSTFT技术的发展及观测频度加密，发现在TWSTFT结果中仍存在1—3ns左右的周日变化剩余系统误差，故TWSTFT的系统误差研究已成为国际上的热点．

The two-way satellite time and frequency transfer （TWSTFT） is one of the most ac- curate means for remote clock comparison with an uncertainty in time of less than 1 ns and with a relative uncertainty in frequency of about 10-14 d-]. The transmission paths of signals between two stations are almost symmetrical in the TWSTFT. In principal, most of all kinds of path delays are canceled out, which guarantees the high accuracy of TWSTFT. With the development of TWSTFT and the increase in the frequence of observations, it is showed that the diurnal variation of systematic errors is about 1 ～ 3 ns in the TWSTFT. This problem has become a hot topic of research around the world.