百皮秒级不确定度的时间传递方法研究

The accuracy and stability of the frequency standards and the time scales that are generally located on different sites is much higher and higher, and the transfer method with lower uncertainty than GNSS time and frequency transfer and two way satellite time and frequency transfer should be developed for verification of their performances.Since the communication networks based on optical fiber that is better transmission medium were developed quickly, time and frequency transfer through optical fiber with lower uncertainty has been more and more feasible and attractive. Studies on optical fiber time and frequency abroad have been started earlier and most of them have been focused on frequency transfer. Studies on time transfer are fewer, and there hasn't been international comparison results published formally between two time scales of national timing lab.Domestic researches have been initiated much more lately, and there has been some test results using the optical fibers inside the labs, and there hasn't been any studies on calibration of time transfer link and evaluation of transfer uncertainty. Based on the theories and technology of spread spectrum, modulation-demodulation,correlation and code division multiple access(CDMA), using optical fiber as the transmission medium instead of space and satellites, single way and two way time and frequency transfer will be studied, calibration method of optical fiber time transfer link will be explored,and then time transfer through real optical fiber link with one hundred level of uncertainty will be implemented,and at the same time, frequency transfer with high precision will be acquired, and finally technology experience for demostic network construction of optical fiber time and frequency transfer in furure will be accumulated.

频率基标准和时间尺度（时标）的准确度和稳定度越来越高，且通常分布在不同地点，为验证它们不断提高的性能指标，须开发比GNSS时间频率传递和卫星双向时间频率传递更低不确定度的远程时间频率传递方法。基于更优良传播介质光纤的通信网络发展迅速，使得利用光纤进行更低不确定度的时频传递更具可能和吸引力。国外对光纤时频传递的研究开展较早，绝大部分集中在频率传递方面；时间传递方面研究较少，国际上尚无任何两家时间实验室时标之间的正式发表的比对结果。国内此方面的研究起步较晚，尚处于实验室试验阶段，无时间传递链路校准和不确定度评定方法的研究。基于扩频伪码调制解调技术及相关理论和码分多址技术，使用光纤替代空间及卫星作为传播介质，研究单双向时频传递，探索光纤时间传递链路校准方法，进而在实际的光纤链路中实现百皮秒级不确定度的光纤时间传递，同时得到高精度的频率传递结果，最终为未来我国光纤时间频率传递网建设积累技术基础。

随着时间频率标准指标的不断提高，要求我们使用更低不确定度的方法进行时间频率传递。.频率基标准和时间尺度（时标）的准确度和稳定度越来越高，且通常分布在不同地点，为验证它们不断提高的性能指标，须开发比 GNSS 时间频率传递和卫星双向时间频率传递更低不确定度的远程时间频率传递方法。基于更优良传播介质光纤的通信网络发展迅速，使得利用光纤进行更低不确定度的时频传递更具可能和吸引力。国外对光纤时频传递的研究开展较早，绝大部分集中在频率传递方面；时间传递方面研究较少，国际上尚无任何两家时间实验室时标之间的正式发表的比对结果。国内此方面的研究起步较晚，尚处于实验室试验阶段，无时间传递链路校准和不确定度评定方法的研究。基于扩频伪码调制解调技术及相关理论和码分多址技术，使用光纤替代空间及卫星作为传播介质，研究单双向时频传递，探索光纤时间传递链路校准方法，进而在实际的光纤链路中实现百皮秒级不确定度的光纤时间传递，同时得到高精度的频率传递结果，最终为未来我国光纤时间频率传递网建设积累技术基础。. 项目研究开发了基于双向和单向的光纤时间频率传递方法及装置，研制了光纤时间传递链路校准方法，开发了光纤双向时间频率传递数据处理软件，基于卫星双向时间频率传递思路，设计实现了时间频率光纤比对实验平台。. 进一步的，项目基于实验室光纤和实际光纤链路对实验平台进行时差测量的稳定性和准确性进行了充分验证。我们完成了在63km和109km的两条实际光纤链路下的共钟差实验和时间传递实验，可以得到时间稳定度低于6 ps/s和0.9ps /100s的结果，最终不确定度评估结果优于200 ps，可满足100公里范围内高精密时间和频率比对。