光纤时间传递的大范围高分辨率时延控制方法研究

Study on the time delay control method with large range and high resolution in optical fiber time transfer

随着原子钟准确度和稳定度的不断提升,对于时间传递技术的要求越来越高。光纤时间传递以其高精度高稳定性能以及安全、可靠等诸多优势已成为重要的时间传递方式。时延控制单元是光纤时间传递的一个重要环节。光纤时间传递的基本原理是先通过估算或实测等方法获得两地之间的传输时延,然后通过对传输时延进行补偿实现时间的传递同步。通过FPGA(field-programmable gate array)和PLL(phase locked loop)移相技术的应用实现了一种可用于光纤时间传递的大范围高分辨率时延控制技术,经多次实验证明,所述系统可对大范围的时差值进行有效控制,将实测时差值存在的偏差都控制在±20 ps 以内;并对时延控制模块输出的1 PPS 信号的实测时差数据进行分析得标准差值为8.2 ps,时延控制模块输出的1 PPS 信号的稳定度为4.33 ps@1 s,0.94 ps@1 ks。

With the increasing accuracy and stability of atomic clocks, the requirements for time transfer technology are getting higher and higher. Optical fiber time transfer has become an important time transfer method due to its high accuracy and high stability, as well as safety, reliability and stability. The delay control unit is an important part of fiber optic time transfer. The basic principle of optical fiber time transmission is to obtain the transmission delay between the two places through estimation or actual measurement, and then realize the synchronization of the transmission of time by compensating for the transmission delay. In this paper, a large-range high-resolution time-delay control technology that can be used for fiber time transfer is realized by the application of FPGA and PLL phase shifting technology. It has been proved by many experiments that the system described in this paper can effectively control a large range of time difference, and control the deviation of measured time difference to within ±20 ps. The measured time difference data of 1 PPS signal output by the time delay control module was analyzed to obtain a standard deviation of 8.2 ps. The stability of 1 PPS signal output from the delay control module is 4.33 ps@1s, 0.94 ps@1ks.