Design and realization of a disciplined clock module used in time transfer system with optical fiber

ZHU Shao-hua1, 2, LU Lin1, ZHANG Bao-fu1, ZHU Yong1, WU Chuan-xin1

(1. Institute of Communications Engineering, PLA University of Science and Technology, Nanjing 210007, China;

2. PLA Army 94865, Hangzhou 310021, China)

Abstract:A design approach of disciplined clock module used in time transfer system with optical fiber is presented and the hardware system is introduced. On the basis of analyzing the transfer characteristic of optical fiber and the VCXO(voltage controlled crystal oscillator) theoretically and experimentally, a time disciplined program with kalman filtering algorithm has been developed, which is suitable for optical fiber channel. The tests show that the disciplined clock model can take the advantages from the oscillator with good short-term stability and from the optical time transfer system with good long-term stability, and the time-transfer precision and the long-term stability of output 1 PPS are better than 0.25 ns（1σ）and better than 10-14 respectively.

Key words: time transfer via optical fiber; clock discipline; kalman filterring