A Satellite-Ground Precise Time Synchronization Method and Analysis on Time Delay Error Caused by Motion

Currently for the accuracy of long-range time transfer can only reach up to 100 ps, limiting the wide application of high-precision time-frequency reference in space science. The study of the satellite-ground precise time synchronization method can provide an effective solution for developing long-range time transmission technology. In this paper, a satellite-ground time synchronization method based on two-way time difference measurement is studied. Simultaneously, we propose a method for correcting the time delay error caused by satellite and ground station motion, and the related analysis is carried out. The simulation results show that when we control the attitude error within 72 as (0.02°), the phase center calibration error is less than 1 mm, the precise orbit determination error is less than 10 cm (three axes), the satellite-ground time synchronization performance is better than 0.02 ps after correcting the time delay error caused by target motion based on the two-way time difference measurement without considering other error factors. With the other error impacts (ignore calibration error of atmospheric parameters), the satellite-ground synchronization performance can reach 0.45 ps. The research of satellite-ground precise time synchronization and error correction can provide an inevitable technical accumulation and reference for high-precision time-frequency transmission technology in space.