A Method of Remote Nanosecond Time Reproduction

With the development of science and technology, nanosecond Time-Frequency Signal are needed in astronomical observation, national defense security, communication and other fields. The time comparison system developed abroad can reproduce the standard time signal with an uncertainty of 10 ns locally at the user, the accuracy of national time reproduction system is better than 5 ns within 2000 km. The above time reproduction system based on satellite common view time comparison is limited by baseline length, not suitable for long-distance users to provide time distribution services. Compared with the common view time comparison method, the all-in-view time comparison does not require that both sides have the same visual satellite at the same time. The precise clock and orbit products are used to precisely correct the clock error and ephemeris error. Therefore, the all-in-view time comparison can realize the time comparison between any two places in the global range. In this paper, a long baseline time recurrence method based on all-in-view time comparison is proposed, applying all-in-view time comparison method to time reproduction system, which can effectively solve the problem that the time service system based on the common view principle is limited by the baseline length. To improve the timing accuracy of this method, calculate all-in-view comparison of ultrafast prediction products respectively, and regard IGS comparison as the Vondrak filter value of the prediction time comparison, determining the best smoothing factor, and then filtering the prediction time comparison which is considered as the all-in-view clock to adjust the reproduction terminal constantly. This method can real-time reproduces Immediately better than 5 ns time frequency signal at super long distance.