A Method of National Standard Time High Precision Remote Reproduction

The Coordinated Universal Time (UTC) scale maintained at the National Time Service Center (NTSC), is known as UTC(NTSC), with a deviation from UTC of less than ±10ns. In order to enable the remote users access to high precision time as maintained at NTSC, based on the UTC(NTSC) time frequency signal and common-view time comparison method, a set of UTC(NTSC) remote reproduction system is developed to achieve time and frequency calibration as well as establish traceability to UTC (NTSC) for remote users. This paper discusses the following 1) a method based on UTC(NTSC) time frequency remote reproduction, based on improved common-view method, which can realize the measurement of time difference between local reference time and the continuous satellite clock., The dead time in the observation cycle of traditional common-view has been removed.2) Design and realization of UTC(NTSC) remote reproduction system. This system includes a primary terminal, distribution terminals and a data processing center. The primary terminal measures bias between UTC(NTSC) and satellite clocks. The distribution terminal is used to measure the bias between local time and satellite clock, and steer the lock time and frequency signal to synchronize with UTC(NTSC).The data processing center deals with the data from primary terminal and distribution terminals. 3) Analysis of measurement uncertainty, in order to estimate the measurement uncertainty of system, Zero-baseline and long-baseline experiments were carried out. In the zero-baseline experiment, the system timing accuracy was 0.8ns. However, in order to verify that users steering with different types of clocks with the system, the long-baseline experiment shows that the frequency stability (day) of a cesium clock can reach 2.84×10^-14, and rubidium clock reaches 8.24×10^-14.