基于改进的卫星共视法的远程时间比对研究

Study on remote time comparison based on improved satellite common-view method

为了解决标准卫星共视法中存在的两个局限性:一是其完整的观测周期为16 min,只有13 min有观测数据,存在3 min观测间隙;二是数据事后交换处理模式,导致比对结果生成严重滞后,不满足实时性的要求。本文提出了一种改进的卫星共视法,改进的卫星共视法不使用国际权度局规定的共视跟踪表,而是采用时间频率连续比对的方法,以10 min(或其整数倍)作为一个观测周期,并同时对观测数据进行处理,当一个周期结束时,立即进入下一个观测周期,去除了标准卫星共视法中每个观测周期内的观测死区时间,增加了观测数据量,实现了时间频率的连续比对。最后,文中利用改进的卫星共视法研制了一套高精度远程时间频率校准系统,并与标准卫星共视法比对结果进行了对比分析,得出零基线情况下,改进的卫星共视法授时精度达到0.295 ns,与相同条件下标准卫星共视法比对结果 0.554 ns相比有了提高。另外,在长基线条件下,改进卫星共视法的授时精度达到3.12 ns,频率稳定度天稳达到8.24 e-14。

Traditional satellite common-view method has two limitations. The first limitation is that the complete observation period is 16 minutes, which includes 13 minute observation data time and 3 minute observation gap. The second limitation is the data post-exchange processing mode, which leads to serious resuh generation lag, and does not meet the real-time requirements. In this paper an improved satellite common-view method is proposed. The improved satellite common-view method does not use the common view tracking table suggested by International Bureau of Weights and Measures （ BIPM ） and adopts a time and frequency continuous comparison method. The improved satellite common-view method takes 10 minutes （or its integer multiple） as an observation period, and in the observation period the observation data are processed at the same time; when an observation period comes to the end, the next one starts. In this way, the 3 minute dead time in each observation period in the traditional satellite common-view method is removed, the amount of observation data is increased, and the time-frequency continuous comparison is achieved. Based on the improved satellite common-view method, a set of high precision remote time and frequency calibration system was developed, and the result was compared with that for the traditional satellite common-view method. It is concluded that under the zero baseline test condition, the improved satellite common- view method achieves the timing accuracy of 0.295 ns, which is improved greatly compared with that for the traditional satellite common- view method （0. 554 ns） under the same condition. In addition, under long baseline conditions, improved satellite common-view method achieves the timing accuracy of 3.12 ns, and day frequency stability of 8.24 e-14