一种转发式卫星授时新方法

为了减少对GPS提供的高精度授时服务的依赖，建设拥有自主知识产权的且具有投入成本低、精度高的授时系统。提出了一种利用地面高稳定度原子钟作为时频基准，通过通信卫星转发实现卫星广播授时的新方法。详细研究了利用地面高稳定度原子钟和通信卫星组成的导航星座进行多星授时、单星授时的原理和测量方法，分析研究了影响授时精度的原因。由于转发式卫星授时系统的时频基准源稳定度高，其测距精度也会相应的提高。只要精确扣除时延误差，同样可以实现高精度授时。粗码的授时精度可达20ns以内，短精码的授时精度可达10ns左右。总之该系统具有组建灵活简便、应用面广等优势和特色。

Study of a Forwarding Approach of Satellite Time Service

To reduce the dependence on the high-precision time service provided by the GPS, it is desirable for our country to establish a low-cost and high-precision time service system of independent intellectual property rights. In this paper, we present a new method of satellite time service achieved through the broadcasting of a communication satellite and using a high-stability ground-based atomic clock as the timefrequency reference. We study the theory and measurement of multiple-satellite and single-satellite time services with the navigation constellations constituted by high-stability ground-based atomic clocks and communication satellites. We particularly analyzed factors affecting time accuracy in these two types of methods. Because of the high stability of the time-frequency source our proposed forwarding approach of satellite time service can have improved ranging accuracy. As long as the systematic error of time delay is precisely corrected, highly accurate time service can be achieved with our approach as well： Time accuracy with the coarse acquisition code can be within 20 ns and that with the fine short code is about 10 ns. In short our proposed system has the advantages of flexibility, convenience, and broad applications.