中文摘要：

讨论了星地双向时间同步的基本原理,推导了其数学模型和误差模型,分析了星地双向时间同步精度的误差因素,理论论证了时间同步精度可达0.9ns。进一步研制了星地双向时间同步软件,并应用于COM-PASS在轨试验阶段时间同步数据的处理。结果表明,COMPASS试验阶段,星地时间同步精度达到1.0ns。

英文摘要：

In this paper, the basic theory and mathematical model of two-way satellite-ground time transfer are presented. The error model is deduced and error budgets are analyzed and concluded that the accuracy approaches 0.9 ns. Furthermore, software was developed and actual two-way satellite-ground observations from COMPASS validation testing were pro- cessed. The results indicate that the accuracy of satellite-ground time transfer in COMPASS validation phase is 1.0 ns.