中文摘要：

介绍长河二号导航系统的授时功能及授时系统的授时原理。通过监测和控制罗兰C信号的绝对发射时刻，提出了一种基于罗兰C信号绝对发射时刻的台链粗同步方法。并通过实验．验证了基于罗兰C信号绝对发射时刻的台链粗同步方法相比于传统的台链粗同步方法，用时更少，粗同步精度更高，操作更简单，提高了导航信号的利用率。

英文摘要：

Time service functions and principle of Navigation System Changhe No. 2 are introduced. Through monitoring and controlling absolute transmission time of Loran-C signal, a method of station-link coarse synchronization based on absolute transmission time of Loran-C signal is presented. It is proved by experiments that this method consumes less time and is more precise than commonly used methods. Besides, the operation is simpler and the signal utilization improved.