针对导航战、城市或者室内环境中，可见卫星数目小于3颗，用户位置未知时，接收机无法完成授时等问题，并结合我国已有卫星导航系统(北斗和CAPS系统)现状，提出了一种基于IGSO卫星的多普勒定位单向授时方法。该方法通过测量卫星信号的多普勒频移，采用积分多普勒计数计算用户位置，完成单向授时功能。分析结果表明，使用3颗IGSO卫星搭载透明转发器载荷，可使我国领土范围内的定位授时可用性基本达到100%；静态观测用户，长期测量定位精度可达3m以内，授时精度误差小于100ns。由于该方法最少只需观测1颗IGSO卫星信号，这为导航战背景及微弱信号环境下的定位授时服务，提供了新的解决方法。

In the condition of navigation war, civil or indoor environment, when the visible satellite number is less than 3 and users’ position is unknown, one-way timing solution is no longer unavailable. Based on the characteristics of Chinese navigation satellite system such as COMPASS and CAPS, a doppler positioning timing method based on IGSO satellite is proposed. By measuring the doppler frequency shift and counting the integral Doppler, the user position and time are computed. Analysis result shows that the positing and timing usability can reach nearly 100% in Chinese domain when using 3 IGSO satellites with transponders. The position precision can achieve 3m and the timing error is less than 100ns for static users with long time measurement. Because only one IGSO satellite is needed and there is no requirement for demodulating navigation message, this method provides a novel timing method for the navigation war background and weak signal environment. 