高轨航天器GNSS信号传播链路建模与强度分析

在高轨环境下，由于卫星信号传播链路复杂、损耗衰减较大、信号强度不均匀给全球导航卫星系统（GNSS）应用带来新问题。本文建立了GNSS信号从发射端到高轨航天器接收终端的传播链路模型。通过全链路模拟和等价增益仿真，得到了高轨航天器接收信号强度的分布规律。在此基础上，比较分析了GNSS双星座、三星座和四星座联合导航系统的可用性，为高轨航天器GNSS信号特性分析、多模接收机的灵敏度选择、捕获跟踪算法的设计等工程应用提供理论参考。

Modeling and intensity analysis of GNSS signal link for high-orbit spacecraft

In the application of global navigation satellite system (GNSS) in high-orbit environment, satellite signal propagation link is complex with large attenuation and non-uniform intensity distribution. These signal link characteristics influence theoretical analysis and engineering application. In order to solve these new problems,GNSS signal link model from GNSS transmitting antenna to high-orbit spacecraft receiver was established. Based on the signal link model,signal intensity distribution of high-orbit spacecraft was obtained by the equivalent gain overall link simulation. On this basis, the availability of dual constellation, three constellations or four constellations integrated GNSS was discussed and compared. It provides reliable theoretical basis for engineering applications such as GNSS signal characteristic analysis, sensitivity selection of multimode receiver and acquisition and tracking algorithm design.