全球导航卫星系统多星故障排除新方法

在全球导航卫星系统中,多颗卫星同时发生故障的概率会随着观测卫星数的增加而增加,从而,在接收机自主完好性监测中需考虑多星故障的处理.针对故障检测比故障排除简单、且故障检测率比故障排除率高的特征,以故障检测为基础,提出了一种新的多星故障排除方法——随机搜索法.该方法采用二进制对观测卫星进行编码,通过随机初始化方式获得初始无故障星座,再通过逐步搜索未选卫星方式来得到最终的含有最多无故障卫星的星座,实现故障排除功能.仿真结果表明:大部分情形下,新方法能获得99%以上的故障排除率,既能进行单星故障排除,也能进行多星故障排除,能有效满足全球导航卫星系统关于自主完好性的要求. 

Novel method of multiple-satellite faults exclusion for global navigation satellite system

In global navigation satellite system (GNSS), with the increase in the number of observational satellites comes an increase in the probability of simultaneous multiple-satellite faults. Therefore, the multiple-satellite faults should be taken into account in receiver autonomous integrity monitoring (RAIM). The approach of fault detection is simpler than that of fault exclusion and the fault detection rate (FDR) is higher than the fault exclusion rate (FER), considering the features of satellite navigation system, a novel multiple-satellite faults exclusion method was proposed based on fault detection, named random search method (RSM). The binary code for observational satellites was employed in the new method. Firstly, the initial fault free constellation was obtained by random initialization in RSM. And the final fault free constellation with the largest number of observational satellites was obtained by the search of unselected satellites gradually based on the initialization result. And so, the function of fault exclusion was realized. Simulation results show that, in most cases, the FER of RSM is more than 99%. And the new method has the capable of fault exclusion either for single satellite fault or for simultaneous multiple-satellite faults, and it can effectively meet the requirement of autonomous integrity of GNSS.