多模卫星导航系统的RAIM算法研究

研究了多模卫星导航系统的RAIM（接收机完好性自主检测）算法，根据多模卫星导航系统的定位模型，基于最小二乘法的原理计算伪距残差，构造奇偶矢量进行故障检测和故障排除。在只有一个观测量出现粗差的前提下，仿真了GPS与多模GPS／GLONAss／Galileo系统下的卫星可见数和DOP（精度因子），对比了衡量RAIM算法可用性的水平保护门限值（HPL）及这2种系统下的故障检测率与故障排除率。仿真结果表明：与GPS相比，多模导航系统具有更多的可见星，RAIM算法的可用性更高，并且其故障检测和故障排除的性能更好。因此，多模卫星导航系统不仅能为用户提供更高的定位精度，还能为用户提供更好的完好性保障。

Study on RAIM algorithm of multi-mode navigation system

The RAIM（receiver autonomous integrity monitoring） algorithm for multi-mode navigation system is analyzed in this paper. Based on the least squares solution of multi-mode navigation positioning model, the parity vector is developed for the fault detection and fault exclusion. For GPS navigation system and multi-mode GPS/GLONASS/Galileo navigation system, the number of satellites in view of user and the values of DOP（dilution of precision） are simulated on the assumption that there is only one fault in the observed quantifies. The values of HPL（horizontal protection level） which are used to measure the availability of RAIM algorithm and the behaviors of fault detection and fault exclusion are compared between these two systems. Simulation results demonstrate that compared with GPS, there are more satellites in view, better availability of RAIM algorithm, and better performance of fault detection and fault exclusion for the multi-mode GPS/GLONASS/Galileo navigation system. Therefore, the multi-mode navigation system not only can provide higher positioning precision, but also can provide better integrity than GPS system.