GPS和Galileo系统下RAIM算法可用性分析

Analysis on RAIM Availability of Different Navigation Systems

介绍了RAIM算法中故障检测及其完好性保证的原理,采用STK仿真得到GPS和Galileo系统的卫星坐标及中国区域内的格网点坐标,结合航空用户对完好性需求,比较了GPS和Galileo系统下、不同类型导航性能需求的RAIM算法的可用性结果,分析了截止高度角、可视卫星数对故障检测可用性的影响。结果表明:当截止高度角越低、可视卫星数越多,故障检测的可用性越高;相同截止高度角条件时,Galileo系统下的RAIM可用性要高于GPS系统;单一的GPS导航系统难以满足垂直引导进近和精密进近等高等级的航空需求。

Basic theory of RAIM algorithm was described. Coordinates of GPS and Galileo satellites and coordinates of grids in China area was generated using STK. Concerning integrity requirements of aviation user, results of RAIM availability of different type of required navigation performances in GPS and Galileo system were obtained and compared, and effects of cut-off angle and visible satellites number on fault detection were analyzed. Results showed that： the lower cut-off angle was, the more visible satellites number was and the higher fault detection availability was; when cut-off angle was the same, RAIM availability was higher under Galileo system than under GPS system; single GPS satellite system couldn＇t fulfill higher grade aviation requirements of APV and precision approach.