以全球定位系统(GPS)为研究对象,研究水平定位误差保护级(HPL),阐述自主完好性监测(RAIM)算法故障监测和可用性原理。结合导航性能在航空应用中的需求,对影响RAIM可用性的因素进行数据仿真分析。结果表明,漏检率一定时,RAIM可用性随着误警率降低而降低;误警率一定时,RAIM可用性随着漏检率降低而降低。RAIM算法的可用性随着截止高度角降低和可视卫星数增加而提高。研究结果为采用RAIM算法进行故障卫星的检测和隔离提供了一定依据。
Based on global positioning system (GPS), the horizontal positioning level (HPL) and the availability of re- ceiver autonomous integrity monitoring (RAIM) were ana- lyzed. According to the navigation performance requirements of aviation users, the factors which affected the availability of RAIM were simulated. Simulation results show that RAIM a- vailability decreases with the decreasing of probability of false alarm, when the probability of missed detection is constant. And RAIM availability decreases with the decreasing of proba- bility of missed detection, when the probability of false alarm is constant. With the decreasing of cut-off angle and the in creasing of visible satellite numbers, the RAIM availability becomes higher. The results can provide some reference for application of GPS RAIM algorithm to detect and isolate fault satellite.