接收机自主完好性监测的算法分析

Analysis of RAIM algorithm

RAIM技术在接收机端实现卫星完好性监测,因此,监测算法的原理、正确性和灵敏度值得分析与研究。文中给出了RAIM故障检测和识别的数学模型,同时给出了两者的完好性保证算法。对告警门限值、误警率、漏检率之间的关系进行了较为全面的分析,分析了故障检测和故障识别功能与误警率、漏检率之间的关系。分析结果表明:可视卫星数相同时,误警概率越低,FD和FI的精度越低;误警概率相同时,可视卫星数越多,FD的灵敏度越高,FI的灵敏度越低;RAIM可用性一定时,同时满足低漏检率和低误警率是不可能的。

RAIM technology achieves satellites integrity monitoring in navigation receiver, so validity and sensitivity of monitoring algorithm is deserved to analysis and investigation. This paper gives mathematical model of RAIM fault detection and isolation and their integrity insurance algorithm. This paper also analyzes relationship among statistic threshold, probability of fault alarm and probability of missing detecting, and analyzs relationship among FDI function and probability of fault alarm and probability of missing detecting. The results shows： Under condition of the same satellites in view, the lower fault alarm probability is, the lower precision of fault detection and isolation are; while fault alarm probability is the same, the more satellites in view, the more sensitive fault detection is while the less sensitive fault isolation is; Under condition of fixed availability of RAIM, we can not get low probability of missing detecting and low probability of false alert at the same time.