卫星导航接收机自主完好性监测算法研究

Study of GPS receiver autonomous integrity monitoring algorithm

针对航空导航定位高可靠性的要求和GPS接收机观测噪声分布的特点,研究将粒子滤波算法应用于接收机自主完好性监测(RAIM)中。通过粒子滤波算法对状态进行精确估计,利用对数似然比建立一致性检验统计量进行故障检测与隔离。对算法进行了数学建模,描述了完整的RAIM算法详细流程。通过实测数据对提出的RAIM算法进行验证,结果表明:粒子滤波算法在非高斯测量噪声情况下可以对GPS接收机状态进行精确的估计,利用对数似然比建立的一致性检验统计量能有效地检测并隔离故障卫星,验证了该算法应用于GPS接收机自主完好性监测的可行性和有效性。

Aimed at high reliability of the aeronautical positioning and the measurement noise feature of GPS receiver, the particle filter algorithm is applied to GPS receiver autonomous integrity monitoring （RAIM）. Estimating the state precisely with particle filter algorithm and using the log-likelihood ratio as a consistency test statistics to achieve the fault detection and isolation, satellite fault detection is undertaken by checking the cumulative log-likelihood ratio （LLR）of system state with detection threshold. Meanwhile, a detailed descrip- tion of the algorithm flow is given. Based on real GPS data, the proposed RAIM algorithm is tested. Experi- mental results demonstrate that the particle filter algorithm under conditions of non-Gaussian measurement noise can estimate the state of GPS system accurately, and the log-likelihood ratio as the statistic of consis- tency test can effectively detect and isolate false satellites. Therefore, experimental results validate the feasibility and validity of particle filtering and likelihood of ratio methods for RAIM.