Parity space projection line based fault detection method for advanced receiver autonomous integrity monitoring

The advanced receiver autonomous integrity monitoring (ARAIM) is an augmentation of future multi-constellation global navigation satellite system for fulfilling stringent navigation integrity specified in safety-critical applications. Until recently, the most extensively used ARAIM algorithm is the baseline algorithm using the multiple hypothesis solution separation (MHSS) test statistics. However, the MHSS tests are redundant, which bring loose threshold for each test statistic, due to duplicate allocations of continuity budget to numerous tests. The loose thresholds reduce the ARAIM performances on fault detection, effective monitoring threshold, and integrity. This paper proposes a new projection line based MHSS (PLB-MHSS) fault detection method in parity space. Specifically, we first develop projection line representations for the MHSS test statistics and the position error distribution. The PLB-MHSS method is then proposed using the largest projection of parity vector onto the projection lines as the test statistic. Finally, a corresponding integrity risk bounding method is developed. Without redundantly allocating the continuity budget, the PLB-MHSS method obtains tight fault detecting threshold. Simulation results show that, compared with the traditional MHSS method, the PLB-MHSS method is more sensitive on fault detection, and decreases about 9% of EMT and more than 13% of vertical protection level on average.