Enhancements of the DichoTomy based RAIM

Receiver Autonomous Integrity Monitoring (RAIM) is an important sort of technique to monitor the integrity of satellite navigation systems. As the deploying and being perfected of many satellite navigation systems, the ranging sources will increase rapidly and so does the false probability of multi-satellites. Thus RAIM algorithms which can detect multi-faults quickly and efficiently have becoming a research hotspot. This paper proposed a DichoTomy based RAIM (DT-RAIM) algorithm using geometry based grouping to detect and identify two faulty satellites simultaneously. For DT-RAIM, all the visible satellites were grouped to two parts twice to achieve a fast and efficient detection. At the same time, the faults can be identified fast and accurately based on comparison between the estimated pseudo-ranges and the measurement ones. The simulation on GPS/Galileo combined constellations shows that the performance of DT-RAIM to detect and identify single faulty satellite is nearly equal to the classical snapshot RAIM. Meanwhile, for two faults, the false detection rate of DT-RAIM is obviously lower than that of Range Consensus (RANCO) algorithm with 2.5 times of User Equivalent Range Error (UERE). The detection rate and identification rate of DT-RAIM almost equal to those of RANCO with 4.5 times of UERE, but the consumed time of DT-RAIM is just 1/20 of RANCO.