Demonstrations of Multi-Constellation Advanced RAIM for Vertical Guidance using GPS and GLONASS Signals

In the near future, many more navigation satellites with dual frequency L1 and L5 will be deployed. The increased number of satellites and the possibility of mitigating the ionospheric delay using dual frequency have opened the door to the possible use of RAIM for vertical guidance. For this purpose, several Advanced RAIM (ARAIM) algorithms have been proposed. Extensive simulation studies have established that with two constellations it might be possible to achieve global coverage of LPV 200, which requires a 35 meter Vertical Alert Limit. Previous work [1], [2], [3] with large amounts of receiver data has demonstrated the ability of ARAIM to compute a Vertical Protection Level (VPL) that bounds the Vertical Position Error (VPE). However, in that effort, only GPS measurements were tested for the validation of ARAIM. Therefore, multi-constellation evaluation of ARAIM performance will be necessary. In addition to GPS, the only full constellation, or nearing Final Operation Capability, is GLONASS. In this paper, we will validate ARAIM further using ten days of GPS and GLONASS measurements collected by a GLONASS capable GNSS receiver. From the stored data, we will compute all the figures of merit that are necessary for LPV-200, in particular the Vertical Protection Level (VPL) and the accuracy. We will test the ability of the algorithm to predict accuracy and its ability to compute a VPL that bounds the Vertical Protection Error. This will represent one of the first demonstrations of multiconstellation ARAIM with real data.