ARAIM with More than Two Constellations

Future Advanced Receiver Autonomous Integrity Monitoring (ARAIM) is expected to bring significant global navigation performance improvement to civil aviation. Currently, the ARAIM research activities are led by a joint working group of the United States (U.S.) and the European Union (E.U.), which focuses on dual-constellation scenario using the Global Positioning System (GPS) and Galileo. However, even though the BeiDou System (BDS) and GLONASS had achieved remarkable developments in recent years, there had been no comprehensive exploration on their potential benefits to ARAIM. In response, this paper investigates the achievable ARAIM service capability and robustness using more than two full Global Navigation Satellite Systems (GNSS) constellations. Moreover, the key issues with the current baseline ARAIM user algorithm under the new operational scenarios are identified. It is shown that due to the exponentially increased number of monitored satellite subsets, the computational load can be significantly increased when additional constellations are employed. To mitigate this impact, an efficient Fault Detection and Exclusion (FDE) algorithm is rigorously developed by grouping multiple fault hypotheses. To accommodate the non-equal performance levels among the constellations, a series of sensitivity analyses are carried out using variable Integrity Support Message (ISM) values, and the results are presented in terms of availability.