Sensitivity of Advanced RAIM performance to mischaracterizations in Integrity Support Message values

With the increasing number of navigation satellite constellations from multiple service providers, an emerging concept for receiver avionics is being developed which will significantly improve the current, widely available operations based on the classical Receiver Autonomous Integrity Monitoring (RAIM). This emerging concept, called Advanced RAIM (ARAIM), is envisioned to eventually provide a worldwide approach capability for Localizer Performance with Vertical Guidance (LPV). One major architectural change of ARAIM from RAIM is introduction of the Integrity Support Message (ISM), which is a set of parameters representing the statistical characterization of the core navigation constellation performance. The ISM values will be periodically updated and used as a priori information in the ARAIM user algorithm. Therefore, it is critical to broadcast ISM values that would provide optimal ARAIM performance balanced between the margins of integrity, continuity, and availability. In this paper, we analyze the sensitivity of ARAIM performance to potential ISM mischaracterization.