Assessing ARAIM Parameter Impacts: A Case Study-Driven Multi-Parameter Sensitivity Analysis

Jianming She, Brian Bian, Jimmy Cook, Jason Burns, Jed Dennis

Abstract:	Advanced Receiver Autonomous Integrity Monitoring (ARAIM) is a safety mechanism to ensure Global Navigation Satellite Systems (GNSS) signals meet the integrity requirements of critical aviation operations. The key integrity metrics computed on-board the aircraft to assure the required safety assurance to perform these approaches are the Horizontal Protection Level (HPL) and the Vertical Protection Level (VPL). ARAIM has the goal of allowing Instrument Approach Procedures (IAP) to a Localizer Performance with Vertical Guidance with a 200 ft Height Above Threshold (HAT) minima (LPV-200) by monitoring multiple constellations and the use of Integrity Support Data (ISD). A challenge has arisen which we call the “pit” anomaly. This anomaly causes the protection levels (HPL, VPL) to decrease counterintuitively as ranging error variance grows. Traditional single-parameter sensitivity analyses do not capture this nonlinear anomaly. This study applies a multi-parameter sensitivity analysis (mPSA) using the GNSS Performance Analysis Tool (GPAT) to investigate interactions among key integrity support parameters. Thirty-six three-parameter combinations are simulated, with User Range Accuracy (URA) for Galileo fixed as the reference axis. Results highlight parameter regimes that trigger or mitigate the pit, providing insight into conditions where protection levels evolve monotonically with error variance. The findings highlight the need to enhance ARAIM algorithms to ensure intended flight operations are supported without counter-intuitive protection level responses driven by ISDs.
Published in:	Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025) September 8 - 12, 2025 Hilton Baltimore Inner Harbor Baltimore, Maryland
Pages:	348 - 366
Cite this article:	She, Jianming, Bian, Brian, Cook, Jimmy, Burns, Jason, Dennis, Jed, "Assessing ARAIM Parameter Impacts: A Case Study-Driven Multi-Parameter Sensitivity Analysis," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 348-366. https://doi.org/10.33012/2025.20307
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