GNSS Augmentation by Low-Earth-Orbit (LEO) Satellites: Integrity Performance Under Non-Ideal Conditions

Sukrut Oak, Sam Pullen, Sherman Lo, Isaiah Colobong, Juan Blanch, Todd Walter, Mark Crews, Robert Jackson

Abstract:	In previous work (Pullen, 2022; Pullen, 2023), we introduced the concept of augmenting GPS with six inclined geosynchronous satellites (I-GEOs) that would provide GPS-Block-III-quality military and civil ranging signals along with conveying Satellite-based Augmentation System (SBAS) messages to users. This would create a new means to distribute SBAS messages globally and would support Advanced Receiver Autonomous Integrity Monitoring (ARAIM) for users not equipped to use SBAS. This paper extends this concept to ranging augmentation from satellites in Low Earth Orbit (LEO) such as those in the current Globalstar, IridiumNext, and OneWeb orbits. For each arrangement of combined GPS and LEO satellites, the Stanford MAAST GNSS simulation software package is used to evaluate the protection levels (error bounds) that would apply to military or civil aviation IFR approaches (such as LPV approaches) for ARAIM users without differential corrections. The first set of “baseline” results are the most optimistic because they assume that ranging signals from LEO satellites have the same error bounds and fault probabilities as do GPS satellites. Since this is unlikely to be the case, sensitivity studies have been performed using MAAST in which the LEO elevation mask angle and per-satellite fault probability are increased above those for GPS.
Published in:	Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023) September 11 - 15, 2023 Hyatt Regency Denver Denver, Colorado
Pages:	1436 - 1453
Cite this article:	Oak, Sukrut, Pullen, Sam, Lo, Sherman, Colobong, Isaiah, Blanch, Juan, Walter, Todd, Crews, Mark, Jackson, Robert, "GNSS Augmentation by Low-Earth-Orbit (LEO) Satellites: Integrity Performance Under Non-Ideal Conditions," Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023), Denver, Colorado, September 2023, pp. 1436-1453. https://doi.org/10.33012/2023.19455
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