Limiting the Potential Impact of SBAS Spoofing

Todd Walter, Rebecca Wang, Juan Blanch

Peer Reviewed

Abstract:	Satellite Based Augmentation Systems (SBASs) were developed to protect against potential satellite clock and ephemeris errors as well as to reduce the impact of ionospheric delays. Most importantly SBASs provide strict upper limits on the remaining errors after applying such corrections. The SBAS signals are generated using trusted processes and their contents are certified to be safe for aviation use. SBAS aviation receivers are designed to trust these signals absolutely. However, the initial development did not include protections against the possibility of spoofing as it was not perceived as a significant threat at that time. Since that initial timeframe, spoofing has now become properly recognized as a significant threat, and the community is working to implement protections against spoofed SBAS signals. SBAS providers are actively developing the standards to implement SBAS message authentication. When finally fielded, SBAS message authentication will protect against the risk of spoofed SBAS signals creating erroneous positioning information. Unfortunately, applying message authentication to the very limited SBAS message bandwidth is a complicated endeavor requiring significant changes for both the providers and the users. Fully developed standards are still several years away, and implementation and fielding will take even longer. This paper describes simple methods to limit the error that SBAS spoofing could potentially induce on an SBAS user’s position solution. One method examines the magnitude of the correction errors and flags the SBAS signal when its corrections exceed the satellite range error commitments from the constellation service providers. Another method evaluates the relative distance between the SBAS and uncorrected position solutions.
Published in:	Proceedings of the ION 2026 Pacific PNT Meeting April 13 - 16, 2026 Hilton Waikiki Beach Honolulu, Hawaii
Pages:	598 - 607
Cite this article:	Walter, Todd, Wang, Rebecca, Blanch, Juan, "Limiting the Potential Impact of SBAS Spoofing," Proceedings of the ION 2026 Pacific PNT Meeting, Honolulu, Hawaii, April 2026, pp. 598-607. https://doi.org/10.33012/2026.20583
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