Performance of Optimal INS Monitor Against Jamming Then Spoofing Scenarios

Birendra Kujur, Samer Khanafseh, Boris Pervan

Abstract:	In this paper, we demonstrate the performance of the proposed optimal Inertial Navigation System (INS) monitor (Kujur et al. (2024)) under scenarios involving jamming followed by spoofing of Global Navigation Satellite System (GNSS) signals. Previously, we evaluated the monitor’s effectiveness against slow spoofing scenarios without prior jamming (Kujur et al. (2024), Kujur et al. (2023), Kujur et al. (2025)). In a more sophisticated attack, a spoofer may deliberately jam GNSS signals and subsequently introduce spoofed signals. This scenario is analogous to GNSS recovery—i.e., reacquisition and validation—after GNSS signals have been excluded due to spoofing detection. Specifically, once spoofing is detected, GNSS signals are rejected for positioning, and after a period of exclusion, they may be reacquired and validated as either authentic or spoofed. During INS coasting under jamming, IMU calibration degrades. However, even with this degraded calibration, the discrepancy between INS and spoofed GNSS remains sufficient for spoofing detection, even after prolonged jamming periods lasting several minutes. Performance analyses were conducted across various IMU grades. Additionally, we present a preliminary analysis of realistic tracking errors encountered by a spoofer. The results indicate that even with a highly accurate tracking device, the spoofer is unlikely to maintain low centimeter-level tracking error due to large, random positional variations of the aircraft caused by disturbances such as wind gusts. In conclusion, the analysis confirms the monitor’s robust capability to detect GNSS spoofing in realistic scenarios involving jamming followed by spoofing.
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:	1501 - 1510
Cite this article:	Kujur, Birendra, Khanafseh, Samer, Pervan, Boris, "Performance of Optimal INS Monitor Against Jamming Then Spoofing Scenarios," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 1501-1510. https://doi.org/10.33012/2025.20245
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