Session A2: GNSS Security: Interference, Jamming, and Spoofing 1

Navigating Interference - Examining In-Flight GNSS Spoofing Patterns and Signal Disruptions
Michael Felux, Sophie Jochems, Valentin Fischer, Benoit Figuet, Raphael Monstein, ZHAW - Zurich University of Appl. Sci.
Location: Beacon A

Global Navigation Satellite System (GNSS) Radio Frequency Interference (RFI) poses a significant issue to aeronautical navigation systems, particularly in areas where the integrity of GNSS signals is critical for both en-route and approach operations. In the Eastern Mediterranean, RFI has been a persistent issue over the past several years, leading to disruptions in aeronautical navigation systems, with knock-on effects on different systems such as the surveillance capabilities of aircraft. Initially, the interference was primarily characterized by widespread GNSS jamming, however, since the second half of 2023, the nature of the threat has evolved, with GNSS spoofing having now become the predominant concern in the Eastern Mediterranean, as well as several other regions including the Black Sea, Russia, Pakistan and occasionally also South Korea.
GNSS spoofing presents a greater challenge than jamming because the aircraft may consider the GNSS signals as valid, leading the receiver to output position and time information to the aircraft, without the aircraft necessarily detecting and rejecting the information, but rather using it for several systems reaching far beyond pure navigation. In some of our previous studies (e.g., Felux et al. 2024, Osechas et al. 2023) we documented the impacts of GNSS jamming and spoofing on aviation operations and on the ADS-B system.
Efforts and studies have been made to locate the sources of RFI using both ground-based and space-based measurements, as well as analyzing ADS-B data from affected flights (e.g. Liu et al. 2024, Chew et al., 2023). Despite these efforts, publicly available information on the exact specifics of GNSS spoofing remains limited, particularly with respect to which constellations and signal frequencies are targeted by spoofing attacks.
In this study, we present an analysis of GNSS signals collected in flight on a scheduled commercial flight from Europe to Amman, Jordan, in September 2024. The flight crew took a commercial receiver capable of tracking multiple GNSS constellations and frequencies and recorded the signals in the flight deck. This flight route crosses Cypriot and Egyptian airspace, regions that were known to be affected by GNSS spoofing during the period of the flight. The pilots confirmed that the position on their Electronic Flight Bags (EFB) was affected by spoofing during the flight. The data to be analyzed includes several navigation metrics such as carrier-to-noise ratio (C/N0), pseudoranges, carrier phase measurements, and potential alterations to the navigation messages for the GPS and Galileo constellations on the L1/E1 and L5/E5a frequencies.
In addition to the GNSS data, we analyze ADS-B data from the same flight to explore the correlation between GNSS spoofing and the performance of ADS-B, focusing on the availability of position messages and the associated navigation accuracy and integrity metrics, such as Navigation Accuracy Category for Position (NAC_p) and Navigation Integrity Category (NIC). This cross-analysis aims to provide insights into how spoofing affects the reliability of ADS-B position reports, which are critical for air traffic surveillance and situational awareness.
By analyzing real-world data from an active interference zone, this research aims to contribute to the development of robust spoofing detection techniques and mitigation strategies, which are essential for maintaining flight safety and the integrity of satellite-based navigation systems.
Felux, M., Fol, P., Figuet, B., Waltert, M., & Olive, X. (2024). Impacts of Global Navigation Satellite System Jamming on Aviation. NAVIGATION: Journal of the Institute of Navigation, 71(3).
Osechas, O., Fohlmeister, F., Dautermann, T., & Felux, M. (2022). Impact of GNSS-band radio interference on operational avionics. NAVIGATION: Journal of the Institute of Navigation, 69(2).
Liu, Z., Lo, S., Blanch, J., & Walter, T. (2024, January). Localizing the October 2022 Texas Jamming Incident Using ADS-B Data with an Improvement in Model Confidence. In Proceedings of the 2024 International Technical Meeting of The Institute of Navigation (pp. 524-531).
Chew, C., Roberts, T. M., & Lowe, S. (2023). RFI mapped by spaceborne GNSS-R data. NAVIGATION: Journal of the Institute of Navigation, 70(4).