GNSS, jamming and spoofing: a clearly documented risk

The chapter on maritime cybersecurity provides a detailed description of the threats affecting GNSS systems. It recalls that associated attacks (spoofing, jamming) can lead to a loss of reliable positioning and to navigation errors, directly impacting maritime safety. It also emphasizes that users must “plan” (or at least anticipate!) “potential GPS disruptions, authenticate the reliability of received data and consider alternative positioning sources” (cyber chapter, pp. 278–280).

This brings me back to a case that is frequently cited in public and private reports, both in France and internationally: the collision that occurred off the coast of Oman between two vessels, which continues to be mentioned as an example of a collision “linked” to GPS spoofing.

What catches my attention is not the hypothesis itself.
GNSS interference in that region is documented and certainly not a new phenomenon. It obviously deserves to be taken seriously.

TL,DR: The BIMCO webinar, held on the 3rd of septembre 2025, was moderated by Jakob Larsen and featured NATO MARCOM officers Eric (French Navy) and Kadir (Turkish Navy) on GPS jamming and spoofing threats to maritime operations. Eric highlighted recent incidents: Ursula von der Leyen’s aircraft disrupted by jamming in Bulgaria, the merchant vessel Green Admire spoofed near Russia, and widespread interference in the Eastern Mediterranean linked to military activity. He emphasized that GNSS disruption is now a deliberate tool of hybrid warfare, not accidental.

It is likely that we will soon see many screenshots and analyses claiming that GPS spoofing is responsible… or that it is not.

As is often the case with this type of event, it is better to wait for the results of the investigation before drawing conclusions.

ESA has awarded a contract to the Swiss company CYSEC SA to identify possible approaches for strengthening the security of satellite-based ship tracking and positioning services used in the maritime sector. The main risks involve spoofing and jamming of satellite positioning systems (GNSS), as discussed previously here.

Since May 2019, the U.S. authorities have recorded numerous unlawful activities in the region. In two of those cases, GPS interference occurred at the same time as other suspicious events.

Today, the relatively low cost (a few tens of euros for a basic receiver), the miniaturization of hardware, and the widespread availability of GPS receivers have led many to assume that this global infrastructure will always be available. These advantages have also enabled the rapid expansion of GPS usage across many sectors where it was previously absent: healthcare, pet tracking, sports, agriculture, domestic robotics such as lawn mowers, photography, and even port cranes (see also this article). As a result, it is now difficult to estimate how many GPS receivers are currently deployed worldwide.

I have mentioned this several times before: GPS signals (and GNSS more broadly) are essential for the safe day-to-day operation of the maritime sector. We have already discussed the risks associated with spoofing or jamming of these signals, the specific risks related to autonomous maritime vehicles, as well as several real-world examples, including incidents in the Persian Gulf.

On March 10, 2020, the United States formally raised concerns with the Maritime Safety Committee of the International Maritime Organization (IMO) regarding the increasing number of disruptions affecting GPS and GNSS signals. The submission, available here, calls on the IMO to urgently address cases of jamming and spoofing that threaten the safety of ships and seafarers.