1. Study: GPS interference in the Baltic Sea becoming more complex and stronger

• Mobile Measurement Uncovers Combined Tactics
• 30 Hours of Uninterrupted Attack
• Four Coordinated Interference Sources Active

The intense disruption activity of satellite navigation systems (GNSS) such as GPS in the southeastern Baltic Sea region has reached a more dangerous level. This is the result of a study by Polish researchers commissioned by the security firm Hensec, which has now been published. The study builds on earlier reports of massive GNSS interference in this strategically important region. However, it reveals a significant shift in the attackers’ approach: away from purely imprecise jamming towards coordinated, combined attacks of spoofing and active jamming that directly endanger navigation.

The new measurement campaign, conducted by experts from GPSPatron and the University of Maritime in Gdynia, differs methodologically from previous surveys that relied on stationary sensors on land. To more accurately map the real and dynamic threat to shipping in the operational area, the scientists installed a highly developed interference detector, the GP-Probe TGE2, directly on board a research vessel. This mobile measuring laboratory operated systematically throughout the southern Baltic Sea region for a period of almost four months, from June 23 to October 14, 2025, regularly approaching the maritime border with the Russian exclave of Kaliningrad (Königsberg).

Mobile Measurement Uncovers Combined Tactics

This maritime perspective allowed the researchers to capture effects that ships are actually exposed to and unprotected from. These have remained hidden from land-based observation posts due to the Earth’s curvature and signal shadowing. The data obtained paints an alarming picture of the current electronic warfare situation in the area. While previous analyses only showed large-scale jamming – i.e., blocking – of signals from multiple satellite constellations, the measurements now document a much more sophisticated and targeted tactic.

The attackers are therefore relying on a combination of GPS-L1 spoofing and simultaneous jamming. In spoofing, highly precise artificial satellite signals are generated and sent to the receiver, which can simulate a false position. This position is shifted by meters, misleading the crew. At the same time, the attackers actively disrupt the signals of competing constellations such as Glonass, Galileo, and Beidou.

This coordinated approach forces standard GNSS receivers to process only the faked GPS signals, as the real signals from other systems are suppressed. This constitutes a significant manipulation of ship navigation, which in the worst case can lead to collision courses and drifting into restricted areas.

30 Hours of Uninterrupted Attack

The intensity of these electronic attacks has reached new records. The strongest disruptions occurred in concentrated bursts from late June into July. During these phases, the overall availability of global satellite navigation temporarily dropped to 83.5 percent, posing a serious threat to the operational safety of cargo and passenger ships.

Over a four-day observation period, the scientists registered active spoofing attacks that systematically falsified the recorded ship position. They documented the most extreme incident in the first week of July, when a continuous spoofing attack was directed at ship navigation for almost 30 hours.

Such prolonged, intense disruptions pose a serious and direct security risk to all maritime traffic, as they massively impair position determination and course tracking and are difficult to detect as such. Precise spoofing signals are also difficult to expose through a plausibility check. The detailed analysis also reveals a complexity in the attack structure that strongly suggests central control and coordination. The researchers clearly identified that the interference does not originate from a single source but from four different, synchronously operating systems.

Four Coordinated Interference Sources Active

These included a dedicated GPS spoofer, two so-called chirp jammers that emit frequency-modulated interference signals, and a broadband analog jammer. The different spectra and bandwidths of these signals indicate that they are spatially separated systems that are activated in a coordinated manner to achieve maximum interference effect and to outwit receiver evasion mechanisms. Compared to previous findings, the technical interference landscape has thus changed significantly.

The mobile measurement platform documents a spatial trend: interference intensity increases considerably on the open sea. While in the port of Gdansk, for example, only weak interference was sometimes registered by civilian sources such as car jammers, the signal strength increased by up to 15 decibels on the open sea. This corresponds to an enormous increase in transmission power, which can only be achieved by powerful, apparently military systems. The clearest and most persistent interference values were recorded by the team on courses leading towards the Kaliningrad maritime border.

This confirms that the navigation zones at sea and the main shipping routes are most affected. The results underscore the need for shipping companies and ports to secure their navigation systems against such combined attacks and to actively promote alternative navigation methods such as independent, non-satellite-based inertial systems that use accelerometers or gyroscopes, for example. The experts warn: Only in this way can safety in maritime traffic in the Baltic Sea be sustainably ensured under the changing electronic conditions.

(vbr)

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This article was originally published in German. It was translated with technical assistance and editorially reviewed before publication.