GNSS interference in the Baltic Sea has become more systematic and geographically widespread, according to Sweden’s transport authority. The manipulation of satellite navigation signals is affecting south-eastern Sweden and some of the region’s busiest air and maritime routes, reinforcing concerns about Russia’s hybrid activities along NATO’s northern flank.
Sweden is particularly affected around Gotland and Öland, as well as along routes connecting the country with Finland, Poland and the Baltic states. The Swedish Transport Agency (Transportstyrelsen) says the region is now experiencing both continuous jamming and increasingly organised spoofing.
Jamming prevents navigation devices from receiving a reliable satellite signal. Spoofing is more difficult to detect because it transmits false information, causing receivers to calculate an incorrect position or time.
“The clearest change in 2026 is that spoofing, meaning the transmission of manipulated signals, has become more systematic and geographically widespread, particularly since the end of May,” said Jörgen Andersson, head of the airspace and airports section at the Swedish Transport Agency.
Baltic Sea GNSS interference has become harder to detect
GNSS, or Global Navigation Satellite System, is the general term for satellite services that provide positioning, navigation and timing information. It includes the United States’ GPS, the European Union’s Galileo, Russia’s Glonass and China’s BeiDou.
Earlier interference in the Baltic region frequently caused signals to disappear entirely. The growing use of spoofing creates a different security problem because aircraft and ships may continue receiving apparently valid information that places them in the wrong location.
Manipulated positioning data can produce discrepancies between navigation instruments, incorrect time information and false terrain warnings. Pilots may need to rely on alternative navigation systems, while air traffic controllers can reroute flights or introduce additional safety procedures.
The disruption can also affect maritime navigation. Commercial vessels depend on satellite positioning for route planning and for the Automatic Identification System, known as AIS, which communicates their identity and location to other ships and coastal authorities.
Swedish officials have not reported a direct loss of operational control. Aircraft and ships have alternative instruments and procedures, but repeated interference increases workloads and reduces the reliability of systems that have become central to civilian transport.
The interference is part of a wider security threat
The Swedish authority describes the incidents as interference by a foreign power. The wider pattern has increasingly been connected to Russian electronic warfare activities.
In October 2025, the International Civil Aviation Organization formally condemned recurring GNSS radio-frequency interference originating from Russian territory. The decision followed evidence submitted by Sweden, Finland, Estonia, Latvia, Lithuania and Poland concerning disruptions affecting civil aviation in northern and eastern Europe.
The European Union has also placed GNSS disruption within a broader series of Russian hybrid operations. These include cyberattacks, sabotage, interference with critical infrastructure and covert activities intended to create insecurity without crossing the threshold of conventional military conflict.
Satellite navigation interference fits this model because it can disrupt civilian activities over a large area while making responsibility for each individual incident difficult to prove. Signals transmitted from Russian territory, including the Kaliningrad region, can reach international airspace and waters without requiring aircraft, ships or personnel to cross a border.
The strategic importance of the Baltic Sea has increased since Finland and Sweden joined NATO. The region is surrounded almost entirely by NATO members, but it also contains important Russian military facilities and routes connecting mainland Russia with Kaliningrad.
Sweden sees no clear decline in disruption
The Swedish Transport Agency received 142 reports of GNSS interference by 28 May 2026. It recorded around 336 during the corresponding period in 2025.
The authority has warned against interpreting the lower number as a clear improvement. The 2026 data remain preliminary, while the European Union Aviation Safety Agency has changed its reporting criteria, making direct comparisons difficult.
Officials say interference remains at a high level and that there have been no clear signs of a decline since late winter. The geographical expansion of spoofing may also make the phenomenon less visible in traditional reporting systems.
In July, the European Union Aviation Safety Agency updated its guidance for airlines, pilots, air traffic controllers and national authorities. The measures include new operational and training requirements, common communication procedures and preparations for maintaining sufficient air traffic control capacity during disruption.
NATO has also increased its attention to deliberate electromagnetic interference against civil aviation. The Alliance considers jamming and spoofing capable of causing delays, diversions and cancellations, while also affecting trade and the resilience of critical infrastructure.
The immediate consequences in Sweden remain manageable through alternative navigation procedures. The broader concern is that persistent satellite navigation interference is becoming a normal feature of the Baltic security environment. Its expansion shows how electronic warfare can place pressure on civilian infrastructure and transport networks even without a conventional attack.
