GPS jamming traced to Russia after flights over Europe suspended

Finnair has cancelled flights to Tartu in Estonia this month because of an ongoing GPS jamming attack – and there is evidence that the attack is being controlled from Russia.

A GPS jamming attack in the Baltic region that prompted a Finnish airline to pause some flights to Estonia for a month was probably launched from Russia, according to officials and an analyst.

A map indicating the likely location of the GPS jammer, shown by plotting the highest density of intersecting radio horizons of jammed aircraft
@auonsson/twitter Data: airplanes.live (CC-BY-SA)

The jamming incidents are part of an ongoing pattern of GPS interference in Europe. A NATO military official told New Scientist that the attacks have escalated significantly since Russia’s full-scale invasion of Ukraine in February 2022.

“It’s really never been a question of whether or not this is Russia – who else could it be?” says Dana Goward at the Resilient Navigation and Timing Foundation, a Virginia-based non-profit focused on protecting and augmenting GPS signals. Goward says that, since December, “we’ve had more and more observations and analysts determining that yes, it is Russia”.

One target of such GPS interference has been the country of Estonia that shares a border with Russia and was formerly invaded and occupied by the Soviet Union during the mid to late 20th century. Suspected Russian jamming of GPS signals in the airspace above Estonia’s capital Tallinn began in 2023 and “increased significantly” at the start of 2024, says Üllar Salumäe at the Estonian Transport Administration. “Currently we receive 20 to 30 reports from different aircraft daily about GPS jamming,” he says.

Such GPS jamming has not significantly impacted flight safety at the Tallinn Airport so far because of alternative navigational aids on the ground and radar coverage that help to guide aircraft, says Salumäe. But a smaller regional airport located in Estonia’s second largest city, Tartu, lacks ground-based navigation aids and air traffic control services to guide incoming and outgoing aircraft.

That is why GPS interference forced two flights operated by Finnair – Finland’s flag carrier airline – to abandon their landing approaches at Tartu Airport and turn back on 25 and 26 April. The airline has since decided to suspend flights between Tartu and the Finnish capital of Helsinki until 1 June.

There is no definite information available yet on the source of the jamming that forced the flight diversions, says Erko Kulu at the Consumer Protection and Technical Regulatory Authority in Estonia. But Estonia has previously identified similar GPS interference in Estonian airspace as originating from a source located in Russia’s Leningrad region.

Now an open-source intelligence analyst using the pseudonym Markus Jonsson has found additional evidence for the probable source of the attack. Jonsson traced the GPS jammer by mapping the “radio horizons” – essentially, circles representing the jammer’s maximum range – for each affected aircraft wherever they first reported the jamming. This revealed that the geographic area with the highest density of intersecting radio horizons, which is the most likely source of the jammer, is south-west of Saint Petersburg in Russia.

Such GPS disruptions have primarily been detected at high altitudes, and so have little effect on the ground-based GPS equipment that Estonia’s telecom networks, power grid and financial services systems rely upon, says Kulu. Still, Estonia’s minister of foreign affairs, Margus Tsahkna, described the latest GPS jamming incidents in Estonia as a “hybrid attack” by Russia and said that the government would raise the issue with the European Union and NATO.

Another transmitter that analysts have geolocated to Kaliningrad – a Russian enclave located between Lithuania and Poland – has been frequently jamming GPS signals in the airspace above Poland, Sweden and Germany. It launched a marathon 63-hour-long attack on GPS signals that impacted more than 1600 aircraft over Europe in March.

GPS interference has also impacted ships operating in the Baltic Sea. The Swedish Maritime Administration confirmed that it issued a navigational warning about GPS interference in the south Baltic Sea from 24 to 29 April.

“Every place else on the globe that this is happening to any degree – Ukraine, the Middle East, Kashmir and Myanmar – people are shooting at each other,” says Goward. “So I think it’s incumbent upon folks to resolve this before it devolves into an aircraft or ship accident, or people shooting each other.”