A plane carrying European Commission president Ursula von der Leyen was knocked off course this week because of GPS interference, according to the commission, and had to circle a Bulgarian airport before the pilot landed the aircraft assisted by paper maps.

Was the jet deliberately targeted? That question is “best asked to the Russians”, said commission spokesperson Arianna Podesta.

Von der Leyen was one of the highest-profile individuals to be caught by jamming of GPS navigation signals around the Baltics and eastern Europe.

Since Russia’s full-scale invasion of Ukraine in 2022, GPS interference has affected large areas of Europe, Ukraine and Russia, wreaking havoc with GPS-guided weapons and civilian navigation.

GPS satellites work by broadcasting position and timing data in continuous transmissions from orbit.

Receivers in vehicle satnavs, aircraft flight systems, and even precision weapons decode these signals from multiple satellites to calculate their position in space.   

Because these signals are weak — sent from medium Earth orbit — they are easy to interfere with. A transmitter near the receiver can jam it by simply broadcasting a stronger signal on the same frequency to drown out the GPS transmission.

In warfare, jamming these signals can ground aircraft and drones and cause weapons to miss their targets.

“Precision guidance munitions are severely affected — smart bombs are rendered dumb by GPS spoofing and jamming. Small drones face spoofing and jamming routinely,” said Todd Humphreys, professor of aerospace engineering at the University of Texas at Austin.

“There are many possible workarounds [for navigation],” he said, “But nothing is so cheap, globally accessible and complete as GPS/GNSS.”

GNSS is the generic term for global navigation satellite systems, while GPS is the specific name for the US system. Russia’s GNSS system is named Glonass, while China uses Beidou.

Financial markets, power grids and telecoms all rely on GPS to function, and outages or errors ripple through their systems.

Large-scale GPS interference is already unsettling the smooth running of everything from daily commutes to national security near conflict zones, and may one day become a global problem.  

 

Pilots reported that the GPS for a private jet carrying von der Leyen had faced interference while landing at Plovdiv airport in Bulgaria on August 31.

Russia denied involvement, though a “heat map” of GPS interference affecting aircraft instruments by GPSJam.org, shows Bulgaria and much of the Black Sea region as a jamming hotspot. 

But, unusually, the transponder onboard von der Leyen’s plane appears to have been able to establish the plane’s position and broadcast it throughout the incident.

The aircraft’s location was reported accurately and continuously on flight tracking websites because its so-called Automatic Dependent Surveillance–Broadcast (ADS-B) system appeared to be unaffected.

“It is peculiar, and I don’t have a good explanation for it,” said Tom Withington, an expert on electronic warfare with the Royal United Services Institute.

However, something did appear to go wrong on the aircraft. Radio traffic recordings posted online by an open source researcher show the pilots discussing “some issue with GPS scanner” with air traffic controllers, which meant they had to take an “unconventional” approach.

“If the pilots redirected due to jamming, it’s a near certainty that both of the GPS receivers used in the flight management system were jammed. Pilots don’t divert for no reason,” said Humphreys.

Experts pointed out that the GPS receiver used to fly the plane and the one used to broadcast its position via ADS-B are separate. Humphreys said it was possible that the receiver used to broadcast its position proved more resilient to jamming.  

 

Both Russia and Ukraine use a variety of electronic warfare weapons to neutralise the drones and precision-guided munitions of the other side, according to a senior UK military official, who described Ukraine as ‘‘a sea of electronic jamming”.

This jamming has spilled across Ukraine’s borders and affected much of eastern Europe and the Baltic region. Aircraft pilots now consult “heat maps” of likely GPS interference before they take off.

Military experts accuse Russia of harassing Nato aviation from an outpost in Kaliningrad — in 2024 two Finnair flights were forced by GPS jamming to turn around and return to Finland.

Meanwhile civilian aircraft in the Black Sea region, such as von der Leyen’s plane, have been affected by a jump in GPS outages due to apparent jamming, which may be coming from Russian-occupied Crimea.

Russian jammers range from massive, stationary Tobol dish antennas that can jam signals across large swaths of Europe, to truck-mounted Zhitel or Krasukha electronic warfare arrays that defend infantry units.

Erik Kannike, chief strategy officer for Estonian technology company SensusQ, said Russia’s Tobol system would be capable of targeting a single satellite uplink — as on von der Leyen’s plane — without wider disruption.

Other conflict areas have seen a similar trend. As many as 50,000 spoofing attacks on airports in the Middle East in 2024, which caused aircraft to misread their locations, originated most likely from Ein Shemer Airfield in northern Israel, according to a paper co-authored by Humphreys.

Many weapons supplied by the US to Ukraine that rely on GPS, such as Himars missiles and Excalibur GPS-guided artillery shells, have largely stopped working due to Russian jamming. 

“Basically there is no such thing as GPS anymore,” said Andriy Zvirko, head of strategy for Sine Engineering, a Ukrainian drone communications and navigation company. “On the battlefield, GPS as a reliable navigation tool has essentially disappeared.”

One of the problems specific to Ukraine, according to Withington, is that Nato’s encrypted GPS frequency — resistant to jamming — is withheld to prevent leaks to Russia.

Civilian users, including airlines, cannot access it, and even encrypted signals can be jammed by advanced systems

Still, jamming is energy intensive and hard to sustain, and Russia and Ukraine are both successfully sending missiles and drones into each other’s territory despite the interference.

Electronic warfare has forced both sides to innovate rapidly, using adaptive antennas and hopping radio frequencies. Many newer weapons systems can use at least two guidance systems in addition to GPS.

These include the high-tech descendants of gyroscopes used in early aircraft for inertial navigation. Another navigation technology is “optical guidance”, which matches 3D satellite maps with terrain.

“Despite years of research, no one has found a replacement for GPS that is cheap, globally accessible and also provides accurate timing, yet not vulnerable to jamming and spoofing like GPS/GNSS is,” Humphreys said.

Most promising, he said, are low Earth orbit satellite constellations such as Elon Musk’s Starlink, Amazon’s Kuiper, and Xona, a satellite positioning service.

Other official flights that have suffered GPS outages while flying near Russia include an aircraft carrying former UK defence minister Grant Shapps in 2024 and two flights carrying the chief of Germany’s armed forces Carsten Breuer. Breuer said he did not know whether the jamming targeted his aircraft or was part of a wider campaign.

GPS jamming is not capable of discriminating an individual vehicle or aircraft, experts say. “Spot” jamming is directed against individual frequencies in a given area, while “barrage” jamming targets a wider bandwidth to deny an adversary control and communications. 

Another tactic, however, is spoofing, or “meaconing” of GPS, which manipulates fake or real signals to mislead a receiver about its real position.

Unlike GPS jamming, which simply blocks signals, spoofing broadcasts counterfeit signals that appear legitimate but carry false data. “These can lead to very dangerous outcomes,” said one senior Nato military official.

Spoofing of this type may have been behind the crash of Liberian oil tanker Front Eagle in the Strait of Hormuz in June, and other incidents in which ships’ GPS signals were mixed up. 

Withington said: “You should always keep a map in your car.”