GPS jamming is emerging as an increasingly prevalent — and troubling — weapon of war
By Katie Hunt, CNN
(CNN) — Within 24 hours of the first US-Israeli strikes on Iran, ships in the region’s waters found their navigation systems had gone haywire, erroneously indicating that the vessels were at airports, a nuclear power plant and on Iranian land.
The location confusion was a result of widespread jamming and spoofing of signals from global positioning satellite systems. Used by all sides in conflict zones to disrupt the paths of drones and missiles, the process involves militaries and affiliated groups intentionally broadcasting high-intensity radio signals in the same frequency bands used by navigation tools. Jamming results in the disruption of a vehicle’s satellite-based positioning while spoofing leads to navigation systems reporting a false location.
Though commercial vessels are not the target, the electronic interference disrupted the navigation systems of more than 1,100 commercial ships in UAE, Qatari, Omani and Iranian waters on February 28, according to a report from Windward, a shipping intelligence firm.
Jamming and spoofing also slowed marine traffic moving through the Strait of Hormuz, a congested shipping lane that handles roughly 20% of the world’s oil and gas exports and where precise navigation is essential, Windward’s data showed. Traffic through the critical waterway has since ground to a near halt, with vessels being attacked and insurers dropping maritime coverage.
“What we’re seeing in the Middle East Gulf at the moment, is extremely dangerous for maritime navigation,” said Michelle Wiese Bockmann, a senior maritime intelligence analyst at the company. Windward said the interference forced some tankers to reverse course or go dark, a state in which signals from a vessel’s Automatic Identification System, or AIS — which automatically transmits key information about a vessel such as position, speed and rate of turn — are no longer broadcast or detected.
“You don’t know where ships are. The whole point of AIS is collision avoidance,” she said. “When you have vessels thrown onto land or thousands of nautical miles across the sea, it is deeply, deeply troubling and dangerous.”
Windward in its analysis identified 21 new clusters where ships’ AIS were being jammed in the region in the first 24 hours after the Iran war began. A day later that number had jumped to 38, Bockmann said. Maritime data and analytics company Lloyd’s List Intelligence said it had logged 1,735 GPS interference events affecting 655 vessels, each typically lasting three to four hours, between the start of the war and March 3. Daily incidents have more than doubled, rising from 350 when the conflict began to 672 by March 2, the firm reported.
As use of this warfare tactic grows, experts worry the impacts could reach far beyond battlespaces.
Endemic problem
The jamming or spoofing of signals used in global navigation satellite systems, or GNSS, isn’t a new phenomenon. Interference has been a major issue for shipping and aircraft since the Russian invasion of Ukraine in 2022, during which drones were widely deployed in combat for the first time.
Bockmann described the problem now as “endemic” in certain regions near conflict such as the Baltic Sea, Black Sea and parts of the Middle East, where what she termed “grey zone aggression,” or military activity that isn’t overtly hostile, is commonplace.
Ramsey Faragher, the director and chief executive of the Royal Institute of Navigation in London agreed, noting that the jamming and spoofing navigational signals is an “easy, straightforward shield” to protect against drone attacks. However, the resulting electronic fog messes with the navigation systems of commercial vessels that aren’t involved in the conflict.
“We’ve known for decades that the signals that civilians rely on from space are vulnerable to jamming and spoofing. It’s just that it’s never been this serious a problem before,” said Faragher, who coauthored a January report on the impact of GNSS interference on maritime safety.
“It’s just become a normal part of conflicts because small, GPS-guided drones are being used so much more widely than they were, say, 20 years ago,” Faragher added.
In June 2025, electronic interference with navigation systems was thought to be a factor in the collision between two oil tankers, Adalynn and Front Eagle, off the coast of the UAE, Bockmann and Faragher noted. The operator of the Front Eagle called it a “navigational” incident.
Electronic interference in navigation systems is also a threat to aircraft that fly routes in affected regions. A plane carrying the European Commission President Ursula von der Leyen was impacted by GPS navigation jamming while trying to land in Bulgaria in September, forcing pilots to reply on paper maps. It was unclear whether the jamming was deliberate, and the Kremlin denied any involvement.
The number of global positioning system signal loss events affecting aircraft increased by 220% between 2021 and 2024, according to data from the International Air Transport Association. Last year, IATA said that the aviation industry must act to stay ahead of the threat.
Cockpits are seeing their navigation displays “literally drift away from reality,” said a commercial pilot, who didn’t want to be identified because he was not permitted to speak publicly. He said that he and his colleagues have experienced map shifts, where the aircraft location appears to move up to 1 mile away from the actual flight path, false altitude information that leads to phantom “pull up” commands, and systems suggesting an aircraft was on a taxiway, a path that connects runways with various airport facilities, when taking off.
These incidents force pilots to rely on manual actions that increase workload, often during the most exhausting points of long-haul flights, he said.
Why GPS is so vulnerable
There are multiple global navigation satellite systems, with the US-run Global Positioning System, or GPS, being the best-known and most used. The EU operates a parallel system called Galileo, China has its own BeiDou satellites and Russia has a system known as GLONASS.
Publicly accessible GNSS signals are open in nature, and until recently, only military GNSS signal contained security features, according to the Royal Institute of Navigation report. Since last year, however, Galileo has a feature that allows users to authenticate the data they receive and understand whether it has been tampered with. Generally, however, GPS signals are easy to overpower because they weaken as they travel over 20,000 kilometers to reach Earth from orbit, the report noted.
The navigation systems all function similarly: A receiver calculates where something is using radio signals from a constellation of satellites. To determine any position, a GPS typically needs a line of sight from four satellites.
Interference is often easy to spot on AIS tracking maps, which may appear to show vessels in an affected area moving in perfect geometric “crop circles,” Bockmann said. Another obvious indicator is when a ship’s position jumps to a fixed position on land, often an airport or base associated with the spoofing source, according to the Royal Institute of Navigation report.
It is possible, the report noted, for GPS manipulation to mimic a specific route and it has been used by vessels seeking to evade sanctions or fish in protected areas, and by pirates wanting to misdirect cargo ships into unsafe locations for theft or ambushes.
A real-world test
On highly automated, modern ships, GPS interference can be hard to detect. And while it’s perfectly possible to navigate using alternative tools, including radar, inertial systems such as accelerometers and gyroscopes, visual watchkeeping, and celestial navigation, younger mariners are often less familiar with these techniques and tools.
It’s a similar situation to how few young people today know how to drive a stick shift car, according to Bockmann. “It takes away all the bells and whistles, and it makes you go back to old school ways of navigating,” she said.
The impact of GPS interference also creates compliance headaches for shipping companies, Bockmann said. For example, for the ships that have their signals diverted to sites on Iranian land, it draws unwanted and unnecessary attention from banks, insurers and other companies monitoring potential breaches of sanctions.
Faragher said that the hazards posed by GPS interference are compounded by the fact that many systems onboard a modern vessel unrelated to navigation use GPS data to calculate position, velocity and time. These systems include safety kits such as gear that mariners wear to help locate them should they fall overboard.
“When it hits the water, the electronics wake up and it turns on its GNSS, listens to the satellites and sends your position,” he said. “If you fell overboard with one of those things inside a spoofing region, the probability is incredibly high that your true location would not get sent,” he said.
Faragher is particularly worried about such a scenario happening in the Iran war, since commercial shipping vessels appear to have already been hit by missiles.
“What I’m hoping we don’t have happen is a ship is sunk, the crew abandon ship, and their rescue is delayed or disrupted because their emergency broadcast position information is wrong because of the jamming and spoofing,” he said.
The war unfolding in the region is perhaps the biggest real-world test to date of how resilient maritime navigation and monitoring are when satellite positioning becomes unreliable. Solutions do exist, such as enhancing receivers with anti-spoofing features and encryption, or installing a type of antenna that is specifically designed to protect against the effects of jamming and spoofing, but upgrading and replacing existing systems takes time and money, Faragher said.
Alternative navigational tools that don’t rely on GPS, but instead harness quantum technology, are also in development but remain a long way off operational use.
“GNSS is a wonder of the modern world. You can switch it on and within a few seconds, it works out where you are to within a meter and what time it is to within a nanosecond,” Faragher said.
“Unfortunately, the luxurious era of those signals not being messed about with intentionally is over,” he said. “We need to rapidly catch up.”
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