Interference with GPS signals is becoming an increasingly common — and worrying — weapon of war

As the use of this warfare tactic grows, experts fear the impacts could reach far beyond the battlefields.

Twenty-four hours after the first US and Israeli attacks on Iran, ships in the region’s waters discovered that their navigation systems were malfunctioning, erroneously indicating that the vessels were at airports, a nuclear plant and on Iranian territory.

The location confusion was the result of widespread interference and spoofing of signals from global positioning satellite systems. Used by all parties in conflict zones to disrupt the path of drones and missiles, the process involves militaries and affiliated groups intentionally transmitting high-intensity radio signals in the same frequency bands used by navigation tools. Jamming results in disruption of a vehicle’s satellite positioning, while spoofing causes navigation systems to report a false location.

Although commercial vessels are not the target, electronic interference disrupted the navigation systems of more than 1,100 commercial ships in the waters of the United Arab Emirates, Qatar, Oman and Iran on February 28, the day of the first US and Israeli attacks on Iran, according to , a maritime intelligence company.

Interference and counterfeiting have also slowed shipping traffic through the Strait of Hormuz, a congested shipping route that handles about 20% of the world’s oil and gas exports and where precise navigation is essential, Windward data shows. Since then, traffic on this important waterway has been practically paralyzed, with ships being attacked and insurance companies canceling maritime coverage.

“What we are seeing in the Middle East Gulf right now is extremely dangerous for maritime navigation,” says Michelle Wiese Bockmann, the company’s senior maritime intelligence analyst. Windward says the interference has forced some tankers to reverse course or enter silent mode, a state in which signals from a ship’s Automatic Identification System (AIS) — which automatically transmits important information about a ship, such as its position, speed and rate of turn — are no longer transmitted or detected.

“We don’t know where the ships are. The objective of AIS is to avoid collisions”, says Bockmann. “When you have vessels washed ashore or thousands of nautical miles out to sea, that is deeply concerning and dangerous.”

In its analysis, Windward identified 21 new clusters where ships’ AIS were being blocked in the region in the first 24 hours after the start of the war with Iran. A day later, that number rose to 38, says Bockmann. Maritime data and analytics company Lloyd’s List Intelligence said it recorded , each typically lasting three to four hours, between the start of the war and March 3. Daily incidents have more than doubled, from 350 when the conflict began to 672 on March 2, the company said.

As the use of this warfare tactic grows, experts fear the impacts could reach far beyond the battlefields.

endemic problem

Interference or spoofing of signals used in global navigation satellite systems, or GNSS, is not a new phenomenon. Jamming has been a major problem for maritime and air transport since Russia’s 2022 invasion of Ukraine, during which drones were widely used in combat for the first time.

Bockmann describes the current problem as “endemic” in certain regions close to conflict, such as the Baltic Sea, the Black Sea and parts of the Middle East, where what he calls “grey zone aggression”, or military activity that is not overtly hostile, is common.

Ramsey Faragher, director and chief executive of the Royal Institute of Navigation in London, agrees, noting that jamming and spoofing navigation signals is an “easy and straightforward protection” against drone attacks. However, the resulting electronic haze interferes with the navigation systems of commercial vessels that are not involved in the conflict.

“We’ve known for decades that the signals from Space that civilians rely on are vulnerable to jamming and spoofing, it’s just that it’s never been such a serious problem before,” emphasizes Faragher, co-author of one on the impact of GNSS interference on maritime security.

“This has become a normal part of conflicts because small GPS-guided drones are being used much more widely than they were, say, 20 years ago,” adds Faragher.

In June 2025, electronic interference with navigation systems was considered a factor in the collision between two oil tankers, the Adalynn and the Front Eagle, off the coast of the United Arab Emirates, Bockmann and Faragher indicate. The operator of the Front Eagle.

Electronic interference with navigation systems is also a threat to aircraft flying routes in the affected regions. A plane carrying European Commission President Ursula von der Leyen failed to land in Bulgaria in September, forcing pilots to resort to paper maps. It was unclear whether the interference was deliberate, with the Kremlin denying 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, to get ahead of the threat.

Flight decks are seeing their navigation screens “literally moving away from reality,” says a commercial pilot, who declined to be identified because he is not permitted to speak publicly. The same source indicates that he and his colleagues have already experienced map changes, in which the aircraft’s location appears to indicate that it moves up to 1.6 km from the actual flight path, false altitude information that leads to phantom “climb” commands, and systems that suggest the aircraft was on a takeoff runway, a path that connects the runways to various airport facilities.

These incidents force pilots to rely on manual actions that increase the workload, often during the most exhausting moments of long-haul flights, he adds.

Why GPS is so vulnerable

There are several global satellite navigation systems, with the Global Positioning System (GPS), operated by the USA, being the best known and most used. The EU operates one, China has its own, and Russia has a system known as .

Publicly accessible GNSS signals are open in nature, and until recently, only military GNSS signals contained security features, according to the Royal Institute of Navigation report. Since last year, however, it has allowed users to authenticate the data they receive and know if it has been tampered with. However, generally speaking, GPS signals are easy to master because they weaken as they travel more than 20,000 kilometers to reach Earth from orbit, the report notes.

All navigation systems work in a similar way: a receiver calculates the location of something using radio signals from a constellation of satellites. To determine any given position, a GPS typically needs line of sight to four satellites.

The interference is often easy to detect on AIS tracking maps, which may appear to show vessels in an affected area moving in perfect geometric “circles,” Bockmann says. Another obvious indicator is when a ship’s position jumps to a fixed position on land, often an airport or base associated with the source of spoofing, according to the Royal Institute of Navigation report.

It is possible, the report notes, that manipulating the GPS signal could mimic a specific route, something that has been used by vessels seeking to avoid sanctions or fish in protected areas, and by pirates looking to divert cargo ships to unsafe locations for robberies or ambushes.

Test in the real world

On modern, highly automated ships, GPS interference can be difficult to detect. And while it’s perfectly possible to navigate using alternative tools, including radars, inertial systems like accelerometers and gyroscopes, visual surveillance and celestial navigation, younger sailors are often less familiar with these techniques and tools.

It’s a situation similar to how few young people today know how to drive a car with a manual gearbox, compares Bockmann. “This eliminates all extra resources and returns you to traditional navigation methods”, he says.

The impact of GPS interference also creates headaches for shipping companies in terms of compliance, adds Bockmann. For example, for ships whose signals are diverted to locations within Iranian territory, this attracts unwanted and unnecessary attention from banks, insurance companies and other companies monitoring for possible sanctions violations.

Faragher says the risks posed by GPS interference are compounded by the fact that many systems aboard modern vessels, unrelated to navigation, use GPS data to calculate position, speed and time. These systems include safety kits, such as equipment that sailors wear to help detect their location if they fall overboard.

“When they hit the water, the electronic components activate and turn on the GNSS, capture satellite signals and send their position,” explains Faragher. “If you fall overboard with one of these devices within a spoofing region, it is very likely that your true location will not be sent.”

Faragher is particularly concerned about the possibility of such a scenario playing out in the Iran war, as the .

“What I hope doesn’t happen is that a ship is sunk, the crew abandons ship and their rescue is delayed or interrupted because the location information transmitted in the event of an emergency is wrong due to interference and spoofing,” he says.

To date, the war unfolding in the region is perhaps the biggest real-world test of the resilience of maritime navigation and monitoring when satellite positioning becomes unreliable. There are solutions, such as enhancing receivers with anti-spoofing and encryption features, or installing a type of antenna specifically designed to protect against the effects of interference and spoofing, but upgrading and replacing existing systems requires time and money, highlights Faragher.

Alternative navigation tools that do not rely on GPS but that use quantum technology are also in development, but are still a long way from being used operationally.

“GNSS is a wonder of the modern world. You just turn it on and within a few seconds it determines your location to within one meter and the time to within a nanosecond,” says Faragher.

“Unfortunately, the luxurious era in which these signals were not the target of intentional interference has come to an end,” he adds. “We need to recover from this delay quickly.”