How electronic warfare is affecting civilians and aviation

About 36,000 feet in the air en route from Doha, Qatar, to Madrid, Víctor Alegre, a commercial pilot, heard his GPS alert him that he was 1,800 feet from the ground. He knew this was an error, but one he had never experienced before in his 33 years of flying as a commercial pilot.

This interruption is an example of GPS spoofing, a technology that has started to be used more commonly in modern warfare. GPS spoofing occurs when the GPS signal is intercepted by a third party and incorrect information is relayed back to the device.

The GPS spoofing incident Alegre experienced on March 27 aligns with data collected by SkAI Data Services, showing numerous flights that had spoofed locations to Cairo and Beirut.

Alegre shared footage with ABC News showing two separate sets of coordinates. The first one from the plane's internal Inertial Reference System (IRS) -- which can track the aircraft's location using the aircraft's internal systems -- and the second, the spoofed GPS. The GPS was showing the plane above Cairo, while the IRS was 200 miles away, toward Doha.

Alegre explained the situation was quickly noticed in the cockpit as the altimeter was giving an incorrect reading of 570 meters (1,870 feet).

"It was unbelievable, you know that you are cruising at 36,000 feet, and the highest mountain is 20,000 feet, so you realize that this was a spoof," Alegre told ABC News.

Alegre said they reported the issue to traffic control and disconnected the warnings after it had been ongoing for an hour.

In Alegre's video, the audio of the Ground Proximity Warning can be heard -- "Terrain ahead, pull up" -- which incorrectly indicated a detected collision with the terrain.

"It is not a big issue, as long as the system disregards the [spoofed] GPS position," but he added that this situation may be more dangerous when the spoofing occurs on planes that rely on GPS systems to navigate.

"The Israel region is by far the most impacted by GPS spoofing," said Benoit Figuet, co-founder of SkAI Data Services, which uses open-source data and machine learning to help the aviation industry with risk analyses.

While the primary use of the technology is for warfare, it impacts commercial and civilian pilots also transiting through the airspace, like Alegre, and can have significant security ramifications.

Figuet said that for pilots, "the inaccuracy introduced by spoofing into the GPS also affects altitude estimates," adding, "It can trigger false Ground Proximity Warnings, which are critical safety alerts that warn pilots when their aircraft is too close to the ground or an obstacle."

After Israel's strike on the Iranian embassy in Damascus, Syria, on April 1, Israel took precautionary measures against a possible retaliation from Iran, one of which was activating GPS jamming.

"Jamming is really blocking those signals so that you can receive GPS," Clayton Swope, deputy director of the Aerospace Security Project at the Center for Strategic and International Studies, told ABC News, while spoofing is "trying to confuse your receiver to think you're somewhere else."

Both technologies have been extensively used in the war in Israel and Gaza as well as the ongoing war in Ukraine.

On April 4, IDF spokesman Daniel Hagari released a statement saying that the IDF had "proactively activated GPS jamming" to "neutralize threats" in the area. The IDF did not comment further on the precautions.

On the same day, local media in Israel reported that GPS signals in the northern and southern regions of Israel were disrupted, causing cell phones and GPS devices to show false GPS readings.

Swope added that GPS spoofing and jamming are widely seen in various parts of the world at any moment, and it may be unclear why these incidents occur.

Electronic warfare is not new to battlefields around the world and has been used in wars dating back to before World War I, Benjamin Jensen, a senior fellow at the International Security Program at the Center for Strategic and International Studies, told ABC News.

But the increase in wars and technological advancements leads to more use of positioning systems, both defensively and offensively, Jensen added.

"[There has been] an increased trend towards more war, and it's become cheaper to conduct precision strikes in those wars," increasing the use of electronic warfare, Jensen said.