GPS Jamming, Spoofing Fixes Still ‘Years Away’

SAN JUAN, Puerto Rico – Work on improving GPS receivers to detect and alleviate jamming and spoofing impacts on aircraft systems is “years away” from fruition, an avionics engineer said Feb. 13.

Speaking to the NBAA International Operators Conference (IOC2025), Honeywell Principal Applications Engineer David Woodcock said his company expects to introduce improvements to its MKV-A Enhanced Ground Proximity Warning System (EGPWS) and corresponding Epic avionics software by the second quarter of 2026. These will fix incorrect geometric altitude and false alerts and improve sensor selection by hybrid GPS/traditional inertial reference systems (IRS).

The avionics manufacturer list 35 business jet types that use the MKV-A EGPWS, including Bombardier, Cessna, Dassault, Gulfstream, Hawker and Learjet models.

Honeywell is also working with aircraft manufacturers and certification authorities on longer-term GPS antenna and receiver improvements but “these all require hardware and wiring changes to your aircraft,” Woodcock advised. “All of that needs to be developed and will take time. [The solutions] are easily several years away.”

Less intrusive software updates could provide monitors for detection and disabling of spoofed signals, with improved alerting, but also are years away.

“If we fix this at the source in the software, we don’t have to touch ground prox or weather radar—none of that has to be changed,” Woodcock said. “The problem with this is the standards don’t exist yet. We’re still looking at 2027-29 before the minimum operational requirements are formalized.”

Instances specifically of GPS spoofing—when radio frequency (RF) signals from GPS satellites are overpowered by counterfeit signals—have increased dramatically in the last two years and were a prominent topic at IOC2025. In a September 2024 report, the aviation crowdsourcing organization OpsGroup said 1,500 flights per day were being spoofed, up from an average of 300 flights per day at the start of the year.

Nearly all GPS spoofing incidents affecting civil aircraft at the time of the report were occurring in conflict zones and involved military units targeting hostile drones, GPS-guided munitions and shipping, OpsGroup said. The highest level of spoofing was in the eastern Mediterranean region, near Israel, Lebanon, Cyprus and Egypt. Other areas of significant spoofing included the Black Sea, western Russia and the India-Pakistan border.

“The greatest safety concern is the degraded functionality of the GPWS,” the working group that prepared the report states. “The system does not operate correctly after spoofing, even if GPS coverage is restored.”

“The number of false alerts is astounding,” the report adds. “There is an increasing normalization of risk. As a result, there was widespread apprehension in the Work Group that the decades-long work to reduce Controlled Flight Into Terrain accidents is at great risk of being undone.”

Spoofing Impact Is More Serious

Increasingly interconnected, avionics systems rely on GPS as a timing and position source and are especially vulnerable to its disruption. Woodcock described impacts on hybrid IRS, flight management system, EGPWS, and weather radar systems. The symptoms of GPS jamming—when signals from GPS satellites are overpowered by RF “noise” or interference from the ground—are minimal because avionics are designed to compensate for the loss of GPS, he said.

In the case of spoofing, “the symptoms are much more severe,” Woodcock said. “This is because when the minimum performance standards were developed in the nineties, nobody considered spoofing to this degree, so you’re pretty much left with very basic protections.”

Speaking of EGPWS effects, Woodcock added: “Because the signal is still considered good by the ground prox, [the system] will continue using it. You will notice a conflict in your depictions. The position and geometric altitude becomes inaccurate. The good news is that spoofing affects only the enhanced modes of the ground prox. You can turn off the terrain using the terrain button and you’ll be left with your classic modes which are all rad-alt and vertical speed-based.”

The FAA in January 2024 issued Safety Alert for Operators (SAFO) 24002, providing guidance to aircraft operators and manufacturers on recognizing and mitigating disruptions to GPS and other Global Navigation Satellite Systems. “You should have SAFO 24002 in your hip pocket before you enter contested airspace,” Bombardier Global 7500 Captain Daniel Galvin advised fellow pilots.

During a separate briefing on the Middle East region at IOC2025, Galvin described his own encounters with GPS spoofing.

“Spoofed information renders GPS position hundreds of miles off-course, which I personally experienced,” he said. “While transiting Cairo airspace, it showed my airplane over Amman, Jordan, over 150 miles away. What’s more insidious is where it can show you half-a-mile off, and then half-a-mile slowly grows to a mile, a mile-and-a-half, two miles.”

Galvin offered a number of tips for pilots should they transit known spoofing regions, including:

• Know your likely entry and exit points into spoofing areas. We spend a lot of time going and back and forth from the United States and from western Europe into India and the Middle East. We use the western route from Cairo and we know where we’re going to go in and where we’re going to come out.
• Consider declining direct routing so as to remain on an airway. You can always revert back to VOR navigation if you need it. One of the things that can happen is the spoofing can affect airplanes that have auto-tune for VORs.
• You will know the spoofing event is over when the correct time displays on clocks, groundspeed is consistent and altitude and position return to normal values.
• Unless you are able to prove with certainty that all systems are operating as normal you need to avoid RNP (Required Navigation Performance) approaches. This can also affect the look-ahead features on systems like TAWS (Terrain Awareness and Warning) and EGPWS.
• Advise air traffic control of prior spoofing. They will pay closer attention to your altitude and track on your flight. When you brief the approach, be sure to include discussion of possible false EGPWS alerts.

In his presentation, Woodcock listed the following GPS Jamming/Spoofing information sources.

Honeywell Service Information Letters (SIL): D202311004193, Effects of GPS Jamming/Spoofing on Avionics; D202309004138, Effects of GPS Jamming/Spoofing on EGPWS; D202408004460, Effects of GPS Jamming/Spoofing on Weather Radar Systems.

Gulfstream maintenance and operations letter All-MOL-23-0015 and aircraft specific jamming/spoofing procedure briefs.

Dassault Falcon Service Advisory FSA-35-50-009 and Falcon Portal GPS jamming and spoofing guidelines.

Embraer Flight Operations Letters 145-001-23, 170-003-23, 190E2-005-23.