Surge in GPS jamming and spoofing incidents: How aviation sector is responding to this clear, growing threat

India is not alone though, as GNSS interference is one of the key challenges that the global aviation industry has been grappling with over recent years in various parts of the world. While there are mitigation measures, fallbacks, and redundancies to prevent significant harm to flight safety from GPS jamming and spoofing, it is a risk that is clear and present, and also evolving.

Spoofing and jamming of these crucial signals could potentially disrupt navigation, lead to misrouting of aircraft, and reduce the distance between aircraft. As per Europe’s aviation regulator EASA, GNSS interference has become a significant safety risk, particularly in geographical areas surrounding conflict zones and the eastern Mediterranean, West Asia, Baltic Sea, and the Arctic area, where it can increase pilots’ and air traffic controllers’ workload.

According to global airline trade association IATA, the number of GPS signal loss events jumped by 220 per cent between 2021 and 2024, as per the data from its Global Aviation Data Management Flight Data eXchange (GADM FDX). And with continued geopolitical tensions, it is difficult to see this trend reversing in the near term, the association noted. From August 2021 to June 2024, the FDX programme member airlines experienced over 580,000 GPS signal loss instances of around 18.4 million flights processed by the programme. The number has evidently gone up since IATA published this data.

GNSS interference: Jamming and spoofing

Aircraft depend on global navigation satellite systems (GNSS) for position, navigation, and timing (PNT) information, which is key to aircraft and air traffic management operations. The American Global Positioning System (GPS) is the most popular GNSS, and the terms are often used interchangeably. But there are other GNSSs as well, like Europe’s Galileo, Russia’s GLONASS, and China’s BeiDou.

These systems include ground infrastructure and satellite constellations that provide PNT information by determining the position of a GNSS signal receiver. Aircraft are equipped with these receivers, just like modern mobile phones and vehicles equipped with navigational aids. While these systems have a high degree of accuracy, satellite navigation signals are weak and, therefore, vulnerable to interference.

In the context of aircraft, GNSS interference can broadly be classified into two categories—jamming and spoofing. Put simply, jamming involves overpowering GNSS receivers with strong radio interference, making the equipment GNSS-based navigation unusable for some time. While this type of interference can be accidental and unintended, or a result of natural causes like solar storms interrupting signals, a bulk of instances experienced by aircraft are deliberate.

Spoofing is a lot more serious than jamming, or a disruption in signals. GNSS or GPS spoofing is a deliberate act that involves transmitting counterfeit lookalike signals to deceive the receiver into believing that the aircraft position or time, or both, are not what they are supposed to be. This could cause abnormal behavior by certain aircraft systems, and unwarranted warnings—like that of terrain or low altitude—being sounded in the cockpit regarding. Spoofing essentially tells the aircraft that it is where it is not supposed to be, and can create confusion in the cockpit.

“Airspace users rely on the normal functioning of aircraft systems, including automated monitoring, caution, and warning sub-systems. Avionics such as Flight Management Systems (FMS) require GNSS for navigation and timing. GNSS position is also used by the Terrain Avoidance Warning System (TAWS) or Enhanced Ground Proximity Warning Systems (EGPWS). Therefore, interference-free GNSS PNT service is essential for flight safety,” IATA said in a safety risk assessment document published in September 2024.

Countering the growing threat

While theoretically, such interference could pose a credible threat to flight safety, pilots are adequately trained to identify the jamming or spoofing, and react calmly and methodically, essentially by cross-referencing the faulty GNSS data with independent data from other systems on the aircraft and on the ground, and air traffic control inputs. They can then switch to other navigational aids and systems that are independent of the GNSS or GPS. In some extreme cases, though, such interference has resulted in rerouting and even diversion of flights.

According to experts, given that modern aircraft have multiple sensors and ways to establish their position, speed, and altitude, pilots have sufficient resources at their disposal to identify the correct PNT data.

But how do pilots know that the aircraft is being targeted? Common indications of GNSS spoofing include inconsistencies in aircraft position, abnormal differences between ground speed and actual airspeed, sudden changes in time displayed in the aircraft, and false terrain avoidance alerts, among others. But if the spoofing attack is highly sophisticated, signs can be too small to be noticed by aircraft systems and the flight crew immediately. Jamming, however, can be diagnosed relatively easily in most cases as the GPS signals would be overwhelmed and even lost.

Pilots monitor the flight path on a regular basis, using multiple navigation systems. This means that when the GNSS data is untrustworthy, they can spot the problem and switch to other systems, like the Inertial Reference System (IRS), which is self-contained and doesn’t require external data to calculate the aircraft’s location. IRS does the computation based on data and location entered before take-off, and through a combination of lasers, gyroscopes, and accelerometers while the plane is airborne. While spoofing and jamming have emerged as clear threats to aviation safety, the threat is known, understood, and pilots are trained to identify and respond appropriately.

“Whilst the GPS signals used by aircraft can be spoofed, it would take a sizable and advanced effort to both spoof the signal and negatively affect the flight. Aircraft cross reference position information with other data sources to verify its accuracy. GPS signals in commercial aviation tend to be used together with the Wide Area Augmentation System WAAS for general navigation and the Ground Based Augmentation System (GBAS) during precision approaches to airports. At a very basic level, crews can also revert to inertia-based navigation systems to determine and verify their positions,” flight tracking service Flighradar24 said in a blog post.

Existing ground-based systems to the rescue

As aircraft use of GNSS is subjected to increasing levels of interference, airlines and the broader aviation ecosystem are becoming increasingly dependent on conventional ground-based navigation aids (GBNAs) as a back-up to the loss of GNSS capabilities. According to IATA, these Minimum Operating Networks (MON) will be a necessary mitigation until reliable system capabilities can be developed to suitably protect against GNSS interference.

“States and air navigation services providers (ANSPs) are encouraged to re-evaluate GBNA infrastructure under their control and establish a MON that facilitates continued safety of flight in circumstances where GNSS can potentially be unreliable or unavailable,” IATA said.

India, too, is ensuring that MONs are being retained to counter the threat from GNSS spoofing and jamming.

“Minimum Operating Network (MON) consisting of Conventional (ground-based) Navigation and Surveillance Infrastructure are retained in accordance with global best practices. India is participating in global platforms to keep itself abreast of the latest methodology & technology for timely implementation of the same,” Civil Aviation Minister K Rammohan Naidu said Monday.

Between November 2023 and February 2025, over 450 incidents of GNSS interference were reported in India’s border regions, mostly around Amritsar and Jammu, the government had informed the Parliament earlier this year. The sphere of these incidents, however, appears to be expanding deeper into the country.

“Some flights reported GPS spoofing in the vicinity of IGIA (Indira Gandhi International Airport), New Delhi while using GPS based landing procedures, while approaching on RWY 10 (Runway 10). Contingency procedures were used for GPS spoofed flights approaching to RWY 10. There were no effects on movements of flights, on other runway ends having conventional navigational aids being operational,” Naidu informed the Rajya Sabha on Monday.

On spoofing and interference incidents at other Indian airports, Naidu said that after DGCA made it mandatory for such incidents to be reported in 2023, regular reports are being received from major airports in India. “GNSS Interference Reports are being received from Kolkata, Amritsar, Mumbai, Hyderabad, Bangalore and Chennai airports,” the minister said but did not elaborate on the time period during which these incidents occurred.