GPS Spoofing: Deceptive GPS lead over 20 planes astray in Iran

In the past two weeks, more than 20 airline and corporate jets flying over Iran strayed from its intended path after they were led off course by deceptive GPS signals sent from the ground, overpowering the aircraft’s own navigation systems. These misleading GPS signals affected various aircraft, including Boeing 777s, 737s, and 747s. One such Boeing 777 was so significantly diverted from its route that the crew had to inquire with the Baghdad Air Traffic Control, asking, “What time is it, and where are we?” This revelation comes from a report by Ops Group, a flight data intelligence website. Indian airlines such as Air India (AI), IndiGo, and Vistara frequently traverse this airspace on their journeys to destinations like San Francisco, Istanbul, Baku, and London. AI and IndiGo employ Boeing 777 aircraft for these routes, with IndiGo’s 777 aircraft operated by Turkish Airlines. Despite these concerning incidents, none of the three airlines or the Directorate General of Civil Aviation (DGCA) responded to queries of journalists. The cause of these troubles is known as GPS signal spoofing, described as the covert replacement of a genuine satellite signal with a manipulated one, causing a GPS receiver to provide incorrect position and time data. This definition originates from the US Radio Technical Commission for Aeronautics, which provides technical guidance for government regulatory authorities. While GPS signal interference of this nature has existed for over a decade, it’s the first time civilian passenger flights have encountered such a substantial threat. According to Ops Group, most of the recent GPS spoofing incidents occurred within Iran’s airspace, specifically in airway UM688. In response, the US Federal Aviation Administration (FAA) issued a memorandum to airlines titled ‘Iraq/Azerbaijan – GPS jamming and spoofing poses safety risk.’ The US civil aviation regulator cautioned that reported potential spoofing activities in Iraq and Azerbaijan pose a safety risk to civil aviation operations within the Baghdad and Baku flight information regions (FIR). A senior commander from an Indian airline, speaking anonymously, remarked, “We don’t use airway UM688, but we do traverse Iranian airspace. While we haven’t encountered spoofing, we did experience GPS jamming on a flight last week.” Unlike spoofing, GPS jamming is more easily detectable, as the erratic readings quickly reveal that GPS signals are being disrupted. The commander explained, “GPS jamming is relatively common during long-haul flights. It occurs when we enter Russia from the North Pole or approach areas like the Estonian border or Simferopol in Crimea. There are established procedures to handle jamming, relying on the aircraft’s navigation system, which doesn’t depend solely on GPS.” In contrast, spoofing is far more insidious. The aircraft’s GPS receiver cannot discern false GPS signals, and the flight management system accepts these counterfeits, causing the aircraft to deviate from its intended course. According to Capt Amit Singh, an air safety expert, “In most commercial jets, the aircraft’s navigation system will detect a disparity between the aircraft’s inertial reference system (IRS) position and GPS position. Pilots should deactivate GPS inputs; if they fail to do so and continue off course, air traffic control (ATC) will alert them.” The safety implications are significant. As Capt Singh pointed out, “UM688 is a heavily trafficked route, with many flights from West Asia to Europe and the US passing through. Some areas along this route are conflict zones with ongoing military activities, making straying from the flight plan extremely unsafe.” What baffled the targeted pilots was how the counterfeit GPS signals managed to manipulate the IRS, an independent system capable of computing position without relying on GPS signals. This is related to the functioning of modern airliner jets’ IRS systems, which typically have 2-3 independent IRS units and two independent GPS receivers used to compute a ‘GPIRS position.’ When these deceptive GPS signals reach the aircraft, they lead to an erroneous GPIRS position calculation. Capt Singh explained, “The aircraft’s system detects a discrepancy between IRS and GPS signals. If the crew does not disable the GPS signals at this point, the aircraft will deviate from its intended flight path.”