Mumbai: Fake GPS signals from an unknown source on the ground in the Iran-Iraq area misdirected at least 20 airline and corporate jets in the last fortnight, media reports said, citing flight data intelligence crowdsourcing website Ops Group.

Forbes reported that the site, which boasts of a membership of 8,000 pilots, flight dispatchers, schedulers, and controllers, started reporting the GPS spoofing incidents since Monday.

The fake GPS signals sent from the ground took over the aircraft’s inbuilt navigation, OPSGROUP stated.

Earlier this week, Ops Group reported that, “[Twelve] separate reports have been now received by OPSGROUP, and in most cases the [Inertial Reference System] becomes unusable, VOR/DME sensor inputs fail, the aircraft UTC clock fails, and the crew have been forced to request vectors from ATC to navigate.”

Since then, reports of GPS spoofing have risen to 20. In one such incident Embraer 650 business jet crew en route from Europe to Dubai “nearly entered Iran airspace (OIIX/Tehran FIR) with no clearance” after both GPS navigation units aboard the airplane and GPS signals to both pilot/co-pilot iPads” were lost.

The crew reported that the Inertial Reference System (IRS), an independent, standalone system that can compute position without GPS signal’s help, didn’t work anymore.

According to the Times of India, this is largely related to the functioning of the IRS system in modern commercial jets. Each plane is equipped with 2-3 separate IRS units and two independent GPS receivers to determine the aircraft's position. However, since IRS can be susceptible to inaccuracies, many modern commercial jets use inputs from both IRS and GPS to calculate a more reliable 'GPIRS position'.

TOI quoted Captain Amit Singh, an air safety expert, as saying, “The aircraft system will show a disagreement between IRS and GPS signal and if at this point crew do not disable the GPS signals, the aircraft will be steered off its flight path.”

The Forbes report cited Ops Group as saying that airplanes, both commercial and business, that traverse Airway UMB688 in northern Iraq (a major air route connecting Europe and the Middle East) have encountered total failures in their navigation systems due to deceptive GPS signals. These incidents seem to involve more complex cyber elements beyond simply substituting accurate GPS position data with misleading coordinates.

In a separate incident, a Bombardier Challenger 604 business jet needed continuous ATC radar guidance to reach its destination in Doha, Qatar, as it experienced a loss of GPS signal.

According to Times of India, Ops Group said in its report that among aircraft waylaid by rogue GPS signals were the Boeing 777, 737 and 747. The report added that a targeted 777 was led so much off course that the crew was forced to ask Baghdad ATC, “What time is it, and where are we.”

Indian carriers Air India, IndiGo and Vistara overfly this airspace en route destinations like San Francisco, Istanbul, Baku and London. Air India and IndiGo operate 777 on these routes, with IndiGo’s 777 aircraft operated by Turkish Airlines, according to TOI.

Time of India quoted a senior commander of an Indian career, who requested anonymity, as saying, “We don’t fly airway UM688, but we do overfly the Iranian air. We haven't experienced spoofing but, on a flight, last week we experienced GPS jamming.”