All about GPS spoofing and how it throws flights off track | Explained

GPS spoofing occurs when fake satellite signals are transmitted to an aircraft’s navigation system.

With the government on Monday confirming that there were instances of GPS spoofing in and around Delhi's Indira Gandhi International Airport (IGIA), there  is growing fear surrounding the incident and whether it has the ability to jeopardize routine flight functioning.

Civil Aviation Minister Kinjarapu Rammohan Naidu, in a written reply in the Rajya Sabha, said that the spoofing incidents occurred during approaches using GPS-based landing procedures on Runway 10, prompting pilots to switch to contingency protocols. Naidu said that multiple flights approaching the airport reported GPS spoofing.

Naidu's statement comes after several aircraft approaching Delhi airport reported spoofing incidents, with navigation systems showing false locations up to 60 nautical miles away. Some flights were forced to divert to nearby cities.

GPS spoofing involves a radio transmitter near a target that interferes with the actual GPS signals being transmitted. GPS signals are often weak and transmitted through satellites. A stronger radio transmitter can be used to override the weaker signal and send illegitimate coordinates and information to the receiver.

Spoofing is a type of GPS interference. It involves a device transmitting signals on the same frequencies used by GPS satellites, blocking the receivers from acquiring or maintaining the right satellite signals.

Unlike jamming, another type of GPS interference which disrupts signals entirely, spoofing deceives the receiver into trusting false data. In jamming, the aircraft loses its positioning, while in spoofing, pilots get wrong signals about their locations. Both jamming as well as spoofing can cause significant disruptions in aircraft navigation systems.

Over the years, GPS spoofing has transformed into a threat, as the malpractice is now being used against ongoing operations due to the easy availibity of expensive hardware and software which is capable of sending fake GPS signals.

New Delhi's Indira Gandhi International (IGI) Airport on November 7, witnessed a technical issue which affected the air traffic control (ATC) system, in turn disrupting more than 800 flight operations and causing delays across the Indian airspace. According to a Times of India report, the IGI Airport in Delhi witnessed multiple GPS spoofing incidents over the last few days, which contributed to the flight operation disruption.

To ensure unhindered flight operations, New Delhi continues to maintain a Minimum Operating Network (MON) of ground-based navigation and surveillance systems, a redundancy model also used globally. This network serves as a failsafe in case of satellite-based system failures.

The Airports Authority of India (AAI) has also sought support from the Wireless Monitoring Organisation (WMO) to trace the source of interference. A high-level meeting directed the WMO to deploy more resources and investigate suspected transmission zones identified by DGCA and AAI.