On June 27, 2026, an IndiGo Airbus A320 approached the runway at Udaipur airport. Observers saw nothing out of the ordinary from inside the cabin. However, the plane was not using traditional ground-based radio signals for guidance. Instead, it relied on corrections from satellites positioned far above the country. A system of 15 ground stations across India detects GPS inaccuracies and sends fixes via satellites over the equator. Under oversight from the Directorate General of Civil Aviation, this marked the first time a passenger jet in India landed with Gagan, the nation’s indigenous navigation aid. Smaller propeller-driven aircraft had achieved this earlier, but never a larger jet. Gagan, or GPS Aided GEO Augmented Navigation, was developed by the Indian Space Research Organisation and the Airports Authority of India. It functions as an enhancement to GPS rather than a separate positioning network like NavIC. The system corrects signal distortions caused by the ionosphere, which are especially variable over India. Fifteen precisely located ground stations compare GPS readings with their known positions and calculate adjustments. These are relayed through satellites such as GSAT-8 and GSAT-10. The aircraft applies the corrections and receives reliability alerts if needed. The approach used was an LPV procedure, providing both lateral and vertical guidance similar to an Instrument Landing System but without airport ground equipment. This capability could reduce costs at smaller airports and support more efficient flight paths.
