GAGAN

GAGAN stands for GPS Aided GEO Augmented Navigation. It is an Indian satellite-based augmentation system (SBAS) developed by the Indian Space Research Organisation (ISRO) with the Airports Authority of India (AAI) and support from Indian aviation authorities. The system provides navigation corrections and integrity information to improve the accuracy, integrity, and availability of GPS signals over the Indian region. GAGAN is designed to enable higher precision in instrument flight procedures and to enhance en-route navigation and air traffic management for civil aviation, with potential benefits for other GNSS users in the area.

The architecture of GAGAN includes a space segment and a ground segment. The space segment consists of a geostationary satellite carrying an SBAS payload that broadcasts augmentation messages to user receivers. The ground segment comprises a network of reference stations spread across the region, a Master Control Center to process the reference data and generate corrections, and a monitoring and management center to ensure system integrity. The augmentation messages are transmitted on L-band frequencies and are intended for compatible GNSS receivers to apply in real time.

GAGAN became operational in the 2010s and has received certification from India's Directorate General of Civil Aviation (DGCA) for use in specified aviation procedures within Indian airspace. It is part of India's modernization of its air navigation services and is modeled on other SBAS programs such as WAAS and EGNOS. By improving GNSS performance, GAGAN supports safer and more efficient flight operations and can benefit other sectors that rely on precise positioning and timing.