The GPS-aided GEO augmented navigation (GAGAN) is an implementation of a regional satellite-based augmentation system (SBAS) by the Government of India. It is a system to improve the accuracy of a GNSS receiver by providing reference signals. The Airports Authority of India (AAI)'s efforts towards implementation of operational SBAS can be viewed as the first step towards introduction of modern communication, navigation and surveillance / air traffic management system over the Indian airspace.
The project has established 15 Indian Reference Stations (INRES), 2 Indian Master Control Centre (INMCC) and 3 Indian Land Uplink Station (INLUS) and installation of all associated software and communication links. It will be able to help pilots to navigate in the Indian airspace by an accuracy of 3 m (9.8 ft) and will be helpful for landing aircraft in marginal weather and difficult approaches like Mangalore International and Kushok Bakula Rimpochee airports.
