GPS Aided Geo Augmentation Navigation (GAGAN)
It is a planned implementation of Satellite Based Navigation System (SBNS) developed by Airports Authority of India (AAI) and ISRO. GAGAN is expected to provide a civil aeronautical navigation signal consistent with International Civil Aviation Organization (ICAO) Standards and Recommended Practices as established by the Global Navigation Satellite System Panel. GAGAN was launched in August 2010. With this India has become the 4th Country in the World to have satellite based navigation system. It is a system to improve the accuracy of a GNSS receiver by providing reference signals.