Gagan Working

GAGAN provides augmented information for the GPS receivers to enhance the accuracy and reliability of position estimates.

GAGAN system’s architecture has two segments, one is ground segment and the other is space segment.  At present the ground segment consists of 15 reference stations spread all over India and three master control centres (two are in operation and one in shadow mode). These 15 reference stations are stationed at various fixed positions which receive GPS signals. The locations of reference stations are precisely chosen by the survey so that any errors in the received GPS signals can be detected.





The GPS information collected by these 15 reference stations is forwarded to the INMCC either by terrestrial or satellite communication network. At INMCC, GPS information is processed and correction (augmentation) messages are generated.

These correction (augmentation) messages are sent to INLUS (Indian Land Uplink Station) which further uplinks them to three geostationary communication satellites GSAT-8, GSAT-10 and GSAT-15.

The GEO satellites broadcast these correction messages on a GPS like signal. Any SBAS enabled GPS receiver can receive this GPS like signal having correction messages as an additional source for the calculation of user’s position with accuracy better than 7.6 meters can be achieved