Ground segment of GAGAN i.e. Indian Reference Station (INRES) at Delhi, Kolkatta, Guwahati, Portblair, Ahmedabad, Banglore, Jammu and Trivanthapuram is in place. Except Portblair, other stations have been connected to Indian Master Control Center (INMCC) with fiber optic cable in synchronous loop mode. Portblair is connected through dedicated satellite communication network. Its integration and connectivity test with seven INRES with INMCC have been completed. The INRES data is being received through fiber optic cable at INMCC Banglore for corrections and validation checks of the erroneous data. Preliminary Site Acceptance Test (PSAT) of GAGAN ground element was conducted in May 2006 with help of satellite emulator.

GAGAN is an Indian Space Based Augmentation System (SBAS). Airports Authority of India (AAI) and Indian Space Research Organization (ISRO) to provide the seamless navigation service for all the phases of fl ight over Indian airspace jointly undertake this project. The AAI’s efforts towards implementation of operational SBAS can be viewed as the first step towards introduction of modern CNS/ATM system over Indian airspace…

In order to provide seamless navigation to the world aviation community by airport service providers, the International Civil Aviation Organization (ICAO) has adopted a new strategy on the implementation of Future Air Navigation System (FANS) and use of non-visual aids for approach, and landing. The solution for the above requirements is Global Navigation Satellite System (GNSS). A stand alone GPS fails to provide the required navigation accuracy for all phases of the flight. Therefore, to achieve the required navigation accuracy, the core constellation i.e. GPS, GLONASS, and Galileo (under planning stage) needs augmentations to fulfill the GNSS, particularly in satellite-based augmentations such as WAAS (USA), EGNOS (Europe), MSAS (Japan), GRAS (Australia) and GAGAN (India). It also includes ICAO’s acceptance of an offer to make the Global Orbiting Navigation Satellites System (GLONASS) available for use by civil aviation. The ICAO Council had earlier accepted a similar offer concerning the GPS. These three satellite constellations (GPS / GLONASS / Galileo) are the key components of the GNSS. This article describes briefly, the different systems including GAGAN (India) and the status of GNSS.