Study Material | Test Series
Drishti IAS
call1800-121-6260 / 011-47532596
Drishti The Vision Foundation
(A unit of VDK Eduventures Pvt. Ltd.)
Satellite-based Navigation System GAGAN Launched
Jul 16, 2015

The system known as GAGAN (global positioning system aided geo-augmented navigation system) is intended to provide accurate navigation services over the Bay of Bengal, South East Asia, Indian Ocean, Middle East, and African regions.

Key Features

  • GAGAN works by augmenting and relaying data from GPS satellites with the help of two augmentation satellites and 15 earth-based reference stations.

  • The process corrects any anomalies in the position data and gives accurate routes, landing guidance and time saving information to the pilots.

  • GAGAN also fills a vital gap between EU's European Geostationary Navigation Overlay Service (EGNOS) and Japan's Multi-functional Satellite Augmentation System (MSAS) coverage areas.

  • The system utilises the satellite-based wide area augmentation system (SBAS) technology which has been developed by Raytheon.

  • GAGAN has been jointly developed by the Indian Space Research Organisation (ISRO) and Airports Authority of India (AAI). 

  • The system has been completed in 15 years at a total cost of Rs.774 crores.

At any given time there are 10-11 GPS satellites over India. The GPS co-ordinates are useful but not always accurate. The augmentation satellites with GAGAN payload and the earth reference stations give us a clear and more accurate data for navigation and other purposes.

Exact Air Route Guidance

■ GAGAN is intended to serve as a low-cost substitute for Instrument Landing System (ILS) and provide very accurate route guidance for the aircraft to save time and fuel.

■ Fuel cost is a major consideration in the Indian aviation scenario as 45-50 percent of total cost is dependent on it. 

■ Fuel in India is nearly 50-55 percent costlier than in other neighbouring countries like Singapore or Dubai due to the addition of state levies ranging from 3-35 percent. 

■ Accurate guidance for planning shorter routes and safer landing patterns is expected to provide the aviation sector cost-saving options.

■ The technology has one major drawback that only those aircraft that are fitted with SBAS will be able to use the new technology.

Support to Indian Railways

♦ GAGAN will also provide navigational support to Indian Railways.

♦ ISRO will provide satellite-generated information to the railways through space technology-based tools that will provide safety at unmanned level crossings.

♦ There are host of requirements for using GAGAN in railways. ISRO is providing some solutions.

♦ At some places the railway tracks are under stress. If water accumulation happens, then based on digital elevation model data, other host of information which they generate, can be given.

♦ There is specific information provided for aligning the railway tracks, particularly in mountainous regions, and also identifying tracks which are most stable when going through tunnels. In all these things, space technology is useful.

♦ ISRO is also trying to provide space technology-based tools for enabling Railways to deal with unmanned level crossings.

♦ With the use of GAGAN software system, a train would know the location of any unmanned level crossing and soon a warning signal can be given.

♦ As soon as the warning signal will be given, the train's hooter will automatically start when it comes near an unmanned crossing.

♦ The GAGAN signal is being broadcast through two Geostationary Earth Orbit (GEO) satellites—GSAT8 and GSAT10.


Helpline Number : 87501 87501
To Subscribe Newsletter and Get Updates.