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GAGAN (GPS Aided GEO Augmented Navigation)
- Context: GAGAN (GPS Aided GEO Augmented Navigation) is India’s indigenous Satellite-Based Augmentation System (SBAS), jointly developed by ISRO and the Airports Authority of India (AAI) to improve GPS accuracy, enable safe satellite-based aircraft navigation and landing, support other sectors, and strengthen India’s self-reliance in satellite navigation.
About GAGAN
- Full form: GPS Aided GEO Augmented Navigation (GAGAN)
- Developed by: ISRO + Airports Authority of India (AAI)
- Type: Satellite-Based Augmentation System (SBAS)
- Objective: Improve GPS accuracy and provide integrity information for aviation safety
- Operational since: 2015
- India’s status: Among few countries (USA, Europe, Japan) with SBAS
Purpose / Importance
- Enhances GPS accuracy for aircraft navigation
- Provides real-time correction of GPS error
- Gives integrity alerts if GPS signal is unreliable
- Ensures safer aircraft landing and navigation
- Supports India’s goal of Aatmanirbhar Bharat (self-reliance)
Key Infrastructure
- 15 Indian Reference Stations (INRES): Monitor GPS signals
- 2 Indian Master Control Centres (INMCC): Process data and generate corrections
- 3 Indian Land Uplink Stations (INLUS): Send corrections to satellites
- 4 Communication Networks: Connect all systems
- 3 Geostationary Satellites: GSAT-8, GSAT-10, GSAT-15 (carry GAGAN payloads)
Satellite Features (Important Concept)
- Geostationary satellites appear fixed over Earth
- They orbit at the same speed as Earth’s rotation
- Broadcast corrected navigation signals continuously
Indian Navigation Systems
- GAGAN: Enhances GPS (aviation-focused)
- NavIC: India’s indigenous navigation system for positioning, navigation, timing

