GAGAN: India’s Satellite-Based Augmentation System

GPS alone can’t safely land a plane. India built its own system to fix that — and now only three other regions in the world have one like it.

📑 Contents

Timeline.

Key Dates.

From Launch to Certification.

21 May 2011. GSAT-8 launches, India’s first satellite to carry a GAGAN navigation payload.
29 September 2012. GSAT-10 launches, adding a second GAGAN payload to the constellation.
2015. GAGAN becomes fully operational, certified by India’s DGCA.
10 November 2015. GSAT-15 launches, completing GAGAN’s 3-satellite constellation.
June 2026. The DGCA conducts India’s first satellite-based landing system approach on a commercial jet, using GAGAN.

What GAGAN Does.

Accuracy, Integrity, and Air Traffic Management.

Full Name. GAGAN (GPS Aided GEO Augmented Navigation) is India’s indigenous Satellite-Based Augmentation System (SBAS).
Developers. It was jointly developed by the Indian Space Research Organisation (ISRO) and the Airports Authority of India (AAI).
Accuracy and Integrity. GAGAN provides additional accuracy with real-time GPS corrections. It also provides integrity information, alerting pilots if a GPS signal is unsuitable for navigation.
Air Traffic Management. By improving position-reporting accuracy, GAGAN also allows for more uniform, high-quality air traffic management across Indian airspace.
Global Standing. Fully operational since 2015, GAGAN placed India among a select group of nations, alongside the US, Europe, and Japan, with an operational SBAS.
Equatorial First. GAGAN is the first SBAS certified for the equatorial region.

Architecture and Interoperability.

How GAGAN Is Built.

Infrastructure. GAGAN’s architecture includes 15 Indian Reference Stations (INRES) and 2 Indian Master Control Centres (INMCC). It also has 3 Indian Land Uplink Stations (INLUS), 4 communication networks, and 3 geostationary satellites carrying GAGAN payloads: GSAT-8, GSAT-10, and GSAT-15. (Source: PIB)
First Satellite-Based Landing. In June 2026, the DGCA conducted India’s first satellite-based landing system approach on a commercial jet, using GAGAN. (Source: PIB)
Interoperable. GAGAN is interoperable with foreign SBAS systems: the US’s WAAS, Europe’s EGNOS, and Japan’s MSAS. (Source: PIB)
GAGAN vs. NavIC. GAGAN differs from NavIC. GAGAN enhances GPS signals for aviation navigation and landing, across the Indian Flight Information Region. NavIC is India’s own independent regional navigation satellite system, providing positioning, navigation, and timing services. It covers India, and up to 1,500 km beyond its borders. See SciTech0014 — Navigation Technology for NavIC’s own story.
South Africa Link. In 2025, India signed an agreement with South Africa, to establish a NavIC reference station there, extending NavIC’s reach beyond national boundaries. (Source: PIB)

Beyond Aviation.

Why “Aviation Only” Is a Common Exam Trap.

Not Aviation-Only. Beyond aviation, GAGAN also supports maritime navigation, road transport, and railways. It also helps with disaster management, defence and security, telecommunications synchronisation, and surveying and geospatial mapping. A 2025 UPSC question tested exactly this “aviation only” misconception, and the correct reading rejects it.
Deliberate Interoperability. GAGAN’s interoperability with WAAS, EGNOS, and MSAS reflects a deliberate design choice. It isn’t a closed, purely domestic system. It was built to international civil aviation standards from the start, keeping Indian aviation compatible with the rest of the world’s satellite-navigation infrastructure.
Two Approaches. GAGAN and NavIC represent two different approaches to reducing India’s dependence on foreign satellite-navigation systems. GAGAN augments an existing foreign system, GPS. NavIC builds an independent one from scratch.
Related Effort. A related, more recent effort tackles time rather than position. See SciTech0091 — White Rabbit Technology and Indian Standard Time, on reducing India’s reliance on GPS for precision timing.