Desi Gagan enables 1st satellite-guided jet landing in India
An Indian jet aircraft completed the country's first satellite-guided precision landing using the indigenous GAGAN (GPS Aided GEO Augmented Navigation) system, marking a milestone in India's civil aviation navigation infrastructure.
The landing used the LPV (Localizer Performance with Vertical Guidance) procedure — a precision approach category that allows descent as low as 200–250 feet above the runway using only satellite-based navigation signals, without dependence on conventional ground-based Instrument Landing System (ILS) infrastructure.
This achievement extends GAGAN's demonstrated capability from turboprop aircraft (the first GAGAN-aided LPV landing was by an IndiGo ATR-72 at Kishangarh Airport, Rajasthan, in April 2022) to jet aircraft, expanding the system's practical aviation utility.
GAGAN is jointly developed and operated by the Airports Authority of India (AAI) and the Indian Space Research Organisation (ISRO), making India one of only four countries globally with an operational Satellite-Based Augmentation System (SBAS).
The system addresses a critical infrastructure gap: hundreds of Indian airports lack expensive ILS ground equipment, and GAGAN LPV approaches enable safe landings in low-visibility and marginal weather conditions without such hardware.
GAGAN — India's Satellite-Based Augmentation System (SBAS)
GAGAN stands for GPS Aided GEO Augmented Navigation. It is India's implementation of a regional SBAS — a system that receives GPS signals, detects errors (primarily caused by ionospheric disturbances), computes correction messages, and broadcasts them to aircraft via geostationary satellites, improving GPS accuracy from tens of metres to approximately 3 metres.
Key Details
- Jointly developed by: Airports Authority of India (AAI) and Indian Space Research Organisation (ISRO); built with technical collaboration from Raytheon (US).
- Signal broadcast via: GSAT-8 and GSAT-10 geostationary satellites.
- Accuracy: Navigation within 3 metres; enables precision approach LPV procedures.
- Coverage: Indian FIR (Flight Information Region) with GEO footprint extending from Africa to Australia; potential for regional expansion.
- LPV service specifications: 40-metre lateral limit; descent to 200–250 feet above runway; requires SBAS-capable avionics.
- Ionospheric correction model: ISRO GIVE Model-Multi-Layer Data Fusion (IGM-MLDF) — developed indigenously.
- India's distinction: First country in the Asia-Pacific region to have an operational indigenous SBAS; only fourth globally (after WAAS/USA, EGNOS/Europe, MSAS/Japan).
The first jet landing confirms GAGAN's progression from experimental validation to operational jet-category capability — a key threshold for commercial airline deployment at tier-2 and tier-3 airports lacking ILS.
Instrument Landing System (ILS) vs SBAS/LPV
The Instrument Landing System (ILS) is the conventional ground-based precision approach aid, requiring expensive transmitter infrastructure at each runway. SBAS-based LPV approaches replicate ILS-equivalent precision using space-based signals.
Key Details
- ILS categories: CAT I (200 ft decision height, 550 m visibility), CAT II, CAT III (near-zero visibility) — each requires progressively more expensive ground infrastructure.
- LPV approaches: Provide ILS CAT I equivalent precision (decision height ~200 ft) without any ground transmitter; infrastructure cost is near-zero at the airport.
- India has 65 LPV procedures certified by AAI as of 2022, covering airports that previously could not offer precision approaches.
- DGCA (Directorate General of Civil Aviation) is the regulatory authority overseeing the certification of SBAS approach procedures in India.
- UDAN (Ude Desh ka Aam Naagrik) scheme aims to connect underserved airports — GAGAN LPV directly enables safer operations at these typically infrastructure-light regional airports.
A jet-certified GAGAN LPV capability unlocks the use of regional jet aircraft (not just turboprops) at India's smaller UDAN-scheme airports, which is a transformative step for regional connectivity policy.
NavIC — India's Own Satellite Navigation Constellation
NavIC (Navigation with Indian Constellation), formerly IRNSS (Indian Regional Navigation Satellite System), is India's independent satellite navigation system — distinct from GAGAN, which augments the US GPS.
Key Details
- NavIC coverage: Primarily India and ~1,500 km around it (regional system); 7 operational satellites.
- Accuracy: ~5 metres for Standard Positioning Service; ~20 cm for Restricted Service.
- GAGAN vs NavIC: GAGAN augments GPS signals for aviation precision approach; NavIC is a standalone navigation solution for broader use cases (transport, fishing, disaster management, defence).
- Long-term integration of NavIC signals into SBAS-type systems is under development as India expands its independent space-based infrastructure.
- Nodal agency: ISRO for NavIC; AAI + ISRO jointly for GAGAN.
Both GAGAN and NavIC represent India's strategic investment in space-based positioning, navigation, and timing (PNT) sovereignty — reducing dependence on US GPS or other foreign systems for critical national infrastructure.
- GAGAN full form: GPS Aided GEO Augmented Navigation.
- Type: Satellite-Based Augmentation System (SBAS).
- Developed by: AAI + ISRO (Raytheon technical collaboration).
- Satellites used: GSAT-8 and GSAT-10 (geostationary).
- Navigation accuracy: ~3 metres.
- LPV decision height: 200–250 feet above runway; 40-metre lateral limit.
- First GAGAN landing: IndiGo ATR-72, Kishangarh Airport (Rajasthan), April 2022 — turboprop category.
- Current milestone: First jet aircraft category landing using GAGAN LPV approach.
- Global SBAS peers: WAAS (USA), EGNOS (Europe), MSAS (Japan) — India is the 4th country and 1st in Asia-Pacific.
- LPV procedures certified: 65 as of 2022 (AAI).
- Key regulatory body: DGCA (certification); AAI (infrastructure and procedures).
- Policy relevance: UDAN regional connectivity scheme benefits directly from GAGAN-enabled precision approaches at smaller airports.