Homegrown GAGAN guides India’s first satellite-guided commercial jet landing

IndiGo's Airbus A320 has successfully completed India's first commercial jet landing using the indigenous GAGAN satellite navigation system. The DGCA-supervised demonstration is expected to accelerate the adoption of satellite-based precision approaches, improving safety, efficiency and accessibility across the country's expanding airport network

New Delhi: In a landmark achievement for Indian aviation, an IndiGo Airbus A320 has successfully completed a satellite-guided landing using India’s homegrown GAGAN navigation system. The demonstration flight, conducted on June 27 under the supervision of the Directorate General of Civil Aviation (DGCA), marks the first time a commercial jet in the country has landed using this technology.

Unlike the traditional Instrument Landing System (ILS), which depends on ground-based radio equipment installed at airports, the Airbus A320 used a Satellite-Based Landing System (SLS) approach. Although IndiGo had previously tested the technology on its ATR turboprop aircraft, this is the first successful demonstration involving a commercial jetliner. Passengers onboard would not have noticed any visible difference, as the aircraft was guided by satellite-based navigation rather than airport-based transmitters.

---

The aircraft carried out a Localiser Performance with Vertical Guidance (LPV) approach. This procedure provides pilots with both horizontal and vertical guidance during landing, say experts.

According to Airbus, LPV enables stable and precise approaches comparable to ILS while eliminating the need for specialised landing infrastructure at airports. Experts say that the system is beneficial for airports which lack ILS facilities. It can also serve as an alternative in two cases: one when ILS is unavailable due to maintenance, and two when flights are diverted.

What is spotlighted by this achievement is the growing role of GAGAN, or GPS-Aided GEO-Augmented Navigation, India’s Satellite-Based Augmentation System jointly developed by the Indian Space Research Organisation (ISRO) and the Airports Authority of India (AAI). GAGAN enhances GPS signals by correcting errors and continuously monitoring their reliability for aviation use rather than functioning as an independent navigation system like GPS or India’s NavIC.

The correction data is transmitted through ISRO’s GSAT-8 and GSAT-10 geostationary satellites, which provide uninterrupted coverage across Indian airspace, say experts.

This distinction is important because while NavIC independently determines location, GAGAN improves the accuracy and integrity of GPS navigation.

Standard GPS, commonly used in smartphones, is accurate enough for everyday navigation. However, it lacks the precision required for aircraft landings. Moreover, the GPS signals are affected by atmospheric disturbances, especially over India, which lies beneath the equatorial ionisation anomaly where signal distortions can vary significantly, experts point out.

Commercial aviation, therefore, requires not only greater positional accuracy but also constant assurance that navigation data remains reliable.

To achieve this, GAGAN relies on a network of 15 accurately surveyed ground reference stations across the country. These stations compare their fixed positions with GPS readings to detect even minor errors. The corrections are processed at dedicated control centres before being relayed through GSAT-8 and GSAT-10 to aircraft in real time, significantly improving navigation accuracy.

Another critical feature is the system’s integrity monitoring capability. GAGAN continuously checks the reliability of navigation signals and alerts pilots within seconds if any anomaly is detected, enabling immediate corrective action.

IndiGo first introduced LPV operations on its ATR fleet in 2022 and has since expanded Satellite-Based Augmentation System-enabled capabilities across more aircraft. Meanwhile, AAI has published 23 LPV approach procedures at airports across India, with plans to increase that number to more than 40 by the end of the year.

ISRO says GAGAN is designed to support precision civil aviation by delivering the accuracy and reliability required for safe landings while also improving air traffic management through more direct and fuel-efficient flight paths. The system is compatible with similar satellite-based augmentation networks used internationally, ensuring uninterrupted navigation support for aircraft operating across borders.

According to experts, the successful satellite-guided landing of IndiGo’s Airbus A320 represents a major step forward in India’s aviation capabilities. It is expected to accelerate the adoption of satellite-based precision approaches, making air travel safer, more efficient and accessible across the country’s expanding airport network.