Explained: India’s Own Satellite System Will Help New Aircraft Fleet Land At Small Airports

As India aims to become a regional aviation hub, the Union government is investing nearly $12 billion in constructing new airports and upgrading existing ones.

In the goal of transforming its aviation landscape, the government is set to increase the number of airports from 150 to about 200 within five years.

Adding to this, India's total aircraft fleet is targeted to grow from around 700 to more than 1,500 by 2030, with most planes financed through sale and leaseback deals, making the country attractive to aircraft lessors.

Last year, Air India placed orders for 470 planes from Airbus and Boeing, while Indigo, the country's largest airline, has about 500 planes on order.

This total, which includes both wide-body and narrow-body aircraft, represents the largest orders by Indian carriers and one of the largest single aircraft orders globally.

What these aircrafts will also bring is the capability to capture ‘augmented satellite signals’, to carry out an approach and landing without any help from ground-based navigation aids currently used, as it enables the use of India's own satellite navigation system, GAGAN.

GAGAN, short for GPS-aided geo-augmented navigation, is a precise navigation system developed in India to assist with aircraft landings, especially during the critical landing phase.

This initiative has been a significant step by the Indian government towards implementing satellite-based navigation services in the country.

At present, most aircraft in India’s fleet are not equipped to receive GAGAN signals and must rely on expensive instrument landing systems (ILS) or ground-based navigation aids at smaller airports.

India’s Own Satellite Navigation For Aircraft Landing

GAGAN enhances the precision of global navigation satellite system (GNSS) receivers by supplying reference signals.

Developed through collaborative efforts of the Airports Authority of India (AAI) and the Indian Space Research Organisation (ISRO), it serves as a regional satellite-based augmentation system (SBAS) for India and neighbouring equatorial countries.

It is the fourth operational SBAS globally, alongside the WAAS (US), the EGNOS (EU), and Japan’s MSAS, and is compatible with all three systems.

The primary goal is to set accurate aircraft navigation during landing across Indian airspace and adjoining regions. This is achieved through a network of ground stations and satellites that provide GPS signal corrections, giving a better position accuracy. 

The GAGAN system consists of 15 earth-based reference stations, two master control centres, three land uplink stations and three geostationary satellites.

The reference stations gather GPS satellite data, while the master control centres process this information to generate GPS correction messages, thereby improving overall position accuracy for aviation operations.

Delay In Its Integration

In May 2022, AAI successfully conducted a test using this satellite navigation system to assist in the landing of an IndiGo ATR72 aircraft at Kishangarh Airport in Rajasthan.

However, the full utilisation of the country’s own navigation system has been delayed, as many airplanes lack the necessary equipment to receive GAGAN signals.

According to a Times of India report, despite ISRO launching the first GAGAN satellite approximately 13 years ago, its application in the aviation sector has been limited. Airlines have so far only installed GAGAN-enabled receivers on select turboprop aircraft like ATRs and Bombardiers.

Major airports across the country utilise the high-precision instrument landing system (ILS), which provides precise descent angle guidance and directs aircraft to the centreline of the runway.

During periods of low visibility or near-zero visibility, pilots rely on ILS to safely land aircraft. This system involves costly ground equipment worth millions of dollars.

However, many small airports lack ILS capabilities.

Instead, pilots have to rely on basic ground-based navigation aids for approach and landing. These signals are part of the global navigation satellite system (GNSS), like the USA's GPS, similar to those used by motorists.

However, these GNSS signals are not sufficiently accurate or reliable for use in challenging visibility conditions.

An Added Boost In India’s Growing Aviation Sector

While larger airports in India may use it as a backup system, it is for the expanding network of smaller airports, where this homegrown augmented satellite signal will be useful.

This precision will prove invaluable at small airports lacking costly ILS installations.

GAGAN promises to enhance these aviation centres which are currently without precision approach capabilities — by lowering flight delays, conserving fuel, and advancing flight safety, especially in adverse weather.

Additionally, it improves aircraft position reporting accuracy, thereby supporting consistent and superior air traffic management.

It will offer the same accuracy as a ground-based landing system comprising antennae and beacons that transmit signals to aircraft to help pilots land.

It will also provide increased accuracy in position reporting of aircraft, allowing for more uniform and high-quality air traffic management.

The government recognises the potential for smaller airports to enhance regional connectivity, and also cater a substantial portion of traffic to larger airports.

Much like the impact of the wide area augmentation system in the US, which enabled numerous small airports to conduct instrument landings without ground-based ILS equipment, India will benefit similarly in its aviation sector growth in the coming years.