Transformative technology

India has recently urged its immediate neighbours and the nations in Southeast Asia to test its latest advanced navigation technology and aviation infrastructure which enables an aircraft to land and take-off with the help of satellite data and localiser signals, a combination of which provides accurate information even during bad weather. The appeal was made at the International Civil Aviation Organisation's 57th Conference of Directors General of Civil Aviation for Asia and Pacific Regions at Incheon in South Korea. A detailed presentation was made at the conference by the Indian side regarding its experimentation with GPS-Aided GEO Augmented Navigation (GAGAN), which is a regional Satellite-Based Augmentation System (SBAS). The technology has been developed jointly by the Indian Space Research Organisation (ISRO) and the Airports Authority of India (AAI).

At the conference, it was announced that after a series of simulator-based trials in Hyderabad, an airline successfully landed an ATR-72 turboprop aircraft at the Kishangarh airport in Rajasthan on April 28 using GAGAN and operated the LPV (Localizer Performance with Vertical Guidance) approach. The landing was the first one in the entire Asia-Pacific region. The ICAO conference was also informed that India was planning to implement these procedures at all regional airports in the Tier 2 and Tier 3 cities. The main thrust would be given to cities which are not equipped with ILS (Instrument Landing System) approaches. The GAGAN system has the capability to cater 45 reference (ground) stations. Currently, only 15 are being used. The signals from this system are capable of providing service to all neighbouring countries — Myanmar, Bangladesh, Nepal and Bhutan — along with those in South-East Asia, such as Thailand, Indonesia, Malaysia, Singapore and others over Australia and Africa, subject to installation of Indian Reference Stations at strategic locations in these countries. The conference was told that India was in a position to share its experience and knowledge with the governments interested in developing these procedures using the GAGAN signal, which is available through three GAGAN GEO satellites — GSAT-8, GSAT-10 and GSAT-15.

India is the fourth country in the world, after the USA, Europe and Japan, to take up the challenge of establishing a regional SBAS that will redefine navigation over India and adjacent regions. It is known that GPS (Global Positioning System) signals do not always pin-point accurate data and are susceptible to factors and disturbances such as ionospheric interference, the location of a moving vehicle or even the functioning of the GPS satellite. Simply put, when a stationary object (a ground station) is on the Earth's surface, its location in the global reference frame is fixed and does not change. But when a satellite gives location data about that particular building, it tends to make some minor errors owing to ionospheric disturbances or other factors. However, since the pin-point location of the building (ground station) is known, one can identify that the satellite data has an error. GAGAN's capability is that it can calculate this difference/error in satellite data through its Master Control Centre and eventually send this corrected data via satellite to the travelling aircraft/vehicle, thus enabling the pilot to pin-point a location.

Many advanced countries have their own localised solutions to such problems. SBAS signs are used by aircraft to get their position within three metre precision. Significant effort is being made to propose energy efficient routing protocols with the help of GAGAN, which have accuracy of almost up to one metre. While the Global Positioning System (GPS) is a space-based radio navigation framework claimed by the United States government and worked by the United States Air Force; GAGAN or the GPS Aided GEO Augmented Navigation is the implementation of a regional SBAS by India, which is based on the Wide Area Augmentation System used by several countries across the world. GAGAN comprises three segments – space segment (GEO and GPS), ground segment (15 Indian reference stations or INRES, three master control centres and three ground uplink stations) and the user segment. Its prime objective is to establish, deploy and certify satellite-based augmentation systems for safety-of-life civil aviation applications in India and its vast surroundings.

Aviation regulator DGCA has already mandated that all aircraft registered in India after July 1, 2021, should be fitted with GAGAN equipment. These equipment are interoperable with all international SBAS systems — WAAS (American), EGNOS (European) and MSAS (Japanese). Once fully adopted in India's civil aviation sector, GAGAN is expected to modernise the airspace, reduce flight delays, save fuel and improve flight safety, as pilots using GAGAN need not take a circuitous, non-precise approach for landing. A senior pilot, working with a leading airline in India, said GAGAN has brought the probability of error in GPS data to a bare minimum. According to the pilot who requested anonymity, the location data coming from GAGAN augments and adds more perfection to the existing GPS location. The accuracy provided by GAGAN is as good as that offered by the ground-based Instrument Landing System which guides pilots to make precise landings at major airports. While ILS is available only at major and busy airports, it is also very expensive and difficult to maintain. Therefore, in smaller airports such as those in Tier 2 and Tier 3 cities where ILS is not available, the GAGAN system can be used for landing guidance. Sometimes, the ILS also faces temporary outages at large airports. In such situations, GAGAN can come into play and rule out the possibility of flight operations being interrupted, the veteran pilot said.

Civil Aviation Minister Jyotiraditya Scindia held discussions with American aerospace giants on collaborating in furthering the GAGAN project, besides further strengthening collaboration with the industry in India. During his recent visit to the US, Scindia held a series of meetings with senior industry leaders, focussed on "ways to strengthen" collaboration between India and the US across the aviation sector. He tweeted: "Had a productive interaction with members of @USIBC from the aviation community. Spoke about the growing focus & opportunities in regional connectivity & urban air mobility in India." Following his discussions with top brass of the industry, including firms like Raytheon Technologies, Pratt & Whitney and Sikorsky, he said he "discussed potential collaboration for enhancing the civil aviation infrastructure ecosystem in India, including setting up MRO (maintenance, repair and overhaul) facilities and furthering our GAGAN project."

Once fully rolled out, GAGAN will make several smaller airports, such as those in the Northeast or in the hilly areas of Uttarakhand or Himachal Pradesh, capable of having compliant aircraft land in low-visibility scenarios. This new technology provides a substantial operational benefit in poor weather and low visibility conditions, akin to those witnessed during heavy fog in Delhi when the costly Category-III of the ILS is operated. An aircraft can also derive maximum benefit in terms of improved safety during landing, reduction in fuel consumption, reduction in delays, diversions and cancellations, through the use of GAGAN.

While GAGAN is primarily meant for aviation, the technology will also provide benefits to several other segments such as intelligent transportation, maritime, highways, railways, security agencies and the telecom sector. The AAI has, in coordination with the Indian National Centre for Ocean Information Services, already developed the GAGAN Message Service (GMS) which, when implemented, would send alert messages to fishermen, farmers and affected people during natural disasters. The additional capabilities of GAGAN are also being explored to utilise it in other non-aviation fields such as surveying, agriculture, power sector and mining. GAGAN denotes the significant aviation capability of the country. With its complete implementation, India would achieve an important milestone in performance-based navigation.

Views expressed are personal