Cold wave has arrived in North India and bought with it freezing temperature and dense fog. Inevitably the dense fog disrupts air traffic with numerous cancellation and unannounced delays. We Have witnessed horror stories about Passengers assaulting pilots, even of passengers sitting on runways to protest diverting of flights. Delay or cancellation of flight leads to a cascading effect of flights being affected in regions unaffected by fog. I recently had my flight from Pune to Chennai cancelled for no apparent weather reason. I am sure it was not the only flight affected. We are used to this becoming an annual affair and have shrugged our shoulders treating it as a necessary evil which we must learn to live with. But is it really so? Don’t we have modern airport compared to best in the world?

Most airports in India use the instrument landing system (ILS) radio navigation. These are further classified as ILS Cat II and ILS Cat III. Airports typically apply the Category II (CAT-II) procedure for flights and pilots when visibility is 275-550 meters, and CAT-III below 275m, down to 50m. This is further complicated by requirements of Runways equipped for; and pilots trained for these categories. Only CAT-III B certified pilots can land when the visibility is about 50m. CAT III C can land on auto-pilot even in zero visibility and is currently used at airports like New York’s JFK International Airport and London’s Heathrow airport, but sadly not on any of Indian Airports.

Delhi airport has four runways but only two are compliant with ILS CAT III standards. Of the two non-compliant runways, one has been non-operational for weeks. Of the compliant runways, one was reportedly downgraded to CAT 1 due to nearby building work but was made operational again on 16 January.

I don’t have figures for the no. of pilots trained for Cat III B but, airlines will have to train more pilots to be CAT-III B compliant, and the cost is estimated to be around ₹7 lakh per pilot.

Why should we expect Airlines invest for something which happens just for a month every year, when they can just treat is a PR problem and operate smoothly for next 11 months? However, we should expect the AAI to invest in CAT III runways as they are using the taxpayer’s money, but again this would be only one half of Jigsaw without adequate no of trained pilots.

Fortunately, technology is finding a way. Some airlines are experimenting with the global position system (GPS) as alternatives to ILS. Airbus has integrated these new technologies with an ILS look-alike interface, which can help pilots to perform “straight-in” approaches using satellite positioning, even in low-visibility conditions. Under development is The Microwave Landing System, which uses microwave frequencies, is very precise but has significantly higher costs. Currently it is being experimented with by US Airforce.

 Although GPS signals can be affected by atmospheric conditions, interference or jamming posing a significant security threat, most nations are working on the GPS system called Global Navigation Satelite System (GNSS).

I was pleasantly surprised to know that India is one of the few countries which is working on this. Our Goverment and ISRO had the vision to start work on this as far back as 2012. The GPS-aided GEO augmented navigation (GAGAN) is an implementation of a regional satellite-based augmentation system (SBAS) by the Government of India. It is a system to improve the accuracy of a GNSS receiver by providing reference signals. The Airports Authority of India (AAI)’s efforts towards implementation of operational SBAS can be viewed as the first step towards introduction of modern communication, navigation and surveillance / air traffic management system over the Indian airspace. And could be the way out of our present predicament.

The project has established fifteen Indian reference stations, three Indian navigation land uplink stations, and three Indian mission control centers along with all associated software and communication links. It will be able to help pilots to navigate in the Indian airspace by an accuracy of 3m. 

Flight inspection of GAGAN signal is being carried out at Calicut International Calicut, Rajiv Gandhi International Hyderabad, Dr. Babasaheb Ambedkar International Nagpur and Kempegowda International Bangalore airports. The results have been satisfactory so far.

 Success of GAGAN will be another feather in the cap of ISRO and AAI. We celebrate the moon and Mars mission of ISRO, but this could a bigger achievement and could impact us and our everyday life.

Next time you read about Launching of G-SAT satellite on page 10 of your newspaper link it to GAGAN because the first GAGAN transmitter was integrated into the GSAT-4 geostationary satellite. As of today 19, GSAT satellite of ISRO have been launched (without much fanfare) and 15 of them are currently operational. (Last one to be successfully launched was GSAT-24 in July 2022).

A flight management system based on GAGAN will improve airport and airspace access in all weather conditions, enhance reliability and reduce delays by defining more precise terminal area procedures and optimized airspace corridors.

GAGAN will increase safety by using a three-dimensional approach operation with course guidance to the runway, which will reduce the risk of an accident whereby an airworthy aircraft, under pilot control, inadvertently flies into terrain, an obstacle, or water.

GAGAN will also offer high position accuracies over a wide geographical area like the Indian airspace. These positions accuracies will be simultaneously available to 80 civilian and more than 200 non-civilian airports and airfields and will facilitate an increase in the number of airports to 500 as planned.

GAGAN has its primary function in Airtraffic control but is also being used successfully in other applications.

Karnataka Forest Department has used GAGAN to build a new, accurate and publicly available satellite-based database of its forestlands. This is a follow-up to the Supreme Court directive to states to update and put up their respective forest maps, to the public. The updated maps will rid authorities of ambiguities related to forest boundaries and give clarity to forest administrators, revenue officials as well as the public,

The Indian National Centre for Ocean Information Services (INCOIS) along with AAI has launched a new satellite-based GEMINI (Gagan Enabled Mariner’s Instrument for Navigation and Information) system that will alert deep-sea fishermen of upcoming disasters. The GEMINI app on the cellphone decodes the signals from GEMINI device and alerts the user on imminent threats like cyclones, high waves, strong winds and also helps to coordinate with Coast guard on search and rescue missions.

GAGAN finds application in our country defenses too with various Indian manufactured missiles including the BrahMos will use it for guidance.

As of 2023, four global systems are operational: the United States’s Global Positioning System (WAAS), Russia’s Global Navigation Satellite System (GLONASS), China’s BeiDou Navigation Satellite System, and the European Union’s Galileo. GAGAN could be the fourth and India will take another step on our road to development.

 I look forward to the day when GAGAN will be fully operational, and my travel plans will not be hijacked by the weather be it fog or rains. I hope this blog will promote interest in technology esp. that which affects us directly. Also take a moment to appreciate not only ISRO and AAI but the unknown Scientists, engineers and lowly technicians for whom it is just a 9 to 5 job. They are contributing to nation building like thousands of other working-class heroes.

Next time you look up to sky Thank the Lord for GAGAN.