NEW DELHI: Do you get irritated because of the aircraft you are flying in taking too much time circling over Delhi or Mumbai before landing, or the lack of late flights to Allahabad? India has adopted a new navigation system that may help address some of these issues. The GPS-Aided Geo Augmented Navigation, or Gagan, can allow as many as 50 aircraft to safely operate in airspace that two planes take at present. It can also help ease landing in airports that are poorly lit and do not have instrument landing systems. India, which spent Rs 774 crore to develop the system indigenously, launched it on July 13 with little fanfare. Only the US, European countries and Japan have similar systems in place. Current rules say two aircraft must maintain a distance of 18 kilometres between them to ensure safe operations. With Gagan, that distance can be reduced to as little as 360 metres, said a senior Airports Authority of India (AAI) official. “Just imagine the number of aircraft we will be able to fit in the space consumed by only two aircraft in the past,” the official said. One of the advantages will be during landings, because the distance between planes approaching the runway in congested airports like Delhi can be reduced significantly, though it is unlikely that it will be cut to as low as 360 metres. Gagan is much more precise in informing about the location of the plane than the radar-based system most of the world still uses. “The location that Gagan provides is exact and the error, if any, could be only of up to 7.6 metres. Our analysis, however, has found that the error has been only of 1 to 1.5 metre,” said the official. The system was built by the AAI and the Indian Space Research Organisation. The Indian government invested Rs 378 crore in the project, while the AAI put in Rs 226 crore and the remaining Rs 170 crore came from ISRO. Gagan works using signals from two communication satellites – geosynchronous satellites (GSAT) 8 and 10 – ISRO had put into orbit. The signals form these satellites are received at 15 reference stations across the country. There are also three uplink stations, two in Bengaluru and one in Delhi. “While we need only two stations for the uplink, we have built a third one for back up,” said the AAI official. Officials said India’s Gagan system was capable of providing en-route and approach with vertical guidance to aircraft. This means that the aircraft will not just be guided during its cruise but also during its landing and takeoff. “The ability of Gagan to guide planes during landing and takeoff enables us to land at airports without instrument landing system, but with basic lights. This will give great push to the government’s plan to increase regional air connectivity,” said another AAI official. Instrument landing is a ground-based instrument approach system that provides precision lateral and vertical guidance to an aircraft approaching the runway, using a combination of radio signals and, in many cases, high-intensity lighting. While the system is up and running, it is not compulsory for airlines to adopt it yet. The biggest hurdle in the implementation of Gagan in the country is the inability of the current fleet of aircraft to work on this system. Also, to better utilise Gagan, the rules on the safe distance that aircraft need to keep while in air need to be changed. Aircraft need to have a receiver called Space Based Augmentation System (SBAS) to be able to receive signals from the Gagan satellites. “This receiver and training to pilots will cost about Rs 2 crore per aircraft and the airlines are not very keen about implementing it,” said the first AAI official. According to airlines, a lot of aircraft in the country cannot be upgraded to this system. “We are talking to aircraft manufacturers on installing these equipment in the aircraft. We will eventually need to do it,” said a SpiceJet executive, who did not want to be named.