UK air navigation service provider NATS believes a trial of a satellite-based tracking service over the Atlantic is showing the potential for “big benefits”.
The Aireon service uses the automatic dependent broadcast signals (ADS-B) already transmitted by aircraft, but uses satellites to pick them up over remote areas and transmit them back to ground stations. That means aircraft can be tracked in real-time, even over areas with no radar coverage.
NATS started the trial of Aireon’s service at the end of March, together with NAV Canada, to monitor aircraft crossing the busy North Atlantic and see if separation could be reduced.
Due to the lack of radar coverage across the ocean, aircraft previously had to report their position every 14 minutes and stick to an organised track structure (OTS), a system that has been used for decades and where aircraft were assigned a route, flight level and Mach speed for Atlantic crossings to ensure safe separation was maintained.
NATS today says that of the 113 million ADS-B reports received in April via the Aireon service, all arrived within a target 8 second update rate and that they reached controllers within an average time of just 0.17 seconds, compared with a target of 2 seconds.
“Having high update rate, low latency, real-time surveillance means we have been able to safely reduce the distance between aircraft (14nm nose to tail, down from 40nm) and offer airlines that were previously assigned fixed speeds and heights the opportunity to take advantage of more flexible flight paths and optimum trajectories,” Andy Smith, manager of air traffic control development at Prestwick, writes in a NATS blog.
He said that between 15 April and 27 May, around 12,000 flights flew their optimum speed for a total of 620,000 minutes.
The technology could therefore spell the end for the OTS, instead meaning airlines can fly the trajectories that they request, in turn saving time, fuel and CO2 emissions.
“Over the coming years, we estimate that 90% of airspace users will be assigned their requested trajectories, something that will support the progressive reduction and eventual removal of the OTS,” Smith states.
The trial continues, with the next milestone, expected this autumn, to reduce lateral separation minima from 23nm down to first 19nm and then 15nm.
Smith says air traffic controllers love the new system. “If I told the team that I was taking away their new tools and ADS-B surveillance tomorrow, I’d probably have a fight on my hands, such has been the positive impact upon the way they work and the quality of service they can now offer our airline customers.”