As well as improving procedures, expanding surveillance over the Atlantic has also been a major focus for Nav Canada and other ANSPs. The introduction of ADS-B has made this possible, since it has been impractical to build radar stations in remote locations that would help fill vast gaps in surveillance.
Nav Canada has ADS-B ground stations along its northeast coast that supplement its radar stations and provide offshore coverage. It has also sited ADS-B stations on the southern tip of Greenland that extend surveillance farther into the Atlantic.
The Greenland stations have yielded many benefits since they became operational in early 2012. Surveillance means aircraft are under direct air traffic control, allowing oceanic controllers based at Gander, Newfoundland, to further reduce separation and approve altitude changes even more readily. This has a domino effect on the North Atlantic routes, Lachance says. If westbound flights are able to achieve optimum altitudes, this in turn frees up more levels for following flights.
Nav Canada intends to add to its oceanic ADS-B surveillance by putting a ground station on the Hibernia off-shore oil platform, and an agreement with the platform's owners is expected soon.
Other ANSPs are also extending Atlantic ADS-B coverage. Iceland's Isavia and Denmark's Naviair are working on a connected series of ADS-B stations in the Faroe Islands, Iceland and Greenland that is intended to provide a surveillance corridor from European to North American airspace (AW&ST Oct. 22, 2012, p. 41).
This corridor will be farther north than routes for the bulk of the transatlantic traffic that Nav Canada and NATS are responsible for, but it will still cover some important traffic flows.
Isavia is responsible for installing the Iceland network—which largely overlays existing radar coverage—while Naviair is responsible for the Greenland and Faroe Islands sites. Isavia will provide high-altitude ATM services across all of these networks from its Reykjavik center.
This was originally intended to be a joint procurement project, but Naviair opted to pursue its own contract process for the Greenland ADS-B sites. Isavia selected Comsoft to provide its ADS-B stations, which have already been deployed and tested. They are expected to be used operationally this summer. Naviair, meanwhile, awarded a contract to Saab Sensis. Installation is expected this summer with surveillance data being transmitted by year-end. Limited operational use could begin in 2014, Isavia says.