NATS Services is now using a Sensis Wide Area Multilateration (WAM) system in the North Sea off the coast of Scotland for helicopter flight following. Air traffic controllers are using the WAM surveillance information as a supplement to established procedural flight rules until the WAM system completes testing and regulatory approval for flight information services later this year.

There are more than 25,000 helicopter flights carrying a half million passengers each year between Aberdeen Airport and the oil and gas operations in the North Sea. Low-level radar coverage only extends 80 miles off the shore, forcing controllers to rely on pilot's positional radio updates provided every 10 minutes. In addition, established in-bound and out-bound flight paths are, in many cases, not the most efficient routes due to the lack of surveillance.

To improve safety and efficiency, NATS Services required a solution that provided high accuracy surveillance that was compatible with future technologies such as Automatic Dependent Surveillance - Broadcast (ADS-B). NATS Services selected Sensis WAM to cover 25,000 square miles of the North Sea with multilateration sensors placed on 16 oil platforms. One of the platforms is floating, making the development of the solution more challenging.

John Mayhew, NATS Services' general manager at Aberdeen said "with Sensis WAM, controllers have radar-like surveillance to accurately monitor and identify helicopters, in many cases all the way to the flight deck on the oil platform."

Sensis WAM uses multiple low-maintenance, non-rotating sensors to triangulate aircraft and helicopter locations based on transponder signals to provide air traffic controllers with precise aircraft position and identification information regardless of weather conditions. With a higher update rate and greater positional accuracy than traditional radar, Sensis multilateration provides effective surveillance for increased safety, capacity and efficiency of airspace.

Meantime, Era says its WAM solution for the Dutch air navigation service provider (ANSP) Luchtverkeersleiding Nederland (LVNL) has been installed in the Netherlands North Sea area.

The solution utilizes Era's MSS multilateration and ADS-B surveillance system and is supported by HITT, the prime contractor for the Project.

Era's MSS surveillance sensors have been installed both on- and offshore to provide low-level and over-flight surveillance coverage for the Dutch portion of the North Sea. The system covers an area spanning roughly 350km by 500km with all data fusion being performed by LVNL at the Schiphol Air Traffic Control Center.

The Era solution was designed to track Mode S and ADS-B equipped aircraft traveling to the offshore platforms as well as over-flights within the large coverage area. MSS provides situational awareness and flight safety to LVNL and properly equipped aircraft.

Era Systems Senior Vice President Kevin Layton said "our MSS solution will provide LVNL with one-second update rates and will be one of the largest multilateration-based oceanic surveillance deployments of its kind."