Europe expands satellite SAR with new ground sites

A trio of satellite ground stations has taken shape on three islands at the far corners of Europe, ready to pick up distress calls from all across the continent and its surrounding waters.

The stations sit on Spitsbergen in the Norwegian Arctic, Maspalomas on the largest island of Spain’s Canary Islands and Larnaca on the island nation of Cyprus, forming a triangle enclosing Europe. The three are coordinated and overseen from a control centre in Toulouse, France.

Each site is equipped with four antennas to detect distress calls relayed via satellites in medium-altitude orbits, so far including 14 GPS satellites, two European Galileos and one Russian Glonass.

The three stations are interlinked to operate jointly, so that all 12 antennas can track satellites together. A northern summer of testing has confirmed the heightened efficiency of this approach.

The ESA-built Maspalomas Medium-Earth Orbit Local User Terminal (MEOLUT) on Gran Canaria, the largest island of Spain’s Canary Islands.

“This new search and rescue infrastructure, designed by ESA and financed by the EU as part of Galileo, is our contribution to the Cospas–Sarsat system, the world’s oldest and largest satellite-aided rescue system,” explains the European Space Agency’s (ESA) Fermin Alvarez Lopez.

Founded by Canada, France, the USSR and the US, Cospas-Sarsat is a global satellite system for rapidly detecting distress calls to be forwarded to local search and rescue authorities. Since its inception in 1979, it has helped to rescue more than 35,000 people.

Cospas-Sarsat distress beacons can be bought off the shelf, then activated by anyone in distress on land, in the air or on the sea. Satellite repeaters pick up and amplify the beacon signals, then transmit them down to ground stations.

These stations identify the approximate location of the signal and then pass the information to the rescue authorities.

Cospas-Sarsat's extension to MEOSAR (Medium Earth Orbit Search and Rescue) will extend its search and rescue coverage (the area outlined in red).

“Up until now, Cospas-Sarsat has relied on satellites in low and high orbits,” adds Fermin.

“But medium orbits with satellites such as Galileo are better: they combine a wide field of view with strong Doppler shift, making it more likely a distress signal is pinpointed promptly and accurately.”

The broad coverage also means fewer ground stations are required - just three can handle the entire European service area.

Once the stations were completed, testing began, Igor Stojkovic, ESA’s search and rescue engineer explains: “We have been demonstrating the system performs as required, ahead of handing it over to its operator, part of France’s CNES space agency, in December ahead of service beginning in 2016.”

Distress beacons emit UHF bursts every 50 seconds. The stations are required to detect and locate all signals received to within 5 kilometres after 10 minutes.

Courtesy of the European Space Agency.