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New sites will boost European search and rescue

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Posted November 19, 2014

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

The ground network for Galileo’s search and rescue service has now passed a major exam, coming a step closer to saving lives.

The ESA-built Maspalomas Medium-Earth Orbit Local User Terminal (MEOLUT) on Gran Canaria, the largest island of Spain’s Canary Islands, part of an extension of the international Cospas–Sarsat search and rescue programme into medium-altitude orbits, spearheaded by Galileo. Each site is equipped with four antennas to track four satellites. There are three sites in all, forming a triangle around Europe: Maspalomas, Spitsbergen in the Norwegian Arctic and Larnaca in Cyprus. These three sites are monitored and controlled from the Search and Rescue Ground Segment Data Service Provider site, at Toulouse in France. The stations are networked to share raw data, effectively acting as a single huge 12-antenna station, achieving unprecedented detection time and localisation accuracy in relaying search and rescue signals to local authorities. Copyright ESAS-Fermin Alvarez Lopez

The ESA-built Maspalomas Medium-Earth Orbit Local User Terminal (MEOLUT) on Gran Canaria, the largest island of Spain’s Canary Islands, part of an extension of the international Cospas–Sarsat search and rescue programme into medium-altitude orbits, spearheaded by Galileo. Each site is equipped with four antennas to track four satellites. There are three sites in all, forming a triangle around Europe: Maspalomas, Spitsbergen in the Norwegian Arctic and Larnaca in Cyprus. These three sites are monitored and controlled from the Search and Rescue Ground Segment Data Service Provider site, at Toulouse in France. The stations are networked to share raw data, effectively acting as a single huge 12-antenna station, achieving unprecedented detection time and localisation accuracy in relaying search and rescue signals to local authorities. Copyright ESAS-Fermin Alvarez Lopez

These 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 summer of testing has confirmed the heightened efficiency of this approach.

The ESA-built Svalbard Medium-Earth Orbit Local User Terminal (MEOLUT) on Spitsbergen Island, part of an extension of the international Cospas–Sarsat search and rescue programme into medium-altitude orbits, spearheaded by Galileo. Copyright ESA-Fermin Alvarez Lopez

The ESA-built Svalbard Medium-Earth Orbit Local User Terminal (MEOLUT) on Spitsbergen Island, part of an extension of the international Cospas–Sarsat search and rescue programme into medium-altitude orbits, spearheaded by Galileo. Copyright ESA-Fermin Alvarez Lopez

“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 ESA’s 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 creation in 1979, it has helped to rescue more than 35 000 people.

The ESA-built Larnaca Medium-Earth Orbit Local User Terminal (MEOLUT) in Cyprus. Copyright ESA-Fermin Alvarez Lopez

The ESA-built Larnaca Medium-Earth Orbit Local User Terminal (MEOLUT) in Cyprus. Copyright ESA-Fermin Alvarez Lopez

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.

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

Cospas–Sarsat's extension to MEOSAR (Medium Earth Orbit Search and Rescue) will extend its search and rescue coverage (the area outlined in red). On the ground the Galileo programme is contributing a Toulouse-based test bench, and a networked trio of MEOSAR ground stations – known as Local User Terminals (LUTs) – to cover Europe, based in Svalbard in the Norwegian Arctic, Cyprus and the Canary Islands. Existing LUTs are distributed on a per country basis, but it is an advantage of MEOSAR that fewer ground stations will be needed for greater coverage. Galileo engineers have introduced another innovation: for the first time those in distress will receive a reply, letting them know their signal was picked up and help is on the way. Copyright Cospas-Sarsat

Cospas–Sarsat’s extension to MEOSAR (Medium Earth Orbit Search and Rescue) will extend its search and rescue coverage (the area outlined in red). On the ground the Galileo programme is contributing a Toulouse-based test bench, and a networked trio of MEOSAR ground stations – known as Local User Terminals (LUTs) – to cover Europe, based in Svalbard in the Norwegian Arctic, Cyprus and the Canary Islands. Existing LUTs are distributed on a per country basis, but it is an advantage of MEOSAR that fewer ground stations will be needed for greater coverage. Galileo engineers have introduced another innovation: for the first time those in distress will receive a reply, letting them know their signal was picked up and help is on the way. Copyright Cospas-Sarsat

“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 – hence 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.”

For three decades the Cospas–Sarsat system has used transponders on satellites such as Europe’s MSG and MetOp to pick up distress calls from ships and aircraft. Copyright Cospas-Sarsat

For three decades the Cospas–Sarsat system has used transponders on satellites such as Europe’s MSG and MetOp to pick up distress calls from ships and aircraft. Copyright Cospas-Sarsat

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

“With all three stations working together we’ve demonstrated significantly better performance than requirements – because 12 eyes are better than four,” comments Francesco Paggi of Thales Alenia Space Italy, working on the qualification.

“So all signals have been detected inside the service area within a minute, with 99% of test localisations performed to less than 5 km, and 79% within 2 km, after 10 minutes.

Like the US GPS and Russian Glonass, European Galileo satellites will carry Cospas–Sarsat MEOSAR (Medium Earth Orbit Search and Rescue) transponders. Galileo will also offer ‘return link messaging’  so that, for the first time, those in distress will receive replies confirming their call has been picked up and help is on the way. Copyright NOAA

Like the US GPS and Russian Glonass, European Galileo satellites will carry Cospas–Sarsat MEOSAR (Medium Earth Orbit Search and Rescue) transponders. Galileo will also offer ‘return link messaging’ so that, for the first time, those in distress will receive replies confirming their call has been picked up and help is on the way. Copyright NOAA

“Then these localisations are automatically passed on to regional Mission Control Centres within a minute and a half for forwarding on to the closest search and rescue agency.”

Illustrating the system’s responsiveness, automatic distress signals from two recent tragedies were detected rapidly during the qualification: the crash of Malaysia Airlines Flight 17 in Ukraine in July, and the collision of two Italian Tornado jets the following month.

Simulated distress signal beacon localisation performance during qualification testing of the Maspalomas Medium-Earth Orbit Local User Terminal (MEOLUT), on Gran Canaria, part of an extension of the international Cospas–Sarsat search and rescue programme into medium-altitude orbits, spearheaded by Galileo. The station has first to detect Cospas–Sarsat distress signals within its service area, then locate their position so that the information can be relayed on to the relevant search and rescue authority to react. Precision improves greatly as more satellites are detected, with the majority of detections within 5 km geographical accuracy and many within 2 km. In practice, the three MEOLUTs work together as one giant station, improving system performance still further. Copyright ESA

Simulated distress signal beacon localisation performance during qualification testing of the Maspalomas Medium-Earth Orbit Local User Terminal (MEOLUT), on Gran Canaria, part of an extension of the international Cospas–Sarsat search and rescue programme into medium-altitude orbits, spearheaded by Galileo. The station has first to detect Cospas–Sarsat distress signals within its service area, then locate their position so that the information can be relayed on to the relevant search and rescue authority to react. Precision improves greatly as more satellites are detected, with the majority of detections within 5 km geographical accuracy and many within 2 km. In practice, the three MEOLUTs work together as one giant station, improving system performance still further. Copyright ESA

Igor explains: “The accuracy of localisations increases with the number of satellites actually used, because the stations perform the same kind of ranging used for satnav services, except in reverse – with somewhat reduced precision because the beacon signals originally designed in the 1970s were not optimised for ranging from medium orbits.

“So as more equipped satellites go into orbit, the performance should get even better.”

A set of reference beacons is now being added for continuously monitoring the system’s performance.

Source; ESA

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