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Cospas-Sarsat celebrates 25 years of aiding search and rescue around the world

By A/SLt David Lavallee, 1 Canadian Air Division Public Affairs

As people go about their business around the world, travelling to and from in boats, planes, trains and cars, they do so in the quiet confidence that they will reach their destinations safe and sound.

What most of them don’t realize is that they are being watched—rather, listened to—from high above their heads, on the remote chance that something goes wrong and they need help.

For a quarter century, the Cospas-Sarsat satellite system has been monitoring the Earth, “listening” for emergency beacons activated by planes, ships or individuals in distress. Today, it has evolved into a global search and rescue (SAR) network used by a partnership of 38 countries.

Cospas-Sarsat is a Russian and English acronym, COSPAS meaning “Cosmicheskaya Sistyema Poiska Avariynich Sudov" (Russian for "Space System for the Search of Vessels in Distress"), while SARSAT means “Search And Rescue Satellite-Aided Tracking.”

Since the system became operational in 1982, Cospas-Sarsat has provided information that aided in the rescue of over 20,531 persons in 5,752 distress situations.

“The system really sees the whole world,” says Major Alain Tanguay of the Canadian Mission Control Centre (CMCC) at 8 Wing Trenton. CMCC monitors the SAR satellites and the computer network that receives and distributes all data relating to SAR beacons in Canada.

The Cospas-Sarsat system was the result of an agreement between Canada, the United States, France and the former Soviet Union. Coming online in 1982, the system’s first operational use happened on September 10 of that year, when a light aircraft crashed in Canada. Thanks to the system’s detection and relaying of the plane’s distress beacon, three people were rescued.

Photo Credit: Original graphic by NOAA-SARSAT

Basically, how the system works is that a person, plane or ship in distress activates an emergency beacon on one of three set frequencies—121.5 MHz, 243 MHz or 406 MHz. One of the Cospas-Sarsat satellites orbiting the earth picks up the beacon, and relays it to a Local User Terminal (LUT), which processes the signal and passes it along to a Mission Control Centre, like CMCC.

Based on the information received and location of the emergency, the MCC then forwards the message onto a Rescue Coordination Centre (RCC), which dispatches a SAR team to the site. Here in Canada, there is the CMCC in Trenton, three Joint Rescue Coordination Centres (JRCCs) and two Marine Rescue Sub-Centres (MRSCs) to respond to SAR situations, which are handled by the Air Force and/or the Coast Guard, which have SAR teams standing by 24 hours a day, seven days a week all year round.

Although the process may seem complicated, in reality, it happens very quickly. “When it comes to SAR operations, the name of the game is speed,” says Major Tanguay. “When an emergency situation happens, such as a plane crashing or a boat getting caught in rough seas, people are in distress, they are in danger. We need to get a team out there as soon as we possibly can. The information and direction we get from the Cospas-Sarsat system allows us to do that.”

There are two different types of satellite used in the Cospas-Sarsat system: Geostationary Search and Rescue (GEOSAR), which orbit Earth in a fixed position relative to the surface, and Low-Earth Orbit Search and Rescue (LEOSAR) satellites, which circle around the globe.

The LEOSAR satellites are used to locate where an emergency site is based on where the beacon is transmitting from, something their stationary GEOSAR satellites cannot do. This can present a challenge when a signal is received.

“When we receive a signal from a GEOSAR satellite, the system cannot provide a precise location of the beacon’s source,” says Major Tanguay. “As a result, we have to wait for a LEOSAR satellite to pass overhead and locate it. Unfortunately, that adds precious time to our ability to respond quickly to the emergency.”

There is a solution, however. The key lies in the three set frequencies used by distress beacons. The 121.5 MHz and 243 MHz signals are able to communicate with the satellites, but because they are analog frequencies, they cannot transmit much information.

However, beacons that employ the 406 MHz frequency are using a digital signal, which means that they can embed a vast amount of data in their signal. This can include coordinates from a global positioning system (GPS), which gives the MCC a more precise location for an emergency, as well as a beacon identification number. Once registered into the national database, this number can tell the MCC the type of aircraft or boat involved in the emergency, and how many people might be aboard.

It is for that reason that, as of February 1, 2009, the Cospas-Sarsat system will begin monitoring the 406 MHz frequency alone.

“The 406 MHz signal can provide us with much more information about the emergency, such as the location of the site with GPS and the type of plane or boat involved, which can also indicate how many people may be involved,” says Major Tanguay. “That translates into a quicker, better-prepared response to emergency situations.”

While the transition to 406 MHz poses some challenges, especially when beacon identification numbers are not registered in the database, in the end, it will better enable the system to help save lives.

“The more information we have going into an emergency situation, the better,” says Major Tanguay. “I think the Cospas-Sarsat system will continue to help us in that regard for a long time to come.”

Acting Sub-Lieutenant David Lavallee is an aspiring Public Affairs Officer working with the Public Affairs section at 1 Canadian Air Division/Canadian NORAD Region headquarters in Winnipeg, Manitoba.

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