International Search and Rescue Satellite System

Canada has one of the world's largest areas of responsibility for search and rescue (SAR), covering 18 million square kilometres of land and water, more than 243,042 kilometres of coastline, three oceans, three million lakes (including the Great Lakes), and the St. Lawrence River system.

COSPAS-SARSAT satellites are an integral part of Canada's SAR system and are critical to reducing the time between the beginning of a distress event and the delivery of SAR services.

International COSPAS-SARSAT Programme

The International COSPAS-SARSAT Programme (the Programme) is a satellite-based distress-alerting system. Using satellites, the system detects, locates and distributes aircraft, maritime and personal distress alerts to over 200 SAR coordination centres and points of contact around the world.

Canada, France, the Russian Federation (formerly the Union of Soviet Socialist Republics) and the United States of America, are founding nations of the International COSPAS-SARSAT Programme and signatories to the International COSPAS-SARSAT Programme Agreement. These four founding nations continue to be at the heart of the Programme.

How the system works

The COSPAS-SARSAT system has three distinct segments that work together to provide distress-alerting and location data to SAR authorities in Canada and around the world.


These devices are activated when there is an incident. Most aircraft and maritime vessel beacons activate automatically when they are in distress. Personal locator beacons carried by adventurers and some secondary aircraft and vessel beacons must be activated manually. Their signals are carried on a channel dedicated for this purpose only.

Public Safety provides guidance to personal locator beacon manufacturers who wish to sell their products in Canada. The guidance includes best practices and basic requirements to ensure safety. Manufacturers who meet the basic criteria receive a letter of recommendation to include with their request for Canadian approval to the authority on personal locator beacon certification, the Department of Innovation, Science and Economic Development Canada.

The 406 Megahertz Personal Locator Beacon Performance Document sets out the minimum requirements that these beacons must meet.

Space segment

The satellites are positioned in three orbits around the earth to detect and relay distress alerts to ground stations. The satellites themselves do not belong to the Programme; they are provided by various nations participating in the Programme. They each host the SAR payloads and work together to ensure signals are directed to the ground segment.

Ground segment

This segment consists of ground stations, mission control centres, beacon registries and communication links. They receive, process and distribute information from the space segment to SAR authorities.

How the system works

Source: International Cospas-Sarsat Programme

Image description

Illustration of how a distress signal moves through the beacon, satellite and ground segments of the International COSPAS-SARSAT System (Programme) resulting in a Search and Rescue (SAR) Response representing in 6 stages.

Stage 1
Three types of distress beacons recognized by the Programme; Personal Locator Beacons (PLB), Emergency Locator Transmitters (ELT) and  Emergency Position-Indicating Radio Beacons (EPIRB) can be used to send a distress signal to the search and rescue satellites (Stage 2), depicted by a solid red arrow which represents communications between the COSPAS-SARSAT beacon and space segment, identifying 406 megahertz as the uplink frequency used by the beacons to communicate with the satellites.
Stage 2
Three search and rescue satellite constellations receive the signal from an activated beacon. These are Geo-stationary search and rescue satellites (GEOSAR), Medium-altitude Earth Orbit search and rescue satellites (MEOSAR) (carried on Galileo, Glonass and GPS navigation satellites) and the Low-altitude Earth Orbit search and rescue satellites (LEOSAR). The search and rescue satellites relay the distress message to a Local User Terminal (Stage 3), depicted by a solid red arrow which represents communications between the COSPAS-SARSAT space and ground segment, identifying a downlink frequency of 1544 to 1545 megahertz.
Stage 3
The Local User Terminal (LUT) on the ground segment, which receives the distress message from the search and rescue satellites relays the data to a Mission Control Centre (MCC) (Stage 4) , depicted by a solid red arrow which represents communications between COSPAS-SARSAT ground segments.
Stage 4
The Mission Control Centre (MCC) receives the data from the LUT and sends it to the closest Rescue Coordination Centre (Stage 5), depicted by a solid green arrow which represents communications within a countries search and rescue system. Collocated at the Mission Control Centre is the Return Link Signal Provider (RLSP) which sends a confirmation signal through the search and rescue satellites back to the beacon user informing them that their distress message has been received.
Stage 5
The Rescue Coordination Centre receives the distress alert and location data from the Mission Control Centre and activates the search and rescue response (Stage 6), depicted by a solid green arrow, which represents communications within a countries search and rescue system.
Stage 6
Search and rescue responders are sent to the location of the distress alert, depicted by a solid green arrow which represents communications within a countries search and rescue system.

In Canada, the system is critical to saving lives and reducing the time between the detection of a distress alert to the delivery of SAR services. It is also vital to reducing the risks to SAR responders by reducing the number of false alerts and by providing accurate distress location data.

In Canada, COSPAS-SARSAT saves an average of 45 lives a year and globally it is an average of 1,000 lives a year or three per day.

Federal partners

Public Safety is Canada's coordinating authority for the Programme and houses the country's Permanent Representative. The representative coordinates Canada's position and has the authority to speak on behalf of Canada on matters related to the general management and administration of the Programme in Canada and internationally.

Multiple federal departments are integral to Canada's efforts, in addition to Public Safety, they include:

International agreement

In 1979, Canada, France, the United States of America and the Union of Soviet Socialist Republics (USSR) agreed to combine their efforts to develop a satellite-based distress-alerting system: a remarkable feat during the cold war era.

This joint effort brought together the Search and Rescue Satellite-Aided Tracking (SARSAT) Programme (developed by Canada, the US and France) with the USSR's Cosmicheskaya Sistema Poiska Avariynich Sudov (COSPAS). The International COSPAS-SARSAT Programme Agreement was signed by the four nations in 1988 and is a recognized international treaty under the United Nations.

The system is unique: its services are free, offered worldwide and without discrimination. In 2014, the Programme was inducted into the Space Technology Hall of Fame, which recognizes technologies developed for space use that now improve life on Earth.

The four nations continue to exercise full control of the Programme's activities with the support of the International COSPAS-SARSAT Secretariat.


The International COSPAS-SARSAT Programme hosts a tri-lingual YouTube Channel. Among the videos, you will find:

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