What is COSPAS-SARSAT?
COSPAS-SARSAT is an international satellite search and rescue (SAR) system established by international agreement in 1982 between the USA (NOAA), USSR/Russia (Roscosmos), Canada (CSA), and France (CNES). The name combines the Russian acronym COSPAS (Cosmicheskaya Sistyema Poiska Avariynykh Sudov — Space System for Search of Vessels in Distress) and SARSAT (Search and Rescue Satellite-Aided Tracking).
How it works
Distress beacons — EPIRBs (maritime, 406 MHz), ELTs (Emergency Locator Transmitters, aviation), and PLBs (Personal Locator Beacons) — broadcast a digital 406 MHz signal containing a unique identification code and, in GPS-equipped models, precise coordinates. This signal is received by instruments aboard LEO and GEO satellites and retransmitted to Local User Terminals (LUTs) on the ground. Mission Control Centres (MCCs) process the alert and relay it to the appropriate National Rescue Coordination Centre (RCC) for dispatch of SAR resources.
MEOSAR: the next generation
The Medium-altitude Earth Orbit SAR (MEOSAR) system uses search-and-rescue instruments aboard GPS (SARR payload), GLONASS, and Galileo navigation satellites at 19,000–23,000 km altitude. The higher orbital altitude provides near-instantaneous global coverage — any activated beacon is detectable by multiple MEOSAR satellites simultaneously within minutes, with position accuracy better than 100 metres using Doppler processing and GPS integration. By 2025, MEOSAR is the primary operational COSPAS-SARSAT detection system.