Search & Rescue
Satellites
Cospas-Sarsat System Overview
Local User Terminal
Distress Call Utilizing
Emergency Beacon
Mission Control
Center
Rescue Coordination Center
LAND
AIR
The Cospas-Sarsat Search & Rescue System
24
2
SAR
1. Distressed pilot activates beacon (ELT, PLB).
2. Beacon transmits a 406 MHz emergency message containing your Unique Identifier Number (UIN) to
the LEOSAR (polar orbiting) and GEOSAR* (geostationary) satellite systems.
3. The satellites relay the 406 MHz emergency message to a ground station called the Local User Terminal
(LUT). The LUT calculates the location of the signal by measuring the Doppler shift caused by the rela-
tive movement between the satellite and the beacon and forwards the location to the Mission Control
Center (MCC).
4. The MCC continues to receive information from additional satellite passes and further refines the beacon
position (2.6 m search radius). An alert message is generated that is combined with the registration
information from the database and is forwarded to the appropriate Rescue Coordination Center (RCC).
5. The RCC makes contact with the persons listed in the database to verify the existence of an emergency
and gathers additional information about the beacon users. The RCC will dispatch the closest, capable
Search and Rescue (SAR) forces.
6. Local SAR forces launch a rescue mission and if the beacon is not GPS enabled, use the 121.5 MHz
homing signal to pinpoint the beacon.
* On average, worldwide, this notification (steps 2 through 5) takes one hour. For self-locating beacons
that provide GPS position data in their first transmissions, the search radius is reduced to 100 m and the
notification can take as little as three minutes. (Data provided by Cospas-Sarsat.)
Responsible Use Guide — ELT/PLBs are satellite signaling devices of last resort, for use when all
other means of self-rescue have been exhausted, where the situation is grave with imminent danger,
and the loss of life, limb, eyesight or valuable property will occur without assistance.
Register your beacon online – free of charge – at www.beaconregistration.noaa.gov and update every
two years.
Learn more at
cospas-sarsat.int
