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1. INTRODUCTION
1.1. COSPAS-SARSAT system description
COSPAS-SARSAT is a global distress warning system operating in the 406.0 - 406.1 MHz frequency band.
The 406 MHz frequency coded with the beacon ID, is used to determine the position of the beacon to alert the nearest
Search and Rescue Services (S.A.R.).
The system consists of:
(1)
Distress beacons;
(2)
Satellites on polar orbits (LEOSAR) and geostationary satellites (GEOSAR);
(3)
Local User Terminals (LUTs);
(4)
Mission and Rescue Control Centers (MRCC's).
(5)
MCCs receive alerts produced by LUTs and forward them to Rescue Coordination Centers (RCCs) or Search
and Rescue (S.A.R.) Points Of Contacts.
1.2. Immediate alerting and location calculation
When activated, the SafeLink beacons transmit, in the 406 MHz frequency, a coded message with a unique number
to identify the distress and the beacon's owner, and the GPS position. This message is picked up by the COSPAS-
SARSAT satellites which store it and continuously retransmit it to the Local User Terminals (L.U.T) Thanks to the
geostationary satellites (GEOSAR), the distress is received within minutes and transmitted anywhere in the world.
Thanks to the orbital satellites (LEOSAR), the position of the distress is calculated within one nautical mile anywhere
in the world using Doppler techniques. The typical waiting time for calculating a position in average latitudes is less
than one hour.
Thanks to the built-in GPS receiver, its position (accuracy typically about 120 meters) will be transmitted by the
beacon within minutes following the distress.
The data are processed and retransmitted to Mission and Rescue Control Centers (MRCC's) and to the Search And
Rescue Center (RCC or S.A.R.) nearest to the distress to organize the rescue operations.
The 121.5 MHz frequency is also transmitted by the beacon and is used as a homing frequency in the final stages of
rescue.
COSPAS-SARSAT System
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