Anatomy Of A Rescue - ACR Electronics Cobham ResQLink PLB-375 Product Support Manual

2. Anatomy Of A Rescue

HOW THE BEACON WORKS
How your beacon summons help
406 MHz beacons are a type of portable emergency equipment that
transmits a distress signal to search and rescue (SAR) organizations. The
purpose of these beacons is to aid SAR teams in tracking and locating
ships or individuals in jeopardy as rapidly as possible.
The 406 MHz frequency is a worldwide dedicated emergency frequency
that is detected by a network of satellites called the Cospas-Sarsat
system. This satellite system was established by, and continues to be
supported by, its primary benefactors - the USA, Russia, Canada and
France. The Cospas-Sarsat system has saved over 30,500 lives - and
counting - since its inception. To learn more about the system visit
www.cospas-sarsat.org.
When a 406 MHz beacon is activated, the digital distress message is sent
to Cospas-Sarsat satellites and, in turn, the distress message is relayed
to SAR forces. The distress message contains the beacon UIN and on
some models the GPS location of the beacon. Additional information
about the beacon is accessed by SAR forces from the beacon registration
database. At the same time the 406 MHz signal is activated, a 121.5 MHz
signal is turned on. The 121.5 MHz signal is used by SAR forces to home
in on the beacon as they approach it.
The 406 MHz signal is detected by multiple satellites and from that
information the location of the beacon can be calculated. This data alone
User Tip
Learn more about the Cospas-Sarsat satellite
is sufficient for SAR to find persons or ships in distress in a reasonable
system: www.cospas-sarsat.org
timeframe. However, as a further enhancement, some beacons have a
GPS engine onboard. This feature allows the beacon to acquire current
location coordinates from an internal GPS receiver. The purpose of this
feature is to send an even more precise location of the beacon to the
satellites, i.e., latitude and longitude data. This helps SAR to reach the
location even faster.
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