In the field of Search and Rescue (SAR), distress radio beacons, also
collectively known as distress beacons, emergency beacons,
or simply, beacons, are
tracking transmitters which aid in the detection and location of
boats,
aircraft, and/or persons in
distress. In the proper sense, the term refers specifically to the
three types of
radiobeacons (listed below) that interface with
Cospas-Sarsat, the international
satellite system for Search and Rescue. When activated, such beacons
send out a
distress signal that, when detected by
non-geostationary satellites, can be located by
triangulation. In the case of
406 MHz beacons which transmit digital signals, the beacons can be
uniquely identified almost instantly (via
GEOSAR), and furthermore, a
GPS position can be
encoded
into the signal (thus providing both instantaneous identification and
position.) Often using the initial position provided via the satellite
system, the distress signals from the beacons can be
homed
by SAR aircraft and ground search parties who can in turn come to the
aid of the concerned
boat,
aircraft, and/or persons.
There are three types of distress radio beacons compatible with the
Cospas-Sarsat system:
EPIRBs (Emergency
Position-Indicating Radio Beacons) signal maritime distress,
ELTs (Emergency Locator
Transmitters) signal aircraft distress
PLBs (Personal Locator Beacons)
are for personal use and are intended to indicate a person in distress
who is away from normal
emergency services, e.g.,
9-1-1.
Also in use for crew saving applications in shipping and lifeboats at
terrestrial systems.
The basic purpose of distress radio
beacons (EPIRB) is to get people rescued within the so-called "golden
day"(the first 24 hours following
a traumatic event) when the majority of survivors can still be saved.
