The beginnings of Sarsat date back to 1970 when a
plane carrying two U.S.
congressmen crashed in a remote region of Alaska.
A massive search and rescue effort was mounted, but to this day, no trace
of them or their aircraft has ever been found. In reaction to this tragedy,
congress mandated that all aircraft in the United
States carry an Emergency Locator
Transmitter (ELT). This device was designed to automatically activate after
a crash and transmit a homing signal.
Since satellite technology was still in its infancy, the frequency
selected for ELT transmissions was 121.5 MHz, the international aircraft
distress frequency. This system worked, but had many limitations. The
frequency was cluttered, there was no way to verify who the signal was
originating from, and most importantly, another aircraft had to be within
range to receive the signal.
After several years, the limitations of ELTs began to outweigh their
benefits. At that time, a satellite based system was conceived. It would
operate on a frequency reserved only for emergency beacons (406 MHz), it
would have a digital signal that uniquely identified each beacon, and it
would provide global coverage.
The SARSAT system was developed in a joint effort by the United
States, Canada,
and France.
In the United States,
the SARSAT system was developed by NASA. Once the system was functional,
its operation was turned over to NOAA where it remains today.
As the system began to take hold, more and more emergency beacons
found their way onto the market. ELTs continued to operate exclusively on
121.5 MHz, but maritime beacons (EPIRBs) were being built that operated on
406 MHz. The U.S.
Coast Guard in their role as maritime search and rescue specialists
immediately began to see the benefits of 406 MHz, and in 1990, took
proactive steps to bring it into widespread usage. As a result, today there
are over 75,000 EPIRBs in the NOAA 406 MHz Registration Database. With 406
MHz ELTs and PLBs the number of 406 MHz Emergency Beacons registered now
totals over 82,000! Is your beacon registered too???
A similar system, COSPAS, was developed by the Soviet
Union. The four nations, United
States, Canada,
France
and the Soviet Union banded together
in 1979 to form Cospas-Sarsat. In 1982, the first satellite was launched,
and by 1984 the system was declared fully operational.
Although Cospas-Sarsat satellites were primarily designed to function
on the much improved 406 MHz frequency, they still had to make a provision
for the thousands of 121.5 MHz beacons already in use. For this reason, the
satellites were designed to receive 121.5 MHz as well.
Since that time, however, 121.5 MHz beacons have become a source of
cronic false alerts. Not to mention, they are not as accurate nor as
advanced as the improved 406 MHz beacons. Because of their continual
problems a decision was made internationally that on February 1, 2009 the
Cospas-Sarsat satellites will no longer detect any 121.5 MHz beacons.
The Cospas-Sarsat organization also continued to grow. The four
original member nations have now been joined by 29 other nations that
operate 45 ground stations and 23 mission control centers worldwide or
serve as Search and Rescue Points of Contact (SPOCs). Cospas-Sarsat continues to be a
model of international cooperation. During the eighties, the Soviet
Union and the United
States were able to put aside
their Cold War differences and tackle some tough technical questions.
Today, new technology continues to evolve and the member nations are
actively incorporating that technology into The
Cospas-Sarsat System of Tomorrow
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