Eye Current

Search and Rescue Goes Digital

1st generation EPIRBs

Starting February 1st, Cospas-Sarsat will discontinue monitoring of the 121.5 & 243 MHz frequencies. These frequencies are used for analog based emergency position-indicating radio beacons (EPIRB). Search and rescue (SAR) groups world wide will only monitor the 406 MHz frequency, which is dedicated to digital locators. The 406 MHz digital band has many advantages over the older Analog systems.

Since the locators send data to the satellites, rather than just a continuous signal, much more will be known about the emergency before a SAR group arrives, such as the type of vehicle and owner. In addition, the accuracy will be greatly enhanced from a 20km initial fix to 100m if locator has a GPS fix. The most important reason for the switch is the reduction of false positives. With the older analog bands, only about 1 in every 50 alerts was real, whereas with the digital system that is reduced to about 1 in every 17 alerts being real.

With fewer false positives and greatly increased accuracy, SAR groups around the world will be better able and faster to respond to life threatening emergencies within the critical "golden day". They will also be able to do this with much less wasted resources.

The phase out of Analog transponders has been a long time coming. The first warnings were sent by the US Coast Guard out in 2000, and the Analog devices have not been manufactured in the last several years. For most large boats the cost of upgrading to the new system was negligible. The change February 1st is world wide and both the International Civil Aviation Organization and the International Maritime Organization recommended the switch.

posted by RGonzales @ 8:25 AM