A Personal Locator Beacon, or PLB, is a device that emits a radio signal, usually at 406 MHz , to the international COSPAS-SARSAT satellite system. In general, the PLB signal is located using satellite trilaterate (at the largest scale), and radio direction finding (at local scale). Some recent PLBs contain a GPS, and can send the PLB’s position, encoded as binary data, in the radio signal. This provides a secondary, redundant way to locate the beacon.
It’s important to note that PLB’s are often referred to as a “beacon” but they are very different from, and do not do the same thing as an Avalanche Transceiver. They also function on an entirely different system than Satellite Emergency Notification Devices (SEND).
When a Personal Locator Beacon is activated, the following events occur
- The beacon sends a 406 MHz signal, with optional GPS location, at 50 second intervals.
- The GPS initially sends a very general location
- As time goes on the GPS calculates a more accurate location
- It is important to leave the beacon ON so it can continue to transmit the location
- The COSPAS-SARSAT system calculates the signal location to approximately 20km and sends it to a ground station
- As mentioned above, the location becomes more accurate with time
- The ground station alerts the local rescue authority
In British Columbia, this is the Joint Rescue Coordination Centre (JRCC) in Victoria BC
- If the JRCC determines the PLB to be on land or inland water, they forward the message to Ground Search and Rescue.
In BC, this is Emergency Management BC’s Emergency Coordination Centre
- The ECC activates the SAR team nearest to the PLB activation
- The SAR team communicates with the JRCC for updated locations