Personal Locator Beacon
A Personal Locator Beacon (PLB) is a an emergency beacon to alert rescue authorites and to indicate the location and the identity of a person in distress. These beacons are designed to be carried by an individual person. A PLB has to activated manually.
PLBs operate on 406 MHz. The signal of a PLB is detected by the COSPAS-SARSAT satellite network anywhere in the world. The network passes the alert to the nearest rescue authority.
The COSPAS-SARSAT satellite network can detect the location of the PLB with an accuracy of 2 to 5 km. Newer PLBs can have a GPS navigation receiver integrated into the distress signal. These PLBs will transmit an accurate location.
The PLB also transmits a low-power "homing" signal on 121.5 MHz. This allows rescue forces to home in on a beacon as soon as they are in the vicinity.
The transmission of the PLB contains a personal identity. PLBs have to be registered at the local authorities.