A PLB (Personal Location Beacon) serves as an alarm for SAR stations in case of accidents at sea, in the bush or in the air. In order to do this, the PLB first determines its own position after an alarm and then transmits the distress call via one or several satellites. Firstly the emergency transmitter determines its own position with the help of the GPS satellite navigation system. This is performed by a built-in GPS receiver. The PLB starts to transmit the distress call immediately via one or several COSPAS-SARSAT satellites. The PLB is typically a device that is carried by an individual and is activated manually.