A Personal Locator
Beacon (PLB), supporting two operation
modes local monitoring and remote monitoring. The apparatus includes a PLB that supports the present
operation mode, as well as a local monitoring mode, employing the same
transmitter, and automatically switching between
modes. Upon activation, the PLB first tries to communicate with a local monitoring
station, at a
low transmission power, and at a high repetition rate, in purpose of dealing with the PLB call locally, without involving the remote monitoring
station. Then, if not acknowledged by a local monitoring
station, the PLB increases its transmission power, enabling access to a remote monitoring station. In a preferred embodiment, the PLB is carried by a person onboard a vessel, to alarm upon a Man Overboard (MOB) accident, the local monitoring station is installed onboard the same vessel, and the remote monitoring station is part of a
satellite Search and Rescue (SAR)
system, as Cospas-Sarsat.