Vehicle locating unit proof of life subsystem and method
A vehicle locating unit features a receiver which receives a signal from a network of communication sources and a transponder activated when a communication source sends a message to the receiver. There is a transmitter for sending signals to the communication sources and a proof of life subsystem configured to periodically send a proof of life message via the transmitter to the communication sources.
1 . A vehicle locating unit with proof of life functionality comprising:
a receiver which receives a signal from a network of communication sources;
a transponder activated when a communication source sends a message to the receiver;
a transmitter for sending signals; and
a proof of life subsystem configured to periodically send a proof of life message via the transmitter.
2 . The vehicle locating unit of claim 1 in which the proof of life message includes a unique vehicle locating unit identification code.
3 . The vehicle locating unit of claim 2 in which the proof of life message further includes an identification code of a communication source transmitting the strongest signal to the receiver to approximate the position of the vehicle.
4 . The vehicle locating unit of claim 3 further including a signal strength determining subsystem for determining the communication source with the strongest signal transmitted to the receiver.
5 . The vehicle locating unit of claim 1 in which the transmitter transmits the proof of life message to the network of communication sources.
6 . A method of servicing failed vehicle locating units, the method comprising:
configuring the vehicle locating unit to periodically send a message to one or more communication sources;
logging said message in a database; and
servicing said vehicle locating unit if said message is not received.
7 . The method of claim 6 in which the message includes a unique vehicle locating unit identification code and an identification code of a communication source transmitting the strongest signal to the vehicle locating unit to approximate the position of the vehicle locating unit.
8 . A method of operating a vehicle locating unit, the method comprising:
receiving signals from a network of communication sources;
activating a transponder when a communication source sends a message to vehicle locating unit; and
periodically sending a proof of life message to the communication sources.
9 . The method of claim 8 in which the proof of life message includes a unique vehicle locating unit identification code.
10 . The method of claim 9 in which the proof of life message further includes an identification code of a communication source transmitting the strongest signal to the receiver to approximate the position of the vehicle.