Abstract: Improved power management for a vehicle locating unit is achieved by receiving a transmission from a communication source, each transmission including at least one message frame having a data field and at least one auxiliary field; entering a wake mode upon indexing the assigned message frame of the receiver in the transmission; matching the pattern of bits of at least one auxiliary field of the indexed frame with one or more stored patterns of bits expected for that auxiliary field; and returning to the sleep mode as soon as a mismatch is determined or processing the message if no mismatch occurs.

Abstract: An adaptive range vehicle recovery system including an adaptive range vehicle locating unit including a narrowband baseband generator for generating a narrowband signal, a wideband baseband generator for generating a wideband signal, a timing control circuit responsive to an activation signal to transmit, alternately, said narrowband signal at a first rate, and said wideband signal at a second rate and responsive to a track signal to transmit one of said wideband and narrowband signals at a third, different, rate; and also to an adaptive range vehicle recovery system including an adaptive range vehicle track unit including a data decoder including, a wideband decoder for detecting data from a wideband baseband signal, a narrowband decoder for detecting data from a narrowband baseband signal, a bandwidth detector responsive to a received signal to distinguish narrowband and wideband signals and an input switching circuit responsive to said bandwidth detector for directing the wideband signal to the wideband de

Abstract: Synchronization for achieving low power battery operation of a vehicle locating unit in a stolen vehicle recovery system whose radio receiver receives periodic transmissions, includes receiving periodic transmissions; turning on a radio receiver for a limited time to detect an expected message; if an expected message is not found, turning off the receiver and turning it on again after a time asynchronous with the transmission period; and after finding an expected message, waiting for the period of the transmissions less the length of an expected message and then looking for a synchronization symbol in the expected message and synchronizing subsequent actuation of the receiver using that synchronization symbol.

Abstract: Improved power management for a vehicle locating unit is achieved by receiving a transmission from a communication source, each transmission including at least one message frame having a data field and at least one auxiliary field; entering a wake mode upon indexing the assigned message frame of the receiver in the transmission; matching the pattern of bits of at least one auxiliary field of the indexed frame with one or more stored patterns of bits expected for that auxiliary field; and returning to the sleep mode as soon as a mismatch is determined or processing the message if no mismatch occurs.

Abstract: A method of checking messages from a network of communication sources includes initially testing the signal strength of a plurality of communication sources, storing the identity of the communication sources with the two strongest signals, and alternatively entering a sleep mode and a wake-up mode, the wake-up mode synchronized to the communication source with the strongest signal. The method further includes testing the signal strength of one additional communication source, switching synchronization to the additional communication source if said source presents a signal stronger than the signal of a stored communication source with the strongest signal, and replacing the identity of any stored communication source if an additional communication sources tested in sequence presents a signal stronger than the signal of said stored communication source.

Abstract: A method of checking messages from a network of communication sources includes initially testing the signal strength of a plurality of communication sources, storing the identity of the communication sources with the two strongest signals, and alternatively entering a sleep mode and a wake-up mode, the wake-up mode synchronized to the communication source with the strongest signal. The method further includes testing the signal strength of one additional communication source, switching synchronization to the additional communication source if said source presents a signal stronger than the signal of a stored communication source with the strongest signal, and replacing the identity of any stored communication source if an additional communication sources tested in sequence presents a signal stronger than the signal of said stored communication source.

Abstract: A vehicle locating unit with improved power management. A receiver receives a signal from a network of communication sources. A signal strength monitoring subsystem determines which of the communication sources are transmitting the strongest signals. A power management subsystem is responsive to the signal strength monitoring subsystem and is configured to alternatively enter sleep and wake-up modes, synchronize the wake-up mode to the communication source transmitting the strongest signal, and test the signal strength of at least one additional communication source according to a predefined sequence.

Abstract: A vehicle locating unit with a receiver for receiving a signal from a network of communication sources, a transponder activated when a communication source sends a message to the receiver, and a power supply regulating circuit for regulating a nominal input voltage and powering the receiver and the transponder. A protection circuit is responsive to an injected input voltage and configured to clamp the injected (high level) input voltage at a predetermined maximum voltage.

Abstract: An adaptive range vehicle recovery system including an adaptive range vehicle locating unit including a narrowband baseband generator for generating a narrowband signal, a wideband baseband generator for generating a wideband signal, a timing control circuit responsive to an activation signal to transmit, alternately, said narrowband signal at a first rate, and said wideband signal at a second rate and responsive to a track signal to transmit one of said wideband and narrowband signals at a third, different, rate; and also to an adaptive range vehicle recovery system including an adaptive range vehicle track unit including a data decoder including, a wideband decoder for detecting data from a wideband baseband signal, a narrowband decoder for detecting data from a narrowband baseband signal, a bandwidth detector responsive to a received signal to distinguish narrowband and wideband signals and an input switching circuit responsive to said bandwidth detector for directing the wideband signal to the wideband de

Abstract: A vehicle locating unit with improved power management. A receiver receives a signal from a network of communication sources. A signal strength monitoring subsystem determines which of the communication sources are transmitting the strongest signals. A power management subsystem is responsive to the signal strength monitoring subsystem and is configured to alternatively enter sleep and wake-up modes, synchronize the wake-up mode to the communication source transmitting the strongest signal, and test the signal strength of at least one additional communication source according to a predefined sequence.

Abstract: A vehicle locating unit with a receiver for receiving a signal from a network of communication sources, a transponder activated when a communication source sends a message to the receiver, and a power supply regulating circuit for regulating a nominal input voltage and powering the receiver and the transponder. A protection circuit is responsive to an injected input voltage and configured to clamp the injected (high level) input voltage at a predetermined maximum voltage.

Abstract: 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.