SYNCHRONIZATION SYSTEM AND METHOD FOR ACHIEVING LOW POWER BATTERY OPERATION OF A VEHICLE LOCATING UNIT IN A STOLEN VEHICLE RECOVERY SYSTEM WHICH RECEIVES PERIODIC TRANSMISSIONS
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Accused Products
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.
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Citations
54 Claims
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1-34. -34. (canceled)
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35. A low-power device for synchronizing a vehicle locating unit in a stolen vehicle recovery system with an assigned message frame in a phased transmission from any of a plurality of phased transmission sources, each of the plurality of phased transmission sources capable of emitting a corresponding phased transmission during a discrete period of a transmission cycle for the plurality of phased transmission sources, the device comprising:
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a selectively-actuatable receiver for receiving, during periods of actuation, at least a portion of phased transmissions from the plurality of phased transmission sources; and a microprocessor configured to execute computer-readable instructions to; a. activate the receiver for a period of actuation; b. de-activate the receiver for a delay period of time asynchronous with the transmission cycle of the plurality of phased transmission sources if a transmission is not received; and c. repeat (a) and (b), until d. receive phased transmissions from the plurality of phased transmission sources emitting a transmission signal during the transmission cycle; e. identify a transmission source having a strongest signal by comparing, by the microprocessor, a strength of signal for each of the received phased transmissions; f. for the identified transmission source with the strongest signal, compare, during the corresponding discrete period of the transmission cycle, by the microprocessor, at least a portion of each received phased transmission to a plurality of expected stored commands; and g. synchronize activation and de-activation of the receiver with a timing offset associated with one of the expected stored commands. - View Dependent Claims (36, 37, 38, 39)
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40. A stolen vehicle recovery system comprising:
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a plurality of phased transmission sources, each of the plurality of phased transmission sources capable of emitting a corresponding phased transmission during a discrete period of a transmission cycle for the plurality of phased transmission sources; a vehicle locating unit disposable on a vehicle; and a low-power device for synchronizing the vehicle locating unit with an assigned message frame in a phased transmission from the plurality of phased transmission sources, the device comprising; a selectively-actuatable receiver for receiving, during periods of actuation, at least a portion of phased transmissions from the plurality of phased transmission sources; and a microprocessor configured to execute computer-readable instructions to; a. activate the receiver for a period of actuation; b. de-activate the receiver for a delay period of time asynchronous with the transmission cycle of the plurality of phased transmission sources if a transmission is not received; and c. repeat (a) and (b), until d. receive phased transmissions from the plurality of phased transmission sources emitting a transmission signal during the transmission cycle; e. identify a transmission source having a strongest signal by comparing, by the microprocessor, a strength of signal for each of the received phased transmissions; f. for the identified transmission source with the strongest signal, compare, during the corresponding discrete period of the transmission cycle, by the microprocessor, at least a portion of each received phased transmission to a plurality of expected stored commands; and g. synchronize activation and de-activation of the receiver with a timing offset associated with one of the expected stored commands. - View Dependent Claims (41, 42, 43, 44)
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45. A low-power method for synchronizing a vehicle locating unit of a stolen vehicle recovery system with an assigned message frame in a phased transmission from one of a plurality of phased transmission sources, the vehicle locating unit comprising a receiver and a microprocessor, each of the plurality of phased transmission sources capable of emitting a corresponding phased transmission during a discrete period of a transmission cycle for the plurality of phased transmission sources, the method comprising:
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a. activating the receiver for a period of actuation; b. de-activating the receiver for a delay period of time asynchronous with the transmission cycle of the plurality of phased transmission sources if a transmission is not received; and c. repeating steps (a) and (b), until d. receiving phased transmissions from the plurality of phased transmission sources emitting a transmission signal during the transmission cycle; e. identifying a transmission source having a strongest signal by comparing, by the microprocessor, a strength of signal for each of the received phased transmissions; f. for the identified transmission source with the strongest signal, comparing, during the corresponding discrete period of the transmission cycle, by the microprocessor, at least a portion of each received phased transmission to a plurality of expected stored commands; and g. synchronizing activation and de-activation of the receiver with a timing offset associated with one of the expected stored commands. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53, 54)
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Specification