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Clandestine location reporting by a missing vehicle

  • US 5,629,693 A
  • Filed: 05/17/1995
  • Issued: 05/13/1997
  • Est. Priority Date: 11/24/1993
  • Status: Expired due to Fees
First Claim
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1. Apparatus for determining and reporting the present location of a missing vehicle, the apparatus comprising:

  • a location determination (LD) unit, including an LD signal antenna and LD receiver/processor, positioned on the vehicle to receive LD signals from at least three distinguishable LD signal sources and to process these LD signals so that the processed signals can be used to determine the present location of the LD antenna;

    a cellular phone unit positioned on the vehicle and comprising;

    a cellular phone handset that receives audio signals at a first port and converts these audio signals to electronic signals and that receives electronic signals at a second port and converts these electronic signals to audio signals; and

    a cellular phone radio transceiver and antenna that receives electronic signals at a signal port and transmits these signals as outgoing radiowave signals at a selected frequency to a central station that is spaced apart from the cellular phone transceiver, that receives incoming radiowave signals from the central station and issues these signals as electronic signals at the signal port, and that can generate and issue an audibly perceptible or visually perceptible incoming call signal that indicates when the radio transceiver and antenna is receiving an incoming radiowave signal intended for that transceiver, where the cellular phone transceiver and antenna are capable of receiving and responding to an LD interrogation signal from the central station that requests information on the present location of the LD antenna; and

    a controller, positioned on the vehicle, connected to and selectively controlling and acting as an interface between the LD unit and the cellular phone unit, for passing signals between the LD unit and the cellular phone unit, wherein (i) when the cellular phone unit receives an incoming phone call, the controller causes the cellular phone unit to delay issuance of an incoming call signal for a selected initial time interval of length Δ

    td ;

    (ii) when the cellular phone unit receives an LD interrogation signal during an initial time interval of length Δ

    td as part of the incoming phone call, the controller causes the cellular phone unit not to issue an incoming call signal indicating receipt of an incoming call, causes the LD unit to provide the cellular phone unit with information on the present location of the LD antenna, and causes the cellular phone radio transceiver and antenna to transmit this present location information to the central station; and

    (iii) when the cellular phone unit does not receive an LD interrogation signal during an initial time interval of length Δ

    td as part of the incoming phone call, the controller causes the cellular phone unit to operate as a normal cellular phone and to issue an incoming call signal that is perceptible by an occupant of the vehicle.

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