System and method for estimating distance between a mobile unit and a vehicle using a TOF system

  • US 10,288,724 B2
  • Filed: 11/20/2015
  • Issued: 05/14/2019
  • Est. Priority Date: 04/12/2011
  • Status: Active Grant
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First Claim
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1. A method of estimating distance between a mobile unit and a vehicle, said method comprising:

  • providing a time of flight subsystem including circuitry incorporated in the mobile unit and circuitry incorporated in the vehicle;

    generating, by the time of flight subsystem, a time of flight distance signal by periodically transmitting a time of flight signal between the mobile unit and the vehicle and measuring the time taken for transmission of the time of flight signal between the mobile unit and the vehicle;

    disposing a travel sensor at the mobile unit;

    generating a travel sensor signal using the travel sensor;

    initializing, by the mobile unit circuitry, a value of a distance estimate signal based on the time of flight distance signal;

    determining, by the mobile unit circuitry, movement of the mobile unit based on variance in the travel sensor signal; and

    changing, by the mobile unit circuitry, the initialized value of the initialized distance estimate signal based upon determination of movement of the mobile unit, wherein the value of the initialized distance estimate signal is increased by a first predetermined quantum responsive to the time of flight distance signal being greater than the initialized distance estimate signal, and wherein the value of the initialized distance estimate signal is decreased by a second predetermined quantum responsive to the time of flight distance signal being less than the initialized distance estimate signal.

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