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STEP FILTER FOR ESTIMATING DISTANCE IN A TIME-OF-FLIGHT RANGING SYSTEM

  • US 20120262340A1
  • Filed: 04/11/2012
  • Published: 10/18/2012
  • Est. Priority Date: 04/12/2011
  • Status: Active Grant
First Claim
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1. A method of estimating a distance between a mobile node and a base station, said method comprising:

  • providing a display on the mobile node;

    providing a time of flight subsystem including circuitry incorporated in the mobile node and the base station and generating a time of flight distance signal by periodically transmitting a time of flight signal between the mobile node and the base station and measuring the time taken for transmission of the time of flight signal therebetween;

    providing an accelerometer on the mobile node and generating an accelerometer signal therewith;

    initializing the value of a distance estimate signal based on the time of flight distance signal;

    detecting a human step based on variances in the accelerometer signal;

    changing the value of the distance estimate signal by a predetermined quantum only upon detection of a human step, the change being an increase or decrease depending on a direction of the time of flight distance signal relative to the distance estimate signal; and

    periodically displaying the value of the distance estimate signal on the display.

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