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Ultrasonic in-building positioning system based on phase difference array with ranging

  • US 7,796,471 B2
  • Filed: 02/05/2009
  • Issued: 09/14/2010
  • Est. Priority Date: 02/20/2008
  • Status: Active Grant
First Claim
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1. A method for determining position of a mobile electronic device within a building, comprising:

  • emitting, in the building at least one of an electromagnetic and an optical initiation signal from the mobile electronic device;

    identifying the mobile device by detecting the initiation signal at a base station disposed in the building;

    transmitting a control signal from the base station to cause emitting an acoustic pulse from the position of the mobile electronic device;

    detecting the acoustic pulse at the base station at at least three known spaced apart locations along each of at least two lines extending in different directions;

    determining the time differences of arrival of acoustic pulses at each of the detecting locations;

    determining a phase difference of the acoustic pulse between each of the detecting locations;

    determining a relative position of the device with respect to the base station known position from the time differences of arrival and phase differences; and

    at least one of storing or displaying the relative position.

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