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System and method for estimating the position and orientation of a mobile communications device in a beacon-based positioning system

  • US 9,846,222 B2
  • Filed: 01/07/2016
  • Issued: 12/19/2017
  • Est. Priority Date: 08/12/2014
  • Status: Active Grant
First Claim
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1. A lighting device, comprising:

  • a light source;

    a modulator coupled to the light source; and

    a processor coupled to the modulator and configured to;

    control the light source to emit visible light for general illumination within a space; and

    control the modulator to;

    modulate, based on a signal received from the processor by the modulator, the intensity of visible light emitted by the light source such that the light source broadcasts a modulated visible light signal;

    vary the modulation of the intensity of the emitted visible light, between a number of modulation rates and within a range, during each of a plurality of cycles, each cycle corresponding to a timeframe to transmit a same code symbol or light source identifier, such that a frequency of the modulated visible light signal varies in each cycle across a frequency range that is assigned to the same code symbol or light source identifier, wherein the frequency range is comprised of multiple frequencies;

    maintain each respective rate of modulation during a respective cycle for some period of time, each period of time being a fraction of the respective timeframe corresponding to the respective cycle such that the collection of time periods for the respective number of modulation rates of the respective cycle varies the frequency of the modulated visible light signal across the frequency range and equals the respective timeframe to transmit the same code symbol or light source identifier; and

    repeat the plurality of cycles some number of times.

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