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Method and system for modifying a beacon light source for use in a light based positioning system

  • US 9,723,676 B2
  • Filed: 06/19/2012
  • Issued: 08/01/2017
  • Est. Priority Date: 07/26/2011
  • Status: Active Grant
First Claim
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1. A method, comprising:

  • determining in response to an input data signal a power modulation frequency of a light source configured to emit light for general purpose illumination;

    determining in response to a dimming input signal a light output duty cycle for a light source, wherein the duty cycle comprises a proportion of time the light source is in a high-luminosity output state and a corresponding proportion of time the light source is in a reduced-luminosity output state;

    supplying power to drive the light source to output light that transmits data and provides general purpose illumination in accordance with the determined power modulation frequency and duty cycle;

    calculating a decrease in average luminosity of the general purpose illumination light output by the light source caused by modulating the power supplied to the light source based on the proportion of time the light source is in the reduced-luminosity output state; and

    raising the reduced-luminosity output state of the general illumination light source by adding a DC bias to the power supplied to the light source to thereby compensate for the calculated decrease in average luminosity of the light source due to power modulation in response to the input data.

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