Method and system for modifying a beacon light source for use in a light based positioning system
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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Abstract
In one aspect, the present disclosure related to a method for modifying a beacon light source for use in a light-based positioning system. In some embodiments, the method includes selecting a modulation scheme for the light source, determining a duty cycle for the light source based on the modulation scheme, the duty cycle having a proportion of time the light source is in an on state and a corresponding proportion of time the light source is in an off state, the proportion of time the light source is in an off state resulting in reduced luminosity of the light source, and supplying additional power to the light source to compensate for the reduced luminosity of the light source by the duty cycle.
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Citations
26 Claims
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1. A method, comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 19, 21, 22, 23, 24, 26)
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10. A light source for general purpose illumination, comprising:
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an emitter configured to emit light broadcasting a modulated data signal modulated and in accordance with a light output duty cycle as general purpose illumination; a modulator configured to; determine a modulation frequency based on an input data signal; determine the light output duty cycle based on a dimming signal and the determined modulation frequency, wherein the determined light output duty cycle comprises a proportion of time the general purpose illumination light source is in a high-luminosity output state and a corresponding proportion of time the general purpose illumination light source is in a reduced-luminosity output state, and wherein frequency modulating the power supplied to the general purpose illumination light source decreases an average luminosity of the general purpose illumination light source; and a driver configured to; add, in response to the decreased average luminosity of the general purpose illumination light due to power modulation in response to the input data, a DC bias to the power supplied to the general purpose illumination light source to raise the reduced-luminosity output state of the light source to compensate for the decrease in average luminosity of the general purpose illumination light source. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 20, 25)
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Specification