RFOG modulation error correction
First Claim
1. A resonator fiber optic gyro (RFOG) comprising:
- at least one laser configured to generate at least two light waves;
a resonator having an optical fiber loop, the resonator configured to allow the light waves generated by the at least one laser to travel in clockwise (cw) and counter-clockwise (ccw) directions in the optical fiber loop;
at least two intensity modulators configured to perform intensity modulation of the light waves before introduction into the resonator;
two photodetectors configured to detect components of the light waves rotating cw and ccw in the resonator; and
a processor in signal communication with the photodetectors, the processor configured to reject intensity signals due to backscatter based on the intensity modulations and determine rate of rotation based on the detected components.
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Accused Products
Abstract
Systems and methods for performing modulation error correction. An example system applies common phase/frequency modulation to first and second laser beams, a first intensity modulation to the first modulated beam, and a second intensity modulation to the second modulated beam. Signals outputted are demodulated according to the frequency of the common phase/frequency modulation. Then the first of these demodulated signals is demodulated based on the frequency of the intensity modulation of the first beam, and the second of these demodulated signals is demodulated based on the frequency of the intensity modulation of the second beam. Then, rate of rotation is determined based on demodulated signals. Frequencies of the intensity modulations are unequal and not harmonically related, and intensity modulation encodes each light beam with a unique signature.
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Citations
19 Claims
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1. A resonator fiber optic gyro (RFOG) comprising:
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at least one laser configured to generate at least two light waves; a resonator having an optical fiber loop, the resonator configured to allow the light waves generated by the at least one laser to travel in clockwise (cw) and counter-clockwise (ccw) directions in the optical fiber loop; at least two intensity modulators configured to perform intensity modulation of the light waves before introduction into the resonator; two photodetectors configured to detect components of the light waves rotating cw and ccw in the resonator; and a processor in signal communication with the photodetectors, the processor configured to reject intensity signals due to backscatter based on the intensity modulations and determine rate of rotation based on the detected components. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method comprising:
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applying common phase/frequency modulation to first and second laser beams; applying a first intensity modulation to the first modulated beam; applying a second intensity modulation to the second modulated beam; sending the first intensity modulated beam through an optical resonator in a clockwise (cw) direction; sending the second intensity modulated beam through the optical resonator in a counter-clockwise (ccw) direction; and analyzing the signals outputted from the optical resonator to determine rate of rotation and reject intensity signals due to backscatter based on the intensity modulations. - View Dependent Claims (15, 16)
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17. A system comprising:
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a means for applying common phase/frequency modulation to first and second laser beams; a means for applying a first intensity modulation to the first modulated beam; a means for applying a second intensity modulation to the second modulated beam; a means for sending the first and second beams through the optical resonator; and a means for analyzing the signals outputted from the optical resonator. - View Dependent Claims (18, 19)
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Specification