Honeywell International Inc.

Waymon Ho

Lee Kevin Strandjord

Glen Aaron Sanders

Tiequn Qiu

Chuck Croker

Systems and methods for resonance switching RFOGs with feed-forward processing are provided. In one embodiment, a system comprises: a fiber optic resonator; first and second laser sources coupled to the resonator, wherein the first source launches a first beam into the resonator and the second source launches a second beam into the resonator in an opposite direction; a first servo loop that locks the first beam to a first resonant mode of the resonator during a first state and to a second resonant mode of the resonator during a second state; a second servo loop that locks the second beam to the second resonant mode during the first state and to the first resonant mode during the second state; a feed-forward rate processor coupled to the servo loops that calculates a FSR average across a prior resonance switching cycle of resonant frequency measurements and applies the average to current measurements.

Systems and methods for resonance switching resonator fiber optic gyroscopes (RFOGs) with feed-forward processing

A RFOG, comprising: a master laser emitting a reference optical signal; first and second slave lasers emitting first and second optical signals; an optical resonator ring cavity coupled to the lasers, the first and second optical signals propagating in first and second directions through the optical resonator ring cavity; one or more signal generators to inject first and second modulation signals at first and second frequencies on both optical signals; first and second photodetectors that generate first and second signals; first and second demodulators to demodulate the first and second signals using first and second reference signals and the first and second frequencies; a differencing function to output the difference between resonance frequencies of the first and second signals; at least a third demodulator to detect reference phase errors; and at least one phase servo to adjust the phase of at least one of the first and second reference signals.

Resonator fiber optic gyroscope resonance detection demodulator reference phase corrector

A method of measuring beat frequency comprises modulating a first optical signal and a second optical signal, wherein the first modulated optical signal includes a first carrier frequency and a first plurality of sideband frequencies and the second modulated optical signal includes a second carrier frequency and a second plurality of sideband frequencies. The method also comprises combining a fraction of the first modulated optical signal with a fraction of the second modulated optical signal into a combined signal and determining a carrier beat frequency. The method further comprises selecting a frequency range from the combined signal; performing a fast Fourier transform (FFT) on an electrical signal representing the selected frequency range; tracking the carrier beat frequency based on the FFT; and outputting a rate signal based on the tracked carrier beat frequency, the rate signal indicating a rotation rate of the resonator fiber optic gyroscope.

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Glendale, AZ, United States of America

Waymon Ho