Honeywell International Inc.

USA As Represented by Secretary of the Navy

David A Doheny

Norman Gerard Tarleton

Lee Kevin Strandjord

Steven J Sanders

Jeffrey Earl Lewis

Austin Taranta

Derek Mead

Sorin Mosor

Stephan Enzone

John L Kollig

Lee K Standjord

Systems and methods for environmentally insensitive high-performance fiber-optic gyroscopes are provided. In one embodiment, a loop closure electronics apparatus for a fiber optic gyroscope having an optical phase modulator characterized by a transfer function that includes an error component of at least second order is provided. The apparatus comprises: a first digital circuit that generates a digital bias modulation signal; a second digital circuit that generates a digital feedback signal; at least one digital-to-analog converter that produces an electrical signal that drives the phase modulator from the digital bias modulation signal and the digital feedback signal; and a compensator that includes an analog filter of at least second order and a digital filter of at least second order, wherein the analog filter and the digital filter pre-filter the electrical signal to compensate for the error component.

Systems and methods for environmentally insensitive high-performance fiber-optic gyroscopes

A synchronous fiber optic gyroscope includes a light source, an optical coupler in optical communication with the light source, an optical modulator in optical communication with the coupler, and a fiber optic coil in optical communication with the modulator. A detector is configured to receive an optical signal from the coupler and convert the optical signal to an electrical signal. A loop closure signal processor has a first input configured to receive the electrical signal from the detector. A phase lock loop has an output operatively connected to a second input of the processor. A direct digital synthesizer is operatively coupled to an input of the phase lock loop, with the synthesizer configured to generate a low-frequency signal that is transmitted to the phase lock loop. The phase lock loop converts the low-frequency signal to a high-frequency signal that is transmitted to the second input of the processor, and the phase lock loop provides signal modulation that is synchronous with signal demodulation.

Synchronous radiation hardened fiber optic gyroscope

A digital feedback system for an optical gyroscope include a fiber optic sensing coil, an optical phase modulator, a photo detector and a processor. The sensing coil induces a phase differential between light waves traveling though the coil. The optical phase modulator causes a second phase differential between the light waves. The photo detector receive the light waves and outputs an intensity signal representing a phase difference between the light waves. The processor determines a rate of rotation of the fiber optic sensing coil based on the phase difference. for the system operates by generating a closed loop feedback signal, demodulating the signal to determine the phase difference, determining a rate of rotation, periodically incrementing a feedback ramp signal once every &#x3c4; second period based on the rate of rotation, and resetting the feedback ramp signal when the ramp is incremented a predetermined number of times since a previous reset.

Digital feedback systems and methods for optical gyroscopes

A least-mean-squares based algorithm is used to adaptively update dither stripper gains, in a dither stripper of a ring laser gyro. The algorithm is used in conjunction with a dither estimator of the dither stripper. The dither stripper substantially reduces effects of dithering a ring laser gyro, during operation of the ring laser gyro.

Dither stripper having least-mean-squares adaptive updating of dither stripper gains

A system for detecting the eigen frequency of a sensing coil in a fiber optic gyro (FOG) that includes a fiber coupler connected to the light source, an integrated optics chip (IOC) capable of modulating light received from the light source via the fiber coupler, a sensing coil in communication with the IOC, a first modulation generator for imparting a first modulation signal to the light, and a photodetector for receiving light returning from the sensing coil that is representative of a rotation rate of the sensing coil. Along with the foregoing there is provided a second modulation generator for imparting a second, preferably sinusoidal, modulation signal to the light, a high-frequency demodulator in communication with a signal produced, at least indirectly, by the photodector, and a low-frequency demodulator in communication with the high-frequency demodulator. The high-frequency demodulator receives the first modulation signal as a reference frequency and the low-frequency demodulator receives the second modulation signal as a reference frequency. An output of the low-frequency demodulator represents a magnitude and sign of a frequency difference between a frequency of the second modulation signal and an even-harmonic of the eigen frequency.

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Clearwater, FL, United States of America

David A Doheny