| 摘要 |
The invention is a method for compensating for fringe visibility errors in a fiber-optic gyro. The light beam phase is modulated utilizing a phase-modulation generating function comprising a stepped waveform with steps of height 2 pi k- phi SE+j phi M- gamma ZS at time intervals tau where a phase step phi specified by the phase-modulation generating function is transformed into a change in light-beam phase of ( phi X/X) phi X where phi X is the change in light phase produced by a phase step X. The integer k takes on the value -1, 0, or 1, j takes on the value -1 or 1, phi SE is a phase determined by the fiber-optic gyro, phi M is a predetermined phase value, and gamma ZS is a phase designed to compensate for the fringe visibility errors. The phase gamma ZS represents a small perturbation to the modulation and is a function of zone Z and state S where the zone identifier Z and state identifier S denote one of a plurality of operating conditions of the fiber-optic gyro. The zone identifier Z depends on the relative magnitudes and signs of phi SE and phi M, and the state identifier S is a function of k and j. Estimates of the Sagnac residual phase compensated for fringe visibility errors are then obtained by adding calculated fringe visibility compensation terms to phi SE.
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