Scale factor nonlinearity (SFN) and dynamic range (DR) are the two significant parameters used to evaluate the performance of a resonator fiber optic gyro (RFOG). The inherent SFN of an open-loop RFOG with triangular phase modulation is first analyzed theoretically, and its relationship with the DR is simulated, showing that the DR is significantly constrained by the SFN. For our system, when the SFN is 1%, the DR is less than ±82 deg/s. To decrease the SFN in a certain DR, a real-time compensation method based on a field-programmable gate array is proposed. The compensation model is set up and the compensation scheme is illustrated. With the proposed method, the SFN of the RFOG is decreased from 1.53% to 0.057% with a DR of ±100 deg/s.
A closed-loop resonator integrated optic gyro (RIOG) scheme based on triangular wave phase modulation is proposed.
Only one integrated optic modulator (IOM) is employed. Triangular wave is applied on the IOM to modulate the passing
light wave, and the feedback serrodyne wave is superimposed upon the triangular wave to compensate the resonant
frequency-difference. The experimental setup is established and the related measurements are performed. The results
show that the proposed scheme can realize the closed-loop RIOG employing an IOM, which has the advantage of
miniature size. A bias stability of 0.39 deg/s (10 s integration time) over 1 hour is achieved. Moreover, good linearity and
large dynamic range are also experimental demonstrated.