Angle error from vibrating in tri-axial interferometric fiber optic gyroscopes and the evaluation with dual-laser Doppler vibrometers

Abstract

Abstract In this paper, we accurately obtained the depolarized interferometric fiber optic gyroscope (D-IFOG) output error caused by elasto-optic effect in vibration environment. We established the optical transmission model of D-IFOG and simulated the stress distribution of D-IFOG caused by vibration based on finite element method. The computational results show that the angular velocity error has a phase difference of 90° with the sinusoidal excitation, and when the vibration’s amplitude is 4 g and the frequency is 70 Hz, for triaxial D-IFOGs, the maximum angle error of Y-axis is up to 3.54 × 10−4°, and that of X-axis and Z-axis is 6.26 × 10−5°. And we set up a high-precison dynamic angular measurement system based on dual-laser Doppler vibrometers to evaluate the angular error in D-IFOGs. The experimental results are consistent with those of numerical simulations, which have verified the angle error model. This work is meaningful for the follow-up D-IFOG’s vibration error compensation.