On Specification and Measurement of the IFOG Vibration Error

In stabilization applications, cross-sensitivity to linear vibration of the interferometric fiber-optic gyroscope (IFOG) is increasingly becoming of concern. This vibration error is expressed as the quotient of input acceleration and output angular power spectral densities. The obtained results show that this quotient tends to flatten out to white noise with increasing overall vibration error. Therefore, it was found sufficient to express the vibration error as a gain factor expressed in units of angle per acceleration, which can be used to relate linear vibration to angular noise. The theoretical model has been confirmed by measurements on an industrial scale. The test setup itself was verified independently by autocollimator measurements. Based on these measurements, a development project to reduce vibration error was monitored. It was demonstrated that the proposed hardware improvement reduced vibration cross-sensitivity from > 4 arcsec/g to < 1 arcsec/g.