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Noise characteristics in IFOG

IFOG (Interferometric Fiber Optic Gyroscope) is the most promising angular velocity sensor in the inertial guidance market due to its attractive advantages, which is often regarded as the next generation gyro that can ultimately replace the traditional mechanical gyroscope. In order to improve the performance of IFOG, especially to low down the bias drift and angle random walk (ARW) of IFOG, it is valuable to research the noise characteristics of IFOG. In this paper, the ultra low frequency random noise and the relatively high frequency random noise has been investigated respectively. The experimental data of a practical open loop IFOG is obtained by different sampling frequency, through which the different frequency scope of the noise can be researched separately. The frequency spectral analysis of the noise deduces the follow result: (1) the relative high frequency (higher than about 0.001 Hz) random noise can be approximately modeled as Gaussian white noise (GWN), and its spectral range is determined by the system bandwidth of IFOG. The angle random walk of IFOG is determined by this kind of noise. (2) The ultra low frequency (lower than about 0.001 Hz) random noise can not be Gaussian white noise, which is much more great than other noises, and with the rise of frequency, the power of the relevant frequency component is lower down sharply. The ultra low frequency noise is often regarded as the source of bias drift of IFOG.