Random noise study of the digital closed-loop fiber optic gyroscope

The random noise of the fiber optic gyroscope(FOG) is not only concerned with the noise of the optical path in system, but also concerned with a various of noise in the modulation and demodulation circuit. The characteristics of the shot noise, thermal noise of the detector and the relative intensity noise of light source were analyzed. The random noise model was established by use of the closed-loop transfer function. The relationship between the fiber optic gyro random walk coefficient (RWC) and these noises was analyzed. According to the theoretical results, some parameters of the gyro were adjusted, and the performance of the gyro was optimized. The theoretical results were compared with the experimental data analyzed by Allan variance, the random walk coefficient model was proved correct.