Design of output filter of digital closed-loop fiber optic gyroscopes

The output of digital closed-loop fiber optic gyroscope (FOG) was decimated from a high sample rate feedback signal. To avoid alias in frequency domain during decimation process, a low-pass filter was needed. A multi-stage decimation filter was designed on the theory of multi-rate digital signal processing. Compared with the one stage low-pass filter, the designed three stage decimation filter has much less computation and better filter character. The testing results show that the designed decimation filter did not change the static performance of the fiber optic gyroscope, but it suppressed the high frequency error caused by vibration, and improved the precision of the fiber optic gyroscope.