A Notch Filter for the Spin Component of a Two-Axis Gyro

Strapdown navigation system performance is increasingly dependent upon the noise characteristics of the measurement sensors. In this paper, a method of annihilating the noise component at gyro spin frequency is proposed which uses a digital finite impulse response (FIR) filter implemented in series with the gyro incremental output. The innovation is to exploit the all-zero nature of FIR filters (infinite attenuation at discrete frequencies) to produce the notching effect. Such a solution based on a FIR filter requires less processing than the corresponding digital notch design based upon the analog prototype. This technique is applied to a two-axis gyro simulation, and results are presented which indicate a noticeable improvement in noise level.