The method of averaging using an adaptive notch filter in vibratory gyroscopes

This paper presents an adaptive notch filter to achieve more accurate demodulation variables in the method of averaging. The main advantage of this notch filter is a very sharp attenuation gain at twice of the estimated resonance frequency, which is the main frequency component of the oscillatory noise in the demodulated variables. The position of the sharp attenuation gain can be adjusted in real time to catch the resonator's resonance frequency change. As a result, it can demodulate the control variables up to very high accuracy. Performing the method of averaging on the cleaner signals will result in much higher rotation angle estimation accuracy when the method of averaging is running in the whole angle mode. Simulation results show that with the adaptive notch filter, the oscillation in the system's quadrature and precession angle can be eliminated very well. The adaptive notch filter also effectively reduces the DC drift in the precession angle.