A Low-Noise Readout Circuit for Gyroscopes

In order to suppress the noise of gyroscopes, the method based on lock-in amplifier and capacitor matching of the low-noise readout circuit is proposed. Firstly, the principle to suppress the noise by lock-in amplifier is analyzed, and the noise model of front end is proposed. Secondly, the noise optimization for the charge amplifier is presented according to the noise model of front end. Finally, a readout circuit is constructed by this approach. The measurement results show that the parasitic capacitance of front end is 18 pF, and the noise at resonant frequency (4 kHz) is 133 nV/Hz1/2, and the overall bias stability is 30°/h, and the noise level is 0.003°/(s·Hz1/2). The noise of the gyroscope with the low-noise readout by this method is suppressed effectively.