A Phase compensation method for MEMS quadruple mass gyroscope in zero bias drift

This paper proposes a system phase analysis for MEMS quadruple mass gyroscope (QMG) and improves the stability by 20 times. The improvement factors come from the phase noise model analysis and front-end amplifier design. To make sure which factor is dominant in zero bias and improve the stability, a series of experiments are carried out here to discuss their drift contribution, including environmental change. Meanwhile, a new systematic phase noise method is applied for stability analysis, which helps find the dominant physics sources to improve the zero bias. Combing the experimental results and the theoretical noise model, we establish the actual noise model. By analysis, the dominant noise sources mainly come from the demodulation reference signal and the sense signal, both influenced by the front-end amplifier. In this paper, we design a two-stage capacitive amplifier instead of the trans-impedance amplifier, in which, the noise of input current introduced by cross-resistance (signal noise) and the overall phase shift of the loop (demodulation noise) are greatly reduced. Finally, the stability is improved by an order of magnitude after relative compensation circuit design.