MEMS陀螺噪声理论与模型综述

工作在闭环检测模式下的MEMS陀螺具有较好的整体性能,是目前具有发展潜力的微陀螺方案之一。但是多个闭环的存在使得测控系统噪声源变多,通过构建噪声模型可以量化各噪声源对零偏输出的贡献,并且探明结构和电路参数对噪声性能指标的影响,从而调整设计参数与控制方式,优化设计。首先阐述了MEMS陀螺谐振系统中的噪声源———热噪声和闪频噪声产生机理,然后将陀螺噪声模型分为相位噪声模型和幅度噪声模型,分别讨论国内外研究机构噪声建模的进展,如针对幅度频率耦合导致的额外相位噪声,讨论了非线性相位噪声模型和幅度噪声模型。非线性相位噪声模型通过引入非线性刚度来完善相位噪声谱表达式,幅度噪声模型通过考虑不同输入点的噪声在力平衡环路的传递过程来量化各噪声源影响因素。最后,对噪声模型的发展进行了展望,可以通过构建与调幅陀螺相联系的相位噪声模型和零偏不稳定性噪声模型,实现对陀螺噪声分析的完善。

Review on the Theory and Modeling of MEMS Gyro Noise

The MEMS gyroscope operating under closed-loop detection has a good overall performance and is one of the potential micro-gyro solutions. Due to the existence of multiple closed-loops, it makes the measurement and control system noise source increase, and by constructing a noise model, the contribution of each noise source to the zero bias output can be quantified, and the influence of structural and circuit parameters on the noise performance index can be investigated, so as to adjust the design parameters and control methods, and optimize the design. First, the noise sources in MEMS gyro resonant systems are described: thermal noise and flash noise generation mechanism. Second, the gyro noise model is divided into the phase noise model and the amplitude noise model, and the progress of noise modeling in domestic and international research institutions is discussed respectively. For the additional phase noise caused by amplitude-frequency coupling, the nonlinear phase noise model and amplitude noise model are discussed. The nonlinear phase noise model introduces nonlinear stiffness to perfect the noise spectrum expression, and the amplitude noise model considers the transfer process of the noise input at the different points in the force balance loop and quantifies the influence of each noise source. Finally, the development of the noise model is foreseen and can be improved by constructing a phase noise model linked to the amplitude modulated gyro and a zero bias instability noise model for gyro noise analysis.