Accuracy Analysis of Digital Closed-Loop Quartz Flex Accelerometer Based on Differential Capacitance Detection Technology

The digital closed-loop quartz flex accelerometer (DCLA) can acquire higher measuring accuracy, which plays an important role in the inertia navigation system while noise is one of the main factors to restrict the precision of DCLA. In this paper, the working principle and noise characteristics of DCLA are introduced and analyzed. According to the system mathematical transfer function and equivalent noise model, the accuracy caused by each error source is calculated based on the noise transmission and comprehensive rules, and the theoretical accuracy is 12.65μg. Building a DCLA experimental prototype, under the 0g/±1g stability test, the bias stability of 0g/±1g is 17.278μg, 16.629μg and 18.201μg, respectively. The result shows that theoretical analysis is basically in consistent with experimental results, and the error is less than 6μg, which provides the theoretical and practical guidance for improving the accuracy of DCLA. Moreover, the research method can be used for the noise analysis of other weak signal detection system.