D/A量化对数字闭环光纤陀螺测量精度的影响分析

D/A quantization effect on precision of digital closed-loop fiber optic gyroscope

光纤陀螺全数字闭环检测方案的最小反馈相移由D/A的位数确定。通过建立全数字闭环光纤陀螺的Sigma-delta模型,从量化噪声的角度分析了D/A位数对数字闭环光纤陀螺测量精度的影响。研究了闭环检测对量化噪声的抑制作用及其对光纤陀螺输出精度的影响。实验结果与理论分析吻合,结果表明:由于闭环系统本身对量化噪声的抑制作用,量化噪声不会成为影响中、低精度光纤陀螺检测系统精度的主要误差源,实际D/A选型过程中可以根据系统对非线性、动态范围的要求结合的理论计算方法对D/A位数进行选取。

The minimum feedback phase shift in closed-loop fiber optic gyroscope （FOG） was determined by D/A bits. Sigma-delta model of closed-loop FOG was provided by adding quantization error in the feedback node. And the effects of D/A bits on system measurement precision were analyzed in the respect of quantization error. Compared with traditional method of noise match to realize D/A bits selection, inhibitory action of the system to quantization error and its effects on output precision were analyzed. Theory analysis is identified by the experiments. It shows that the quantization error could not be the main error source of factors which affects the system precision, as the result of inherent characteristics of closed-loop system. D/A bits can be selected in application by using the theory analysis provided and practical system requirement of nonlinearity and dynamic range.