重力梯度测量中光栅角编码器安装误差的影响及分析

Influence and analysis of optical angular encoder's installation error in gravity gradiometry

旋转加速度计式重力梯度仪中的台体旋转误差会影响梯度测量精度。若以光栅角编码器作为旋转控制的角度测量元件,其安装误差会产生相应的旋转控制误差。为此,需要对光栅角编码器安装误差的产生机理进行分析,了解其对旋转加速度计式重力梯度仪测量精度的影响程度。利用光学技术方法测量光栅角编码器安装误差所引起的角速度和角加速度的变化,最后通过角位置补偿修正光栅角编码器安装误差以减小运动不平稳性对重力梯度测量的影响。实验表明该方法对光栅角编码器进行补偿可以有效减小码盘安装误差对旋转控制的影响。

The gradient measurement precision in rotary accelerometer-based gravity gradiometer instrument(GGI) will be degraded due to the rotation error of its platform. When an optical angular encoder is used as an angle measurement component to control the rotation, its installation error must be taken into account. In this paper, the mechanism of the installation error was analyzed, and to what extent is the error's influence on measuring precision of GGI was figured out. An optical system was used to measure the velocity/acceleration variations caused by installation error of optical angular encoder. Then the installation error of optical angular encoder was corrected by angle position compensation to reduce the influence of the platform's non-uniform rotation rate on gravity gradiometry. The results show that the proposed compensation method can effectively reduce the installation error's influence on the rotating control of the optical angular encoder.