大倾角状态下数字天顶仪定位的倾斜误差分析

Tilt Error Analysis of Digital Zenith Instrument Positioning at Large Dip Angle

针对数字天顶仪在大倾角状态下进行天文定位时垂直轴和旋转轴之间存在的轴系误差,研究了倾角补偿值的自身修正方法,提高了倾角补偿值的自身精度。从数字天顶仪倾角补偿原理出发,提出在大倾角状态下倾角补偿值精度主要跟倾角仪的读数误差有关。经过理论分析,建立了旋转轴倾斜改正模型,推导计算出旋转轴的倾斜分量,得出了取对称观测位置的倾斜改正平均值就可以消除倾角仪读数线性漂移和零点误差的结果,通过实验对倾斜误差的消除方法进行了验证。结果显示:经过该方法对倾斜误差进行修正后,数字天顶仪的定位精度由以前的0.5″左右提高到0.3″以内。

The self-correction method of inclination compensation value is studied for the axis error between the vertical axis and the rotating shaft at large dip angle,and the accuracy of the inclination compensation value is improved. Based on the principle of inclination compensation of digital zenith instrument,the accuracy of inclination compensation value is proposed to be mainly related to the reading error of inclinometer. A correction model of rotation axis is established based on the theoretical analysis,and the inclination component of rotating shaft is deduced. It is concluded that the linear drift and zero error of inclinometer can be eliminated by correcting the average value of tilt errors of symmetrical observation position. The method of eliminating the tilt error is verified by experiment. The results show that the positioning accuracy of digital zenith instrument is improved from 0. 5″ to 0. 3″ after the correction of tilt error.