由于激光跟踪仪的角度测量精度直接影响仪器的测量精度, 本文提出了用自准直仪结合多面棱体对跟踪仪金属圆光栅测角误差进行离散标定的方法。研究了基于谐波分析的误差补偿方法, 取金属柱面圆光栅测角误差中幅值较大且相位基本不变的谐波分量建立了补偿模型, 避免了最小二乘法不收敛的问题。分析了标定测角误差的不确定度, 结果显示: 水平测角精度补偿前后分别为1.60″和0.90″, 俯仰测角精度补偿前后分别为4.89″和0.91″, 精度分别提高了44%和81%, 从角秒级提高到了亚角秒级。结果表明, 提出的方法可为激光跟踪仪水平和俯仰轴系提供测角误差补偿, 对类似测角系统的误差补偿也有参考价值。

As the angle measurement accuracy for a laser tracker affects the instrument measurement accuracy directly, a discrete calibration method for the angle measurement errors of a metal circular grating in the laser tracker was proposed based on an autocollimator combined with a multi-mirror polyhedron. The error compensation method based on harmonic analysis was studied. Then, a compensation model was built up on the basis of the harmonic wave components whose amplitudes are large and phases remain essentially constant, by which the no convergence from least square method was overcome. Futhermore, the calibration uncertainty of angle measurement errors was analyzed. The analysis results show that the horizontal angle measurement accuracy is reduced from 1.60″ to 0.90″, and the vertical angle from 4.89″ to 0.91″ after compensation. The accuracy is improved by 44% and 81% respectively, and has been from an arc second scale to a sub-arc second scale. The results indicate that the proposed method effectively compensates angle measurement errors for harmonic and vertical axis systems of the laser tracker, and also provides a reference for other error compensation of angle measuring systems.