正交度对高精度二维转台测量精度的影响

Effects of Orthogonality on the Measurement Precision of High-accuracy Two-dimensional Turntable

针对二维跟踪测量转台方位轴和俯仰轴正交度对角度测量精度的影响,基于球面三角计算方法和向量运算方法,文章分别推导获得转台不正交时角度测量误差的计算公式,分析上述公式获得正交度及其测量误差对转台测角精度的影响规律。结果表明,二维转台俯仰运动范围大于10°时,转台方位轴和俯仰轴正交度对方位测角精度影响较大,对俯仰测角精度影响可忽略不计;转台测角精度对正交度的测量误差非常敏感,俯仰角为75°时,若正交度测量误差为3″,则方位角测量误差可达11.2″。基于此提出一种正交度分段拟合的修正方法可将正交度对测角精度的影响控制在4″以内。最后,针对性的介绍了转台旋转轴正交度的两种测量方法及其测量误差主要来源。研究结果对通用二维跟踪测量转台测角精度指标的合理分解具有一定的指导意义。

Considering the influence of orthogonality between azimuth axis and pitch axis on the angle measuring precision of two-dimensional tracking turntable, the formula of angle measuring error is derived based on the spherical triangle method and vector method respectively, when the azimuth axis and pitch axis of turntable is non-orthogonal. The effects of the orthogonality and its measuring error on the angle measuring precision are obtained from the formula. Results shows that when the motion range of the turntable is wider than 10°, the orthogonality between the azimuth axis and pitch axis has great effects on the measuring precision of the azimuth angle, but little effects on the pitch angle. Further results shows that the angle measuring precision is quite sensitive to the orthogonality measuring error. When the pitching angle is 75°; and the orthogonality measuring error is 3″, the azimuth angle error can reach to 11.2″. Then an orthogonality segmented fitting method is proposed, which can control the angle measuring precision within 4″. Finally, two kinds of revolving axes orthogonality measuring methods and their main error source are summarized. These results have some instructional value for the analysis on the angle measuring precision of the general two-dimensional tracking turntable.