Estler W Tyler
National Institute of Standards and Technology, Gaithersburg, MD 20899-0001.
J Res Natl Inst Stand Technol. 1998 Mar-Apr;103(2):141-151. doi: 10.6028/jres.103.008. Epub 1998 Apr 1.
We analyze two types of full-circle angle calibrations: a simple closure in which a single set of unknown angular segments is sequentially compared with an unknown reference angle, and a dual closure in which two divided circles are simultaneously calibrated by intercomparison. In each case, the constraint of circle closure provides auxiliary information that (1) enables a complete calibration process without reference to separately calibrated reference artifacts, and (2) serves to reduce measurement uncertainty. We derive closed-form expressions for the combined standard uncertainties of angle calibrations, following guidelines published by the International Organization for Standardization (ISO) and NIST. The analysis includes methods for the quantitative evaluation of the standard uncertainty of small angle measurement using electronic autocollimators, including the effects of calibration uncertainty and air turbulence.
一种是简单闭合校准，其中一组未知角度段依次与未知参考角度进行比较；另一种是双重闭合校准，其中两个分度圆通过相互比较同时进行校准。在每种情况下，圆闭合的约束提供了辅助信息，该信息(1)能够在不参考单独校准的参考工件的情况下完成校准过程，(2)有助于降低测量不确定度。我们根据国际标准化组织(ISO)和美国国家标准与技术研究院(NIST)发布的指南，推导出角度校准合成标准不确定度的闭式表达式。该分析包括使用电子自准直仪对小角度测量标准不确定度进行定量评估的方法，包括校准不确定度和空气湍流的影响。
