Uncertainty Analysis for Angle Calibrations Using Circle Closure

Published

March 1, 1998

Author(s)

William T. Estler

Abstract

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 auxilliary 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 estimation of the standard uncertainty of small angle measurement using electronic autocollimators, including the effects of calibration uncertainty and air turbulence.

Citation

Journal of Research of the National Institute of Standards and Technology

Volume

103

Issue

2

Pub Type

Journals

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Keywords

angle metrology, autocollimators, calibration, closure, dimensional metrology, indexing tables, measurement uncertainty, optical polygons, self-calibration

Citation

Estler, W. (1998), Uncertainty Analysis for Angle Calibrations Using Circle Closure, Journal of Research of the National Institute of Standards and Technology, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=820892 (Accessed April 27, 2026)

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