Automatic system for gauge block calibration optimized to meet legal length metrology requirements

This paper presents a contactless method for gauge blocks calibration combining laser interferometry and low-coherence interferometry. In the presented system, the contactless measurement of the absolute gauge block length is done as a single-step operation without any change in optical setup during measurement, giving complete information about the gauge block length. The paper also presents a set of optimization steps which have been done in order to transform the original experimental setup into the automatic system which meets legal length metrology requirements. To prove the measurement traceability, we conducted a set of gauge block length measurement comparing data from the optimized system and the established reference systems TESA NPL A.G.I. 300 and TESA–UPC operated in Czech Metrology Institute laboratory.