Allan Variance Analysis of Measurement Data Series for Instrument Verification

The paper is concerned with the analysis of measurand and instrument stability during the calibration verification process, with a view on ensuring that comparison is carried out under suitable assumptions. It will be shown how analysis of the Allan variance allows stability characterization of the measurement circuit and yields information about measurement noise, so that a correct procedure for the verification of the calibration status can be defined. This is of particular significance in the context of an industrial laboratory, where one of the main purposes of the analysis would be to identify improvements to the measurement system, that could allow to perform calibration verification within the limits of available equipment.