Methodology for increasing intercalibration interval of a group measure

Abstract

Pomortsev UDK 62t.3t7Based on mathematical techniques of Markov processes, the usefulness of constructing and utilization of a group measure to increase storage reliability of a physical quantity unit under the conditions of metrological autonomy and decrease in economic expenditures for verification (calibration) of htdividual measuring devices is demonstrated. Utilization of the methodology proposed allows us to provide a scientifically justified determination of an increased intercalibration interval of measuring devices.At the contemporary stage of development of the standard base of the country, attention of specialists, managers and organizers of investigations of the metrological service is focussed on optimization of temporal and material expenditures in the course of utilization of measuring devices.One of the problems to be solved in this instance is to assure metrological autonomy. A route for a solution of this problem may serve the construction -from the initial measuring devices of the given physical quantity -of a group measure which may be utilized for carrying out verification of the period when the functioning of the permanent scheme of transmitting the size of a unit of this physical quantity is disrupted or discontinued [ 1-3]. In turn, in the course of normal operation construction of a group measure can reduce to a large extent economic expenditures for calibration of individual measuring devices contained in the group measure. This is due to the fact that the intercalibration interval of a single measuring device is smaller than the intercalibration interval of a group measure and the calibration can be carried out over a long time period. The assertion above is based on the feature that systematic errors of measuring devices contained in a group measure are viewed in their totality as random variables [4] and with increase of the totality, the confidence interval which characterizes the degree of reproducibility of the measurement results decreases. With a decrease of the confidence interval, the confidence probability Pd increases; hence for an a priori given value Pd this allows us to retain with greater reliability the unit of a physical quantity at a given time interval, and as a result we can achieve an increase in the duration of the storage period of the given unit at Pd = const.The dependence of the time interval between the consecutive calibrations of individually taken measure T l maintaining the same unit of a physical quantity for the equal boundaries of a confidence interval (-A; +A) and the same time interval T~ for n measures (Pd = const) is presented in graphical form in Fig. 1. Thus, when utilizing a group measure of n measuring devices, an intercalibration interval of their totality can be larger than the intercalibration interval of individual measuring devices. Hence the problem of a rigorous estimation of the maximally admissible scientifically substantiated intercalibration interval is at present quite timely.The aim of this paper is to develop -based on the mathemati...

Increasing Metrological Autonomy of in-Plant Measuring Systems

“…The composition of such a complex includes several highly stable measures, which are equipped with means of verification. Moreover, some elements of the complex do not just perform the function of a "reserve" reference of some basic element, but they are full members of the complex and directly influence the formation of the output unit of the physical quantity of the complex reference [5]. This approach can increase the stability of reproduction of a physical unit of the complex reference compared with the stability of individual elements.…”

“…This approach can increase the stability of reproduction of a physical unit of the complex reference compared with the stability of individual elements. Also, creation of the algorithm to process the results of mutual comparisons of the elements of the complex based on the maximum likelihood method can significantly simplify comparisons and improve the efficiency of statistical processing of the data [4,5]. Thus, the implementation of the concept of metrological autonomy in modern conditions can increase the metrological stability of in-plant measuring systems.…”