An international key comparison of free-field hydrophone calibrations in the frequency range 1 to 500kHz

Robinson, Stephen; Harris, P M; Ablitt, Justin; Hayman, Gary; Thompson, A D; Buren, A. L. Van; Zalesak, Joseph F.; Drake, Robert M.; Isaev, А. Е.; Enyakov, A. M.; Purcell, Christopher; Zhu, Hao; Wang, Yuebing; Zhang, Yue; Botha, Pierre; Krüger, D

doi:10.1121/1.2228790

Cited by 25 publications

(7 citation statements)

References 14 publications

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“…The CCAUV.W-K1 key comparison of primary free-field standards for underwater acoustics [14] involved seven NMIs measuring the free-field sensitivity of hydrophones at frequencies from 1 kHz to 500 kHz. In order to cover this interval of frequencies, three hydrophones were chosen as calibration artefacts covering, respectively, the (overlapping) frequency intervals 1 kHz to 100 kHz, 10 kHz to 150 kHz and 100 kHz to 500 kHz.…”

Section: Comparison Of Free-field Hydrophone Calibrationsmentioning

confidence: 99%

Aggregating measurement data influenced by common effects

et al. 2007

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The requirement to aggregate measurement data, in the case where each measured value corresponds to nominally the same quantity, is important throughout metrology. Correlation associated with measured values is shown to arise in a number of measurement problems, with examples taken from the areas of interlaboratory comparisons, including key comparisons, the calibration of measuring systems and instruments, wireless sensor networks and prediction on the basis of different models. Consideration is given to the effect that correlation has on the determination of an aggregated estimate of the measured quantity, and on testing the consistency of measurement data. Approaches to quantifying the correlation associated with measured values are presented, and a formulation is given of the problem of determining the largest consistent subset of data having associated correlation. Results for three measurement problems are given, concerned with an interlaboratory comparison of noise in a coaxial line, the calibration of a thermometer and the analysis of data arising from a wireless sensor network.

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Section: Comparison Of Free-field Hydrophone Calibrationsmentioning

confidence: 99%

Aggregating measurement data influenced by common effects

et al. 2007

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“…The existence of correlation is often evidenced by patterns in the individual behaviour of the DoEs of the participating laboratories across the discrete values of the parameter within the measurement interval. An instance is given by Cox and Harris [6, section 4] in the context of constructing a key comparison reference curve for a key comparison of free-field hydrophone calibrations in the frequency interval 1 kHz-500 kHz [7]. In this instance, DoE value components for 24 consecutive values of the parameter, frequency, took positive values for one of the participating NMIs, an occurrence highly unlikely to happen by chance in the absence of correlation even taking sample selection bias [8] into consideration.…”

Section: Introductionmentioning

confidence: 99%

Statistical reassessment of calibration and measurement capabilities based on key comparison results

Shirono¹,

Cox

2019

Metrologia

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According to the CIPM mutual recognition arrangement, a calibration and measurement capability (CMC) uncertainty for a laboratory offering a particular calibration or measurement service is normally expressed at a 95 % level of confidence. When laboratories' CMC claims are unsupported by the relevant key comparison (KC), after publishing the final report of the KC, modified values may have to be assigned to their CMC uncertainties. In many cases when CMCs apply to a continuous interval of values such as mass fraction or wavelength, KCs are carried out for selected discrete values of the quantity concerned. Since the comparison at each discrete value may only support the CMC uncertainty at that point, it is not immediately apparent how to modify the CMC uncertainties. Under realistic assumptions, we developed a method that is applicable in such an instance and for which the reported CMC uncertainties are amplified so that they are underpinned by the results of the KC. The amplification factors depend on the laboratories' degrees of equivalence (DoEs) for these discrete values, judiciously adjusted to achieve consistency with the key comparison reference values. The method is based on the patterns in the individual behaviour of the DoEs of the participating laboratories for the discrete values, implying the presence of correlation associated with the DoE values. It applies when the weighted mean of some or all of the measured values reported by the participating laboratories in the KC is used to obtain the KC reference value.

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“…Accurate measurement of these performance parameters is important for ensuring unambiguous specification and acceptance testing [1,2]. The transducers, whether used as receivers or projectors, can often exhibit variation in sensitivity as a function of water temperature [3]. There are consequent limitations on the performance of such transducers under real ocean conditions, and the accuracy of their calibration can also be adversely influenced.…”

Section: Introductionmentioning

confidence: 99%

A model for characterizing the frequency-dependent variation in sensitivity with temperature of underwater acoustic transducers from historical calibration data

Nam

Cox

Harris

et al. 2007

Meas. Sci. Technol.

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The performance of underwater electroacoustic transducers often depends on water temperature and, for accurate calibrations, it is necessary to take account of this influence on measurement data. Doing so is particularly important for open-water calibration facilities where the environmental conditions cannot be controlled and seasonal variations in temperature can contribute significant measurement uncertainty. This paper describes the characterization of the sensitivity of underwater electroacoustic transducers in terms of their variation with water temperature. A model containing adjustable parameters is developed for providing frequency-dependent temperature coefficients whose use enables measurement data to be corrected for temperature. Estimates of these coefficients are determined by applying the model to the time history of measurement data obtained over a period of several years. The influence of seasonal temperature variation can then be separated from the slow temporal drift in the transducer sensitivity. The uncertainties associated with the corrected sensitivity values are evaluated.

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An international key comparison of free-field hydrophone calibrations in the frequency range 1 to 500kHz

Cited by 25 publications

References 14 publications

Aggregating measurement data influenced by common effects

Aggregating measurement data influenced by common effects

Statistical reassessment of calibration and measurement capabilities based on key comparison results

A model for characterizing the frequency-dependent variation in sensitivity with temperature of underwater acoustic transducers from historical calibration data

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