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The paper deals with the issues of measurement traceability based on uncertainty of measurements as an integral part of specific measurement technologies based of new information system. A short review of papers devoted to measurement traceability problem in modern conditions is described. It is proposed to further expand a concept of "special technical means" in carrying out of measurements...
The correct functioning of data measuring systems is impossible without timely metrological examination and calibration of measuring channels. Uncalibrated channels can transmit unreliable data, leading to the poor monitoring and incorrect decision making. The overview of the current research in the field of measuring channels calibration shows the low research activity in this area and highlights...
Soil moisture plays an important role in agriculture, hydrology, and land-atmosphere processes. Over the years, there has been a scale gap between traditional point-scale sensors and large-scale soil moisture products from satellite remote sensing. Recent advances suggest the use of cosmic-ray sensors (CRS) that provide integrated soil moisture at subkilometer scale (∼300m radius and 10 to 70cm depths)...
The choice of poses for camera calibration with planar patterns is only rarely considered — yet the calibration precision heavily depend on it. This work presents a pose selection method that explicitly avoids singular pose configurations which would lead to an unreliable solution. Consequently camera poses are favoured that reduce the uncertainty of the calibration parameters most. For this purpose...
In order to calibrate a newly developed miniaturised strain gauge based 6-DOF force and torque sensor, an assembly that uses calibration weights, attached to strings and pulleys to generate forces and torques has been designed. The assembly enables a semi automatic calibration procedure. This paper describes the calculation of the uncertainty of the mechanical and electrical part of the calibration...
Consistent reporting of Limit of Detection (LOD) and its inherent uncertainty is imperative as the number of sensors for challenging applications continues to rise. Here, we demonstrate a Bayesian approach to LOD estimation, which also provides estimates of LOD uncertainty. By using this method to compare seemingly similar sensors, we demonstrate that LOD uncertainty is at least as important as LOD...
This paper describes the design and setup of different measuring systems for the calibration of commercial voltage and current transformer test sets for non-conventional instrument transformers. The calibration systems are recently developed at the national metrology institutes VSL, PTB, METAS and TUBITAK within the frame of the European project “FUTURE GRID — Non-conventional voltage and current...
High intensity focused ultrasound (HIFU) is being increasingly used in medical therapeutics. The properties of the ultrasonic fields applied entail challenging acoustic output measurement tasks: the generation of high-pressure amplitudes sufficient for cavitation; the use of high-frequency components due to the non-linear sound propagation in water; and narrow beam widths at the focus. Conventional...
High-intensity focused ultrasound (HIFU) fields can be characterized by specific hydrophones that are able to withstand the large acoustical pressures used in medical applications. Such hydrophones may show a non-flat frequency response due to their being strengthened by protection layers against cavitation damage. Therefore, hydrophone calibration data should be used in deconvolution in order to...
This paper presents a study of the consistency of the values used as reference for the hardware delays of GPS P1 and P2 for calibration in the TAI network. The inter-signal biases dP1-dP2 are computed from the pseudorange measurements, after applying an ionospheric delay correction, and then compared to the calibrated values. It is shown that the differences between the computed dP1-dP2 and the calibrated...
The experiments and results of these calibation campaigns in the frame of APMP from 2014 to 2016 have been reported and the experiment setups and the corresponding delay measurements have been discussed, and the uncertainty has been evaluated for the campaigns.
The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite uses its 14 reflective solar bands to passively collect solar radiant energy reflected off the Earth. The Level 1 product is the geolocated and radiometrically calibrated top-of-the-atmosphere solar reflectance. The absolute radiometric uncertainty associated with this product includes...
One of the objectives of CLARREO Pathfinder mission is to demonstrate on-orbit data matching for sensor inter-calibration The CLARREO Pathfinder approach for reference inter-calibration is based on measuring spectral reflectance with high accuracy and establishing an on-orbit reference for operating Earth viewing sensors: CERES and VIIRS on JPSS. The mission goal is to be able to provide CLARREO reference...
The Visible-Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (S-NPP) spacecraft as a primary sensor was launched October 28, 2011. There are 22 VIIRS bands: 7 thermal emissive bands (TEBs), 14 reflective solar bands (RSBs) and a Day Night Band (DNB). An on-orbit On-Board Calibrator BlackBody (OBCBB) is used as the TEB calibration source that tracks the...
The Visible Infrared Imaging Radiometer Suite (VIIRS) sensor was on board the Suomi National Polar-Orbiting Partnership (S-NPP) launched on 28 October 2011. The VIIRS includes a day-night band (DNB), which is panchromatic with the wavelengths from 500 nm to 900 nm. Its dynamic range covers from full sunlit scenes to lunar-illuminated images. With successful calibration after launch, DNB on-orbit performance...
The Soil Moisture Active Passive (SMAP) mission was launched on 31st January 2015 in a 6 AM/6 PM sun-synchronous orbit at 685 km altitude to measure soil moisture and free/thaw globally [1]. The passive instrument of SMAP is a fully polarimetric L-band radiometer (1.4GHz) operating with a bandwidth of 24MHz. The radiometer uses a combination of noise-diodes and Dicke-loads for internal calibration...
In this study, the automatic reflectance-based method is used to vicarious radiometrically calibrate the satellite optical sensors using the desert target located in the Baotou site in China. The ground reflected radiance of the desert target were collected automatically using an automatic observation system. The reflectance of the desert target was calculated with the radiance collected with the...
Measurement of the seawater temperature at different depths to get a vertical temperature profile on the water column is presented in this paper: The acquisition system based on optical fiber Bragg gratings (FBGs) and the subsequent data processed is also presented. The temperature measurements are taken in distributed points along the fiber where the Bragg gratings are located. The paper reports...
Many calibration algorithms for vector network analyzers using partially unknown standards can be stated as an eigenvalue problem. The construction of the eigenvalue problem is described and examples for line reflect match (LRM) and thru reflect line (TRL) calibrations are given. Advantages of the new algorithm are that all uncertainties can be taken into account and that it is fully analytic. A further...
The paper introduces an on-orbit calibration method for aerospace hall current sensor based on excitation response with verification by experiments. The method is applicable for long-life on-orbit spacecraft without manual calibration periodically, and it is possible to improve measurement reliability and accuracy for the hall current sensor in a long-term work life.
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