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For the multisensor descriptor systems with correlated noises, the WMF full-order Kalman smoother is presented. First, the centralized fusion descriptor system is obtained. Then this centralized fusion descriptor system is transformed to the descriptor system with uncorrelated noises. Second, the weighted measurement fusion (WMF) descriptor system is presented. Finally, the WMF full-order Kalman and...
Uncertain graphs are employed to describe graph models with imprecise expert data. In uncertain graphs, due to the existence of uncertain edges, edge-connectivity is essentially an uncertain variable. Different from that in a deterministic graph, it is more suitable to investigate the possibility (uncertain measure) that an uncertain graph is $k$-edge-connected, which is the main aim of this paper...
We developed a magnetic flux measurement system which is based on the binary Josephson system two years ago. After that, we continue researching on the improvement of magnetic flux measurement and start to focus on the precision measurement of the mutual inductance with the flux measurement system we built before. This paper introduces the mutual inductance measurement method which is based on the...
A new record of magnetic flux measurement of 1 Wb with the type A uncertainty of less than 1 ppm was presented, which is an improvement over the result that was achieved with our previous magnetic flux measurement circuit with Josephson system. The flux difference measured between the rectangular pulse synthesized with the Josephson system and the flux under test (around 1 Wb) is less than 4 mWb,...
This paper presents an automated microvolt Josephson voltage set-up developed at NIM. It is based on two programmable Josephson SINIS arrays, and can be used to calibrate the lower ranges of nanovoltmeters for low level DC measurements. A low noise bias source developed at NIM has been used and the step flatness of the arrays was verified carefully. The preliminary results of the measurements set...
Magnetic flux is the basic magnetic quantity. The measurement uncertainty of fluxmeter is usually several parts in 104. This paper proposes a new approach of magnetic flux measurement by measuring the flux difference between rectangular pulse synthesized with a binary Josephson system and the flux under test. Experimental results show that the flux measurement repeatability is several parts in 106...
For affecting issues of atmospheric environment of laser measurement, a new type of way was introduced. It's combination of experimental models and theories empirical formula. And discussion is made deeply on the laser measurement affecting of the refraction, scattering and absorption of atmospheric. The results showed that: refractive index of the laser measurement of the impact of close-micron level,...
For the multisensor systems with correlated measurement noises, different measurement matrices and unknown noise variances, based on the autoregressive moving average (ARMA) model and the reduced dimension measurement fusion algorithm, using the correlated method, a self-tuning reduced dimension measurement fusion Kalman filter is obtained, and its convergence in a realization is proved by the dynamic...
A comparison between the National Institute of Metrology (NIM) and the Beijing Institute of Radio Metrology and Measurement (BIRMM) Programmable Josephson Voltage Standards (PJVS) at 1 V level was carried out at Changping campus of NIM from November 16 to November 17, 2009. The measured difference voltage between the two PJVS is 2×10-10 in direct comparison and 4×10-9 in indirect comparison. The results...
We have designed a precision measurement system for programmable Josephson voltage standard (PJVS). The system is mainly developed using a set of homemade multi-functional automatic switching unit with low thermal emf, so that the measurement uncertainty of PJVS measuring solid-state reference can be reduced to 4 part in 109 (1σ).
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