Drift-Free Integration in Inductive Magnetic Field Measurements Achieved by Kalman Filtering

Sensing coils are inductive sensors commonly used to measure magnetic fields, such as those generated by electromagnets used in many kinds of industrial and scientific applications. Inductive sensors rely on integrating the output voltage at the coil’s terminals in order to obtain flux linkage, which may suffer from the magnification of low-frequency noise resulting in a drifting integrated signal. This article presents a method for the cancellation of integrator drift. The method is based on a first-order linear Kalman filter combining the data from the coil and a second sensor. Two case studies are presented. In the first one, the second sensor is a Hall probe, which senses the magnetic field directly. In a second case study, the magnet’s excitation current was used instead to provide a first-order approximation of the field. Experimental tests show that both approaches can reduce the measured field drift by three orders of magnitude. The Hall probe option guarantees, in addition, one order of magnitude better absolute accuracy than by using the excitation current.

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An overview of commercially available Teslameters for applications in modern science and industry

ACTA IMEKO ◽

10.21014/acta_imeko.v6i1.312 ◽

2017 ◽

Vol 6 (1) ◽

pp. 43 ◽

Cited By ~ 5

Author(s):

Dragana Popovic Renella ◽

Sasa Spasic ◽

Sasa Dimitrijevic ◽

Marjan Blagojevic ◽

Radivoje S Popovic

Keyword(s):

Magnetic Field ◽

Temperature Coefficient ◽

Low Frequency ◽

Modern Science ◽

Calibration Procedure ◽

Magnetic Sensors ◽

Performance Ratio ◽

Frequency Noise ◽

Hall Probe ◽

Sensitive Volume

<p>The Hall-effect based Teslameters (also called Gaussmeters) are the mostly applied instruments for measuring DC and AC magnetic flux densities in modern science and industry. This paper gives an overview of commercially available Teslameters at the high-end performance level. The Teslameters have been evaluated by following characteristics that are published by suppliers: probe dimensions, magnetic field sensitive volume, accuracy, magnetic resolution, measurement range, frequency bandwidth, temperature coefficient sensitivity, and price/performance ratio.</p><p>The Teslameter that best matches the measurement needs in various application fields incorporates a 3-axis integrated Hall probe, analog electronics based on the spinning-current technique, an analog-to-digital converter, an embedded computer, and a touch-screen display. The 3-axis Hall probe is a single silicon chip integrating both horizontal and vertical Hall magnetic sensors and a temperature sensor. The spinning-current eliminates most of the Hall probe offset, low-frequency noise, and the planar Hall voltage. The errors due to the Hall sensor non-linearity and the variations in the probe and electronics temperatures are eliminated by a calibration procedure. The errors due to the angular imperfections of the Hall probe are eliminated by a calibration of the sensitivity tensor of the probe. This Teslameter can measure magnetic field vectors from about 100 nT to 30 T, with the spatial resolution of 100 µm, magnetic resolution ±2 ppm of the range, the accuracy 0.002 % of the range, a temperature coefficient less than 5 ppm/°C, and angular errors less than 0.1°.</p>

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Electromagnetic system for detection and localization of the miners caught by accident in mine

10.5194/gi-2016-20 ◽

2016 ◽

Author(s):

Vira Pronenko ◽

Fedir Dudkin

Keyword(s):

Magnetic Field ◽

Inverse Problem ◽

Low Frequency ◽

Emergency Situation ◽

Field Measurements ◽

Experimental Tests ◽

Problem Solution ◽

Electromagnetic System ◽

Field Source ◽

The Magnetic Field

Abstract. The profession of a miner is one of the most dangerous in the world. Among the main causes of the fatalities in the underground coal mines is the untimely alerting of the accident, as well as the lack of information for the rescuers about the actual location of the miners after the accident. In an emergency situation (failure or destruction of underground infrastructure), personnel search behind and beneath of blockage should be provided urgently. But none of the standard technologies (RFID, DECT, WiFi, emitting cable), which use the stationary technical devices in mines, provides the information about the people location caught by accident with necessary precision. The only technology that is able to provide guaranteed delivery of messages about the accident to the mine personnel, regardless of their location and under any destruction in the mine, is low-frequency radio technology able to operate through the thickness of rocks even if it is wet. The proposed new system for miners localization is based on solving the inverse problem that allows the magnetic field source coordinates determining using the data of magnetic field measurements. This approach is based on the measurement of the magnetic field radiated by the miner's responder beacon using two fixed and spaced three-component magnetic field receivers and next the inverse problem solution. As a result, the working model of the system for miner's beacon search and localization (MILES – miner's location emergency system) was developed and successfully tested. The paper presents the peculiarities of this development and the results of experimental tests.

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Analytical solution for unsteady flow behind ionizing shock wave in a rotational axisymmetric non-ideal gas with azimuthal or axial magnetic field

Zeitschrift für Naturforschung A ◽

10.1515/zna-2020-0248 ◽

2021 ◽

Vol 76 (3) ◽

pp. 265-283

Author(s):

G. Nath

Keyword(s):

Magnetic Field ◽

Shock Wave ◽

Analytical Solution ◽

Axial Magnetic Field ◽

Order Approximation ◽

Ideal Gas ◽

Field Region ◽

First Order ◽

First Order Approximation ◽

Flow Variables

Abstract The approximate analytical solution for the propagation of gas ionizing cylindrical blast (shock) wave in a rotational axisymmetric non-ideal gas with azimuthal or axial magnetic field is investigated. The axial and azimuthal components of fluid velocity are taken into consideration and these flow variables, magnetic field in the ambient medium are assumed to be varying according to the power laws with distance from the axis of symmetry. The shock is supposed to be strong one for the ratio C 0 V s 2 ${\left(\frac{{C}_{0}}{{V}_{s}}\right)}^{2}$ to be a negligible small quantity, where C 0 is the sound velocity in undisturbed fluid and V S is the shock velocity. In the undisturbed medium the density is assumed to be constant to obtain the similarity solution. The flow variables in power series of C 0 V s 2 ${\left(\frac{{C}_{0}}{{V}_{s}}\right)}^{2}$ are expanded to obtain the approximate analytical solutions. The first order and second order approximations to the solutions are discussed with the help of power series expansion. For the first order approximation the analytical solutions are derived. In the flow-field region behind the blast wave the distribution of the flow variables in the case of first order approximation is shown in graphs. It is observed that in the flow field region the quantity J 0 increases with an increase in the value of gas non-idealness parameter or Alfven-Mach number or rotational parameter. Hence, the non-idealness of the gas and the presence of rotation or magnetic field have decaying effect on shock wave.

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Computational Low-Frequency Electromagnetic Dosimetry Based on Magnetic Field Measurements

IEEE Journal of Electromagnetics RF and Microwaves in Medicine and Biology ◽

10.1109/jerm.2018.2869021 ◽

2018 ◽

Vol 2 (4) ◽

pp. 302-309 ◽

Cited By ~ 4

Author(s):

Alessandro Arduino ◽

Oriano Bottauscio ◽

Mario Chiampi ◽

Ilkka Laakso ◽

Luca Zilberti

Keyword(s):

Magnetic Field ◽

Low Frequency ◽

Field Measurements ◽

Magnetic Field Measurements

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Low-Frequency Noise Evaluation on a Commercial Magnetoimpedance Sensor at Submillihertz Frequencies for Space Magnetic Field Detection

Sensors ◽

10.3390/s19224888 ◽

2019 ◽

Vol 19 (22) ◽

pp. 4888

Author(s):

Tao Wang ◽

Chen Kang ◽

Guozhi Chai

Keyword(s):

Magnetic Field ◽

Low Frequency ◽

Temperature Stability ◽

Space Missions ◽

Low Noise ◽

Integration Time ◽

Frequency Noise ◽

Low Frequency Noise ◽

Field Detection ◽

Measurement Limit

The purpose of this study was to measure the low-frequency noise and basic performance of a commercial magnetoimpedance (MI) sensor at sub-millihertz frequencies for use in space missions. Normally, space missions require measuring very weak magnetic fields with a long integration time, such as the space gravitational wave detection mission requiring sub-millihertz frequencies. We set up a platform for measuring the performance on this MI sensor, including low-frequency noise, measurement limit, linearity, and temperature stability. The results show that the low-frequency noise of the MI sensor is below 10 nT/√Hz at 1 mHz and below 100 nT/√Hz at 0.1 mHz; its measurement limit is 600 pT. The MI sensor is characterized by high precision, small size, and low noise, demonstrating considerable potential for application in magnetically sensitive experiments requiring long integration time. This is an effect way to solve the problem that there is on one suitable magnetic sensor at space magnetic field detection, but the sensor requires improvements in temperature stability.

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Boundary layers of an anchored magnetic field in a highly conductive flow

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2010.0132 ◽

2010 ◽

Vol 466 (2123) ◽

pp. 3153-3166 ◽

Cited By ~ 1

Author(s):

Manuel Núñez ◽

Alberto Lastra

Keyword(s):

Magnetic Field ◽

Boundary Layer ◽

Asymptotic Analysis ◽

Small Parameter ◽

Order Approximation ◽

First Order ◽

Electrically Conducting ◽

Electrically Conducting Fluid ◽

First Order Approximation ◽

Distance To The Boundary

The effects of the flow of an electrically conducting fluid upon a magnetic field anchored at the boundary of a domain are studied. By taking the resistivity as a small parameter, the first-order approximation of an asymptotic analysis yields a boundary layer for the magnetic potential. This layer is analysed both in general and in three particular cases, showing that while in general its effects decrease exponentially with the distance to the boundary, several additional effects are highly relevant.

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