• Title, Summary, Keyword: magnetometer

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Fabrication of a HTS SQUID Magnetometer for Magnetocardiogram (심자도 측정용 고온초전도 SQUID magnetometer의 제작)

  • Kim, In-Seon;Lee, Sang-Kil;Kim, Jin-Mok;Kwon, Hyuk-Chan;Lee, Yong-Ho;Park, Yon-Ki;Park, Jong-Chul
    • Journal of Sensor Science and Technology
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    • v.6 no.4
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    • pp.258-264
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    • 1997
  • $YBa_{2}Cu_{3}O_{7}$ single layer dc SQUID magnetometers, prepared on $1\;cm^{2}\;SrTiO_{3}$ substrates, have been fabricated and characterized. Based on the analytical description, a SQUID magnetometer design having a 8.5 mm pickup coil with 2.6 mm linewidth, and a SQUID inductance Ls = 50 pH with $3\;{\mu}m$ Josephson junctions is presented. The devices showed a maximum modulation voltage depth of $65\;{\mu}V$ and a magnetic field noise of 0.6 pT /$\sqrt{Hz}$ at 1 Hz. Clear traces of human magnetocardiogram could be obtained with the SQUID magnetometer operating at 77 K.

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Compensation of Magnetometer in the Navigation System for Unmanned Helicopter using an Electric Motor (전기모터를 사용한 소형 무인헬리콥터에 활용될 항법장치용 자장계의 보상)

  • Lee, Gilho;Jo, Sungbeom;Kim, Jungsung;Choi, Keeyoung;Kee, Changdon;Song, Yongkyu;Koo, Wheonjoon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.11
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    • pp.997-1003
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    • 2012
  • GNSS and ARS are the most common sensors in low-end UAVs. However, these sensors are vulnerable to built-in errors and cannot measure the body heading independently. The GNSS/INS cannot fully compensate the IMU errors in initial alignment process and rectilinear flights. For an unmanned helicopter, a magnetometer can be more useful than any other sensors to obtain heading information. However, the electric motor which drives small helicopter UAV keeps the magnetometer from reading the pure magnetotelluric vector. This paper shows the effects of electric motor on the magnetometer readings, and presents a method to compensate the effects. The results are verified with flight test data. The simulation and experimental results in this paper proves that aiding GNSS/INS with magnetometer increases observability and improves accuracy.

Construction of 3-Axis Flux-gate Magnetometer for Attitude Control of Satellite (인공위성의 자세제어용 3-축 Flux-gate 마그네토미터 제작)

  • Son, De-Rac
    • Journal of the Korean Magnetics Society
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    • v.16 no.3
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    • pp.182-185
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    • 2006
  • In this work, we have constructed 3-axis flux-gate magnetometer for the attitude control of satellite. The constructed magnetometer shows uncertainty of ${\pm}1%$, noise level of $0.2nT/\sqrt{Hz}$ at 1 Hz under 1W power consumption. Environment test for satellite component, acceleration test and thermal cycle test were carried out. For the acceleration test, magnetometer was vibrated frequency ranging from 10 Hz to 1 kHz at 15 g (g : gravitational acceleration at earth), and for thermal cycle test, 4 times of thermal cycle were carried out temperature ranging from $-55^{\circ}C\;to\;+80^{\circ}C$ under vacuum of $1x10^{-6}Torr$.

Deep Sea Three Components Magnetometer Survey using ROV (ROV를 이용한 심해 삼성분자력탐사 방법연구)

  • Kim, Chang-Hwan;Park, Chan-Hong
    • Geophysics and Geophysical Exploration
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    • v.14 no.4
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    • pp.298-304
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    • 2011
  • We conducted magnetic survey using IBRV (Ice Breaker Research Vessel) ARAON of KORDI (Korea Ocean Research and Development Institute), ROV (Remotely Operated Vehicle) of Oceaneering Co. and three components vector magnetometer, at Apr., 2011 in the western slope of the caldera of TA25 seamount, the Lau Basin, the southwestern Pacific. The depth ranges of the survey area are from about 900 m to 1200 m, below sea level. For the deep sea magnetic survey, we made the nation's first small deep sea three components magnetometer of Korea. The magnetometer sensor and the data logger was attached with the upper part and lower part of ROV, respectively. ROV followed the planning tracks at 25 ~ 30 m above seafloor using the altimeter and USBL (Ultra Short Base Line) of ROV. The three components magnetometer measured the X (North), Y (East) and Z (Vertical) vector components of the magnetic field of the survey area. A motion sensor provided us the data of pitch, roll, yaw of ROV for the motion correction of the magnetic data. The data of the magnetometer sensor and the motion sensor were recorded on a notebook through the optical cable of ROV and the network of ARON. The precision positions of magnetic data were merged by the post-processing of USBL data of ROV. The obtained three components magnetic data are entirely utilized by finding possible hydrothermal vents of the survey area.

DEVELOPMENT OF A FLUXGATE MAGNETOMETER FOR THE KITSAT-3 SATELLITE (과학위성용 자력계 탑재체 개발에 관한 연구)

  • ;;;;;;Onishi Nobugito
    • Journal of Astronomy and Space Sciences
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    • v.14 no.2
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    • pp.312-319
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    • 1997
  • The magnetometer is one of the most important payloads for scientific satellite to monitor the near-earth space environment. The electromagnetic variations of the space environment can be observed with the electric and magnetic field measurements. In practice, it is well known that the measurement of magnetic fields needs less technical complexities than that of electric fields in space. Therefore the magnetometer has long been recognized as one of the basic payloads for the scientific satellites. In this paper, we discuss the scientific fluxgate magnetometer which will be on board the KITSAT-3. The main circuit design of the present magnetometer is based on that of KITSAT-1 and -2 but its facilities have been re-designed to improve the resolution to about 5nT for scientific purpose. The calibration and noise level test of this circuit have been performed at the laboratory of the Tierra Tecnica company in Japan.

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Measurement of Remanent Magnetization of Rocks Using an Astatic Magnetometer - Emphasizing on the Astatic Magnetometer set up at the Department of Geology, Yonsei University- (무정위자력계(無定位磁力計)에 의(依)한 암석(岩石)의 잔류자기측정법(殘留磁氣測定法) -특(特)히 연세대(延世大) 지질학과(地質學科)에 설치(設置)된 무정위자력계(無定位磁力計)의 제작(製作)을 중심(中心)으로-)

  • Kim, Kwang Ho;Min, Kyung Duck
    • Economic and Environmental Geology
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    • v.14 no.3
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    • pp.155-165
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    • 1981
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Geomagnetic Field Monitoring at King Sejong Station, Antarctica (남극 세종기지에서의 지자기 모니터링)

  • Kim, DonIl;Jin, YoungKeun;Nam, SangHeon;Lee, JooHan
    • Journal of the Korean Geophysical Society
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    • v.7 no.1
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    • pp.11-21
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    • 2004
  • The variation of geomagnetic field and absolute magnetic field at the geomagnetic observatory of King Sejong Station has been measured with 3-component ring core fluxgate magnetometer, proton magnetometer and D-I magnetometer. With data obtained from King Sejong Station during 2003, thediurnal and annual variations of geomagnetic field were researched and compared with those at other observatories. The deviation of daily variation of magnetic field in antarctica decreased gradually during winter season due to sun effect. The rates of componental annual variation of magnetic field at King Sejong Station were calculated using the least-square method under the assumption that the annual variation of magnetic field is linear. The rates are -55.93 nT/year in horizontal intensity, -0.87 min./year in declination, 58.30 nT/year in vertical intensity, and -69.85 nT/year in total intensity of magnetic field. A remarkable variation was caused by the magnetic storms occurred on 29~30 October, which were so powerful that the variation was observed in mid latitudes as well as high latitudes. The values of variation are generally 1500 2000 nT in Antarctica including King Sejong Station, 350 500 nT in East Asia. The measurement of absolute magnetic field shows that ring core fluxgate magnetometer has relatively large error range under cold temperature.

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Development of Resonant-Type Magnetometer Using High Permeability Isotropic Magnetic Material (고투자율 등방성 자기 물질을 이용한 공진형 마그네토미터 개발)

  • Yim, Jeong-Bin;Shim, Yeong-Ho;Ahn, Yeong-Sub
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.11 no.1
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    • pp.29-37
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    • 2005
  • The design and development if Resonant-type Magnetometer(RM) using isotropic magnetic with high permeability is described in this paper. At first, the relationship between the inductance L if the coil winding on a magnetic material and the permeability u(H) appearing in the magnetic material with isotropic and high permeability is defined as a background theory. Then the circuit if RM, which is to obtain the values if L as the change qf frequency is implemented using simple Schmitt Trigger Circuit Through the swinging tests, which is to evaluate the measurement ability if RM, the measurement possibility for the component of earth field was confined.

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A High Precision Pulsed Field Magnetometer for Magnetic Properties Measurements of Rare Earth Magnets (희토류 영구자석의 자성측정을 위한 고감도 펄스마그네토미터)

  • Kim, Y.B.;Kapustin, G.A.
    • Journal of the Korean Magnetics Society
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    • v.15 no.4
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    • pp.250-255
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    • 2005
  • A 8 MA/m-class pulsed field magnetometer has been constructed by composing a pulsed field magnet, a pickup coil, analog integrators, a digital storage oscilloscope and a personal computer. For precision measurements, a 3-axis compensation principle has been applied for the fabrication of pickup coil, and the compensation level of the order of $10^{-6}$ and the sensitivity of $5{\cdot}10^{-7}\;Am^2$ for magnetic moment have been obtained. The high sensitivity of the magnetometer is good enough for measurements of magnetic properties of rare earth magnets in small size or thin films shorter than $3\;mm{\phi}$ in diameter.

Weighted Least Square-Based Magnetometer Calibration Method Robust in Roll-Pitch Limited Conditions (롤피치 제한 조건에 강인한 가중 최소자승법 기반 마그네토미터 캘리브레이션 기법)

  • Jeon, Tae-Hyeong;Lee, Jung-Keun
    • Journal of Sensor Science and Technology
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    • v.26 no.4
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    • pp.259-265
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    • 2017
  • Magnetometer calibration must be performed before the use of three-axis magnetometers to ensure the accuracy of orientation estimation. Recently, one of the most popular calibration approaches is the ellipsoid fitting technique due to its high performance in calibration. To date, in fact, performances of the existing ellipsoid fitting methods have been evaluated with full range rotation data. However, in case of the calibration of magnetometers attached to vehicles, ships, and planes, it is very difficult to collect the full range rotation data since their allowable ranges in terms of roll and pitch are limited to small. This constraint may result in serious performance degradation of some ellipsoid fitting algorithms. Therefore, to be practical, this paper proposes a weighted least square-based magnetometer calibration method that is robust in roll-pitch limited conditions. Furthermore, the proposed method is a linear approach and thus is free from the well-known initial value issue in nonlinear approaches. Experimental results show the superiority of the proposed method to other ellipsoid-fitting calibration methods.