• Title, Summary, Keyword: magnetometer

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Design and Field Test of Automatic Data Logger System for Portable Magnetometer using Raspberry Pi

  • Choi, Eun-Kyeong;Kim, Sung-Wook;Cho, Jinwoo;Lee, Khil-Ha
    • Journal of Environmental Science International
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    • v.25 no.10
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    • pp.1389-1396
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    • 2016
  • A monitoring system for a field magnetometer was configured with assistance of a Raspberry Pi as a data logger. The suggested geomagnetic system uses a semi-real-time data transmission module. The system consists of two parts: a field-observation part and a data-center part. The field-observation part comprises a Raspberry Pi, magnetometer, LTE router, and power source, while the data center part takes samples at the site. The collected magnetometer data are then sent to the data center through the LTE router. The newly designed monitoring system was deployed and checked in Jeju-do island, and found to operate stably. The suggested system is promising in that it is simple and cost saving, providing at least physical insight and knowledge on the complex natural phenomena.

Construction of Feed-back Type Flux-gate Magnetometer (피드백형 플럭스게이트 마그네토미터 제작)

  • Son, De-Rac
    • Journal of the Korean Magnetics Society
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    • v.22 no.2
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    • pp.45-48
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    • 2012
  • Feed-back type 3-axis flux-gate magnetometer using Co-based amorphous ribbon (Metglass$^{(R)}$2714A) was constructed in this work. Measuring range of magnetic field and frequency were ${\pm}100\;{\mu}T$ and dc~10 Hz respectively. For the interface to computer, microcontroller and 24 bit ADC (Analog to Digital Converter) were employed and resolution of digital output was 0.1 nT. Magnetometer noise of analog output was 5 pT/$\sqrt{Hz}$ at 1 Hz. Digital output of the magnetometer showed linearity of $1{\times}10^{-4}$ and the offset drift was smaller than 0.2 nT during 1 h.

DESIGN AND PRELIMINARY TEST RESULTS OF MAGNETOMETERS (MAG/AIM & SIM) FOR SOUNDING ROCKET KSR-III (KSR-III 과학 관측 로켓 자력계(MAG/AIM & SIM)의 초기 시험 모델 개발)

  • KIM HYO-MIN;JANG MIN-HWAN;SON DE-RAC;LEE DONG-HUN;KIM SUN-MI;HWANG SEUNG-HYUN
    • Publications of The Korean Astronomical Society
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    • v.15 no.spc2
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    • pp.57-64
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    • 2000
  • It is realized that the extraterrestrial matter is in ionized state, plasma, so the matter of this kind behaves as not expected because of its sensitiveness to electric and magnetic fields and its ability to carry electric currents. This kind of subtle change can be observed by an instrument for the magnetic field measurement, the magnetometer usually mounted on the rocket and the satellite, and based on the ground observatory. The magnetometer is a useful instrument for the spacecraft attitude control and the Earth's magnetic field measurements for the scientific purpose. In this paper, we present the preliminary design and the test results of the two onboard magnetometers of KARl's (Korea Aerospace Research Institute) sounding rocket, KSR­III, which will be launched during the period of 2001-02. The KSR-III magnetometers consist of the fluxgate magnetometer, MAG/AIM (Attitude Information Magnetometer) for acquiring the rocket flight attitude information, and of the search-coil magnetometer, MAG/SIM (Scientific Investigation Magnetometer) for the observation of the Earth's magnetic field fluctuations. With the MAG/AIM, the 3-axis attitude information can be acquired by the comparison of the resulting dc magnetic vector fields with the IGRF (International Geomagnetic Reference Field). The Earth's magnetic field fluctuations ranging from 10 to 1,000 Hz can also be observed with the MAG/SIM measurement.

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DEVELOPMENT OF MAGNETOMETER DIGITAL CIRCUIT FOR KSR-3 ROCKET AND ANALYTICAL STUDY ON CALIBRATION RESULT (KSR-3 과학 로켓용 자력계 디지털 회로 개발 및 검교정시험 결과 분석 연구)

  • 이은석;장민환;황승현;손대락;이동훈;김선미;이선민
    • Journal of Astronomy and Space Sciences
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    • v.19 no.4
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    • pp.293-304
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    • 2002
  • This paper describes the re-design and the calibration results of the MAG digital circuit onboard the KSR-3. We enhanced the sampling rate of magnetometer data. Also, we reduced noise and increased authoritativeness of data. We could confirm that AIM resolution was decreased less than InT of analog calibration by a digital calibration of magnetometer. Therefore, we used numerical-program to correct this problem. As a result, we could calculate correction and error of data. These corrections will be applied to magnetometer data after the launch of KSR-3.

Fabrications and measurements of single layer YBCO dc-SQUID magnetometers designed with parallel-loop pickup coil (Parallel-loop 검출코일을 가지는 단일층 YBCO dc-SQUID 자력계의 제작 및 특성 연구)

  • 유권규;김인선;박용기
    • Progress in Superconductivity
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    • v.5 no.1
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    • pp.45-49
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    • 2003
  • We have designed and fabricated the single-layer high $T_{c}$ SQUID magnetometer consisting of a directly coupled grain boundary junction SQUID with an inductance of 100 pH and 16 nested parallel pickup coils with the outermost dimension of 8.8 mm ${\times}$ 8.8 mm. The magnetometer was formed from a YBCO thin film deposited on an STO(100) bicrystal substrate with a misorientation angle of $30^{\circ}$. The SQUID magnetometer was further improved by optimizing the multi-loop pickup coil design for use in unshielded environments. Typical characteristics of the dc SQUID magnetometer had a modulation voltage of 40 $\mu\textrm{V}$ and a white noise of $30fT/Hz^{1}$2/. The SQUID magnetometer exhibited a 1/f noise level at 10 Hz reduced by a factor of about 3 compared with that of the conventional solid type pickup coil magnetometers and a very stable flux locked loop operation in magnetically disturbed environments.s.

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The characteristics of DROS magnetometer and MCG measurement (DROS 자력계의 동작특성 및 심자도 측정)

  • Kang, C.S.;Lee, Y.H.;Kwon, H.;Kim, J.M.;Yu, K.K.;Park, Y.K.;Lee, S.G.
    • Progress in Superconductivity
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    • v.8 no.2
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    • pp.164-168
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    • 2007
  • We developed a SQUID magnetometer based on Double Relaxation Oscillation SQUID(DROS) for measuring magnetocardiography(MCG). Since DROS provides a 10 times larger flux-to-voltage transfer coefficient than the conventional DC-SQUID, simple flux-locked loop electronics could be used for SQUID operation. Especially, we adopted an external feedback to eliminate the magnetic coupling with adjacent channels. When the DROS magnetometer was operated inside a magnetically shielded room, average magnetic field noise was about 5 $fT/^{\surd}Hz$ at 100 Hz. Using the DROS magnetometer, we constructed a multichannel MCG system. The system consisted of 61 magnetometers are arranged in a hexagonal structure and measures a vertical magnetic-field component to the chest surface. The distance between adjacent channels is 26 mm and the magnetometers cover a circular area with a diameter of 208 mm. We recorded the MCG signals with this system and confirmed the magnetic field distribution and the myocardinal current distribution.

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Construction of Differential Type Search Coil Magnetometer (차동형 탐지코일 마그네토미터 제작)

  • Kim, J.H.;Son, De-Rac
    • Journal of the Korean Magnetics Society
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    • v.20 no.5
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    • pp.178-181
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    • 2010
  • Search coil magnetometer has been used for detection of ac magnetic field with high sensitivity. To reduce demagnetizing factor of core and increase S/N ratio of search coil magnetometer, the core was divided by two parts and coil was wound on each cores. Two coils were connected serially and put into amplifier as differential mode. Constructed 120 mm length search coil magnetometer shows linearity of 0.03%, sensitivity of 9.3 mV/nT, and resolution of 20 pT at 1 Hz.

Development of Ground-Based Search-Coil Magnetometer for Near-Earth Space Research

  • Shin, Jehyuck;Kim, Khan-Hyuk;Jin, Ho;Kim, Hyomin;Kwon, Jong-Woo;Lee, Seungah;Lee, Jung-Kyu;Lee, Seongwhan;Jee, Geonhwa;Lessard, Marc R.
    • Journal of Magnetics
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    • v.21 no.4
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    • pp.509-515
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    • 2016
  • We report on development of a ground-based bi-axial Search-Coil Magnetometer (SCM) designed to measure time-varying magnetic fields associated with magnetosphere-ionosphere coupling processes. The instrument provides two-axis magnetic field wave vector data in the Ultra Low Frequency or ULF (1 mHz to 5 Hz) range. ULF waves are well known to play an important role in energy transport and loss in geospace. The SCM will primarily be used to observe generation and propagation of the subclass of ULF waves. The analog signals produced by the search-coil magnetic sensors are amplified and filtered over a specified frequency range via electronics. Data acquisition system digitizes data at 10 samples/s rate with 16-bit resolution. Test results show that the resolution of the magnetometer reaches $0.1pT/{\sqrt{Hz}}$ at 1 Hz, and demonstrate its satisfactory performance, detecting geomagnetic pulsations. This instrument is scheduled to be installed at the Korean Antarctic station, Jang Bogo, in the austral summer 2016-2017.

Development of Micro-size Search Coil Magnetometer for Magnetic Field Distribution Measurement

  • Ka, E.M.;Son, De-Rac
    • Journal of Magnetics
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    • v.13 no.1
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    • pp.34-36
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    • 2008
  • For the measurement of the magnetic field distribution with high spatial resolution and high accuracy, the magnetic field sensing probe must be non-magnetic, but the MFM probe and sub-millimeter-meter size Hall probe use a ferromagnetic tip and block, respectively, to increase the sensitivity. To overcome this drawback, we developed a micro-size search coil magnetometer which consists of a single turn search coil, Terfenol-D actuator, scanning system, and control software. To reduce the noise generated by the stray ac magnetic field of the actuator driving coil, we employed an even function $\lambda$-H magnetostriction curve and lock-in technique. Using the developed magnetometer, we were able to measure the magnetic field distribution with a magnetic field resolution of 1 mT and spatial resolution of $0.1mm{\times}0.2mm$ at a coil vibration frequency of 1.8 kHz.

On-line Magnetic Distortion Calibration Method for a Magnetometer (지자기 센서의 온라인 왜곡 보정기법)

  • Kim, Tae-Yeon;So, Chang-Ju;Lyou, Joon
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.9
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    • pp.819-822
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    • 2012
  • This paper describes an on-line magnetic distortion calibration procedure for a magnetometer. The horizontal magnetic field is calculated through the earth magnetic field sensed by 3-axes magnetometer. The ellipse equation is derived from a set of horizontal magnetic field data using least square method and calibration parameters are determined. The calibration process is performed iteratively until parameters are not renewed, and experimental results show the effectiveness of the devised method.