• Geophysics and Geophysical Exploration
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• v.23 no.3
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• pp.208-214
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• 2020

In this study, we have developed a drone magnetic exploration system (proto-type) using a fluxgate magnetic sensor. Hardware of the system consists of a fluxgate magnetometer, an inertial measurement unit (IMU), a GPS, and a communication module. And we have developed monitoring software, which enables it to transmit the measured data to the ground control system (GCS) in real time. The measured magnetic data are finally saved as 1 Hz data after passing through a notch filter and a band-pass filter. For verification of this system, a preliminary test was conducted to check the magnetic responses of a magnetic object first, then the field test was carried out in two iron mines. We tested the developed system on the field test in Pocheon, Gyeonggi and Jeongseon, Gangwon. The magnetic data from the developed drone system was very similar to those from unmanned airship system developed by Korea Institute of Geoscience and Mineral Resources (KIGAM). As a result, preliminary experiment and field test have demonstrated that this system is applicable for outdoor aeromagnetic exploration. It requires more studies to improve filter function and instrument performance to minimize noise in the future.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1001-1006
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• 2003

This paper presents the pedestrian navigation algorithm and the error compensation filter. The pedestrian navigation system (PNS) consists of the MEMS inertial sensors, the fluxgate, and the small-size GPS receiver. PNS calculates the navigational information using the signal patterns of the accelerometers. And the navigational information is completed by integration of the patterns, the fluxgate, and the GPS information. In general, PNS can provide the better solution than the low-cost inertial navigation system.

• Journal of Magnetics
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• v.8 no.1
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• pp.70-73
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• 2003

We have developed a new tracking system of jaw movement. The system consists of two permanent NdFeB magnets and 32 elements of two-axial fluxgate sensor array, The two magnets are attached to head portion and front tooth. This system does not need any attachments of the head portion or mouth such as clutch or magnetic field sensor except magnets. The proposed system is applicable for five degree of freedom. Position accuracy within 2]m was achieved. We developed a 3D computer input device by using the above mentioned technique.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.40.1-40.1
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• 2020

The Korea Astronomy and Space Science Institute is participating as a South Korean partner in the Commercial Lunar Payload Services (CLPS)of NASA. In response, the Korea Astronomy and Space Science Institute is currently conducting basic research for the development of four candidate instrument payloads. The magnetic field instrument is one of them and it's scientific mission objective is the moon's surface magnetic field investigation. Therefore, the development requirement of the lunar surface magnetic field instrument were derived and the initial conceptual design was started. The magnetic field instrument has a 1.2 meter boom which has two three-axis fluxgate magnetometer sensors and one gyro sensor to get a attitude information of the boom. The concept of measuring the lunar surface magnetic field will carry out using multiple sensors by placing semiconductor type magnetic field sensors inside the electric box including boom mounted fluxgate sensors. In order to overcome the very short development period, we will use the KPLO (Korean Lunar Pathfinder Orbiter) magnetometer design and parts to improve reliabilities for this instrument. In this presentation, we introduce the instrument requirements and conceptual design for the Lunar surface magnetic field instruments.

• Journal of Astronomy and Space Sciences
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• v.29 no.4
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• pp.329-336
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• 2012

Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Bohyunsan Observatory to measure the Earth's magnetic field variations in South Korea. In 2007, we installed a fluxgate magnetometer (RFP-523C) to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we use the H, D, Z components of fluxgate magnetometer data to investigate the characteristics of mid-latitude geomagnetic field variation. To remove the temporary changes in Earth's geomagnetic filed by space weather, we use the international quiet days' data only. In other words, we performed a superposed epoch analysis using five days per each month during 2008-2011. We find that daily variations of H, D, and Z shows similar tendency compared to previous results using all days. That is, H, D, Z all three components' quiet intervals terminate near the sunrise and shows maximum 2-3 hours after the culmination and the quiet interval start from near the sunset. Seasonal variations show similar dependences to the Sun. As it becomes hot season, the geomagnetic field variation's amplitude becomes large and the quiet interval becomes shortened. It is well-known that these variations are effects of Sq current system in the Earth's atmosphere. We confirm that the typical mid-latitude geomagnetic field variations due to the Sq current system by excluding all possible association with the space weather.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.131-135
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• 1997

We implementated an ultrasonic wave cane for the blind. The cane detect walking obstacle and provide a walking direction. The cane used time of flight method of ultrasonic-wave for a measurement of obstacle distance and fluxgate geomagnetic sensor for guidance of walking direction. This system can detect an obstacle of upward, forward, downward and that warn to the blind with vibration, pitch sound. And the blind can know walking direction to voice output. As a result, the blind could efficiently avoid a exposed obstacle, obstacles beyond knee, an exposed street obstacle, a branch of tree person's height and it is usable search for surrounding land mark.

• Journal of Magnetics
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• v.16 no.4
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• pp.453-456
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• 2011

Demagnetization for a tube sample which was made of a galvanized steel sheet was performed by applying a magnetic field with a decrement to remove the remanent magnetization of the material. An orthogonal fluxgate magnetic field sensor was used to measure a magnetic field created from a ferromagnetic material. To evaluate the remanent magnetization, the measured magnetic fields were separated into two magnetic field components by the remnant magnetization and the induced one. The horizontal and the vertical bias fields should be controlled separately during demagnetization to remove the horizontal and the vertical components of the remanent magnetization of the tube sample.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1819-1823
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• 2005

Incorrect information on public sites can cause serious problem. One of relevant countermeasures against this problem is to detect of buried underground utilities in real time. Although there have been several method to detect of buried underground utilities, such as investigating of gravity and elastic wave and electric field, they have not been so efficient tools. Because it is too expensive and difficult to use. In this paper, magnetic sensors which could provide an easier and more efficient method are used to detect of buried underground utilities. Also fluxgate method of self detection are used. Input signal is used $1\~10kHz$ frequency. Filtering and signal processing of output signal are used labview software. After experiment, detection system of buried underground utilities which used magnetic shows possibility of precise detecting of laying object based on theorectical analysis for electromagnetic field.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.11
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• pp.1189-1195
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• 2008

We introduce a MEMS-based pedestrian dead reckoning (PDR) system. A walking navigation algorithm for pedestrians is presented and map-matching algorithm for the navigation system based on dead reckoning (DR) is proposed. The PDR is equipped on the human body and provides the position information of pedestrians. And this is able to be used in ubiquitous sensor network (USN), U-hearth monitoring system, virtual reality (VR) and etc. The PDR detects a step using a novel technique and simultaneously estimates step length. Also an azimuth of the pedestrian is calculated using a fluxgate which is the one of magnetometers. Map-matching algorithm can be formulated to integrate the positioning data with the digital road network data. Map-matching algorithm not only enables the physical location to be identified from navigation system but also improves the positioning accuracy. However most of map-matching algorithms which are developed previously are for the car navigation system (CNS). Therefore they are not appropriate to implement to pedestrian navigation system based on DR system. In this paper, we propose walking navigation system and map-matching algorithm for PDR.

• Journal of Astronomy and Space Sciences
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• v.28 no.3
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• pp.173-181
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• 2011

Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Mt. Bohyun Observatory to measure the Earth's magnetic field variations in South Korea. We, in 2007, installed a fluxgate magnetometer (RFP-523C) to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we provide the preliminary and the first statistical analysis using the BOH magnetometer installed at Mt. Bohyun Observatory. By superposed analysis, we find that daily variations of H, D, and Z shows similar tendency, that is, about 30 minutes before the meridian (11:28) a minimum appears and the time after about 3 hours and 30 minutes (15:28) a maximum appears. Also, a quiet interval start time (19:06) is near the sunset time, and a quiet interval end time (06:40) is near the sunrise time. From the sunset to the sunrise, the value of H has a nearly constant interval, that is, the sun affects the changes in H values. Seasonal variations show similar dependences to the sun. Local time variations show that noon region has the biggest variations and midnight region has the smallest variations. We compare the correlations between geomagnetic variations and activity indices as we expect the geomagnetic variation would contain the effects of geomagnetic activity variations. As a result, the correlation coefficient between H and Dst is the highest (r = 0.947), and other AL, AE, AU index and showed a high correlation. Therefore, the effects of geomagnetic storms and geomagnetic substorms might contribute to the geomagnetic changes significantly.