• Journal of Sensor Science and Technology
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• v.10 no.5
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• pp.329-336
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• 2001

This paper describes the steering control and geomagnetism cancellation for an autonomous vehicle using an MR sensor. The magneto-resistive (MR) sensor obtains the vector summation of the magnetic fields from embedded magnets and the Earth. The vehicle is controlled by the magnetic fields from embedded magnets. So, geomagnetism is the disturbance in the steering control system. In this paper, we propose a new method of the sensor arrangement in order to remove the geomagnetism and vehicle body interference. The proposed method uses two MR sensors located in a level plane and the steering controller has been developed. The controller has three input variables ($dB_x$, $dB_y$, $dB_z$) using the measured magnetic field difference, and an output variable (the steering angle). A simulation program was developed to acquire the data to teach the neural network, in order to test the ability of a neural network to learn the steering control process. Also, the computer simulation of the vehicle (including vehicle dynamics and steering) was used to verify the steering performance of the vehicle controller using the neural network. From the simulation and field test, good result was obtained and we confirmed the robustness of the neural network controller in a real autonomous vehicle.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.32.6-32
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• 2001

This paper describes the steering control and geomagnetism cancellation for an autonomous mobile robotusing MR sensors. The magnetic-resistive (MR) sensor obtains the vector summation of the magnetic fields from embedded magnets and the Earth. The robot is controlled by the magnetic fields from embedded magnets. So, geomagnetism is the disturbance in the steering control system. In this paper, we propose a new method of the sensor arrangement in order to remove the geomagnetism and robotbody interference. The proposed method uses two MR sensors located in a level plane and the steering controller has been developed. The controller has three input variables (dBx, dBy, dBz) using the measured magnetic field difference, and an output variable (the steering angle) ...

• Journal of Sensor Science and Technology
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• v.16 no.1
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• pp.17-23
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• 2007

This paper presents a miniaturized turn-counting sensor (TCS) where the geomagnetism and high-rpm rotation of ammunition are used to detect the turn number of ammunition for applications to small-caliber turn-counting fuzes. The TCS, composed of cores and a coil, has a robust structure with no moving part for increasing the shock survivability in the gunfire environments of ${\sim}30,000$ g's. The TCS is designed on the basis of the simulation results of an electromagnetic analysis tool, $Maxwell^{(R)}$3D. In experimental study, the static TCS test using a solenoid-coil apparatus and the dynamic TCS test (firing test) have been made. The presented TCS has shown that the induction voltage of $6.5{\;}mV_{P-P}$ is generated at the magnetic flux density of 0.05 mT and the rotational velocity of 30,000 rpm. From the measured signal, the TCS has shown the SNR of 44.0 dB, the nonlinearity of 0.59 % and the frequency-normalized sensitivity of $0.26{\pm}0.01{\;}V/T{\cdot}Hz$ in the temperature range of $-30{\sim}+43^{\circ}C$. Firing test has shown that the TCS can be used as a turn-counting sensor for small-caliber ammunition, verifying the shock survivability of TCS in high-g environments.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.3
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• pp.253-259
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• 2014

There has been a need for replacing human labors with a robot in such dangerous and hard jobs of various construction sites. For that reason, many researches have been made about the high quality robot, which performs its duty instead of human labors. This study is about auto surveying system development based on VRS-GPS which enables autodriving in dangerous areas where it's difficult for humans to measure directly. This study is about the auto-surveying system development, based on VRS-GPS, which enables auto-drive in dangerous areas, whereas difficult for humans to measure directly. The GPS is made with GRXI and SHC250 controllers of the SOKKIA company. The auto surveying system is composed of DPS module, geomagnetism sensor, bluetooth, gimbals, IMU, etc to automatic drive via enter into a route of position. The developed auto surveying system has installed the carmeras for front and vertical axis as well as systems to grasp situation of surveying with smartphone in real time. The result from analysed RMSE of auto surveying system and VRS-GPS surveying is 0.0169m of X-axis and 0.0246m of Y-axis.

• Journal of Sensor Science and Technology
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• v.22 no.2
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• pp.111-117
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• 2013

The autonomous driving method using magnetic sensors recognizes the position by measuring magnetic fields in autonomous robots or vehicles after installing magnetic markers in a moving path. The Position estimate method using magnetic sensors has an advantage of being affected less by variation of driving environment such as oil, water and dust due to the use of magnetic field. It also has the advantages that we can use the magnet as an indicator and there is no consideration for power and communication environment. In this paper, we propose an efficient sensor system for an autonomous driving vehicle supplemented for existing disadvantage. In order to efficiently eliminate geomagnetism, we analyze the components of the horizontal and vertical magnetic field. We propose an algorithm for position estimation and geomagnetic elimination to ease analysis, and also propose an initialization method for sensor applied in the vehicle. We measured and analyzed the developed system in various environments, and we verify the advantages of proposed methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5215-5220
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• 2013

Recent construction in the field of 3D aversion is increasing interest in automation. This study is results about survey of the coastal landfill using automatic VRS-GPS surveying system. GPS is made with GRXI and SHC250 controller. Automatic surveying system is composed of DPS module, geomagnetism sensor, bluetooth, gimbals, IMU, etc and enables an automatic driving via entered into a route of position. The developed auto surveying system has installed the front and camera for vertical axis and can grasp situation of surveying with smartphone in real time. The comparative result between surveyed result with repetition method auto VRS-GPS surveying system observed surveyed result with VRS-RTK has shown that average error of x-axis is 0.009m, average error of y-axis, 0.010m and average error of height, 0.002m. This possibility was confirmed that field application.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.6
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• pp.137-141
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• 2022

The method of estimating the azimuth by measuring the geomagnetism has been used for a very long time. However, there are many cases where an error occurs in the estimated azimuth due to disturbances in the earth's magnetic field due to metal structures inside and outside the room. Although many studies have been conducted to correct this, there is a limit to reducing the error. In this paper, we propose a method of estimating the azimuth by applying the measured geomagnetic sensor data to the neural network of the LSTM structure. Data preprocessing is very important for learning a neural network. In this paper, data is collected using the built-in acceleration sensor, gyro sensor, and geomagnetic sensor in the smartphone, and the geomagnetic sensor data is uniformly sampled using EKF. As a result, an average azimuth estimation error of 0.9 degrees was obtained using four hidden layers.

• Journal of Sensor Science and Technology
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• v.14 no.6
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• pp.409-414
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• 2005

For an intelligent vehicle driving which uses magnetic markers and magnetic sensors, we can get every kind of road information while moving the vehicle if we use the code that is encoded with N, S pole direction of markers. If we make it an only aim to move the vehicle, it becomes easy to control the vehicle the more we put markers close. By the way, to recognize the direction of a marker pole it is much better that the markers have no effect each other. To get road informations and move the vehicle autonomously we propose the methods of arranging magnetic sensors and algorithm of recognizing the position of the vehicle with those sensors. We verified the effectiveness of the methods with computer simulation.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.85-92
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• 2008

National Oceanographic Research Institute is carrying out an oceanographic survey for the entire sea areas around Korean Peninsula annually starting with the East Sea from 1996 by establishing a national oceanographic basic map survey plan for the sea areas under the jurisdiction of Korea, so this paper used the oceanographic geomagnetism data measured at the southern area of the Yellow Sea using 'Hae Yang 2000' in 1999, aiming at clarifying the cause of geomagnetic abnormality zone during the course of treating and analyzing the geomagnetic data. For treatment of magnetic data, we obtained electromagnetic force values and geomagnetic abnormality values around the investigated sea area through a process of searching and removal of bad data, correction of sensor positions, correction of magnetic field effects around the hull, correction of diurnal variation, normal correction, correction of cross point errors, etc. The electromagnetic force distribution around the investigated sea area was $49000\;{\sim}\;51600\;nT$, which is judged to be within the normal electromagnetic force intensity distribution range around the Yellow Sea. The isodynamic lines are distributed in Northeast-Southwest direction, and electromagnetic force values are increasing toward the northwest. The result of comparing the magnetic abnormality around the sea area among $124^{\circ}$ 49' 48" E, $35^{\circ}$ 10' 48" N $\sim$ $125^{\circ}$ 7' 48" E, and $35^{\circ}$ 33' 00" N sections with the elastic wave cross section and the result of modeling coincide well with the underground geological structure clarified from the existing elastic wave survey cross section. Therefore, it is judged that the distribution of magnetic force abnormality generally shows the effect pursuant to the distribution of the sedimentary basins in the Tertiary period and the bedrocks in the Cretaceous period which are well developed in the bottom of the sea.