• Journal of the Korean Magnetics Society
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• v.24 no.1
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• pp.22-27
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• 2014

North indicating azimuth angle sensors have been used in airplanes, ships traditionally and nowadays employed in smart phones. For the azimuth and roll angle measurement of the sensor, 3-axis acceleration sensor was added to the 3-axis magnetic field sensor. In this work, we have constructed a measuring system for the measurement of the magnetic field and the angle uncertainty of the magnetic field sensors. Measuring system could be useful not only in non-magnetic laboratory but also in normal laboratory, we constructed small size of 3-axis Helmholtz coils for the compensation environment magnetic field (Earth magnetic field and magnetic field from building) and the generation of magnetic field for the test of magnetic field sensor. The constructed measuring system could compensate environment magnetic field below 10 nT level and generate 3-dimensional magnetic field with magnitude uncertainty of 0.2 % and angle error of $0.2^{\circ}$ within the volume of ${\pm}30mm$ diameter at center of Helmholtz coils. For the conformation of developed measuring system, We tested commercially available 3-axis magnetometer and heading sensor.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.190-196
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• 2015

In this paper, we propose multiple location error compensation algorithm for GPS/INS fusion using kalman filter and introduce the way to reduce location error in 9-axis navigation devices for implementing inertial navigation technique. When evaluating location, there is an increase of location error. So navigation systems need robust algorithms to compensate location error in GPS/INS fusion. In order to improve robustness of 9-axis inertial sensor(mpu-9150) over its disturbance, we used tilt compensation method using compensation algorithm of acceleration sensor and Yaw angle compensation to have exact azimuth information of the object. And it shows improved location result using these methods combined with kalman filter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3161-3167
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• 2010

Hall sensors of BLDC(brushless DC) motor are used to detect a position information for a control mechanism, which implements an algorithm for velocity and position control. Actual azimuth and altitude were measured to evaluate a control precision. The measurement revealed comparatively good accuracy that the measured values were $2.02^{\circ}$ and $1.01^{\circ}$ respectively, and the maximum error falls within $1.86^{\circ}$. The developed monitoring system of photovoltaic generation plants is a LCU(Local Control Unit) based on an integrated monitoring system which supports 1:N method for multiple simultaneous connections, remote control and real-time system state monitoring.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2334-2340
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• 2010

Sun position computed by Michalsky shows maximum $1.5^{\circ}$, $0.88^{\circ}$ and 2 minutes differences in azimuth, altitude, and sunrise and sunset times respectively compared with Korean Almanac. The 2-axis solar tracking system, which consist control panel with ATmega128 CPU, BLDC motor-cylinder actuator and 2-axis link mechanism, was developed. Computed azimuth and altitude of sun for a current time, and latitude and longitude of tracker position built are controlled in real time by BLDC motor-cylinder actuators comparing with the position feed-backed by Hall sensor. The use of BLDC motor is free in maintenance. Implementation of a home-return function by Hall sensor is to minimize the cumulative error.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.994-1002
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• 2008

In this paper a novel tracking system is described, regarding the influence of shadow between array, aimed at improving the efficiency of PV tracking system. Comparing with a building site versus capacity power, domestic solar powers have a limited siting. Therefore, each array interferes with the shadow of other arrays. The loss by influence of those shadow can be compensated for by means of control algorithm of the tracking device. The paper suggests a method controlling an altitude for length which is received the shadow influence of PV array. By using an azimuth of current solar position and the length between arrays, the controller of tracking device is able to calculate the length between actual arrays and make a comparison of the shadow length at a specific time with the length between arrays. When the shadow length is longer than the length between arrays, the controller of tracking device can adjust a position by compensating error altitude of the length between arrays at an altitude of current solar position. In the paper, we develop the control algorithm able to minimize the loss caused by the influence of shadow on the PV tracking system, and compared this with conventional output system. The controller has been tested in the laboratory with proposed algorithm and shows excellent performance.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.219-221
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• 2009

This paper analyzes efficiency of photovoltaic(PV) tracking system using solar location algorithm(SLA). Solar location tracking system is needed for efficiently and intensively using PV system independent of environmental condition. PV tracking system of program method is presented a high tracking accuracy without the wrong operating in rapidly changed insolation by the clouds and atmospheric condition. Therefore, this paper analyzes efficiency of PV system using SLA for more correct position tracking of solar. Also, controlled altitude angle and azimuth angle by applied algorithm is compared with data of korea astronomy observatory. And this paper analyzes the tracking error and proves the validity of applied algorithm.

• The Journal of the Acoustical Society of Korea
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• v.35 no.5
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• pp.395-402
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• 2016

In this paper, a wideband adaptive beamforming approach for an acoustic vector sensor linear array is presented. It is a very important issue to estimate the stable covariance matrix for adaptive beamforming. In the conventional wideband adaptive beamforming based on coherent signal-subspace (CSS) processing, the error of bearing estimates is resulted from the focusing matrix estimation and the large number of data snapshot is necessary. To alleviate the estimation error and snapshot deficiency in estimating covariance matrix, the steered covariance matrix method in the pressure sensor is extended to the vector sensor array, and the subarray technique is incorporated. By this technique, more accurate azimuth estimates and a stable covariance matrix can be obtained with a small number of data snapshot. Through simulation, the azimuth estimation performance of the proposed beamforming method and a wideband adaptive beamforming based on CSS processing are assessed.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.1
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• pp.1-8
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• 2011

The accuracy of MR sensor-based electronic compass is influenced by the temperature drift and DC offset of the MR sensor and the OP-amp, the magnetic distortion of nearby magnetic materials, and the compass tilt We design the 3-axis MR sensor and accelerometers-based electronic compass which is compensated by the set/reset pulse switching method on the temperature drift and DC offset, by the execution of hard-iron calibration routine on the magnetic distortion, and by the execution of the Euler rotational equation on the compass tilt. We qualitatively analyze the measured azimuth error on the execution of sensitivity calibration routine which is the normalization process on the different sensitivity of each MR sensor and the different gain of each op-amps. This compensation and analytic result make us design the one degree accuracy electronic compass.

• ETRI Journal
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• v.27 no.3
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• pp.280-288
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• 2005

This paper presents an efficient algorithm for using the two-axis magnetic compass in portable devices. The general magnetic compass module consists of a three-axis magnetic compass and a two-axis inclinometer to calculate tilt-compensated azimuth information. In this paper, the tilt error is compensated using just a two-axis magnetic compass and two-axis accelerometer. The third-axis data of the magnetic compass is estimated using coordinate information that includes the extended dip angle and tilt information. The extended dip angle is estimated during the normalization process. This algorithm can be used to provide the tilt-compensated heading information to small portable devices such as navigation systems, PDAs, cell phones, and so on.

• 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.