• Journal of Digital Convergence
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• v.11 no.4
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• pp.243-249
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• 2013

In this paper, GPS(Global Positioning System) that can be used outdoors and GPS(Global Positioning System) is not available for indoor Wi-Fi(Wireless Fidelity) using the Android-based location information system has been designed and implemented. Pedestrians in a room in order to estimate the location of the pedestrian's position, regardless of need to obtain the absolute position and relative position, depending on the movement of pedestrians in a row it is necessary to estimate. In order to estimate the initial position of the pedestrian Wi-Fi Fingerprinting was used. Most existing Wi-Fi Fingerprinting position error small WKNN(Weighted K Nearest Neighbor) algorithm shortcoming EWKNN (Enhanced Weighted K Nearest Neighbor) using the algorithm raised the accuracy of the position. And in order to estimate the relative position of the pedestrian, the smart phone is mounted on the IMUInertial Measurement Unit) because the use did not require additional equipment.

• Korean Journal of Optics and Photonics
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• v.9 no.1
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• pp.9-14
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• 1998

We present a simple method of determining the absolute order of moire fringes formed by the moire shadow topography with a criss-crossed grating. Two experimental methods in this topography are proposed and demonstrated; one is to change the ratio of x and y pitches in a criss-crossed grating after fixing the position of a light source and a camera, and the other is to change the position of a light source and a camera after fixing the ratio of x and y pitches in a criss-crossed grating.

• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.387-394
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• 2005

This paper describes an idea for determining self-localization using visual landmark. The critical geometric dimensions of a pentagon are used here to locate the relative position of the mobile robot with respect to the pattern. This method has the advantages of simplicity and flexibility. This pentagon is also provided nth a unique identification, using invariant features and colors that enable the system to find the absolute location of the patterns. This algorithm determines both the correspondence between observed landmarks and a stored sequence, computes the absolute location of the observer using those correspondences, and calculates relative position from a pentagon using its (ive vortices. The algorithm has been implemented and tested. In several trials it computes location accurate to within 5 centimeters in less than 0.3 second.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4569-4573
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• 2011

Resolver doesn't have a advantage to price in comparision with encorder. However, resolver is used to the case of detecting a absoluteness position and is used to a fine control in the place of having a stability by mechanic. The position by resolver and the method by speed detecting is applied by observer and have a part of processing analog signal. In this paper, we used the method which output signal of resolver is demodulated by cos and sin waveform and the demodulated analog signal is transmitted to controller. We designed the estimated on the program of a controller and observed the movement on the low speed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4550-4560
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• 2011

Generally, a optical encoder is used to detect velocity for controling the electronic motor, the resolver is used when it is hard structurally to adjust encoder to electronic motor. so, the resolver has weakness in price in compare with encoder, but in case of controling the position of a magnetic polar, the resolver has stead detecting the absolute position of a rotator. This study is about the digital programing velocity detector which uses a minimum hardware : filter for detecting the revolve speed and rotor position of the motor by means of the resolver.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.355-356
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• 2007

21세기는 한국 철도의 르네상스시대라고 부르고 있다. 이는 자동차와 비행기 등 다른 교통수단에 의해 낙후되어있던 철도가 다시 안전하면서도 정확한 운송시간 등으로 그 경쟁력을 확보해가고 있으며 때를 같이하여 고속철도의 개통을 앞두고 있기 때문이다. 이러한 철도의 경쟁력을 강화하는데 크게 기여한 부분 중 하나가 신호 보안장치 즉 열차제어장치의 발전에 있다고 하겠다. 하지만 열차를 제어하기 위해선 실시간격으로 열차의 절대 위치를 알아야만 하는 문제점이 있다. 이를 비교적 쉽게 극복할 수 있는 방법 중 하나가 인공위성을 이용한 통신기술을 이용하는 것이다. 이는 이미 다른 분야에서는 상용화되어 서비스가 이루어지고 있는 GPS(Global Positioning System)이다. 본 논문에서는 열차의 절대 위치를 GPS(Global position system)를 이용하여 구해 보고자 한다. 이를 위해 GPS 신호 추적을 확장형 칼만 필터를 적용하여 열차의 속도 변화에 대한 GPS 신호 추적 루프를 예측 제어함으로써 보다 정확하고 빠른 GPS 위치 정보를 도출하였다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1811-1812
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• 2008

This paper represents a absolute position tracking system with sensor fusion and PD-gain. this paper presents an accurate localization method by relative and absolute sensor fusion and PD control for position tracking of mobile robot. we developed a sensor based absolution position tracking and smooth moving algorithm using this algorithm.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.5
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• pp.200-209
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• 2018

This study proposed a method to select existing facilities as a landmark in order to reset accumulated errors of dead reckoning in a tunnel difficult to receive GNSS signals in automated driving. First, related standards and regulations were reviewed in order to survey 'variety' on shapes and installation locations as a feature of facilities. Second, 'recognition' on facilities was examined using image and Lidar sensors. Last, 'regularity' in terms of installation locations and intervals was surveyed through related references. The results of this study selected a fire fighting box / lamp (50m), an evacuation corridor lamp (300m), a lane control system (500m), a maximum / minimum speed limit sign and a jet fan as a candidate landmark to reset positioning errors. Based on those facilities, it was determined that error correction was possible. The results of this study are expected to be used in repositioning of automated driving vehicles in a tunnel.

• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.76-82
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• 1997

The paper describes simulations and experimental results using a measuring system which utilizes the acoustic holographic method in order to exactly estimate an absolute position of a sound source. The measuring surface is installed to satisfy with a far field to the sound source and is composed of linear arrayed seven microphones. A measurement is simultaneously recorded by a reference microphone setting up a neighbour sound source and the linear arrayed seven microphones which are moved to the same interval. An absolute position of sound source is estimated by the cross-spectrum method to the received sounds between a reference and the measuring microphones. Phase differences of each microphone and time delays during scanning are compensated to the reference microphone and the measuring time of the first column. An optimal interval for each microphone in the measuring surface is decided by a numerical simulation. A source signal makes use of a sinusoid, and S/N ratio is 30dB in the experiment. The optimal microphone's interval in the simulation and the experiment is decided in order to satisfy with the Nyquist space sampling condition related to the wave length of 2kHz sinusoid. Mainlobe width of a estimated 3D hologram in the case of 2kHz source signal is decreased to 87% and 30% in comparison to 500Hz and 1kHz, and then a valid of simulation results is confirmed. Therefore, we verified a utilization of the study for a sound source estimation using 3ㅇ acoustic holographic method.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.544-547
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• 1997

In this paper, we propose a dynamic localization method using a rotating sonar and a map. The proposed method is implemented by using extended Kalman filter. The state equation is based on the encoder propagation model and the encoder error model, and the measurement equation is a map-based measurement equation using a rotating sonar sensor. By utilizing sonar beam characteristics, map-based measurements are updated while AMR is moving continuously. By modeling and estimating systematic errors of a differential encoder, the position is successfully estimated even the interval of the map-based measurement. Monte-Carlo simulation shows that the proposed global position estimator has the performance of a few millimeter order in position error and of a few tenth degrees in heading error and of compensating systematic errors of the differential encoder well.