• 반도체디스플레이기술학회지
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• 제22권2호
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• pp.112-119
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• 2023

In urban environments, signals of Global Positioning System (GPS) can be blocked and reflected by tall buildings, large vehicles, and complex components of road network. Therefore, the performance of the positioning system using the GPS module in urban areas can be degraded due to the loss of GPS signals necessary for the position estimation. To deal with this issue, various localization schemes using inertial measurement unit (IMU) sensors, such as gyroscope and accelerometer, and Bayesian filters, such as Kalman filter (KF) and particle filter (PF), have been designed to enhance the performance of the GPS-based positioning system. Among Bayesian filters, the PF has been widely used for the target tracking and vehicle navigation, since it can provide superior performance in estimating the state of a dynamic system under nonlinear/non-Gaussian circumstance. This paper presents a positioning system that uses the double-stacked particle filter (DSPF) as well as the accelerometer, gyroscope, and GPS receiver on the smartphone to provide higher pedestrian positioning accuracy in urban environments. The DSPF employs a nonparametric technique (Parzen-window) to create the multimodal target distribution that approximates the posterior distribution. Experimental results show that the DSPF-based positioning system can provide the significant improvement of the pedestrian position estimation in urban environments.

• Journal of Positioning, Navigation, and Timing
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• 제8권1호
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• pp.31-40
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• 2019

In recent years, Intelligent Transport Systems (ITS) and Autonomous Vehicle Technology have actively studied around the world. In order to achieve the purpose of Advanced Driver Assistance System (ADAS) and Autonomous Vehicle Technology, it must be obtained accurate and reliable positioning. However, the problem of positioning in the urban area is a low position accuracy caused by the reduction of the number of visible satellites due to high buildings. In this paper, we analyzed the availability of precise positioning system in urban area are using GPS/BDS integrated system. For this study, GPS and BDS satellite signals were collected using two low-cost receivers in the open sky and a designed software based platform for precise positioning performance analysis. And we analyzed the precise positioning performance by changing the mask angle considering the urban area. From the results, it can be confirmed that the performance of precise positioning of GPS only and BDS only decrease in the environment where mask angle is $40^{\circ}$ to $45^{\circ}$, however, GPS/BDS integrated system maintains high performance of precise positioning.

• Journal of Positioning, Navigation, and Timing
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• 제10권1호
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• pp.43-48
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• 2021

Most existing studies on the wide-area differential global positioning system (WADGPS) used standard positioning service (SPS) receivers in their observation reference stations which provide the central control station global positioning system (GPS) measurements to generate augmentation data. In the present study, it is considered to apply a precise positioning service (PPS) receiver to an observation reference station which is located in the threatened jamming area. Therefore, the reference station network consists of a PPS receiver based observation reference station and SPS receiver based observation reference stations. In this case, to maintain correction performance P1C1 differential code bias (DCB) should be compensated. In this paper, P1C1 DCB estimation algorithm was applied to the PPS/WADGPS system and performance test results using measurements in the Korean Peninsula were presented.

• 동력기계공학회지
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• 제2권2호
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• pp.60-66
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• 1998

Positioning performance with a normal pneumatic positioning system, is mainly affected by friction force on the actuator and nonlinear characteristics of the control valve. We proposed a positioning system which is composed of a pneumatic actuator and high speed control valve. for accurate and speedy positioning. Driving piston on the actuator is mounted with externally pressurized air bearings to clear the friction force. This paper studies a method in order that improves positioning ability of the pneumatic positioning system considering the nonlinear characteristics of the control valve and the actuator.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2007년도 춘계학술발표회 논문집
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• pp.447-450
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• 2007

Positioning technology for moving object is an important and essential component of ubiquitous. Also RFID(Radio Frequency IDentification) is a core technology of ubiquitous wireless communication. In this study we adapted kalman-filter theory to RFID-based Positioning System in order to trace a time-variant moving object and verify the positioning accuracy using RMSE (Roong technology for moving object is an important and essential component of ubiquitous Mean Square Error). The purpose of this study is to verify an effect of kalman-filter on the positioning accuracy and to analyze what does each design factor have an effect on the positioning accuracy by means of simulations and to suggest a standard of optimal design factor of a RFID-based Positioning System. From the results of simulations, Kalman-filer improved the positioning accuracy remarkably; the detection range of RFID tag is not a determining factor. The smaller standard deviation of detection range improves the positioning accuracy. However it accompanies a smaller fluctuation of the positioning accuracy. The larger detection rate of RFID tag yields the smaller fluctuation in the positioning accuracy and has more stable system and improves the positioning accuracy;

• 제어로봇시스템학회논문지
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• 제20권12호
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• pp.1204-1208
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• 2014

As required performance of UAV (Unmanned Aerial Vehicle) becomes more complex and complicated, required positioning accuracy is becoming more and more higher. GPS is a reliable world wide positioning providing system. Therefore, UAV generally acquires position information from GPS. But when GPS is not available such as too weak signal or too less GPS satellites environments, UAV needs alternative positioning system such as network positioning system. RSSI (Received Signal Strength Indicator) based positioning, which is one method of network positioning technologies, determines its position using RSSI measurements containing distance information from AP (Access Point)s. In that method, a selected AP's configuration has strong and tight relationship with its positioning errors. In this paper, for, we additionally account AP's configuration information by adopting DOP (Dilution of Precision) into AP selection procedures and provide more accurate RSSI based positioning results.

• 한국멀티미디어학회논문지
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• 제9권9호
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• pp.1222-1230
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• 2006

위치기반 서비스는 사용자의 지리적인 현재 위치를 기반으로 사용자에게 제공되는 서비스를 일컫는다. 위치기반 서비스는 고부가가치를 제공하기 때문에 기업, 산업, 그리고 개인 생활에까지 널리 적용되고 있다. 사용자의 위치 판단(측위)은 위치기반 서비스 시스템 구축에 반드시 필요한 요소 기술이다. GPS로 인하여 건물 외부에서의 측위는 성공적으로 실용되고 있으나, 옥내 측위는 많은 전략이 발표되었음에도 불구하고 일반적인 해법이 아직도 존재하지 않는다. 성공적인 옥내 측위 해법이 존재하지 않는 이유 중 하나는 현존하는 대부분의 측위 전략이 전적으로 측위에만 사용되는 특수 장치를 사용하기 때문이다. 본 논문에서는 부가적인 장비를 사용하지 않는 옥내 측위 전략을 소개한다. 또한, 제안하는 옥내 측위 전략과 GPS 기반의 옥외 측위 방법을 통합하여 옥내외 겸용 측위 시스템을 구축하고, 이 시스템의 실험 결과를 소개한다.

• 동력기계공학회지
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• 제2권2호
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• pp.67-72
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• 1998

To improve control performance, especially positioning speed, of a pneumatic positioning system, dynamic characteristics of a control valve should be considered. In case we design controller including dynamic characteristics of a control valve, it's not easy to design controller gain using simple state feedback because degree of a control system is increased. This study designed controller using loop shaping of $H_{\infty}$ control theory for a model composed of a pneumatic actuator and a control valve, and positioning experiment using this controller was performed. As a result, it was verified that the controller is useful for high speed positioning of a pneumatic positioning system.

• 한국철도학회논문집
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• 제14권2호
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• pp.116-120
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• 2011

현재 초고속 자기부상열차시스템에 적용하고 있는 위치검지기술은 불연속적으로 열차위치를 파악하는 절대위치검지기술과 연속적으로 열차의 위치를 파악하는 상대위치검지기술로 구분된다. 본 논문에서는 대표적인 초고속자기부상열차인 독일 Transrapid에 적용된 절대위치검지장치의 구조와 수치모델을 분석하고, Transrapid에 적용된 절대위치검지장치와 유사한 구조를 가지는 절대위치검지장치의 인식구조별 모델을 설계하고 시뮬레이션을 통해 설계한 모델의 적합성을 검증하고 최적의 절대위치검지장치 구조를 제안한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1179_1180
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• 2009

In the maglev system, accurate train position is essential for safe and efficient train operation. Train positioning systems in the maglev systems are different from conventional railway system because railway train has no wheels. And various train positioning principles and systems have been used in maglev systems. In this paper, we study several positioning principles and systems on adapting existing various maglev systems and analyze functional structure of absolute positioning system in ultra high speed maglev system. Then we propose development scheme on absolute positioning system for developing ultra high speed maglev system.