• Title/Summary/Keyword: Positioning Technology

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Accuracy Analysis of Precise Point Positioning Using Predicted GPS Satellite Orbits (GPS 예측궤도력을 이용한 정밀단독측위 정확도 분석)

  • Ha, Ji-Hyun;Heo, Moon-Beom;Nam, Gi-Wook
    • Journal of Advanced Navigation Technology
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    • v.16 no.5
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    • pp.752-759
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    • 2012
  • In this paper, near-real-time positioning accuracies of precise point positioning technique were analyzed using IGS predicted orbits. As a result, we could get the mean errors of 1~1.6 cm, standard deviation of 1~1.3cm from one year of GPS data. This results were similar level to positioning accuracy using the IGS rapid orbits. Positioning errors of >10cm showed 44% of observed days of orbital anomalies. When the orbital anomalies of the predicted orbits were shown, maximum error was 1.7 km, and maximum of mean errors was 308 m. From this study, we conclude that check and consideration were necessary before using the IGS predicted orbits.

Dynamic Modeling and Input Shaping Control of a Positioning Stage (위치결정 스테이지에 대한 동적 모델링과 입력성형 제어)

  • Park, S.W.;Hong, S.W.;Choi, H.S.;Jang, J.W.
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.2
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    • pp.83-89
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    • 2008
  • This paper presents the dynamic analysis and input shaping control of a positioning stage. Vibration characteristics of the positioning stage are affected not only by the structural dynamics but also by the servo actuators that consist of the mechanism; driving motor and controller. This paper proposes an integrated dynamic model to accommodate both the structural dynamics and the servo actuators. Theoretical modal analysis with a commercial finite element code is carried out to investigate the dynamic characteristics of the experimental positioning stage. Experiments are performed to validate the theoretical modal analysis and estimate the equivalent stiffness due to the servo actuators. This paper deals with an input shaping scheme to suppress vibration of the positioning stage. Input shapers are systematically implemented for the positioning stage in consideration of its dynamics. The effects of servo control gain are also investigated. The experiments show that input shaping effectively removes residual vibrations and then improves the performance of positioning stage.

Enhanced Indoor Positioning Algorithm Using WLAN RSSI Measurements Considering the Relative Position Information of AP Configuration (AP 상대위치 정보를 고려한 향상된 WLAN RSSI 기반 실내 측위 알고리즘)

  • Kim, A Sol;Hwang, Jungyu;Park, Joongoo
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.2
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    • pp.146-151
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    • 2013
  • With the development of mobile internet, requirements of positioning accuracy for the LBS (Location Based Service) are becoming more and more higher. The LBS is based on the position of each mobile device. So, it requires a proper acquisition of accurate user's indoor position. Thus indoor positioning technology and its accuracy is crucial for various LBS. In general, RSSI (Received Signal Strength Indicator) measurements are used to obtain the position information of mobile unit under WLAN environment. However, indoor positioning error increases as multiple AP's configurations are becoming more complex. To overcome this problem, an enhanced indoor localization method by AP (Access Point) selection criteria adopting DOP (Dilution of Precision) is proposed.

A Study on the Improvement of the Accuracy of a Wheeled Vehicle Positioning System by Multisensor Data Fusion (멀티센서 데이터 융합에 의한 차륜형 이동체 위치추정시스템의 정도 개선에 관한 연구)

  • 최진규;하윤수
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.1
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    • pp.119-126
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    • 2000
  • In constructing the positioning system based on a conventional dead-reckoning for a wheeled vehicle with pneumatic tires, the position estimation error is inevitable as changes of the radius of the wheels depend on live load and variable enviroment. Therefore, this paper proposes the positioning system which can estimate the error source i.e. the vehicle parameter errors, such as the right and left wheel radius error, using gyroscope and ultrasonic sensor and correct the parameter to reduce the dead-reckoned position estimation error. The extended Kalman filter was used as a method for the multisensor data fusion. The simulation to verify the effectiveness of the proposed positioning system is performed.

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Unlabeled Wi-Fi RSSI Indoor Positioning by Using IMU

  • Chanyeong, Ju;Jaehyun, Yoo
    • Journal of Positioning, Navigation, and Timing
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    • v.12 no.1
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    • pp.37-42
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    • 2023
  • Wi-Fi Received Signal Strength Indicator (RSSI) is considered one of the most important sensor data types for indoor localization. However, collecting a RSSI fingerprint, which consists of pairs of a RSSI measurement set and a corresponding location, is costly and time-consuming. In this paper, we propose a Wi-Fi RSSI learning technique without true location data to overcome the limitations of static database construction. Instead of the true reference positions, inertial measurement unit (IMU) data are used to generate pseudo locations, which enable a trainer to move during data collection. This improves the efficiency of data collection dramatically. From an experiment it is seen that the proposed algorithm successfully learns the unsupervised Wi-Fi RSSI positioning model, resulting in 2 m accuracy when the cumulative distribution function (CDF) is 0.8.

Design of Wi-Fi based Indoor Positioning System (Wi-Fi 기반 실내위치 측위 시스템 설계)

  • Kim, Tae-jin;Kim, Dong-hyun;Kim, Dong-il
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2022.10a
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    • pp.615-616
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    • 2022
  • Indoor positioning technology is being used in various application services due to the spread of smart devices. In addition to precisely positioning the location, simultaneous positioning of multiple users has been raised as a new problem. In addition, providing Internet services simultaneously with location measurement is essential for use in various applications. This paper aims to solve both of these problems by designing and implementing an indoor positioning system with the IEEE 802.11az standard

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A Study on Precise Positioning with Doppler Measurements for Ground Transportation System (도플러 측정치를 이용한 육상교통 환경에 적합한 정밀 측위 기법 연구)

  • Lee, Byung-Hyun;Jee, Gyu-In
    • Journal of Advanced Navigation Technology
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    • v.14 no.5
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    • pp.632-639
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    • 2010
  • Ground Transportation is one of the most required field that users need positioning information Especially, more precise position can make smart traffic management possible and bring convenience to users. By advanced wireless network, cars can receive the GPS information of reference station in any tim e and any where. Thus land vehicles are possible to process precise positioning. In general, for precise positioning code and phase measurements are used. But receivers provide not only code and phase measurements but also doppler measurements and Doppler is direct measurement of velocity. In this paper, because velocity is very important information required in Ground Transportation, precise positioning for Ground Transportation is studied. For precise positioning RTK(Real-Time Kinematic) was used and double differenced doppler measurements were added, As a Result, positioning error by multipath and cycle slip was soften. However there still remained Positioning error. Thus smoothing technique using doppler measurement in position domain is used for softening positioning error.

Precise Orbit Determination of GRACE-A Satellite with Kinematic GPS PPP

  • Choi, Byung-Kyu;Roh, Kyoung-Min;Yoo, Sung-Moon;Jo, Jung-Hyun;Lee, Sang-Jeong
    • Journal of Positioning, Navigation, and Timing
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    • v.1 no.1
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    • pp.59-64
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    • 2012
  • Precise Point Positioning (PPP) has been widely used in navigation and orbit determination applications as we can obtain precise Global Positioning System (GPS) satellite orbit and clock products. Kinematic PPP, which is based on the GPS measurements only from the spaceborne GPS receiver, has some advantages for a simple precise orbit determination (POD). In this study, we developed kinematic PPP technique to estimate the orbits of GRACE-A satellite. The comparison of the mean position between the JPL's orbit product and our results showed the orbit differences 0.18 cm, 0.54 cm, and 0.98 cm in the Radial, in Along-track, and Cross-track direction respectively. In addition, we obtained the root mean square (rms) values of 4.06 cm, 3.90 cm, and 3.23 cm in the satellite coordinate components relative to the known coordinates.

Tuning of PID Controller for Hydraulic Positioning System Using Genetic Algorithm (유전 알고리즘을 이용한 유압 위치계의 PID 제어기 동조)

  • Kim, Gi-Bum;Park, Seung-Min;Kim, In-Soo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.15 no.3
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    • pp.93-101
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    • 2016
  • This study presents a simple genetic algorithm to systematically design a PID controller for a hydraulic positioning system operated by a proportional solenoid valve. The inverse dead-zone compensator with nonlinear characteristics is used to cancel out the dead-zone phenomenon in the hydraulic system. The object function considering overshoot, settling time, and control input is adopted to search for optimal PID gains. The designed PID controller is compared with the LQG/LTR controller to check the performance of the hydraulic positioning system in the time and frequency domains. The experimental results show that the hydraulic servo system with the proposed PID controller responds effectively to the various types of reference input.

A Novel Technique for Human Traffic based Radio Map Updating in Wi-Fi Indoor Positioning Systems

  • Mo, Yun;Zhang, Zhongzhao;Lu, Yang;Agha, Gul
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.5
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    • pp.1881-1903
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    • 2015
  • With the fast-developing of mobile terminals, positioning techniques based on fingerprinting method draws attention from many researchers even world famous companies. To conquer some shortcomings of the existing fingerprinting systems and further improve its performance, we propose a radio map building and updating technique, which is able to customize the spatial and temporal dependency of radio maps. The method includes indoor propagation and penetration modeling and the analysis of human traffic. Based on the combination of Ray-Tracing Algorithm, Finite-Different Time-Domain and Rough Set Theory, the approach of indoor propagation modeling accurately represents the spatial dependency of the radio map. In terms of temporal dependency, we specifically study the factor of moving people in the interest area. With measurement and statistics, the factor of human traffic is introduced as the temporal updating component. We improve our existing indoor positioning system with the proposed building and updating method, and compare the localization accuracy. The results show that the enhanced system can conquer the influence caused by moving people, and maintain the confidence probability stable during week, which enhance the actual availability and robustness of fingerprinting-based indoor positioning system.