• Journal of Korean Society for Geospatial Information Science
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• v.24 no.3
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• pp.11-18
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• 2016

Since GNSS signals get blocked by buildings in urban canyons or narrow alleys, it is very difficult to secure a enough number of visible satellites for satellite navigation in those poor signal-reception environments. In those situations, one cannot get their coordinates or obtain accurate positions. In this study, a couple of strategies for improving positioning accuracy in urban canyons were developed and their performance was verified. First of all, we combined GPS and GLONASS measurements together and devised algorithms to quality-control observed signals and eliminate outliers. Also, a new multipath reduction scheme was applied to minimize its effect by utilizing SNR values of the observed signals. For performance verification of the developed technique, a narrow alley of 10m width located near the back gate of the Inha University was selected as the test-bed, and then we conducted static and kinematic positioning at four pre-surveyed points. We found that our new algorithms produced an 45% improvement in an open-sky environment compared with the positioning result of a low-cost u-blox receiver. In the alleys, 3-D accuracy improved by an average of 37%. In the case of kinematic positioning, especially, biases showing up in regular receivers got eliminated significantly through our new filtering algorithms.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.84-93
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• 2011

In order to provide the real time and proper information to the pedestrian who is using the transport connection and transfer center through data collecting and processing process, the design of the test-bed (Gimpo airport)'s communication construction and the technology of the pedestrian location tracking has been researched. The design of the communication construction should make sure that it can provide believable data to the user of the transfer center. At the same time, the location tracking should also be considered, so that the require of the communication efficiency and the location tracking efficiency can be met together. In order to make the efficient location tracking technology, the problems related to the commercial technology based real time location identification will be resolved and the new approach method was proposed and be applied and analysed to the test-bed. The wireless access points can be located in the most real-world situation which has added the characteristics of the real building to the electronic map, and through the analysis of theirs location, they can be set as the mainly necessary points for the communication construction design and the location tracking and the method to locate that points has been proposed. How to set, how to apply it to the test-bed and the examination result will be introduced in this paper.

• Electronics and Telecommunications Trends
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• v.29 no.6
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• pp.113-125
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• 2014

최근 모바일 단말 기술의 발전과 무선망의 성능 향상에 따른 다양한 서비스가 제공되고 있는 추세이며, 위치정보인식시스템과 결합된 서비스에 많은 관심이 높아졌다. 본고에서는 GPS(Global Positioning System)의 신호가 미치지 못하는 건물의 실내환경에 적합한 경로 안내서비스 및 지하시설물 안내 등 초정밀 실내 측위 서비스를 제공하기 위한 융합 측위 방안을 제안한다. 융합 측위 방안은 실내외 연속 측위를 위해 실외에서는 GPS를 이용하고 실내환경에서는 WLAN 기반의 측위 전용 AP(Access Point)를 이용, 전파신호의 LoS(Line of Sight)를 확보하여 측위하고 전파음영지역에서는 스마트폰의 가속도, 자이로센서 등 여러 가지 관성센서를 활용하여 PDR(Pedestrian Dead Reckoning) 알고리즘 등을 적용하여 측위한다. 또한 측위 정확도 향상 및 오차를 줄이기 위한 방법으로 LSE(Least Squire Estimation) 및 EKF(Extended Kalman Filter), KNN(K-Neighbor Node)/MSSM(Maximum Signal Strength Model) Algorithm 등 다양한 융합 측위 알고리즘을 적용하여 실내환경에 적합한 최적의 초정밀 실내 측위 서비스를 제공한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.30-31
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• 2018

The localization performance in the ship environment is degraded by RF interference due to steel structure characteristics and NLOS environment. In this paper, a wireless hybrid localization system using ZigBee, UWB, and LF technologies is proposed to improve position estimation accuracy in the ship environment.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.4
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• pp.51-58
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• 2003

Satellite-based positioning system such as global positioning system(GPS) has played a major role in data capture technology for constructing GIS database. Recent advances in satellite-based positioning technology have made the task of precisely locating features fast, easy, and inexpensive, and determined their current latitude and longitude. However, there are still situations where satellite-based positioning service will not provide users with desired precision such as in urban environments, that is, the only severe handicap still hampering satellite-based positioning is the well-known problem of restricted satellite visibilities. As the majority of the creation and updating of road and street network are carried out in urban environments, the obstruction problem considerably impedes the wider application of satellite-based positioning. This paper presents the current GPS-based positioning environment for GIS data acquisition in urban areas. A field experiment with measurement vehicle has been performed under varying operational conditions and areas where shading of satellite signal is encountered due to buildings and overpasses with measurement vehicle in order to evaluate the availability of existing GPS-based positioning. We found that the current GPS-base positioning system we used in this study was insufficient for a precise GIS data acquisition. This research would make a contribution for the development of base data to supplementary technology, which can complement the existing GPS-based positioning.

• Information and Communications Magazine
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• v.32 no.2
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• pp.13-23
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• 2015

Real Time Location System(RTLS)는 실시간으로 사물의 위치 정보 측위를 통해 다양한 서비스를 제공하는 시스템을 말한다. RTLS 시스템은 물류, 헬스케어, 생산 시설 등 사물인터넷(IoT, Internet of Things)과 관련된 다양한 분야에서 활용되고 있다. 최근에는 경마, 미식축구 및 발레 등 여러 스포츠 종목에 도입하고자 하는 시도가 늘고 있어 동계올림픽의 각 종목을 위한 훈련, 분석, 서비스 등에의 적용을 위한 개발을 적극적으로 검토할 필요가 있다. 통상적으로 실시간 위치 추적 시스템(RTLS)은 근거리 및 실내와 같은 제한된 공간에서의 위치 확인 및 위치 추적 시스템을 통칭하고, 이동통신망 기반의 위치기반 서비스(LBS) 처럼 사람 또는 사물의 위치를 확인하지만 주로 제한된 공간에 활용되므로 '실내위치 추적 서비스(IPS: Indoor Positioning System)'라고 불리기도 한다. 본고에서는 먼저 RTLS의 기술과 이를 스포츠에 접목하기 위한 사례를 중심으로 그 동향을 분석한다.

• Electronics and Telecommunications Trends
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• v.20 no.3 s.93
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• pp.33-42
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• 2005

무선인터넷 망이 개방되고 위치정보와 관련된 법률이 제정됨에 따라 위치기반서비스의 산업 활성화에 촉매 역할을 하고 있다. 또한, 이동통신관련 기술의 발달로 위치기반서비스의 기술 발전을 촉진시키고 있다. 네트워크기반과 단말기기반의 측위 기술 및 하이브리드 방식으로 위치 정확도를 향상시키는 기술과 위치정보를 보호하고, 효과적으로 관리하기 위한 플랫폼 기술, 그리고 다양한 서비스를 제공하기 위한 응용 서비스기술이 연구되고 있다. 본 고에서는 위치기반서비스를 구성하는 주요 요소기술의 이슈와 동향에 대해 기술한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.2
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• pp.390-396
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• 2015

The drastic growth of mobile communication and spreading of smart phone make the significant attention on Location Based Service. The one of most important things for vitalizations of LBS is the accurate estimating position for mobile object. Focusing on an image sensor deployed in smart phone, we develop a LED based positioning estimation framework. The developed approaches can strengthen the advantages of independent indoor applicability of LED. The estimation of LED based positioning is effectively applied to any indoor environment. We put a focus especially on the algorithmic framework. of image processing of smart phone. From LED lighting, we can obtain a typical signal image which contains the unique positioning information. Furthermore test-bed based on smart phone platform is practically developed and all data have been harvested from the actual measurement of test indoor area. This can approve the practical usefulness of proposed framework.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.175-180
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• 2012

최근 GPS와 Wi-Fi가 내장된 스마트폰의 보급으로 이를 이용한 위치기반 서비스(Location-based Service)가 발전하고 있다. 하지만 위치기반 서비스들의 오차 범위는 3~4m 내외로 크기 때문에 사용자들은 더 정확한 위치를 제공하기를 바라고 있다. 본 논문에서 위치기반 서비스의 핵심기능을 담당하는 측위기술 중 흔히 사용되고 있는 삼각측량법을 활용하여 핑거프린트 방법의 측위오차를 줄일 수 있는 방안을 연구하였고 프로그램으로 구현한 후 테스트를 실시하였다. 프로그램은 Labview2010으로 구현하였고, 각각의 알고리즘을 모듈화하여 필터링 적용 전 후 및 개선효과를 비교하기 쉽도록 구성하였다. 실내 테스트는 인하대학교의 강의실에서 실시하였고 실외 테스트는 인하대학교 운동장에서 실시하였다. 테스트 결과 실내의 경우 본 논문에서 제시하는 필터링 방법을 적용하기 전의 오차가 1.02미터에서 0.83미터로 감소하였고 실외에서는 0.74미터에서 0.54미터로 오차가 감소하였다.

• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.4
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• pp.130-144
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• 2023

Recently, various positioning technologies are being researched based on signal-based positioning and image-based positioning to obtain accurate indoor location information. Among these, various studies are being conducted on image positioning technology that determines the location of a mobile terminal using images acquired through cameras and sensor data collected as needed. For video-based positioning, a method of determining indoor location is used by matching mobile terminal photos with virtual landmark images, and for this purpose, it is necessary to build indoor spatial information about various landmarks such as billboards, vending machines, and ATM machines. In order to construct indoor spatial information on various landmarks, a panoramic image in the form of a road view and accurate 3D survey results were obtained through c 13 buildings of the Electronics and Telecommunications Research Institute(ETRI). When comparing the 3D total station final result and the terrestrial lidar panoramic image coordinates, the coordinates and distance performance were obtained within about 0.10m, confirming that accurate landmark construction for use in indoor positioning was possible. By utilizing these terrestrial lidar achievements to perform 3D landmark modeling necessary for image positioning, it was possible to more quickly model landmark information that could not be constructed only through 3D modeling using existing as-built drawings.