• Annual Conference of KIPS
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• 2008.11a
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• pp.64-67
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• 2008

위치추적 기술에는 여러가지 기술이 연구개발 되었으며 몇몇 기술은 이미 상용화 되어있다. 실외에서는 GPS를 이용하여 대상의 위치를 추적하는 네비게이션을 통해 이미 상용화되어있으며 실내에서는 IrDA, RSSI 등이 연구되었으며 계속 연구 중에 있다. 하지만 이들은 장애물에 취약하며 큰 오차범위를 가지고 있다. 또한 RF통신을 위한 장비나 IR송수신 장비를 별도로 사용해야한다. 본 연구에서 제안하는 방법을 사용할 경우 쉽게 사용가능한 캠이나 CCTV를 이용할 수 있고 또한 적외선필터를 이용하여 적외선 발광체를 추적할 경우 발광체를 찾기 위한 별도의 영상처리 작업에 소요되는 시간을 줄일 수 있다. 그리고 영상촬영 범위에 따라 단일 장비로 보다 넓은 범위를 제어할 수 있으며 다수의 장비를 이용해 중첩구간을 만들어 준다면 중첩구간을 보완하여 신뢰도를 증가시키고 오차를 줄일 수 있다. 적합한 상황에 사용한다면 저비용으로 고효율성을 가지는 위치추적 시스템을 구현할 수 있다.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.67-73
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• 2008

This paper describes a system for location tracking wireless sensor nodes in an indoor environment. The sensor reading used for the location estimation is the received signal strength indication (RSSI) as given by an RF interface. By tagging users with a mobile node and deploying a number of reference nodes at fixed position in the room, the received signal strength indicator can be used to determine the position of tagged users. The system combines Euclidean distance technique with signal strength obtained by measurement driven log-normal path loss model of 2.4 GHz wireless channel. The experimental results demonstrated the ability of this system to estimate the location with a error less than 1.3m.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.5
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• pp.9-20
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• 2005

In this paper, we propose ubiTrack, a system which tracks users' location in indoor environments by employing infrared-based proximity method. Most of recently developed systems have focussed on performance and accuracy. For this reason, they adopted the idea of centralized management, which gathers all information in a main system to monitor users' location. However, these systems raise privacy concerns in ubiquitous computing environments where tons of sensors are seamlessly embedded into environments. In addition, centralized systems also need high computational power to support multiple users. The proposed ubiTrack is designed as a passive mobile architecture to relax privacy problems. Moreover, ubiTrack utilizes appropriate area as a unit to efficiently track users. To achieve this, ubiTrack overlaps each sensing area by utilizing the TDM (Time-Division Multiplexing) method. Additionally, ubiTrack exploits various filtering methods at each receiver and utilization module. The filtering methods minimize unexpected noise effect caused by external shock or intensity weakness of ID signal at the boundary of sensing area. ubiTrack can be applied not only to location-based applications but also to context-aware applications because of its associated module. This module is a part of middleware to support communication between heterogeneous applications or sensors in ubiquitous computing environments.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.677-687
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• 2021

If a fire breaks out in a building, occupants can evacuate more rapidly if they are able to identify the location of the fire, the exits, and themselves. This study derives the requirements of system development, such as distance non-limitation, a non-additional device, a non-centralized server system, and low power for an emergency, to identify information about the fire and the location of evacuees. The objective is to receive and transmit information and reduce the time and effort of the database for location tracking. Accordingly, this study develops a server-independent system that collects information related to a building fire and an evacuee's location and provides information to the evacuee on their mobile device. The system is composed of a transmitting unit to disseminate fire location information and a mobile device application to determine the locations of the fire and the evacuee. The developed system can contribute to reducing the damage to humans because evacuees can identify the location of the fire, exits, and themselves regardless of the impaired server system by fire, the interruption of power source, and the evacuee's location. Furthermore, this study proposes a theoretical basis for reducing the effort required for database construction of the k-nearest neighbor fingerprint.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.133-138
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• 2019

The indoor navigation system using smart phone is a very important infrastructure technology for users' location based services in large indoor facilities. For this purpose, if the user can estimate the movement distance and direction by using the acceleration sensor and the gyro sensor built in the smartphone, the additional external environment is not necessary, which is a very useful technique. This paper deals with indoor navigation system technology that uses Pedestrian Dead Reckoning (PDR) technology and Kalman filter on a general smartphone and allows the user to trace the position while moving the smartphone in front of his chest. In particular, an extended Kalman filter was designed to estimate the direction of movement, and its performance was verified when walking at a constant speed.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.185-188
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• 2000

본 연구에서는 화자의 음성신호를 이용하여 추출된 공간정보를 통해 화자의 위치를 실시간으로 추적하는 시스템을 제안하고 실시간 구현하였다. 기존의 대표적인 화자 위치 추출 알고리듬인 CPSP(Cross Power Spectrum Phase)는 실내환경에서 심각하게 일어나는 반향신호에 취약한 단점을 갖고 있으므로 구현된 시스템에서는 위치 추적 성능 개선을 위하여 반향신호에 강인한 hybrid window 알고리듬을 제안하여 적용하였다. Hybrid window 알고리듬은 실내 환경에 적합한 hybrid window를 설계하여 수신된 음성신호에 적용함으로써 반향신호에 의한 상호 상관관계를 줄이고 직접 경로에 의한 신호들의 상관관계를 높임으로써 보다 정확한 시간 지연 추정을 가능하게 한다. 제안된 시스템의 성능분석을 위해 DSP를 이용해 실시간 구현된 하드웨어를 이용해 기존의 CPSP 알고리듬과 제안된 hybrid window를 적용한 시스템을 실제 환경에서의 실험하였고 제안한 알고리듬을 적용한 시스템이 $22\%$ 이상 성공적으로 화자의 위치를 추적하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1653-1658
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• 2008

In this paper, it is analyzed propagation distribution characteristics of radio wave, which is radiated on all sides from Access Point device for estimating scheme of wireless AP without GPS receiver environment. To tracking AP device is traced from wireless terminals and wireless terminal is traced from fixed AP devices, above all it is important to analysis the characteristics of receiving power in according to distance. Therefore in this paper, radio propagation characteristics of 2.4GHz wave is analyzed effect extent and quality in according to distance in doors and out doors, and utilized to location estimation.

• Electronics and Telecommunications Trends
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• v.28 no.6
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• pp.99-106
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• 2013

빠른 속도로 보급되고 있는 스마트폰과 함께 위치 기반 서비스(LBS: Location Based Service) 시장 또한 빠르게 성장하고 있다. 실내에서의 위치 기반 서비스 요구사항이 증가하는 반면 실내 위치 추적의 기술적 어려움 때문에 실내 LBS는 기대에 부응하지 못하고 있는 실정이다. 그럼에도 불구하고 그 시장성 때문에 글로벌 IT(Information Technology) 기업들의 다양한 시도와 노력이 이루어지고 있다. 본고에서는 스마트폰 운영체제의 양대산맥인 매Android와 iOS를 개발한 구글과 애플의 지도 및 내비게이션 기술, 위치 기반 개인 비서 서비스 및 근거리 통신 기반 위치 기술 서비스에 대한 최신 동향을 살펴본다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.627-633
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• 2007

This paper describes position tracking system of a container trailer approaching to a gantry crane for loading or unloading a container into or from a ship, respectively. Proposed position tracking system informs the trailer driver of right position to stop the car under a gantry crane. To measure the location of a trailer, we used Cricket Mote modules which adopted RF and ultrasound technology. We present an elaborate method to improve position errors occurring at sensing and calculate three dimensional position by triangulation along with how to reduce location tracking interval for real-time monitoring. The location information was transmitted to a Personal Digital Assistant (PDA) periodically through Bluetooth communication for guidance of the trailer driver. In indoor and outdoor tests, position errors were less than 3 cm and location tracking interval was 0.5 second on average.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.273-279
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• 2014

In this paper, we propose a novel algorithm for three dimensional positioning system and implement a system over indoor wireless channel. A commercial modules are used for mobile and fixed nodes which are product of German company Nanotron Co. This module adopts chirp spread spreading scheme as modulation method to improve the ranging resolution and the module satisfies the IEEE standard 802.15.4a. The distance computation is based on received signal strength(RSS) levels and trilateration method. A testbed was set up to measure and compare the positioning estimation error of the proposed algorithm. The experiments results showed that the accuracy of location estimation was sufficiently good as much as 1m distance error in a wireless environment in an office building.