• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.6
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• pp.775-780
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• 2011

GPS, ARPA, AIS, NAVTEX, VHF as modern aids-to-navigation equipments improve the safe navigation and help to reach a reduction in marine accidents by providing images, numeric values, texts, audio-based information for mates, However, we also noticed that it's complicate and difficult for a mate to acquire and analyze such information from these devices while he should devote himself to bridge watchkeeping especially in the urgent situation. Language is another way to get information and free the eyes and hands, so, to solve the problem above, we are trying to propose a new aids-to-navigation system, which can understand and merge multimedia marine safety information, analyze the situation and provide the necessary information in language. In this paper, we try to fuse data of ARPA/AIS using Euclidean distance for providing integrated information.

• Journal of Intelligence and Information Systems
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• v.15 no.1
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• pp.51-64
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• 2009

A location tracking sensor such as GPS, INS, Radar, and optical equipments is used in tracking Maneuvering Targets with a multi-sensor, and such systems are used to track, detect, and control UAV, guided missile, and spaceship. Until now, Most of the studies related to tracking Maneuvering Targets are on fusing multiple Radars, or adding a supplementary sensor to INS and GPS. However, A study is required to change the degree of application in fusions since the system property and error property are different from sensors. In this paper, we perform the error analysis of the sensor properties by adding a ground radar to GPS and INS for improving the tracking performance by multi-sensor fusion, and suggest the tracking algorithm that improves the precision and stability by changing the sensor probability of each sensor according to the error. For evaluation, we extract the altitude values in a simulation for the trajectory of UAV and apply the suggested algorithm to carry out the performance analysis. In this study, we change the weight of the evaluated values according to the degree of error between the navigation information of each sensor to improve the precision of navigation information, and made it possible to have a strong tracking which is not affected by external purposed environmental change and disturbance.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.411-413
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• 2008

본 연구의 목적은 DGPS 기법을 이용하여 장대교량의 거동을 모니터링하는 기술을 개발하는데 있다. GPS 센서를 이용한 교량거동 모니터링 기술은 다수의 GPS 센서를 시설물 외부에 설치하여 전체적인 거동상태를 모니터링 함으로써 순간적인 세부변위는 물론 장기간의 관측을 통한 기초침하, 크리프 릴렉세이션 등의 거동까지 실시간으로 모니터링 할 수 있는 기술이다. 본 연구의 최종 성과물은 안전관리 대상 주요 시설물의 거동을 비접촉 방식으로 감시하고 그 결과를 그래픽으로 화면을 통하여 사용자에게 제공함으로써 사용자의 직관적인 이해도를 높일 수 있을 것으로 기대되며, 장대교량, 터널, 댐, 건물 등 대형시설물의 거동을 효과적으로 감시하고 그 결과를 전송할 수 있어 광범위하게 사용이 될 수 있을 것으로 판단된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1028-1030
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• 2008

HSDPA, Wibro 의 서비스를 시작으로 제 3 세대 이동통신망이 상용화 서비스가 시작되었다. 하지만 3 세대 이동통신 서비스는 아직 사용자에게 기존의 서비스보다 향상된 서비스를 제공하지 못하고 있다. 이동성지원 및 전송방식 측면에서의 발전은 이루었지만 그에 따른 서비스를 제공하지 못했기 때문이다. 다른 한편으로 현재 서비스되고 있는 TPEG 은 서비스의 초기 단계로 버스나 택시에 GPS 칩이나 RF 칩을 장착해 정보를 수집하여 사용자에게 정량화된 방식으로 정보를 제공하고 있다. 본 논문에서는 이러한 3 세대이동통신망의 서비스 문제점과 기존의 TPEG 서비스의 문제점을 동시에 해결 할 수 있으며, 실시간으로 다수의 차량으로부터 영상과 위치정보를 전송 받을 수 있는 서비스를 개발 하였다. 제안된 서비스는 웹 카메라와 GPS 수신기, UMPC, 3 세대이동통신을 할 수 있는 모뎀를 이용하여 전송하며 일반적인 웹브라우저가 설치된 컴퓨터에서 수신한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.195-202
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• 2014

The Global Positioning System (GPS), which has various military and commercial applications, is designed to estimate the location of the specific user or object. In order to accurately estimate the location, GPS requires at least four satellite signals. The GPS receiver operates on extremely low signal-to-noise ratio (SNR) environment and it may suffer from various interference signals with the extremely high power. In this paper, we introduce a blind adaptive receiver based on the modified despreader, which suppress interference signals and detect GPS signals of interest without requiring explicit angle-of-arrival (AOA) information. We, also, provide the mathematical analysis for the signal-to-interference and noise ratio (SINR) of the modified despeader beamformer output. A representative computer simulation example is presented to illustrate the interference suppression performance of the considered GPS receiver and mathematical analysis of the SINR.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.4
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• pp.337-345
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• 2007

National Geographic Information Institute has installed the first permanent Global Positioning System (GPS) station SUWN in 1995 and, as of today, the number of sites is 14. In this study, we visited all the 14 stations and determined if the site mount and antenna configuration conforms to the international site guidelines published by International GNSS Service and National Geodetic Survey. The environment around each station was also checked for the possibility of causing positioning errors. In addition, the GPS data quality was evaluated using the quality-checking program called TEQC. As a result of site visits, we found that low stations (TABK, CHJU, KWNJ, and WNJU) have unfavorable environment and TEQC results validated it. TEQC results also showed that the GPS receiver change during years 2005-2006 reduced the multipath errors and the number of cycle slips at every station.

• Spatial Information Research
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• v.19 no.4
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• pp.73-79
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• 2011

With the recent increase in demand for geo-registered imagery, Mobile Mapping Systems(MMS), which can quickly construct geographic information, has become important. The main part of MMS is the high-precision observation system, which collects geographic information at a certain speed. MMS has a complex data generation process and requires a standard-specific vehicle for its use, limiting its application range. In this paper, lightweight MMS is proposed to overcome its complexity by replacing the time synchronizer with a high-speed camera and by stabilizing motion with MEMS IMU/GPS. The proposed low-cost, portable method is expected to produce of geo-registered imagery efficiently.

• Journal of the Korea Society of Computer and Information
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• v.19 no.7
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• pp.103-111
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• 2014

This paper proposes a modified algorithm that improves on Dijkstra's algorithm by applying it to purely two-way traffic paths, given that a road where bi-directional traffic is made possible shall be considered as an undirected graph. Dijkstra's algorithm is the most generally utilized form of shortest-path search mechanism in GPS navigation system. However, it requires a large amount of memory for execution for it selects the shortest path by calculating distance between the starting node and every other node in a given directed graph. Dijkstra's algorithm, therefore, may occasionally fail to provide real-time information on the shortest path. To rectify the aforementioned shortcomings of Dijkstra's algorithm, the proposed algorithm creates conditions favorable to the undirected graph. It firstly selects the shortest path from all path vertices except for the starting and destination vertices. It later chooses all vertex-outgoing edges that coincide with the shortest path setting edges so as to simultaneously explore various vertices. When tested on 9 different undirected graphs, the proposed algorithm has not only successfully found the shortest path in all, but did so by reducing the time by 60% and requiring less memory.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.527-528
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• 2022

It is not easy to identify the location of mobile terminals based on drones in the mountainous area, the densely populated urban area, or the space where mobile terminals can easily move by using equipments or modules that can recognize the location of sensors or mobile terminals with LBS (Location-Based Service). However, although the performance of GPS has developed due to the development of technology, it is still widely used in position recognition systems using GPS modules in the sea and onshore, and there is much room for more utilization. Currently, most of the existing sensor networks need to send at least three location information messages to mobile terminals with location information that a plurality of mobile base stations depend on GPS. However, location recognition of mobile repeaters that maintain a certain movement speed using acceleration sensors is necessary for efficient communication network connection.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.7
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• pp.715-722
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• 2016

In this paper, by applying the linear least squared error algorithm, we derive an estimation technique for three dimensional target location when a number of radars are used in detecting a target. The proposed technique is then enhanced by combining GPS information and by assigning variable weights to information sources. The enhanced performance of proposed techniques is confirmed via simulation. It is also observed from simulation results that the performance is robust to the uncertainty of information.