• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.783-790
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• 2010

For safety navigation of ships at sea, ships monitor their location obtained from Global Positioning Satellite System (GNSS). In this study, we computed near-real-time positions of a ship at sea using GPS Precise Point Positioning (PPP) technique and analyzed precision of the near-real-time positions. We conducted ship borne GPS observations in the south sea of Korea. To process the GPS data using PPP technique, GIPSY-OASIS (GPS Inferred Positioning System-Orbit Analysis and Simulation Software) developed by the Jet Propulsion Laboratory was used. Antenna phase center variations, ocean tidal loading displacements, and azimuthal gradients of the atmosphere were corrected or estimated as standard procedures of high-precision GIPSY-OASIS data processing. As a result, the precisions of near-real-time positions was ~1cm.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.10
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• pp.439-446
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• 2015

Recently, semantic trajectories which combine GPS positions and POIs(Point of Interests) become more popular in order to expand location based services. To construct semantic trajectories, the existing algorithms exploit the extent information of POIs described as polygons and find overlapping regions between GPS positions and the extents. However, the algorithms are not applicable in the condition where the extent information is not provided such as in Google Map, Naver Map, OpenStreetMap and most of the open geographic information systems. In this paper, we provide a novel algorithm to construct semantic trajectories only with GPS positions and POI points but without POI extents.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.1 s.24
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• pp.61-69
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• 2003

The study is the open area keeping a few visible satellites and the urban area covered with the high building, an electric pole were chosen for evaluation of accuracy of satellite positioning. First, suggest the validity of RTK-GPS, RTK-GPS/GLONASS and compared the accuracy with that of the classical surveying method. As a result. In urban area, in case of real time kinematic positioning when compare between the method combined by GPS/GLONASS and by GPS alone the result of GPS/GLONASS - combination more excellent. And in open ana positioning combined GPS/GLONASS was more excellent than GPS alone in both real time differential and real time kinematic. So, RTK-GPS, RTK-GPS/GLONASS contribute to the digital mapping of Basic map and the existed map necessary for the building of PBLIS to the computerization of cadastral map in the effectiveness in time and in cost and hereafter the combined GPS/TS is expected to contribute to the development of NGIS, Re-investigation of a land register, the execution drawing on site.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.9-14
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• 2016

The Korea Communication Commission(KCC) measures communication qualities of mobile phones' voice calls, mobile internet, and broadband internet to provide quality communication services. It particularly focuses on measuring qualities of mobile internet data that is on the rise in terms of usage. However, existing quality measurement simply measures the speed of mobile communication through data without providing much information to users and does not disclose measured data, making it hard for individuals to objectively determine their communication quality. Thus, to improve such problems, the author suggests a system that measures qualities of mobile communication through Android. The method guarantees user convenience and reliability and improved mobile communication by making it easy for users to select the quantity of data to be used. It also saves the current GPS obtained through GPS module or mobile communication network and transfers measured data to servers so that the data can be processed into new information and be reinterpreted.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.4
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• pp.461-466
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• 2016

In this paper, a capsule body shaped surveillance/monitoring device is developed. The device includes a camera and GPS module to transmit live video data and real time GPS coordinates respectively using the Intel Edison module. A control application is developed for the smart phones and tablets to wirelessly view the live video stream and location of the capsule device and also to switch between the multiple capsule devices installed at different locations. The coordination between the developed device and the smart phone / tablet is done using the wireless function of the Intel Edison module.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.9
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• pp.629-642
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• 2013

Recently, with the advent of smart phones, it brought many changes in lives of modern people. Especially, application utilizing the sensor information of smart phone, which provides the service adapted by user situations, has been emerged. Sensor data of smart phone can be used for recognizing the user situation, Because it is closely related to the behavior and habits of the user. currently, GPS sensor one of mobile sensor has been utilized a lot to recognize basic user activity. But, depending on the user situation, activity recognition system cannot receive GPS signal, and also not collect received data. So utilization is reduced. In this paper, for solving this problem, we suggest a method of user activity recognition that focused on the accelerometer sensor data using smart phone. Accelerometer sensor is stable to collect the data and it's sensitive to user behavior. Finally this paper suggests a noble approach to use state transition diagrams which represent the natural flow of user activity changes for enhancing the accuracy of user activity recognition.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.27-31
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• 2003

It can be classified in various methods to get the geoidal heights. It can be achieved geometric geoidal heights if we do GPS surveying in leveling point. The aims of this paper are calculation of geometric geoidal heights using GPS/leveling data in study area and evaluation of the global and local geoid models in and around Korean peninsula. For this study, study area was selected in the leveling line from Kunsan to Chonju city and GPS surveying was accomplished in the leveling line. And, also spherical harmonic analysis was made on the three global geopotential models, OSU91A, EGM96, EGM96m under same condition and KOGD2002, Korean gravimetric geoid model was made in this study The results shows that EGM96m is the best model because the differences between geoidal heights of EGM96m and geometric geoidal heights of GPS/Leveling data appear the smallest value among them.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.45-54
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• 2003

This paper deal with the GPS performance for determining the ocean tidal loading components(M$_2$, N$_2$, S$_2$, K$_2$) and the availability of permanent GPS stations(CHJU, KANR) established in Korea. We determined the ocean tidal loading components from GPS observation by spectrum analysis and compared to that from global ocean tidal models(GOT00.2, FES99, CRS4.0, NAO99). Through this study, we have a sense that amplitude and phase lags of ocean tidal loading components from observed GPS data was almost equal to value calculated in ocean tide models. The diurnal ocean tide loading constituents are not considered, because unmodeled troposhere effects increase the noise level near the diurnal frequency band and prevent us from obtaining significant results.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.319-320
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• 2011

이 연구에서는 국토해양부 해양교통시설과 위성항법중앙사무소가 운영하고 있는 DGNSS 기준국의 신호수신환경을 파악하기 위해 관측자료의 TEQC 품질평가와 현장조사를 병행하였다. TEQC는 GPS 수신기로 관측한 원시자료를 RINEX형식으로 변환 편집하고, 관측자료의 품질을 점검하는데 이용하는 GPS 전처리 소프트웨어이다. TEQC 품질점검 기능을 통해 GPS 관측자료의 데이터수신율, L1과 L2 신호의 의사거리 다중경로오차, 사이클슬립에 관한 지수를 산출하였고, 이를 현장조사결과와 상호 비교하였다. 장기 관측 자료의 TEQC 품질지수 결과를 통하여 시간변화에 따른 관측소의 주변환경 및 장비변화 시점을 간접적으로 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.277-279
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• 2020

최근 무선통신기술의 발달로 텍스트나 이미지 등 적은 양의 데이터를 송출하는 것을 넘어 동영상과 같은 많은 양의 데이터 전송이 가능해졌다. 이에 본 논문은 실시간으로 사고의 상황을 효과적으로 구조기관에 전달하기 위해 GPS와 각종 센서를 활용한 GPS 데이터 및 비디오를 실시간으로 전송하는 무선 네트워크 상황 전파 시스템을 제안한다. Raspberry pi module의 카메라와 GPS 데이터는 ffmpeg와 ffserver를 사용하여 서버와 구조기관으로 실시간 송출 및 전송된다. 제안된 시스템은 실제 프로토타입으로 구현되었으며, 실험 결과 제안한 시스템은 즉각적으로 구조기관에 영상 및 GPS 좌표를 송출함으로써 조기에 사고상황을 파악하고 빠른 구조에 이바지함을 보여준다.