• Journal of the Korean Institute of Gas
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• v.3 no.2 s.7
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• pp.53-61
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• 1999

The safety of gas utilities is intimidated by many causes. Among them, subsidence is a dominant cause to decrease the safety of gas utilities. So it is very important to monitor the displacement of subsidence. The purpose of this study is to on-line monitor the subsidence of gas utilities using Static GPS(Global Positioning System)technique. Static GPS technique, which is one of various GPS techniques and originally applied to monitor the crustal activity, was applied for two gas station in Korea Gas Corporation. Prior to applying this technique to the field, i.e, gas station, a preliminary test was peformed to confirm the accuracy of this technique. As a result, it was proved that this technique can measure the displacement of gas utilities three dimensionally by sub-millimeter. After getting confirmation of GPS technique, we applied this technique for two gas stations and monitored the amount of subsidence during 5 months. As a result of field test, we can conclude that the gas stations was subsiding several millimeters in a year.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.4 s.22
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• pp.61-67
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• 2002

This study is aimed to suggest a practical use of GPS continuous stations by conducting the precision analysis using its data. Currently dozens of continuous stations have been installed and operated since the first GPS continuous station built by KAO(Korea Astronomy Observation) in 1985. The utilization of the surveyed information, however, has been under-developed regardless of a significant investment, which leads the necessity of utilization plan. The results of this study show that the mis-closures between the two points at University of Incheon and Suwon/Seoul stations of NGI(National Geography Institute), Seoul stat ion of KAO, and Incheon station of MOGAHA(Ministry Of Government Administration and Home Affairs) are 0.0206m, 0.0118m, 0.0129m and 0.0024m respectively. It indicates that the analyzed mis-closures were less than the allowed values ill the primary/secondary control point specification for GPS surveying, i.e. a mis-closure less than 30mm for the distance less than 30km and a mis-closure less than $IPPM{\times}D(km)$ for the distance greater than 30km.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.105-110
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• 2006

우리나라에 GPS 위성측량이 도입되기 시작한 것은 최근에 이루어 졌으며 많은 발전을 해오고 있지만 해결해야 할 많은 문제점을 가지고 있다. 현재 우리나라의 GPS 위성측량의 사용에 있어서 여러 가지 문제점 중 현재 지구 주위를 운항하고 있는 24개의 GPS 위성으로 지상 어느 곳에서나 24시간 동안 위성신호를 수신할 수 있게 되었지만 고층 빌딩과 같은 도심 계곡, 복잡한 한국지형, 산악지역 등에서의 위성 장애물에 의한 신호의 차단으로 한계가 발생하고 있다. NAVSYNC의 CW25 GPS 수신기는 -156dBm이하의 신호강도에서도 확실한 위치 fix가 가능하고, 이러한 능력은 도심지나, 울창한 숲과 심지어는 건물 안과 같이 신호가 미약한 지역에서도 사용될 수 있다. 이에 본 연구에서는 Indoor GPS 수신기를 이용하여 측지분야에서 검증된 GPS측량방법을 통해 수신데이터를 비교 분석하고 수신기의 정밀도 향상에 관한 연구를 하고자 한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.14 no.2
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• pp.209-218
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• 1996

This study aims to draw a technique for practical using of GPS surveying to decide the positions of cadastrial control points. GPS surveying is carried out at cadastrial triangulation points and supplementary control points. This paper includes characteristics of transformation of WGS84 into Tokyo datum, two dimensional solutions for GPS baseline vector, and combined solutions of both GPS and terrestrial data. As a results of this study, it is verifiable that GPS surveying is very efficient to check the existing control network. 2-D network adjustment technique using GPS baseline vector is applicable to Tokyo datum without coordinate transformation. And it is expected to improve efficiency by using either rapid-static or stop and go kinematic surveying in cadastrial surveying at small areas.

• Ecology and Resilient Infrastructure
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• v.7 no.3
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• pp.171-180
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• 2020

With the increase in industrialization and urbanization, scarcity of space for leisure life has become an important issue. Opportunities such as natural scenery and ecological experiences provided by waterfront spaces around streams are fundamental factors in the development of the community and creation of a hydrophilic park. In the past, on-site surveys have been conducted using human resources to quantify the number of river visitors, but the accuracy of the results was not sufficient owing to limitations in expenses, manpower, space, and time. In this study, to overcome this problem, we estimated the number of visitors using the location information related to hydrophilic parks. The study areas were Samrak Ecological Park and Daejeo Ecological Park located downstream of the Nakdong River. We compared and analyzed the pattern of the visitors by using the large communication data and the visiting pattern based on GPS location information. The GPS location information is based on Google Popular Times and Kakao visitor data. When the GPS location data were used, the pattern for weekday and weekend visitors was clearer than when the large communication data were used. Therefore, it is expected to be similar to the result of GPS location information if the number of visitors is extracted under the condition of precision of pCELL size and residence time of 30 minutes or more when using future communication big data. In addition, if revisions such as the Personal Information Protection Act are made to extract more accurate data, by estimating the number of visitors based on GPS data, more accurate indicators of the number of visitors can be derived.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.5
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• pp.69-74
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• 2010

In this paper, we proposed a compact arbitrary dual-band band-stop filter using CRLH transmission line. The proposed filter used CRLH transmission line as stub and it developed dual-band band-stop characteristics using non-linear phase response of CRLH transmission line. The size of proposed filter is compact. And it can control arbitrary dual stop band. In this paper, designed band-stop filter at GPS band and ISM band As result, the S(2,1) is about -30dB at GPS band and about -29dB at ISM band. The fabricated filter is very compact. Its dimension is 10mm*15mm.

• Journal of applied mathematics & informatics
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• v.27 no.3_4
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• pp.703-714
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• 2009

GPS is especially suitable for location systems in flat areas, but the availability of GPS is limited in highly urbanized and mountain areas, due to the nature of satellite communications. Dead reckoning is generally used to solve a location problem when a pedestrian is out of range of GPS coverage. To extend the apparent coverage of the GPS system for a hiker in mountain areas, we propose an integrated 3D location system that interpolates a 3D dead reckoning system based on information about contour lines. The speeds of hikers vary according to the inclination of the ground in sloped areas such as mountains. To reduce location measurement errors, we determine the angle of inclination based on the contour lines of the mountain, and use the speeds based on the inclination in the location system. The simulation results show that the proposed system is more accurate than the existing location system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.3
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• pp.295-303
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• 2000

The purpose of this research is to enhance efficiency and tide measurement of the bathymetry survey based on the DGPS techniques which is becoming popular today due to a lot of benefits using the GPS. And according to the result of this research, choice and interpolation were possible with the most optimum method according to the various mathematical regressive equations as linear, parabolic, polynomic, reciprocal, hyperbolic, logarithmic and Gaussian functions. And the height of ground surface is easily calculated by 2D+1D transformation of coordinate of WGS84 in Cm-level based on the real time, even though the GPS time and tide were used to be synchronized through step-wised processing before. And because of the synchronization of time, the real time DGPS can cope with the loss of local current and changes of the tide.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.514-519
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• 2017

In this paper, the pseudorange-based GPS performance using the Android's raw measurements is compared with NMEA. In order to compare the performance between the two different implementations, we used Nexus 9 tablets and collected the raw measurements and NMEA data using the GNSS logger application provided by Google. To verify the performance of the final coordinates calculated, the VRS was used as the reference coordinate and compared with the NMEA results. The resulting horizontal, vertical, and 3D RMS errors of the pseudorange-based GPS using the Android's raw measurements are 3.05, 3.82, and 4.97 m, respectively, which correspond to 32% horizontal, 65% vertical and 49% 3D performance improvement compared with NMEA.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.421-422
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• 2008

In this paper, CMOS RF front-end circuits for an L1/L5 dual-band global positioning system (GPS)/Galileo receiver are designed in $0.13\;{\mu}m$ CMOS technology. The RF front-end circuits are composed of an RF single-to-differential low noise amplifier, an RF polyphase filter, two down-conversion mixers, two transimpedance amplifiers, a IF polyphase filter, four de-coupling capacitors. The CMOS RF front-end circuits provide gains of 43 dB and 44 dB, noise figures of 4 dB and 3 dB and consume 3.6 mW and 4.8 mW from 1.2 V supply voltage for L1 and L5, respectively.