• Journal of Korean Society for Geospatial Information Science
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• v.10 no.2 s.20
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• pp.87-95
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• 2002

Real-time Kinematic GPS enables high accuracy Positioning by real time. If ambiguity use an integer solution, can obtain accuracy of several 'mm', and can obtain accuracy of tens 'em' if use real solution. In this study, We accomplish surveying by existent traditional surveying techniques (Total Station), Static GPS techniques and RTK-GPS techniques by Field Calibration about uniformity measuring point and then compared and ana1yzed each techniques positioning accuracy etc.. Result that achieve by Static-GPS in Plane area, about all measuring points, expressed error fewer than 3cm. Result that achieve RTK-GPS Surveying by Field Calibration in Plane area, could know that RTK-GPS techniques by Field Calibration is available in Plane area because expressing errors fewer than all 6cm, except case that do not get fixed solution of ambiguity Field Calibration RTK-GPS could know economically than existent conventional type measurement and existent GPS's measurement techniques that efficiency is very high.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.1 s.19
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• pp.37-49
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• 2002

RTK-GPS(Real Time Kinematic GPS) surveying technique which allows centimeter level three-dimensional coordinates in real time has been recognized as a major advance in the science of GPS positioning. And no longer is it necessary to wait until post-processed results are computed after the surveying has been completed in field. The purpose of this study is to present the accuracy and effectiveness of the determinated parcel coordinate by RTK-GPS surveying technique, through the analysis and comparison of the surveying results both in Total Station and RTK-GPS.

• 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.

• Journal of Astronomy and Space Sciences
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• v.19 no.4
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• pp.377-384
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• 2002

We have developed Real-time Phase DAta processor(RPDAP) for GPS L1 carrie. And also, we tested the RPDAP's positioning accuracy compared with results of real time kinematic(RTK) positioning. While quality of the conventional L1 RTK positioning highly depend on receiving condition, the RPDAP can gives more stable positioning result because of different set of common GPS satellites, which searched by elevation mask angle and signal strength. In this paper, we demonstrated characteristics of the RPDAP compared with the L1 RTK technique. And we discussed several improvement ways to apply the RPDAP to precise real-time positioning using low-cost GPS receiver. With correcting the discussed weak points in new future, the RPDAP will be used in the field of precise real-time application, such as precise car navigation and precise personal location services.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.4
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• pp.65-70
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• 2011

National Geographic Information Institute provides VRS service using permanent GPS networks. VRS-RTK(Virtual Reference System-Real Time Kinematic)GPS surveying which enable to accomplish the real time-based GPS surveying has been increasingly popular. However the positioning accuracy tends to deteriorate as the distance between the rover and base station increases in the VRS-RTK GPS surveying. To analysis this problem in this study, the accuracy of VRS-RTK data was analyzed with 2 different test sites of Geoje city, Gyeongnam province within and without the permanent GPS networks in order to accomplish the cadastral supplementary control surveying. As a result of surveying accuracy analysis at two test sites, positioning errors were ${\pm}0.03m$(RMSE) in both sites. The result was that within the tolerance specified in cadastral surveying law, and indicated the possibility of VRS-RTK GPS surveying in cadastral surveying.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.3
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• pp.301-309
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• 1999

Real-time kinematic (RTK) GPS surveying which allows centimeter level accuracy of three-dimensional coordinates without post-processing has become recognized as a major advance in GPS technology. Employing On-The-Fly initialization technique, the RTK system can escape from cycle slip problems that have affected as a main obstacle factor in traditional kinematic and static approaches. The objective of this research was to evaluate accuracy and effectiveness of the RTK-GPS surveying. First, the continuous RTK observation of a base line was conducted for the purpose of finding out the repeatability of the RTK surveying and the results which were then compared against results from static surveying showed RMS errors of $\pm{3mm}\;and\;\pm{13mm}$ for their respective horizontal and vertical components. On a test network of 30 stations covering the small area, the results of RTK testing were compared against those from not only post-processing kinematic and rapid-static surveyings but conventional surveyings and also the efficiency of RTK were analyzed. In addition, geoid heights which were derived by combination of GPS and spirit leveling about all of the points within the network were compared against those derived by the PNU95 and EGM96 models respectively.

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.1 s.31
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• pp.63-69
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• 2005

Interferometric Synthetic Aperture Radar(InSAR) is a rapidly evolving technique. Spectacular results obtained in various fields such as the monitoring of earthquakes, volcanoes, land subsidence and glacier dynamics, as well as in the construction of Digital Elevation Models(DEMs) of the Earth's surface and the classification of different land types have demonstrated its strength. As InSAR is a remote sensing technique, it has various sources of errors due to the satellite positions and attitude, atmosphere, and others. Therefore, it is important to validate its accuracy, especially for the DEM derived from Satellite SAR images. In this study, Real Time Kinematic(RTK) GPS and Kinematic GPS positioning were chosen as tools for the validation of InSAR derived DEM. The results showed that Kinematic GPS positioning had greater coverage of test area in terms of the number of measurements than RTK GPS. But tracking the satellites near and/or under trees md transmitting data between reference and rover receivers are still pending tasks in GPS techniques.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.455-458
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• 2006

The Real Time Kinematic (RTK) technique is the most productive and accurate GPS positioning method today, as it can be determinate position within few centimeters instantly. This method is widely used for applications such as surveying, structure monitoring and machine guidance etc. In order to perform RTK processing for large scale systems (i.e. precise vehicle monitoring with many rovers), many expensive RTK receivers and same number of bidirectional communication units have to be installed to collect observation data communicate with the reference site and monitor its RTK solutions. Moreover, if applications require remote control or apply sensing instruments, we have to install computers at each rover. To limit expense and complexity of system management with a large number of rovers, we have developed server based RTK processing platform to share RTK function for all rovers. The system can be process many GPS stations with a single personal computer. we have also developed a specialized dual frequency GPS receiver unit without on-board RTK processing capability to reduce receiver cost in order to demonstrate the advantage of our server based RTK platform. This paper describes the concept of our server based RTK platform and specialized GPS receiver unit with existing applications in Japan.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.2
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• pp.139-147
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• 2008

The positioning accuracies tend to deteriorate as the distance between the rover and the reference station increases in the Real-Time Kinematic (RTK) surveys using Global Positioning System (GPS). To solve this problem, the National Geographic Information Institute (NGII) of Korea has installed Virtual Reference System (VRS), which is one of the network-based RTK systems. In this study, we conducted the accuracy tests of the VRS-RTK surveys. We surveyed 50 control points inside the NGII's GPS Continuously Operating Reference Stations (CORS) network using the VRS-RTK system, and compared the results with the published coordinates to verify the positioning accuracies. We also conducted the general RTK surveys at the same control points. The results showed that the positioning accuracy of the VRS-RTK was comparable to that of the general RTK, because the horizontal positioning accuracy was 3.1 cm while that of general RTK was 2.0 cm. Also the vertical positioning accuracy of VRS-RTK was 6.8 cm.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.11-22
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• 2012

In this study, problems of RTK (Real Time Kinematic)-GPS (Global Positioning System) and an accelerometer sensor when applied to structures were experimentally identified through a comparison between results of the displacement measurement using the RTK-GPS, the accelerometer, and LVDT (Linear variable differential transformer). Integrated displacement was calculated by the improved RTK-GPS and accelerometer on the frequency of observation and positioning accuracy. This integrated displacement was also compared with that of LVDT to check the validity of application and feasibility.