• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.257-258
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• 2010

Recently data, which are obtained by the airborne laser scanner system have been utilized to rapidly obtain three-dimensional location coordinates for a large area. According to operation regulation, the distance between a GPS base station and a aircraft GPS is fixed within a radius of 30km. In this paper, we compare data obtained by GPS observation station operated in National Geographic Information Institute with those obtained by GPS base station for making a airborne laser survey.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.55-60
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• 2003

As the distance between GPS rover station and GPS base station increases, more decorrelated positioning errors limit the ability for PDGPS(Precise Differential GPS). The objective of this paper is to present the improvement of using VRS(virtual reference station) based on multiple GPS reference station network to single reference station for static positioning in post-processing mode. For this, the VRS observations from GPS observations of real reference stations are derived by using Web service in post-mode. The coordinates of check point post-processed by 27 kind of VRS observations compared with the known ones.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.1
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• pp.71-78
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• 2009

In general, it is necessary to establish the dedicated GPS base station at the central point of the survey area in GPS/INS aerotriangulation. Although this base station is needed to achieve the required survey accuracy, there are some difficulties in practical operation. To tackle these difficulties and to achieve the effective GPS/INS aerotriangulation, the GPS data of CORS was interpolated and used in stead of those of the usual ground base station. Through this study, it was found that the interpolated CORS data was accurate enough to substitute dedicated GPS base station in GPS/INS aerotriangulation.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2002.10a
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• pp.63-66
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• 2002

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.111-116
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• 2004

This study is given that on the bridge construction in marine by GPS, specially, choice of station for footing construction of marine bridge. You can get positive datum in the checking of marine excavation, if you use together Total Station and GPS. In the result of comparision of upper surveying methods, Surveying datum is gotten error of less than 30mm(The depth of water 10～l5mm, station 7～10mm). This study show that hereafter if you use GPS in bridge construction in marine you can get accurateiy datum.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.6
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• pp.617-624
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• 2008

In general, RTK-GPS(Real Time Kinematic GPS) based on the single reference station is able to determinate the high accurate position of rover on the spot using error correction information of transmitted carrier phase from the base station via wireless modem. However, single reference station method has some weak points to decrease positioning accuracy because it must be obtained carrier phase from the each satellite continuously, allowed to transmit without obstacle and limited to short base line distance between base and rover station. This paper aims to attempt network based GPS carrier phase differential positioning using three multi reference stations to overcome the method of single reference station and RTK network is realized by real time monitoring program with Visual C++. The optimum error correction value of three multi reference stations by RTK networking is selected automatically to correct the position of rover station. In this paper, this algorithm is applied to determine sea water level using GPS buoy, and the accuracy results of water level change were analyzed and compared with each other using single and multi reference stations.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.1
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• pp.41-49
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• 2000

This study was performed to establish PC-based Urban Infrastructure Information System(UIIS) using GPS and TotalStation as an alternative to UNIX-based UIIS. After carryig out this study, the following conclusions were derived: PC-based UIIS costs less time and money than UNIX-based UIIS. The coordinates of the control point of the site were obtained using DGPS, then based on this point, locational data were obtained using RTK GPS and TotalStation in the site with realtime data capture to enhance the accuracy of locational data. And image data were also entered into database together with the text data. So, the multimedia database is possible in UIIS.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.4
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• pp.41-50
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• 2007

This study aims to suggest efficient setting up of GPS (Global Positioning System) for cadastral surveying. In order to perform it effectively, worldly used modern surveying technology GPS introduced. In a practical analysis, GPS observation had been performed in the research area and the results had been compared and analysed with the results of Total Station. As a results, it is shown that GPS is more efficient rather than current surveying method in terms of time, cost and economy. The results of GPS surveying were included in the scope of error tolerance, being accepted by cadastral laws, showing high accuracy of GPS surveying method. With the results of analysis, how to application of GPS for cadastral surveying was suggested.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.4
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• pp.299-307
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• 2007

This study is about the calculation of practical orthometric height for permanent GPS station. We presented the method to determine the orthometric height precisely by combining leveling data, GPS data and gravimetry data, and determined the orthometric heights of thirty GPS stations. To test the result we developed the expected error model fur the determined orthometric heights regarding the accuracy of Korean national benchmarks and the precision of surveying methods used at this project. The reliability of the results was presented by comparing it with expected error model statistically.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1520-1525
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• 2009

In this paper, we study and simulate the suggested position control system using GPS and USN to replace the existing control system of a crane. For the correct approach, the position control system of a crane is divided into the control system of the ground station and the mobile station The hardware is comprised of GPS receiving module to receive the position control data of a crane from GPS satellites, bluetooth communication module for the data communication between the ground station and the mobile station, supersonic sensor module for a precise position control of a crane, motor to replace a crane roller, embedded MCU(ATmega128L) and so on. In here, an embedded MCU controls GPS receiving module, bluetooth communication module and supersonic sensor module. The Software is comprised of three programs. Three programs are the program to filter GGA output part in a receiving data of GPS receiving module, the driving program for supersonic sensor module, the digital map program to monitor a crane location. From the simulation results, it is demonstrated that the proposed system has the capability of crane position control with 1cm precision.