• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.4
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• pp.21-30
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• 2012

This paper presents site survey processes and the results for installing GBAS Category-I ground system into Gimpo international airport. For siting assessment, many things should be taken into account in advance, such as installation requirement of GBAS components, future airport development plan and possible interference effects to existing facilities. Because overall performance of GBAS system can be affected by GPS signal reception environment, on-site survey should be performed carefully to measure actual GPS environmental performance and determine if any adverse multipath or RFI problems exist or not. In addtion, VDB antenna should be located to ensure line of sight for transmitting VHF signal to deliver GBAS message to aircraft. Based on the survey results, final location for GBAS system installation is selected near runway 32 in the Gimpo airport.

• Journal of the Korean association of regional geographers
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• v.15 no.1
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• pp.161-178
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• 2009

The introduction of a world geodetic system for cadastral survey will be started the enactment of the law on survey, hydro-graphical examination and cadastre. However, the cadastral control points are not homogeneous and correspond with national control points because of various reasons. To cope with this problem, the 1,600 high accurate control points, which can be interlocked with national GPS control points, has selected from existing 20,000 cadastral control points. These selected control points were calculated as an accurate world geodetic system and it makes a homogeneous cadastral survey network. Through these measures, for the future carrying out national project, this study will be effectively contributed to establish the cadastral infrastructures for the Korea cadastral reform project.

• Spatial Information Research
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• v.9 no.1
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• pp.51-72
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• 2001

It is frequently pointed out that the conventional field survey for natural environment has may limitations in terms of positional accuracy, real-time GIS data acquisition, and economic efficiency. The aim of this research was to develop an on site real-time mapping technique that enables the surveyor to input data in the field. The idea is based upon the recent trends in the field of Telecommunication and Information Technology that uses a GPS, wireless network computing, moving computing, etc. A virtual office approach has been adopted, in which a portable computer is linked to a GPS and field workers record data on the computer at the site and analyse data on site. This field mapping system has shown to be much less susceptible to the positional accuracy than that of th conventional approach. The Graphic User Interface, in particular, were ideally suited to combining positional information with attribute data which changes with every survey points. This interface allows users to interactively display and query GIS layers reproduced from the past survey results. The GIS database stored in the virtual office will serve to carry out a highly reliable survey since it could play a crucial role in identifying temporal and spatial changes occurred in the site. It is expected that integrated utilization of field data among the related agencies would be increased much more than before since the virtual office survey would be a powerful tool to ensure geometric fidelity in GIS database creation process. This paper also discusses the limitations and future direction of the present prototype research.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.4
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• pp.355-363
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• 2007

The purpose of this study is to maximize the use of framework data by a method for updating road framework data using a economical, rapid, and accurate Vehicle-based kinematic survey to get the latest road data among "transportation framework data" which was built in 2003. We collected data using a Vehicle-based kinematic survey with DGPS (Differential Global Positioning System) in Daejeon and Pyeongtaek city and verified the accuracy of line and point features between surveying and previous results. The result showed that Daejeon city which is located near GPS CORS (Continuously Operating Reference Station)s and receive a signal well had lower errors than 1/5,000 digital base map, and Pyeongtaek city which is located far from the stations and receive a signal badly had errors beyond the limits. The study showed that postprocessing method or Total Station surveying should be used where signals cannot be detected well after analyzing a receiving rate from GPS CORSs, the stations of other organizations should be shared, and further studies are needed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.5
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• pp.74-80
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• 2006

GPS, which has been opened to the public since the 1980's, uses the C/A code time of arrival to estimate the position, and measures the carrier doppler frequency to estimate the velocity. In development from the 1990's, DGPS has improved position accuracy by eliminating common errors and CDGPS has achieved cm-level position accuracy using carrier phase. In this paper, a modified LSAST ambiguity resolution method for CDGPS is proposed to improve reliability and computational efficiency. Also the test results of cm level relative positioning of a moving vehicle using single frequency GPS receivers are compared to INS position. This research result can be widely used for the development of high precision INS, unmanned autonomous driving, survey and mapping, etc.

• 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.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.12
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• pp.631-638
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• 2016

GNSS(Global Navigation Satellite System) such as GPS(Global Positioning System), GLONASS(GLObal NAvigation Satellite System) has been used in various fields for construction of geospatial inforamtion. But RTK or VRS method for high accuracy has some bad points like requirement of additional GNSS device and internet. So, this methods are difficult to take advantage of field survey. In this study, In this study, experiments using DGPS handheld devices and smart devices that can maximize mobility through was to suggest ways to improve the efficiency of field survey work. As a results, field survey work with smart devices is difficult to apply the limits of accuracy yet. On the other hand, DGPS has been found possible to determine the position accuracy within 1m. If DGPS is used in related work can greatly improve the efficiency of field survey work, which is currently much is done by hand, it is expected to serve as the basis for a structured GIS data management.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.192-203
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• 2016

Uganda is a country blessed with the biggest number of mountain Gorillas in the whole world. These animals contribute at least 12% in revenue generation to the Tourism sector through tracking by both local and foreign tourists who pay for the tracking permits. However, Gorilla tracking is also a big challenge even in the presence of highly skilled and well-trained game rangers. Development and implementation of a secure Computer and Mobile based Gorilla Tracking (GT) system that uses GIS and GPS technologies would be the most ideal technology to use. Therefore, this study aimed to find out the critical factors that would affect the Behavioral Intention of the would-be users to successfully decide to use such GIS/GPS-GT system. We used the existing UTAUT model to integrate six factors such as Performance Expectancy, Effort Expectancy, Employee Peer Influence, Facilitating Conditions, Behavioral Intention and System Use. However, Infrastructure Availability and Non-Technical Facilitating Conditions were added to reflect Ugandan ICT context. This amended UTAUT model was used to carry out the survey. The questionnaire was emailed to 220 government employees in the fields of ICT, Tour and Travel, Environmental Groups officials and Farmers who garden near the game reserves. A total of 133 were obtained fully completed, whereas 127 were deemed usable thus yielding a response rate of 58%. The analysis results show that except for non-technical facilitating conditions, effort expectancy, peer influence, performance expectancy and infrastructure availability positively affects behavioral Intention to use GIS/GPS-GT. This indicates that people in Uganda don't bother about regulations and rules in regard to using information system. As long as the system does what they want it to, anything else does not matter. As an employee in an organization is told to use a system by their supervisor, they have no objection to otherwise they risk losing their job. This implies that, supervisors have a great responsibility in the process of developing, implementing and using the system in Uganda.

• 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 Cadastre & Land InformatiX
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• v.47 no.1
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• pp.95-110
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• 2017

The network RTK surveying has been widely used in the field of cadastral surveys in recent years, and its use is gradually expanding. As a result of the implementation of GPS static surveys by civilian companies in accordance with the progress of the cadastral surveys and gradual civilian transfer plans and cadastral surveys, there has been an increase in the number of civilian companies performing surveys. In this paper, we describe the process of applying the results of analysis of conformity using the network RTK site calibration function on the local coordinate system to the GPS static surveying of the cadastral reference points in Anyang city. In addition, the measurement results of the network RTK site calibration function and the results of the GPS static surveying network reconciliation in the local coordinate system were compared, and the performance was determined within 0.04m maximum of RMSE(Root Mean Square Error), and further study on the application method is needed.