• Journal of Korean Society for Geospatial Information Science
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• v.2 no.2 s.4
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• pp.125-130
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• 1994

The original concept of GPS is the feature of instantaneous navigation which is the determination of the position of a moving vehicle(ie, a ship, a car, an air craft) by unsmoothed code pseudoranges. The objective of study is compare the efficiency (or time, accuracy) between GPS surveying by using kinematic method and conventional surveying methods in the intersection, and then suggest research materials for actual application.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.1
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• pp.51-58
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• 1998

The goal of this study is to propose a precision improvement scheme for long baseline determination based on the use of IGS ephemeris and different cutoff angles. It is also to present the adjustment results of ’96 Korea GPS fiducial network. In order to obtain more accurate coordinates in precise geodetic surveying, the revision of specification is necessary for the field operation and procedure of baseline processing.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.399-404
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• 2004

Recently GPS has been playing an increasingly important role in geodesy and positioning, for example, car navigation system, surveying, ITS(intelligent transport systems), LBS(Location Based Service) and so on. For telematics application, reception conditions of GPS signal are important. In some situation, such as in areas between buildings, metropolitan areas or areas with large skyscraper complexes, there are situations whereby the satellite signal is seriously restricted by various obstacles. Before the signal arrives at the receiver, it may be blocked, reflected, delayed, attenuated or scattered by terrestrial obstacles such as buildings. In this paper, we present satellite imagery data for telematics application. Therefore, for propriety of this studies, we made a GPS satellite visibility experiments in Bun-Dang on same time. This paper describes an approach to calculate building level using 0.6m, 1m, 6.6m resampling aerial polo imagery in stead of the satellite imagery and make a comparative study of accuracy. This paper tests the simulation of GPS signal using the building level.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.2
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• pp.157-164
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• 2008

GPS baseline analysis is a mathematical procedure which estimates a baseline vector from carrier-phase double-differenced observations. Least squares technique is generally applied for the processing and integer ambiguities in the observations should be resolved to obtain maximum accuracy of the solution. In GPS control surveying, after assembling the baseline solutions into a network, adjustment is performed to derive final coordinate sets of unknown points. This paper deals with details of GPS baseline analysis for the $2^{nd}$ order national geodetic network adjustment. After reviewing GPS campaigns carried out by National Geographic Information Institute (NGII) and their observations. technical issues and considerations for the GPS baseline analysis are presented with emphasis of selecting the processing strategies and software. Finally, the analyzed results will be evaluated by examining the close of figures formed by joining the processed baseline vectors.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.4
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• pp.309-316
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• 2003

Rapid and accurate data processing is required in many GPS(Global Positioning System) applications including surveying. While one can use four different kinds of GPS satellite orbits, we evaluated the accuracy and precision of each kind of orbits to find the best candidate for rapid and accurate data processing. The four different kinds of orbits we: broadcast orbits from GPS satellites; and ultra-rapid orbits, rapid orbits, and precise orbits provided by international GPS data analysis centers such as IGS. With GIPSY and ultra-rapid orbits, we could get the positioning accuracy of 1.5cm from seven days of GPS data. From this study, we conclude that rapid and accurate data processing is achieved with GIPSY and ultra-rapid orbits.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.3 s.37
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• pp.23-30
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• 2006

The case of a forest area has tome limitations of adopting a ground surveying like as TS (Total Station) and RTK-GPS (Real Time Kinematic-GPS) due to the specificity of the forest area. Therefore, the new method, is different from exist the cadastral re-surveying method in a metro area and a cropland, is applicably considered in the forest area. In this paper, we suggest the applicability of the digital cadastral map of forest which is used at KLIS. According to the result of study, the most important area error value for adopted in the cadastral re-surveying is almost contained the error tolerance. Therefore, KLIS data, if it is related with the actual reference data for adjusting the location boundary, is suitable to be adopted in the cadastral re-surveying.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.113-117
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• 2004

Such social structures as bridges, buildings, dams and towers have been transformed by their own load or fundamental ground. They have been behaved by other external causes. These regular or irregular behaviors threaten to do their users safety. Therefore, to monitor the load of the structures or reaction shown by them could help to verify their behaviors. RTK GPS allows the use of a static base station and remote rover unit to allow for data collection within several seconds and in real time. It is useful for monitoring the behaviors of massive structures like bridges. In this Study, Among GPS methods, we used RTK GPS to analyze the precision of monitoring and then on the basis of it, we developed a monitoring system using RTK GPS when measured the behavior of main tower of a suspension bridge by using RTK GPS. Comparing a deviation between observation values, X axis was 1mm, Y axis was 1mm and Z axis 2.2mm. It turned out that it was possible to monitor and measure structures by RTK GPS.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.3-8
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• 2004

This study describes the validation of the GPS/Levelling using GPS data that were obtained from three Permanent GPS stations of the Jeju island. Each orthometric height of three Permanent GPS stations was calculated from the Bench mark of levelling with Traverse-survey and relative baseline processing The test result shows that the error of closure of orthometric height was about 1.6cm and one of ellipsoidal height was about 1.5cm. This result represents that the geoidal height and undulations are regular in the Jeju island. According to the test results, it is identified that one can calculate the orthometric height using Permanent GPS station data rather than traditional levelling method which has a some complexity especially in Jeju island.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.85-88
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• 2007

Sea level fluctuation present a direct influence to those who live near the coast. The importance of monitoring sea level is evident. Therefore, various techniques have been employed for sea level measurements such as the coastal water level gauges, satellite altimetry and GPS buoy. Especially, GPS buoys have been used to measure water levels, atmospheric parameter and other physical conditions in sea, tide correction, the altimeter range calibration, ocean environment. In this paper, we will mainly concentrate on the kinematic technique for GPS buoy to measure the sea level. A test was carried out to test the method proposed in this paper, which made use of a GPS buoy equipped to monitor the sea level in Busan. We have executed to analysis about applications of GPS buoy.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.27-30
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• 2007

The objective of this study is to improve an accuracy of PWV estimates using GPS in Korea. We determined a weighted mean temperature equation by a linear regression method based on 6 radiosonde meteorological observations, for a total 17,129 profiles, from 2003 to 2005. Weighted mean temperature, Tm, is a key parameter in the retrieval of atmospheric PWV from ground-based GPS measurements of zenith path delay. The accuracy of the GPS-derived PWV is proportional to the accuracy of Tm. And we applied the reduction of air Pressure to GPS station altitude. The reduction value of air pressure from mean sea level to GPS stations altitude is adopted a reverse sea level correction.