• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.8 no.1
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• pp.1-13
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• 1990

The main objectives of this study are to present the new geodetic coordinate system, reference ellipsoid, and the basic scheme about the determination of official coordinates of geodetic control points. Moreover, provisional official coordinates on the basis of precise geodetic survey (1st and 2nd order geodetic networks) are proposed.

• Structural Monitoring and Maintenance
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• v.8 no.4
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• pp.309-328
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• 2021

The objective of this work was to develop a methodology for geodetic monitoring on onshore wind towers, to ascertain the existence of displacements from object points located in the tower and at the foundation's base. The geodesic auscultation was carried out in the Gravatá 01 and 02 wind towers of the Eólica Gravatá wind farm, located in the Brazilian municipality of Gravatá-PE, using a stable Measurement Reference System. To verify the existence of displacements, pins were implanted, with semi-spherical surfaces, at the bases of the towers being monitored, measured by means of high-precision geometric leveling and around the Gravatá 02 tower, concrete landmarks, iron rods and reflective sheets were implanted, observed using geodetic/topographic methods: GNSS survey, transverse with forced centering, three-dimensional irradiation, edge measurement method and trigonometric leveling of unilateral views. It was found that in the Gravatá 02 tower the average rays of the circular sections of the transverse welds (ST) were 1.8431 m ± 0.0005 m (ST01) and 1.6994 m ± 0.0268 m of ST22, where, 01 and 22 represent the serial number of the transverse welds along the tower. The average calculation of the deflection between the coordinates of the center of the circular section of the ST22 and the vertical reference alignment of the ST1 was 0°2'39.22" ± 2.83" in the Northwest direction and an average linear difference of 0.0878 m ± 0.0078 m. The top deflection angle was 0°8'44.88" and a linear difference of ± 0.2590 m, defined from a non-linear function adjusted by Least Squares Method (LSM).

• Journal of Cadastre & Land InformatiX
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• v.45 no.2
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• pp.101-116
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• 2015

In Boundary Point Coordinate Register Area, the accuracy on Transformation of World Geodetic System(WGS) is determined by surveying results at the reference point. However, the present surveying result in reference points indicates the irregular performance due to the limitations of measurement techniques and methodologies, moreover, can be contaminated by various error sources from the unique characteristics of each project district and start time of the project. Therefore, the main purpose of present investigation is to conduct an inquest into error cause by project districts for each type in Boundary Point Coordinate Register Area, and propose the improvement plan of surveying accuracy through the WGS Transformation and verification-surveying.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.561-571
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• 2020

Seven techniques widely used in the geodetic transformations have been reviewed and compared to figure out their theoretical characteristics. A series of numerical tests were performed about four data sets. This was followed by result analyses in terms of transformation residuals and accuracies together with some hypothesis testings based on the student-t distribution to confirm the statistical significance of the techniques. In the case of the transformation between the geodetic frames implemented in the same system, no statistical significance was revealed in the results of the 3D transformation techniques, even if the testing area becomes large as the Asia-Oceania continent. Among the 2D transformations, it was possible for the NTv2 grid modeling technique to deliver improved transformation accuracy. Finally, it was possible from the results analyzed in this study to propose the Helmert transformation to geodetic control points and the NTv2 technique to the 2D spatial data transformation of the geodetic systems.

• Ocean and Polar Research
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• v.23 no.2
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• pp.121-130
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• 2001

Geodetic datums define the size and shape of the earth and the origin and orientation of the coordinate systems used to map the earth. A lot of different datums have been developed and each nation uses its own datum as the basis for coordinate systems used to identify positions in geographic information systems. Recently GPS receivers are widely used to find out location and GPS is based on the World Geodetic System 1984(WGS-84) datum. Therefore the diversity of datums in use today requires accurate conversion between coordinates in different datums. In this study a coordinate conversion program on Windows is developed to transform between Tokyo Bessel(1941), which is the reference datum in Korea, and WGS-84. Several examples of coordinate conversion are presented and computed results are tested and proved to be correct.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.3 no.2
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• pp.11-17
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• 1985

In the three dimensional Cartesian Coordinate System such as the satellite geodesy the relationship of the geoid and the reference ellipsoid must be known. Therefore, the determination of geoidal heights is regarded as one of the most important problem in geodesy. This paper deals with determination of astro-geodetic geoid by the spherical surface polynomials interpolation method. The data that astronomical deflection of the vertical was published by National Geography Institute is applied. The map of geoidal heights is drawn out. This shows that Tokyo Datum have influenced on Korea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.662-671
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• 2020

It is crucial to manage and maintain the geodetic reference coordinates of GNSS continuously operating reference stations (CORSs) in consideration of their fundamental roles in geodetic control and positioning navigation infrastructure. Earthquake-induced crustal displacement directly impacts the reference coordinates, so such events should be promptly detected, and appropriate action should be made to maintain the target accuracy, including update of the geodetic coordinates. To this end, this paper deals with online schemes for the detection of persistent shifts in the coordinate time-series produced by an automatic GNSS processing system. Algorithms were implemented to test filtered results, such as hypothesis tests of the innovation sequence of a Kalman filter and a cumulative sum (CUSUM) test. The results were assessed by the time-series of coordinates of 14 CORS for two years, including the 2011 Tohoku earthquake. The results show that the global hypothesis test is practical for detecting abrupt jumps, whereas CUSUM is effective for identifying persistent shifts.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.2
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• pp.117-124
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• 1995

The main purpose of the present study was to investigate coordinate transformation based on two different systems: one was the World Geodetic System 1984(WGS84) adopted as a reference system for GPS satellite surveying;and another was the current Korean geodetic system based on Bessel ellipsoid. For this purpose, three methods were used to determine 7 parameters as follows: Bursa-Wolf model, Molodensky-Badekas model, and Veis model. The coordinate transformation was carried out using simillity transformation applied the obtained 7 parameters and the precision of transformed coordinate was evaluated. From this results, we found that Bursa-wolf model is more suitable than others for the determination of transformation parameters in Korea.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.1 s.35
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• pp.65-74
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• 2006

A rapidly developed satellite technology is used in comprehensive fields such as spatial data aquisition and applications. Especially a GPS positioning is expected to reinvigorate at the national reference system changes to ITRF(International Terrain Reference Frame). Currently the National Geographic Information Institute(NGII) issues a triangulation point coordinate by separating old and new coordinates and in the year of 2007 it will be scheduled to be changed ITRF. The triangulation point coordinate in Cheju area causes some problems due to the difference original observation and re-observation. Thus in this study a GPS observation is conducted after re-organizing geodetic network based on 1st and 2nd order triangulation in order to check the current triangulation points in Cheju area. After the GPS observation data analysis, stable points were extracted, proposed a geodetic network and its application.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.631-639
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• 2011

There are problems in using existing fisheries maps, because of deterioration of paper maps, as well as various coordinate systems. In this study, accuracy of fishery maps in World Geodetic System are evaluated. Materials on fishery rights in the Jeollanam-do Province, a study area, used many kind of coordinate systems. During digitization, these coordinate systems have been converted and unified in one World Geodetic System, and one projection origin. In this research, the accuracy of the products of digitization is verified using DGPS surveying. The RMSEs are minimum of 4.62m(at the Younggwang Seas) to maximum of 17.47m(at the Jangheung Seas), and average of 11.97m. The results shows that the digitized fishery maps meet the accuracy standard of 1/25,000 digital topographic maps.