• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.955-958
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• 2003

Nepal is a country of mountains The higher order geodetic points were mostly established on the top of mountains and these points were used for the geodetic network extension. Lower order geodetic control networks were established at different times and used for the surveying and mapping activities of the country.. It has been found that the rate of convergence between north and south borders of Nepal to be 21${\pm}$2 mm each year and the rate translation of Kathmandu to 55${\pm}$3 mm/year to the plates. The most intense deformation in Nepal occurs along the belt of high mountains along its northern border res ulting in a strain contraction rate normal to the Himalayan Arc. This belt is approximately 40 km wide and extends into southern Tibet.( 13). Recently Survey Department of Nepal has lunched a program of strengthening the existing geodetic network of Nepal and re-observed the position of higher order geodetic points by using geodetic GPS receivers to evaluate their position and thus to define the precision of the control points once again. This paper describes the observation procedure and the adjustment results of the existing higher order control network of Nepal established in different time using different types of equipment and techniques; and highlights the observation procedure and the result obtained after the post processing of the GPS observation results. Attempt has been made to give the procedure and identify the methodology for the re observation of existing higher order geodetic points by using GPS receiver and post processing the observed data so that the existing higher order geodetic points are within the given accuracy standard.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.1
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• pp.83-89
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• 2023

The Korea Augmentation Satellite System (KASS) system is a Satellite Based Augmentation System (SBAS) under development to provide APV-I SBAS service in the Republic of Korea. The KASS ground segment generates correction and integrity information for GPS measurements of KASS users using the accurate positions of KASS Reference Station (KRS) antenna phase centers. For this reason, the accuracy of KRS reference points through geodetic survey campaigns is one of the important factors for providing the KASS service in compliance with the required navigation performance. In order to obtain accurate positions, two geodetic survey campaigns were performed at several reference points, such as Mark, Center of Mast at Ground Level (CMGL), and Center of Hole in Top Plate (CHTP), of each KRS site using three different survey methods, the Virtual Reference Station (VRS), Flächen Korrektur Parameter (FKP), and raw data post-processing methods. By comparing and analyzing the results, the computed coordinates of the reference points were verified and Antenna Phase Center (APC) positions were calculated using KRS Antenna Reference Point (ARP) data, and the first KASS Site Acceptance Test (SAT#1) was performed successfully using the verified APC coordinates. After the first site survey activities, the KASS operators should maintain the coordinates with the required performance such that the overall KASS navigation performance commitment is guaranteed during the lifetime of 15 years. Therefore, the maintenance plan for the KRS antenna coordinates should be developed before the commissioning of KASS operation planned after 2023. Therefore, this paper presents a geodetic survey method selected for the maintenance activities and provides the rationale for using this method.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.17-20
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• 2007

Many countries have changed her geodetic reference system from local system to global system because of the global network's necessity And, also Korean geodetic reference system changed from Tokyo datum to Global geodetic reference system since 2003 as the revision of Survey Law and Korean reference ellipsoid changed from Bessel 1841 ellipsoid to GRS80. Astronomic surveying has been regarded as an important method for absolute positioning of geodetic datum in each countries under the local geodetic reference system. This paper aims to analyses distribution of geoidal heights and ellipsoidal agreement between Bessel 1841 and GRS80 ellipsoid in Korea through comparing both astrogeotic geoidal heights referred to GRS80 and Bessel 1841 ellipsoid by astronomic surveying data which have been surveyed after 1970 in Korea.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.3-7
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• 2004

Many countries have changed her geodetic reference system from local system to global system because of the global network's necessity. And, also Korean geodetic reference system changed from Tokyo datum to Global geodetic reference system since 2003 as the revision of Survey Law and Korean reference ellipsoid changed from Bessel 1841 ellipsoid to GRS80. The purpose of this paper is evaluation of ellipsoid agreement before and after change due to the introduction of global geodetic reference system in Korea. For the evaluation ellipsoid agreement was analyzed using two Korean geoid model -KOGD2003 and KOBGDM33- on both ellipsoid and area variation caused by change of reference ellipsoid was calculated.

• 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.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.1
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• pp.33-38
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• 2002

The object of this study is to verify the feasibility in the application of the GPS system data to the existing geodetic and cadastral survey system. WGS-84 data, which were converted into domestic geometric coordinate system, were compared with those of the existing triangular coordinate system in Gwangju area. The significant results in this study are summarized below ; GPS system is more speedy and accurate than the existing triangular coordinate system in the survey of points in triangular coordinate or on the map. And the error in the GPS system was more uniform than that of the existing triangular coordinate system. GPS system is more effective than the existing triangular coordinate system in the future geodetic and cadastral survey because GPS data can be processed by the computer. It is necessary to calculate the conversion coefficients to apply GPS data practically to the existing geodetic and cadastral survey system. It can be achieved by the individual investigation on how the existing data in the domestic coordinate system were determined.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.59-63
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• 2007

Each country uses its own datum which well represent its topography. The uses of the space technology such as GPS and the effort of establishing the consistent data over the world, Korea changed the survey act to use a world geodetic system from January 1, 2007. In this study, spatial analysis carried out to transform the GIS DB of electric power distribution system based on the old Tokyo datum the new world geodetic system, KGD 2002. Based on the study, problems on the transformation had been identified and efficient solutions are suggested. The data used for the 7 parameter similarity transformation in this study is the blueprints of the electric equipment and base maps. It is expected that this study provide general scheme and procedure for efficient GIS DB transformation to the new world geodetic system.

• Korean Journal of Geomatics
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• v.5 no.1
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• pp.21-26
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• 2005

According to revisions of survey law taking effect on January 1, 2003, the Korean geodetic datum has been changed from a local geodetic to a world geodetic system. In this study, the datum transformation parameters especially for the maritime geographical data are determined. From database constructed through MGIS, a total of 492 coordinate pairs were selected and used in the parameter determination after outlier testing. Based on the parameter estimation, the Molodensky model is selected for datum transformation. For higher accuracy, Application of network optimization and a least squares collocation with Gaussian model has resulted in the accuracy better than 15 cm in coordinate transformation.

• 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.

• Journal of Cadastre & Land InformatiX
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• v.49 no.2
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• pp.123-134
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• 2019

The introduction of the world geodetic reference system in cadastral sector can apply the international standardization of cadastral survey and can be the basis for the creation of new industries by merging with other industries based on spatial information. With the introduction of the world geodetic reference system, non-coincidence land may cause problems which are whether the cadastral record and the real estate register are not consistent, etc. This problem infringes on the protection of ownership of citizens suggested in the main purpose of ｢Act On The Establishment, Management, Etc. Of Spatial Data｣. We have analyzed at overlapping cases between private land and overlapping cases between national and public land and suggested institutional improvement measures to solve problems arising on the site. As a result, it will be necessary to introduce a transformation verification measure by the world geodetic reference system in order to assign a function as a cadastral records to mapping converted to the world geodetic reference system. It is also expected that the legal and institutional basis should be established for alert adjustment and positioning through verification measures. Finally, it is difficult to determine the transformation factor as the co-ordinates of common points also differ because survey results vary by work area. Therefore, it is deemed necessary to consider the requirement to use the cadastral measurement basis by the world geodetic reference system in 2021.