• Title/Summary/Keyword: 측지계

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Research for Gravity Measurements Using CG-5 Autograv System and Network Adjustment (CG-5 상대중력계를 이용한 중력관측 및 중력망조정에 관한 연구)

  • He, Huang;Yun, Hong-Sic;Lee, Dong-Ha
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.27 no.1
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    • pp.713-722
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    • 2009
  • Gravity measurement can determine the earth gravitational field, also is the fundamental to the research of earth gravitational field, geodesy and geodynamic, vertical movement of the crust, geoid surface, sea level and climate etc. Recently, National Geographic Information Institute (NGII) introduced FG-5 absolute gravity meter in order to lay a foundation for establishment of Absolute Gravity Network, and furthermore NGII plan to construct about 1,200 multi dimensional and function Unified Control Points(UCP) in nationwide. It will play an important role in development of high accuracy geoid model in South Korea. This paper explains the fundamental theory and method of relative gravity measurement, surveys the relative gravity of 21 stations using latest Scintrex CG-5 relative gravimeter. In addition, it calculates gravity values, compare and analysis gravity survey results using datum-free adjustment and weighted constraint adjustment. The results indicate show that datum-free and weighted constraint adjustment methods are available to determine high accuracy gravity achievement, datum-free method is more advantage than weighted constraint adjustment.

Application Method of Site Calibration Function of Network RTK Survey for Local Coordinate System Result Analysis (지역좌표계 성과분석을 위한 네트워크 RTK측량 사이트 캘리브레이션 기능 적용 방안)

  • Shin, Chang Soo;Choi, Yun Soo;Park, Moon Jae
    • 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.

Establishment of the Plane Coordinate System for Framework Data(UTM-K) in Korea (우리나라 기본지리정보 좌표계(UTM-K) 도입에 관한 연구)

  • Choi, Yun Soo;Kim Gun Soo;Park Hong Gi
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.22 no.4
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    • pp.313-321
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    • 2004
  • Korean government has offcially decided to adopt global geodetic reference system(ITRF and GRS80) from 2007 keeping pace with the spread of GNSS. Industries related with LBS and telematics have called for use of the new coordinate system suitable for GIS/GPS applications. The government also defined the single plane coordinate system that covers entire korean peninsula as UTM-K considering DB-based framework data and user-friendliness, and its defects were corrected while being applied to the building of road framework data. The TM projection, and origin scale factor of plane coordinate system, 0.9996were employed in order to satisfy the single plane coordinate system for the entire Korean peninsula. For the origin of plane coordinate system, longitude of 12712730'00" and latitude of 383800'00" were applied and, for the initial value of plane coordinate system, N=2,000.000m and E=1,000,000m were used. In addition to considerable savings in costs, it is expected that the UTM-K is applicable for correcting errors occurred during acquisition of geographic information and for aggregating map data produced by different sources. However, during the initial stage for introduction, confusion is forecasted due to the use of two different coordinate systems, which may be minimized by continued publicity and education.

The 3rd order GPS Network Adjustment to Determine KGD2002 Coordinate Sets (GPS망조정에 의한 세계측지계의 3등기준점 성과산정)

  • Lee, Young-Jin;Lee, Hung-Kyu;Jeong, Kwang-Ho;Song, Jun-Ho
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2007.04a
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    • pp.81-84
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    • 2007
  • This paper describes general procedure and results of the GPS 3rd odor network adjustment which has been carried out for determining coordinates sets with respect to new Korean Geodetic Datum, so-call Korean Geodetic Datum 2002 (KGD 2002). The adjustment begins with minimally constrained adjustments with respect to each of the 69 campaign networks. This was followed by constructing and adjusting sixteen block network. After detecting and removing outliers in the observation file, an attempt was made by applying the empirical stochastic modeling techniques used in the 2nd order network adjustment, so as to determine the magnitude of absolute and relative error for the estimated baseline vector from the GPS data processing. The over constrained adjustment were, in sequence, performed against each of the block network. In this adjustment, both of the 2nd order control points in the block network and the 3rd order control points overlapped with adjacent network whose coordinates were already determined from a preceding adjustment. The final adjustment results have shown that the accuracy of the 3rd order network adjustment was better than 1cm and 2cm in horizontal and vertical component, respectively.

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Accuracy of the Loran C Fix on the Route Between Pusan and Cheju (부산-제주 항로상에서 Loran C 위치정도)

  • 김민석
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.26 no.2
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    • pp.167-172
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    • 1990
  • A number of studies for the improvement of the accuracy of the Loran C fix were carried out previously. But most studies were preformed when a ship was at anchorage, or in port. To investigate the accuracy of the Loran C fix when a ship was underway and in port, a series of observation was made on the route between Pusan and Cheju from Oct. 1988 to Oct. 1989. The obtained results are summerized as follows: 1. There is little difference in the accuracy of the Loran C fix by daytime and night, and the higher the mountain nearby ship, the greater the error of ship's position. 2. When a ship is at anchorage and underway, and the accuracy of ship's position is almost not affected by course while underway. 3. In order to promote the accuracy of the fixed position, a navigator must correct the propagation velocity and the geodetic system simultaneously, but in this paper the authors find that a most accurate position can be obtained by converting the geodetic system only.

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Analysis of Coordinates Transformation between WGS84 and Bessel Ellipsoids According to the Transformation Parameters (매개변환요소에 따른 WGS84와 Bessel 타원체간의 좌표변환해석)

  • Kang, Joon Mook;Shin, Bong Ho;Lee, Yong Chang;Yoon, Cheol Gyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.5
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    • pp.1209-1217
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    • 1994
  • This paper proposed transformation coefficients suitable to South Korea for the establishment of coordinate transformation system between Bessel and WGS84 ellipsoids. For this, the coordinates transformation algorithms concerned with parameter methods was developed, and global test network which has 15 astronomical points in South Korea were designed. Based on signals received from GPS, computed the geoid undulation by GPS/Leveling, and derived parameters(3-, 4-, 6-, and 7-parameter) for transformation between each ellipsoid, applied global networks to study the characteristics of transformation according to parameters. Through the successful application of 7-parameters derived in this study and 7-parameters proposed by DMA for map projection, transformation coefficients suitable to South Korea was proposed.

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Cold-hardiness Tetraploid Induced by Colchicine Treatment in Mulberry Seedings(Morus alba L. Yongchonppong/Kaeryanppong) (지배실생(용천뽕/개량뽕)의 생장점에 Colchicine 처리로 창성한 내동성계 4배체뽕)

  • 박광준
    • Journal of Sericultural and Entomological Science
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    • v.36 no.1
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    • pp.1-7
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    • 1994
  • Four tetraploid mulberry lines, Sawonppon No.11, No.13 and No.14, were induced by the colchicine treatment on the shoot tips of seedlings originated from the cross between Yongchonppong and Kaeryanppong. The major characteristics of the tetraploid lines were as follows: Green tip sprouting stage was similar to Kaeryanppong, a medium budding variety. Leaves were medium- to large-sized cordate type. Leaf surface was rougher and stronger than that of the diploid parents. Leaf thickness, leaf area weight and leaf water content were higher than those of the diploid parents. Average branch length was shorter than that of the diploid parents. Internode length and number of lateral branches were similar to the average values of the two parents. Death atop rate of branch was 1.6%~2.5% indicating strong cold-hardiness of the tetraploid lines. Therefore, these lines could be used as sources of cold-hardiness in developing triploid lines.

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The GRS80 Gravimetric Geoid from GEM9 Potential Coefficients and Terrestrial Gravity Anomalies in the South Korea Region (GEM9 위성자료와 지상자료의 조합에 의한 남한지역의 GRS80 중력지오이드)

  • Cho, Kyu Jon;Lee, Young Jin;Cho, Bong Whan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.1
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    • pp.141-149
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    • 1993
  • The gravimetric geoid of the South Korea Region was computed on Geodetic Reference System 1980(GRS80) using a combination of satellite-derived potential coefficients and terrestrial gravaty data. 10×10 mean gravity anomalies were obtained from surface gravity data for the outer zones, 1×1 equal area mean anomalies were used for the inner zones, and point gravity anomalies were used for the innermost zones in the Stokes integration. The GRS80 potential coefficients were obtained from modification of GEM9 data and Integration was extended over a spherical cap of 30 from the integration area. The results of a free-air geoid show that the systematic mean difference of approximately 2~3m in comparison of OSU89B model.

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3-Dimensional Positioning Using DGPS/DGLONASS (DGPS/DGLONASS에 의한 3차원 위치결정)

  • 강준묵;박정현;이은수
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.19 no.4
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    • pp.317-325
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    • 2001
  • Although GPS has proven to be efficient in the fields of navigation and surveying, it has many problems of positioning in downtown areas. Therefore, if GPS is combined with GLONASS which is similar to GPS in its positioning and signal system, it is expected that accuracy will be improved. However, we should address certain problems that exist related to the coordinate, time, and signal system between the two. The purpose of this study is to develop a GPS/GLONASS combination program by considering the properties of GPS and GLONASS and to solve the problems related to differences in the coordinates system and signal system. It is also to present the efficiency of the program in navigation and geographic information through analyzing 3D positioning accuracy by GPS/GLONASS combination with an application experiment. As a result of this study, the accuracy of the DGPS/DGLONASS positioning program corresponded to that of commercial program, and that's accuracy was better than that of DGPS. Especially, the acquisition of navigation and geographic information was possible by DGPS/DGLONASS combination in downtown area where the continuous 3D positioning is impossible by DGPS only.

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Digital 30sec Gridded Bathymetric Data of Korea Marginal Seas - KorBathy30s (한국 주변해역 30초 격자수심 - KorBathy30s)

  • Seo, Seung-Nam
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.20 no.1
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    • pp.110-120
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    • 2008
  • Gridded bathymetric data of 30 seconds apart in Korea marginal seas (30N44N,117E143E) are produced. In order to make the data, both updated gridded data of 1 minute apart on internet sites and all the digital nautical charts issued by National Oceanographic Research Institute (NORI) in Oct. 2007 are used. The reference level of the gridded data is approximate level of lowest low water and the horizontal coordinates are based on the WGS84 ellipsoid. Especially a developed computer program can collect all the sounding data including depth contour directly from the digital charts and UTM coordinates of the data are converted to the WGS84 coordinates from which accuracy of data is significantly improved. An interpolation method is adopted to produce the gridded data which are compared and analyzed against the existing gridded data. In this gridded data we can see significantly detailed topographic features which could not be found in the previous data.