• Title/Summary/Keyword: Geoidal height

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A study on the Bessel geoidal height to improve the accuracy of coordinate transformation (좌표변환의 정확도 향상을 위한 Bessel 지오이드고에 관한 연구)

  • Shin, Bong-Ho;Kang, Joon-Mook;Kim, Hong-Jin;Choi, Jong-Hyun
    • Journal of Korean Society for Geospatial Information Science
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    • v.2 no.2 s.4
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    • pp.143-151
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    • 1994
  • 3-D coordinates that result form GPS survey are not applied directly in korea because they are based on WGS 84 ellipsoid. Thus they must be transformed into longitude, latitude on the Bessel ellipsoid and orthometric height. Transformation parameters must be determined in order to perform the coordinate transformation. Also, coordinate transformation be preformed on longitude, latitude and ellipsoidal height. First estimation of Bessel geoidal height must be accomplished to acquire Bessel ellipsoidal height This paper suggests accuracy of coordinate transformation according to the estimation method of Bessel geoidal height. Also, This paper suggests that Bessel geoidal height have influence on the coordinates transformation.

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A Study on the Determination of WGS84 Geoidal Height by the Interpolation Methods (보간방법에 의한 WGS84 지오이드고 결정에 관한 연구)

  • 강준묵;김홍진
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.13 no.2
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    • pp.237-244
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    • 1995
  • In this study, we made WGS84 geoidal height model from GPS measurements for bench marks and calculated geoidal height of B.Ms which were selected check points using the hi-linear, trend surface fitting and triangulation interpolation method. From these, the interpolation accuracy was studied. Also, we tried to study accuracy of height transformation by making up orthometric height with latitude and longitude on Bessel ellipsoid for bench marks which were calculated by applying transformation parameters that were got GPS measurements for precise primary control stations. As a result of this study, the WGS84 geoidal height and orthometric height could be determined as a deviation value of 20 cm.

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Calculation of Geoidal Height refered to Bessel Ellipsoid From EGM96 Model (EGM96 모델을 이용한 Bessel 지오이드고의 계산)

  • 최경재;최윤수
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.17 no.1
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    • pp.33-39
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    • 1999
  • In order to calculate geoidal height refered to Bessel ellipsoid, methods to translate geoidal heights from a certain coordinate system to an arbitrary system with the corresponding ellipsoid are studied. and geoidal heights refered to Bessel ellipsoid were computed from EGM96 Model refered to GRS80 using iteration method pro-posed in this paper. Transformation parameters between WGS84 and Bessel were calculated using geoidal heights computed from iteration method. The result of coordinate transformation(standard deviation) were 0.009 second in latitude and 0.006 in longitude and 0.393m in orthometric height.

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The effects of the geoidal height determination in geodetic origin on coordinates transformation between ellipsoids (Geoid 기준설정이 타원체간 좌표변환에 미치는 영향)

  • 강준묵;박운용;이용창
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.12 no.1
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    • pp.69-76
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    • 1994
  • In this paper, the characteristics of coordinate transformation between the WGS84 and the Bessel ellipsoids according to the assumed values of the geoidal height on Bessel ellipsoid at the geodetic datum origin of Korea were investigated. For this, based on GPS data of 11 control points in Chungnam and Chungbuk province, the mean shift values between ellipsoids were calculated in each case. The geoidal heights on the Bessel ellipsoid were modelled in the area and the coordinate transformation coefficients were derived, and then the accuracy of the transformed coordinates according to fluctuations in geoidal heights were studied.

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Calculation of Geometric Geoidal Height by GPS Surveying on 1st and 2nd order Benchmark Line (1, 2등 수준노선에서 GPS 측량에 의한 기하학적 지오이드고의 계산)

  • Lee, Suk-Bae;Kim, Jin-Soo;Kim, Cheol-Young;Kwon, Jay-Hyoun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.27 no.2
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    • pp.213-223
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    • 2009
  • In geoid modelling field, it is very important the GPS/leveling data because it could be check-out the accuracy of gravimetric geoid and computed the hybrid geoid. In this study, GPS surveying was accomplished in the test area including mountainous area to improve the GPS/leveling data density in Korea. And the geometric geoidal heights was calculated using the GPS/leveling data in the test area and the accuracy of the geoidal heights was analyzed. For this study, GPS surveying was accomplished on the 211 1st and 2nd order benchmarks in Gyeongbuk province and 198 GPS/leveling data were achieved after both baseline analysis and network adjustment. Geometric geoidal heights were calculated using these 198 GPS/leveling data and the accuracy analysis was done by comparison with the geoidal heights from EGM2008 geopotential model. The results showed that the bias and standard deviation computed from 190 GPS/leveling data after gross removal was -0.185$\pm$0.079m. And also, the accuracy analyses according to the benchmark order, baseline length, and altitude were accomplished.

A study on the reduction of the distance on reference ellipsoid to the distance on geoid (타원체상 거리의 지오이드면상 거리로의 보정에 관한 연구)

  • 김형태;김용일;어양담;김창재
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.17 no.2
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    • pp.137-143
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    • 1999
  • The straight spatial distance or geodesic distance on WGS84 ellipsoid measured by GPS should be reduced on geoid to be used in Korean Geodetic System. The factors for this reduction are geoidal height and mean radius of the earth. On this study the effects of these factors on reducing distance were analyzed and the result showed that mean geoidal height should be multiplied by $1.6\times{10}^{-7}$ per unit distance for reducing geodesic distance on reference ellipsoid to that on geoid. Condsidering that the geoidal height on Bessel ellipsoid in Korea is -45 m in northeast and -75 m in middle west. It also showed that the difference of geodesic distance between on reference ellipsoid and on geoid is about 7-12 mm per km.

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Accuracy Analysis of GPS Ellipsoidal Height Determination in Accordance with the Surveying Conditions (관측조건에 따른 GPS 타원체고 결정의 정확도 분석)

  • Lee, Suk Bae;Auh, Su Chang
    • Journal of Korean Society for Geospatial Information Science
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    • v.23 no.4
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    • pp.67-74
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    • 2015
  • GNSS/Leveling technology makes it possible to get geoidal height geometrically using GNSS and Leveling technology. GNSS/Geoid technology refers to a technology for obtaining orthometric height by subtracting geoidal height achieved by Geoid technology from ellipsoidal height achieved by GNSS technology. The purpose of this study is to verify the accuracy of the ellipsoidal height determination in order to verify the accuracy of the orthometric height determination by the GNSS/Geoid technology. For the study, a test bed was selected in Kyungnam province and GNSS Static surveying was accomplished in the test bed and then the GNSS data was processed in accordance with various analysis conditions. So, it was verified the accuracy of the ellipsoidal heights determination in accordance with the surveying conditions under the GNSS Static surveying. According to the research results, to ensure the 3cm goal accuracy of the ellipsoidal height determination, it should be surveyed by four fixed points on the survey area periphery and more than two hours of the GNSS occupation time, And also, it was found that should be limited to a baseline distance of 20km under the GNSS Static surveying.

Determination of Marine Gravity anomaly Around the Korean Peninsula from GEOSAT Satellite Altimeter Measurements (GEOSAT 인공위성 해면고도 관측자료를 이용한 한반도 주변해역에서 의 중력이상의 결정)

  • 양철수;최광선
    • 한국해양학회지
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    • v.29 no.4
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    • pp.383-391
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    • 1994
  • Sea surface height geoidal undulation, and gravity anomaly derived from satellite altimeter measurements are described. Assuming mean sea surface height (MSSH) as geoidal undulation, MSSH was converted to gravity anomaly. the result shows that the gravity anomaly derived from satellite altimeter data can be mapped to an accuracy of the surface ship gravity measurements. The data used for the conversion is the two-year mean sea surface height obtained from GEOSAT Exact Repeat Mission. The conversion was carried out using fast Fourier transform with plane approximation. In this process, the so called remove-restore method was employed.

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Geoidal Heights Analyses in and around Korean Peninsula using EGM96 and OSU91A Geopotential Model (EGM96과 OSU91A 지오포텐셜 모델에 의한 한반도 일원에서의 지오이드 비교분석)

  • 이석배;최재화
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.15 no.1
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    • pp.131-139
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    • 1997
  • Geopotential models were used to determine the reference surface in geoid modelling and until now, OSU91A model has been most widely used in the world. But what so called EGM96, GSFC/DMA geopotential model published in the latter half of the 1996 by GSFC/DMA project. In this paper, we intended to compare the results of spherical harmonic analyses using the both geopotential model and the spherical harmonic analyses performed up to degree and order 300 and the gravimetric geoidal heights considering gravity data on each $3'\times{3'}$ grid point in and around Korean peninsula. The results showed that the average geoidal height of study area computed from EGM96 is larger 0.40 m than that computed from OSU91A and the gravimetric geoidal heights us-ing EGM96 is larger 0.35 m than that using OSU91A model.

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Gravimetric Geoid Determination by Fast Fourier Transform in and Around Korean Peninsula (FFT에 의한 한반도 일원에서의 중력지오이드 결정)

  • 이석배;윤홍식;최재화
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.14 no.1
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    • pp.49-58
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    • 1996
  • This paper deals with the gravimetric solution of geoid by Fast Fourier Transform(FFT) technique in and around Korean Peninsula. The used reference surface is OSU91A geopotential model up to degree and order 180 refered to GRS80. The remove and restore technique was applied to obtain the geoidal height in this paper. And the FFT with 20% window was applied to compute the medium wavelength effect from terrestrial gravity anomalies. For the comparison of computed results, the geometric geoidal height was derived from GPS/Levelling data. According to the comparison, the mean value and RMSE of the differences are 0.3819m and 0.4695m respectively.

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