• Title/Summary/Keyword: Geodetic Network

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A Cost-Effective Land Surveying System for Engineering Applications

  • El-Ashmawy, Khalid L.A.
    • International Journal of Computer Science & Network Security
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    • v.22 no.11
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    • pp.373-380
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    • 2022
  • The field of land surveying is changing dramatically due to the way data is processed, analyzed and presented. Also, there is a growing demand for digital spatial information, coming primarily from the GIS (Geographical Information System) user community. Such a demand has created a strong development potential for a new land surveying software. An overview of the development and capabilities of a land surveying software platform based on the Windows system, SurveyingMap, is presented. Among its many features, SurveyingMap provides a lot of adaptability for networks adjustment, geodetic and plane coordinates transformation, contouring, sectioning, DTM (Digital Terrain Model) generation, and large scale mapping applications. The system output is compatible with well known computer aided drafting (CAD) /GIS packages to expand its scope of applications. SurveyingMap is also suitable for non-technical users due to the user-friendly graphic user interface. The system could be used in engineering, architecture, GIS, and academic teaching and research, among other fields. Two applications of SurveyingMap, extension of field control and large scale mapping, for the case study area are established. The results demonstrate that the system is adaptable and reasonably priced for use by college and university students.

Optimal National Coordinate System Transform Model using National Control Point Network Adjustment Results (국가지준점 망조정 성과를 활용한 최적 국가 좌표계 변환 모델 결정)

  • Song, Dong-Seob;Jang, Eun-Seok;Kim, Tae-Woo;Yun, Hong-Sic
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.25 no.6_2
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    • pp.613-623
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    • 2007
  • The main purpose of this study is to investigate the coordinate transformation based on two different systems between local geodetic datum(tokyo datum) and international geocentric datum(new Korea geodetic datum). For this purpose, three methods were used to determine seven parameters as follows: Bursa-Wolf model, Molodensky-Badekas model, and Veis model. Also, we adopted multiple regression equation method to convert from Tokyo datum to KTRF. We used 935 control points as a common points and applied gross error analysis for detecting the outlier among those control points. The coordinate transformation was carried out using similarity transformation applied the obtained seven parameters and the precision of transformed coordinate was evaluated about 9,917 third or forth order control points. From these results, it was found that Bursa-Wolf model and Molodensky-Badekas model are more suitable than other for the determination of transformation parameters in Korea. And, transforming accuracy using MRE is lower than other similarity transformation model.

Design and Development of High-Repetition-Rate Satellite Laser Ranging System

  • Choi, Eun-Jung;Bang, Seong-Cheol;Sung, Ki-Pyoung;Lim, Hyung-Chul;Jung, Chan-Gyu;Kim, In-Yeung;Choi, Jae-Seung
    • Journal of Astronomy and Space Sciences
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    • v.32 no.3
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    • pp.209-219
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    • 2015
  • The Accurate Ranging System for Geodetic Observation - Mobile (ARGO-M) was successfully developed as the first Korean mobile Satellite Laser Ranging (SLR) system in 2012, and has joined in the International Laser Ranging Service (ILRS) tracking network, DAEdeoK (DAEK) station. The DAEK SLR station was approved as a validated station in April 2014, through the ILRS station "data validation" process. The ARGO-M system is designed to enable 2 kHz laser ranging with millimeter-level precision for geodetic, remote sensing, navigation, and experimental satellites equipped with Laser Retro-reflector Arrays (LRAs). In this paper, we present the design and development of a next generation high-repetition-rate SLR system for ARGO-M. The laser ranging rate up to 10 kHz is becoming an important issue in the SLR community to improve ranging precision. To implement high-repetition-rate SLR system, the High-repetition-rate SLR operation system (HSLR-10) was designed and developed using ARGO-M Range Gate Generator (A-RGG), so as to enable laser ranging from 50 Hz to 10 kHz. HSLR-10 includes both hardware controlling software and data post-processing software. This paper shows the design and development of key technologies of high-repetition-rate SLR system. The developed system was tested successfully at DAEK station and then moved to Sejong station, a new Korean SLR station, on July 1, 2015. HSLR-10 will begin normal operations at Sejong station in the near future.

DETERMINATION OF THE INVARIANT POINT OF THE KOREAN VLBI NETWORK RADIO TELESCOPES: FIRST RESULTS AT THE ULSAN AND TAMNA OBSERVATORIES

  • Yoo, Sung-Moon;Jung, Taehyun;Lee, Sung-Mo;Yoon, Ha Su;Park, Han-Earl;Chung, Jong-Kyun;Roh, Kyoung-Min;Wi, Seog Oh;Cho, Jungho;Byun, Do-Young
    • Journal of The Korean Astronomical Society
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    • v.51 no.5
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    • pp.143-153
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    • 2018
  • We present the first results of the invariant point (IVP) coordinates of the KVN Ulsan and Tamna radio telescopes. To determine the IVP coordinates in the geocentric frame (ITRF2014), a coordinate transformation method from the local frame, in which it is possible to survey using the optical instrument, to the geocentric frame was adopted. The least-square circles are fitted in three dimensions using the Gauss-Newton method to determine the azimuth and elevation axes in the local frame. The IVP in the local frame is defined as the mean value of the intersection points of the azimuth axis and the orthogonal vector between the azimuth and elevation axes. The geocentric coordinates of the IVP are determined by obtaining the seven transformation parameters between the local frame and the east-north-up (ENU) geodetic frame. The axis-offset between the azimuth and elevation axes is also estimated. To validate the results, the variation of coordinates of the GNSS station installed at KVN Ulsan was compared to the movement of the IVP coordinates over 9 months, showing good agreement in both magnitude and direction. This result will provide an important basis for geodetic and astrometric applications.

Sea level slope of the Korean Peninsula Coast determined by Local Mean Sea Level (지역별 평균해수면에 의해 결정된 우리나라 해안의 해면경사)

  • KIM, Tae-Woo;YUN, Hong-Sik;KIM, Kwang-Bae
    • Journal of the Korean Association of Geographic Information Studies
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    • v.22 no.1
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    • pp.51-61
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    • 2019
  • Computing the sea level slope at the BM(Bench Mark) in the coast areas around the Korean Peninsula is important for establishing height of BM of the Korean geodetic leveling network. In this study, MSL(Mean Sea Level) was recalculated with the long-term tide observation data based on the IHO(International Hydrographic Organization) standard(18.6 years), and the BM height was reanalyzed by precision leveling. The sea surface topography was analyzed by leveling at Mokpo(Mokpo Starting Point), Busan (09-00-00) and Mukho(20-26-00) BMs, and the sea level slope was computed based on the Korean vertical origin point. As a result of this study, the sea level slope of the west and east coasts between Incheon(-2.27cm) and Mukho(17.56cm) located at $37.5^{\circ}N$ was analyzed as 19.83cm. Domestic geodesists and oceanologists have confronted each other with regard to the issue of latitudinal changes in long term MSL. In the west coast, the Mokpo is 1.12cm higher than Incheon, and the Busan is 2.18cm higher than Mukho. Therefore, the west and east coasts have been analyzed as sea level slope rising to the south. It can be used to solve the reestablishment of the Korean geodetic leveling network and the problem of the elevation discrepancy in the BM.

The Optimized Integration of Single-baseline GPS Solutions for Network-based Kinematic Positioning (네트워크 기반 키너매틱 위치결정을 위한 단일기선 GPS해의 최적 결합)

  • Choi, Yun-Soo;Bae, Tae-Suk;Lee, Jong-Ki;Kwon, Jay-Hyoun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.25 no.3
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    • pp.207-213
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    • 2007
  • For several years, although the demand of high accuracy kinematic positing using multiple bases has been increased, most of the commercial GPS processing softwares can provide the single-baseline solutions only. Thus, we studied the methods to improve the accuracy of the kinematic positioning using the network configuration based on the several single-baseline solutions. As discussed in this study, the positioning accuracy as well as the network stability is improved by introducing the geodetic network adjustment theories into the kinematic positioning application. Three different methods to remove the rank-deficiency, RLESS, BLIMPBE and SCLESS, are analyzed in this study. The 3D RMS error has been improved from 3.5cm(max) to 2.1cm using the network-based kinematic positioning, and it is desired to choose BLIMPBE and SCLESS depending on the accuracy of the base stations.

Improved National Datum Transformation Parameters of South Korea (국가좌표계 변환요소의 개선)

  • 이영진
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.16 no.1
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    • pp.95-101
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    • 1998
  • In this paper, the historical coordinates data of origin SUWON are reviewed and determination procedures are explained with the three dimensional geocentric coordinates of ITRF94 that is determined using VLBI observations. Also three translation parameters are calculated on the origin point. The national transformation parameters between the Korean geodetic system and Korean Terrestrial Reference Frame 1994(KTRF94) system, are determined using least square methods with weigted parameter constraints. The results of transformation show that one set of parameters are applicable to fixing of a position for GPS relative positioning processing and to adjusting of a network for three dimensional geocentric coordinates(KTRF94) computing.

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Geoid Models Referred to the Bessel Ellipsoid of South Korea (벳셀타원체 기준의 남한지역 지오이드 모델(KGM95))

  • 이영진
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.13 no.2
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    • pp.125-133
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    • 1995
  • The geoidal heights of a country may be computed from astrogedetic, gravimetric or satellite data. In this paper, the geoid models to the Bessel ellipsoid(KGM95-A) have been determined by the astrogedetic method, which is surface fitting techniques using deflections of the vertical and geoid height constraints. Transformation equations and the gravimetric geocentric geoid(KGM93-C) were applied to obtain the geoid height referred to the Tokyo Datum of the Korean geodetic network, the comparison of the astrogedetic results and discussions of the geoid information were added.

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Times Series Analysis of GPS Receiver Clock Errors to Improve the Absolute Positioning Accuracy

  • Bae, Tae-Suk;Kwon, Jay-Hyoun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.25 no.6_1
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    • pp.537-543
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    • 2007
  • Since the GPS absolute positioning with pseudorange measurements can significantly be affected by the observation error, the time series analysis of the GPS receiver clock errors was performed in this study. From the estimated receiver clock errors, the time series model is generated, and constrained back in the absolute positioning process. One of the CORS (Continuously Operating Reference Stations) network is used to analyze the behavior of the receiver clock. The dominant part of the model is the linear trend during 24 hours, and the seasonal component is also estimated. After constraining the modeled receiver clock errors, the estimated position error compared to the published coordinates is improved from ${\pm}11.4\;m\;to\;{\pm}9.5\;m$ in 3D RMS.

Investigation of Crustal Deformation due to the Kyungju Earthquake in 2016

  • Hong, Chang-Ki
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.34 no.6
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    • pp.591-596
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    • 2016
  • The $M_w=5.8$ Kyungju (South Korea) earthquake took place on 12 September 2016. This event may cause deformation around Kyungju city, located in the southeastern part of the Korean peninsula. In this study, GPS data was collected from the 17 Korean CORS and processed to determine the deformation. Minimum constraint solutions, to avoid the network distortion, are obtained and an S-transformation is applied to the coordinate difference vector and its covariance matrix for comparisons. In the final step, a statistical test is performed to determine the deformation due to the Kyungju earthquake. Based on the results, it was found that there is no significant deformation around Kyungju city. Hence, it can be said that the re-measurement or re-establishment of the geodetic control points in South Korea is not required.