Realization of Horizontal Geodetic Coordinates 2000

Hiromichi TSUJI and Shigeru MATSUZAKA


This is a record of the realization of the new Japanese Geodetic Datum 2000 (JGD2000), giving specific descriptions of how the Geographical Survey Institute calculated the new Geodetic Coordinates 2000 of horizontal control points including VLBI and GPS permanent stations based on the philosophy and definition of JGD2000. Re-calculation of coordinates of over 100,000 horizontal control points is not an easy task. Its preparation goes back to the early 1990s. Due to the wide variety of survey data and constraints on time and resources, this calculation is not straightforward and is full of trials. For the ease of general readers, this review provides a streamlined calculation procedure of Geodetic Coordinates 2000 of horizontal control points, focusing on their traceability back to ITRF94.


1. Overview
2. Horizontal Geodetic Coordinates 2000 of Space Geodetic Network
  2.1 VLBI
    2.1.1 Brief History of GSIĀfs VLBI Activity
    2.1.2 Network and the Reference Point for JGD2000
    2.1.3 VLBI Data and Connection to GPS Network
    2.1.4 Discussion
  2.2 Continuous GPS Network (GEONET)
    2.2.1 History of Continuous Observation Network
    2.2.2 Network and Data
    2.2.3 Reference Point for GPS and Calculation
    2.2.4 Results and Evaluation
    2.2.5 Completion of the Fundamental Network
2.3 Datum Origin
    2.3.1 Datum Origin and Tokyo-Taisho
    2.3.2 Survey Data and Calculation
    2.3.3 Results
    2.3.4 Evaluation and Checking of the Results
3. Horizontal Geodetic Coordinates 2000 of 1st- to 3rd-order Triangulation Points
  3.1 History of Geodetic Surveys at Triangulation Points
  3.2 General Strategy
    3.2.1 Scenario of Network Adjustment
    3.2.2 Heights of Triangulation Points
  3.3 Yokyo97 Datum
    3.3.1 What is Tokyo97 Datum ?
    3.3.2 Transformation from ITRF94 to Tokyo97
    3.3.3 Justification for using Tokyo97 Datum
  3.4 Adjustment of 1st- to 3rd-order Triangulation Points
    3.4.1 Data and Procedure
    3.4.2 Reduction of Observed Distance to Ellipsoid
    3.4.3 Methods of Adjustments
    3.4.4 Results
 3.5 Transformation from Tokyo97 to JGD2000
4. Horizontal Geodetic Coordinates of 4th-order Triangulation Points by Transformation
  4.1 Local Transformation Parameters from Tokyo Datum to JGD2000
  4.2 Transformation using TKY2JGD
5. Conclusions