• 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
  • Received : 2018.08.07
  • Accepted : 2018.09.29
  • Published : 2018.10.31


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.


instrumentation: interferometers;telescopes;reference systems


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