Principle of Geodetic VLBI

VLBI is a geometric technique which measures the time difference in the arrival of a radio wavefront emitted by a distant astronomical radio source (typically a quasar) between at least two Earth-based radio telescopes.

Knowing the time difference, and the angular separation between the viewpoint and the baseline between the antennas of the telescopes, the distance between the telescopes can be determined.



The Space Geodetic Observation Center make an effort to improve the accuracy of geodetic datum of Korea and manage data from VLBI observation. By participating in international joint observation including the IVS for a study of continental drift and a disaster prediction and prevention service, SGOC is able to make a valuable contribution to global geodesy. Moreover, the positioning and space geodetic technique can be developed.