The GGOS Core Sites co-locate the major observation techniques and a variety of additional sensors and instruments (e.g. meteorological sensors, water vapour radiometers, etc.). The co-location of the different techniques allows not only the integration of individual technique-specific networks into a unique terrestrial reference frame but also to the assessment of the observation quality and accuracy as well as the mutual validation of the results. The integration of the individual technique-specific networks is coordinated by the IERS.

active in progress

Co-located Instruments / Technologies:

Co-location at Ishioka Site (Japan) between VLBI and GNSS to determine the local-tie vector:

Space Domain (geodetic techniques):

  • GNSS – Global Navigation Satellite Systems
  • SLR – Satellite Laser Ranging
  • VLBI – Very Long Baseline Interferometry
  • DORIS – Doppler Orbitography and Radiopositioning Integrated by Satellite

Time Domain (highly-stable frequency standards):

  • Cesium standards
  • Hydrogen-maser

Earth Gravity:

  • Absolute Gravimeters (AG)
  • Superconducting Gravimeters (SG)