VLBI-based Earth Orientation Parameters (EOP)

Observations from a number of different techniques can be used to determine Earth Orientation Parameters such as the Earth's polar motion and the length of day.  One such technique is Very Long Baseline Interferometry (VLBI).  The Earth Orientation Parameters (EOP) obtained through periodic VLBI observations also connect the Celestial Reference Frame (CRF) to the Terrestrial Reference Frame (TRF).  VLBI-based EOP products are updated daily as new VLBI data become available and can be used individually or combined with EOP results from other techniques (e.g. 
IERS Bulletin A

• Intensive Earth Orientation Parameter Series (EOP-I)

  The Intensive Series EOP product is a series of EOP results, one for each UT1 Intensive session. The series is up-to-date with the most recent data and includes a minimum of one year of data.
   

• Session Earth Orientation Parameter Series (EOP-S)

  The Session Series EOP product is a series of EOP results, one for each geodetic session. Data are irregularly spaced and there are multiple results for days on which there were simultaneous sessions. The series is up-to-date with the most recent data and includes a minimum of one year of results.

• Global VLBI Solutions

  The global VLBI solutions from which the above series are derived including explanations, comparisons and format information.