In early 2014, the ITRS Center of the International Earth Rotation and Reference Systems Service (IERS) will begin assembling the next realization of the International Terrestrial Reference Frame, ITRF2013. VLBI Analysis Centers are encouraged to submit their station and velocity analysis for this effort. This web page provides guidelines for Analysis Centers to use in their ITRF2013 submissions, as well as files to support the analysis.

ITRF2013 Participation Call, Instructions, and Checklist

• Call for Participation from Zuheir Altamimi
• Call for Participation from John Gipson
• Submission Instructions
• Submission Checklist (version v2014Feb07)

Files for Use in ITRF2013 Analysis

Axis offsets should not be estimated in the ITRF2013 solutions. Instead, the following a priori file should be used. The solution used to generate this file fixed the axis offset to the ground survey measurement for all sites for which a measurement was available.

• Axis Offsets

Other files for use in ITRF2013 include:

• A priori mean gradient file
• VLBI station eccentricities ("eccdat for IRF2013")
• Thermal deformation file

Sources

The handling of sources requires particular care, as there are several categories of sources.

• ICRF2 Defining Sources

  The ICRF2 defining sources are well-observed sources whose apparent position is stable. Analysts should fix the positions of these sources to their positions as given in ICRF2 at the following link.

  ICRF2 Defining Source Positions

• Special Handling sources

  The Special Handling sources are generally strong sources with unstable positions. Using a fixed position for these sources for all sessions will corrupt the estimates of other parameters such as EOP and station positions. Because of this, the position of these sources should be estimated on a session-by-session basis.

  Special Handling Source List

• Other Sources

  There are many other sources that have been observed in geodetic sessions. Analysts are free to either use the ICRF2 positions for these sources or else solve for their positions on a session-by-session basis. Please indicate how you treat these sources in the description of your solution.