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IVS Combination Center

The IVS Combination Center (CCIVS) was established by the International VLBI Service for Geodesy and Astrometry (IVS) Directing Board in October 2008. It is a joint effort of the German Federal Agency for Cartography and Geodesy (BKG) and the German Geodetic Research Institute of the Technical University of Munich (DGFI-TUM).

The primary tasks of the Combination Center include combining the session-based intermediate results of the IVS Analysis Centers into a final combination product (e.g., Earth Orientation Paramters, EOP), which are then released as official IVS products. In addition to this, the IVS Combination Center contributes to the generation of the official IVS input to any ITRF efforts.

BKG Contributions to the CCIVS

• Ensure correct formatting of results, and their suitability for use in combination products, perform identification and reduction of outliers, compare results from various the Analysis Centers against each other and with respect to external time series, e.g. from IERS or IGS.
• Quality control results are made available at this IVS Combination Center Website.
• Combination products created using the DGFI DOGS software package, which operates by the combination of unconstrained (free) normal equations.
• Official IVS combination products will be distributed to their respective IERS components, as requested.
• Final results calculated at the BKG Data Center.

• Official IVS input to the ITRF created as combined weekly solutions in SINEX format.

Analysis Centers

Analysis Centers produce, in regular intervals:

• Series of Earth Orientation Parameters (EOP)
• Station coordinates
• Source positions

These individual series are combined by the IVS Combination Center at BKG, and made available as official IVS products.