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Citation Instructions

If you use any of the products or data on this page in a publication or a public talk, please refer to the Citation Instructions .

Earth Orientation (EOP) Products

EOP is generated regularly, based on two session types. Intensives are small experiments generally run daily to produce rapid estimation of UT1. The 24 hour sessions are run twice a week and require a few weeks for full processing, but they provide a more thorough estimation of UT1, plus X- and Y-wobble estimation. Periodically, base solutions are produced from all available Intensive and 24 hour sessions with setups reflecting recent scientific updates, and base EOP output is generated. Then the output is updated incrementally as each new session of the appropriate type becomes available.

Latest Intensive EOP time series: Latest 24 hour EOP time series:

Periodic Solutions

The GSFC VLBI group periodically produces two types of TRF solutions, ITRF and NUVEL, using the ITRF and NUVEL1A-NNR (No-Net-Rotation) reference frames, respectively. The ITRF solutions are the primary solution type provided by this group. Using the latest data and appropriate changes in analysis, the group produces a solution approximately once every three months (leading to the name "quarterly solutions".) All solutions are posted on a master site, but only a subset are approved for official release to the IVS community. Once an ITRF solution is officially released, a solution version using the NUVEL1A-NNR frame is sometimes also generated and posted on the web.

Latest solutions: Master solution pages:

Interesting results from these solutions are:

SINEX, NGS Card and Data Base Files

Data files from geodetic VLBI sessions are available in three standard formats-- SINEX files, NGS card files and data base files. Selected IVS (International VLBI Service for Geodesy and Astrometry) Analysis Centers are responsible for providing IVS with forms of these files that are sufficiently processed to be suitable for scientific analysis. The GSFC VLBI Analysis center currently provides IVS with:
  • analyzed databases for all IVS-INT1 Intensive, R1, RDV, R&D and APSG sessions.
  • Sinex files for all IVS sessions.
In addition, until October, 2004, the GSFC VLBI group provided NGS card files for the above sessions.
IVS stores these files at three data centers. IVS also stores version 1 databases, containing basic correlator output, for institutions that prefer to perform their own analysis. All files can be accessed from any IVS data center through the IVS data page .

Other Links
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The GSFC VLBI group generates and/or maintains other file types, either solely or in cooperation with other groups.

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