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VLBI Product Holdings

The CDDIS archive of VLBI products consists of solutions derived by IVS analysis centers from the analysis of VLBI experiment files. These products include the correlated delay and delay rate of simultaneous observations as a function of time, station positions and velocities, positions of quasars (input to the International Celestial Reference Frame, ICRF), EOPs (polar motion and rates, length of- day, UT1-UTC and long-term stability of nutation), and troposphere parameters. Derived product files are typically less than 1 Mbyte in size and are archived in subdirectories by product type.

The format and time span of the products varies by type. Product-specific formats are used: SINEX (Software Independent Exchange) for station positions and troposphere parameters, an IVS standard format for EOP, and an IERS standard format for CRF.

Data Summary

VLBI Product Holdings

Product Formats

  • SP3 and SP3c formats
  • Software INdependent EXchange (SINEX) format

The archive of IVS products is organized in subdirectories by product type (e.g., time series of station positions, EOP values, etc.).

The starting directory for IVS derived product files is: https://cddis.nasa.gov/archive/vlbi/ivsproducts/

The subdirectories under the main product directory are:

SubdirectoryProducts
crfsource positions used as input to the Celestial Reference Frame solutions in IVS CRF format
daily_sinexstation positions and velocities by analysis center, archived in files by experiment in SINEX format
eopiEarth orientation parameters from 1-hour (or intensive) experiments in IVS standard EOP format
eopsEarth orientation parameters from 24-hour experiments in IVS standard EOP format
int_sinexstation positions and velocities by analysis center, archived in files by intensive experiment in SINEX format
trfstation positions, velocities, and correlations used as input to the Terrestrial Reference Frame in SINEX format
tropzenith wet delay (signal propagation delays due to water vapor in the atmosphere) in SINEX format

More information about IVS products can be found on the IVS website.

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