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VLBI level 1A correlator output

doi: 10.5067/VLBI/vlbi_l1a_swin_001

Data Center Citation

Noll, Carey E., The Crustal Dynamics Data Information System: A resource to support scientific analysis using space geodesy, Advances in Space Research, Volume 45, Issue 12, 15 June 2010, Pages 1421-1440, ISSN 0273-1177,

Data Citation

International VLBI Service for Geodesy and Astrometry (IVS) VLBI level 1A correlator output [online]. Available from the NASA Crustal Dynamics Data Information System DAAC, Greenbelt, MD, USA at:, Accessed [[enter user data access date]].

Other standard citation formats may be used for this data set and can be found at the DOI Citation Formatter website.

More information about CDDIS data citations and acknowledgments is available.


  • Name: VLBI level 1A correlator output available from the Crustal Dynamics Data Information System (CDDIS)
  • Format: SWIN
  • Spatial Coverage: 90.0 to -90.0, 180.0 to -180.0
  • Temporal Coverage: 2017-12-03 - present
  • Temporal Resolution: Variable, 1 to 24 hours
  • File Size: Variable, from 50Mb to 400 Gb
  • Platforms: VGOS or legacy S/X VLBI


VLBI Level 1A correlator output constitutes the primary VLBI dataset for a given experiment; all other data products are derived from analysis of the primary dataset. The correlator output is a collection of files that provide 1) time series of auto-correlations at all the observing stations that participated in the experiment and cross-correlations between all baselines of observing stations; 2) time series of amplitudes and phases of phase calibration signals; 3) correlator control files; 4) auxilliary files created by the correlator and used during correlation; 5) the metadata file. Spectral and temporal resolution is variable.

Data Access

The VLBI Level 1A correlator output data are online:

in subdirectories by year as follows:


Code Meaning
YYYY4-digit year
MM2-digit month
DD 2-digit day of month
exp lower case experiment ID
VVV correlator output version with leading zeroes
.bz2 bzip2 compressed file