Products derived from GNSS data archived in the CDDIS are generated and submitted by the IGS analysis and associate analysis centers. IGS products support scientific research in:

• Realization of the International Terrestrial Reference Frame (ITRF)
• Monitoring deformation of the solid Earth
• Monitoring Earth rotation
• Monitoring variations in the hydrosphere (sea level, ice sheets, etc.)
• Scientific satellite orbit determination
• Monitoring the Earth’s ionosphere and troposphere
• Time and frequency transfer

IGS operational products include precise GNSS satellite ephemerides, positions and velocities of stations in the global GNSS network, EOPs (polar motion and rates, length-of-day), and station and satellite clock solutions. Other products derived from the CDDIS GNSS data holdings include troposphere Zenith Path Delay (ZPD) estimates (both dry and wet components) and global ionosphere maps, in support of IGS Working Groups or Pilot Projects.

Spatial coverage

• List of GNSS sites (Tracking Network)
• Map of GNSS sites

Temporal coverage

• GNSS orbit, station position, and EOP products since June 1992
• Troposphere Zenith Path Delay (ZPD) products since January 1997
• Ionosphere Total Electron Content (TEC) products since June 1998

Data volume

• Weekly and daily GNSS orbits, station position, and EOP files: ~1.8 Gbytes/week (compressed)
• Daily troposphere files: ~3.7 Mbytes/day (compressed)
• Daily ionosphere files: ~5.5 Mbytes/day (compressed)

Data formats

• GNSS precise orbits: SP3 and SP3c (typically) formats
• GNSS Earth rotation parameters: IGS-specified format
• GNSS station positions: Software INdependent EXchange (SINEX) format
• GNSS troposphere ZPD: IGS-specified format
• GNSS ionosphere TEC: Ionosphere Exchange (IONEX) format

Related resources

• Guide to using IGS products
• IGS data and product formats
• ITRF solutions
• Current IGS station coordinates
• IGS site logs
• IGS antenna correction file (igs20.atx)
• IGS antenna correction file (igs14.atx)