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GNSS Final Weekly Combined Earth Rotation Parameters Product

doi: 10.5067/GNSS/gnss_igserpp_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, http://dx.doi.org/10.1016/j.asr.2010.01.018.

Data Citation

International GNSS Service, GNSS Final Combined Station Position Solution Earth Rotation Parameter (ERP) Product, Greenbelt, MD, USA:NASA Crustal Dynamics Data Information System (CDDIS), Accessed [[enter user data access date]] at doi: 10.5067/GNSS/gnss_igserpp_001.

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: GNSS Final Combined Station Position Solution Earth Rotation Parameter (ERP) Product available from the Crustal Dynamics Data Information System (CDDIS)
  • Format: IGS ERP format, UNIX compressed ASCII
  • Spatial Coverage: 90.0 to -90.0, 180.0 to -180.0
  • Temporal Coverage: 1992-01-01 to present
  • Temporal Resolution: Daily
  • File Size: 1 Kbyte/day
  • Platforms: GPS, GLONASS


The IGS reference frame products can be used to determine precise coordinates of the observing stations, gravity field parameters, and Earth orientation parameters. The IGS derived products are essential for Earth science research; multi-disciplinary positioning, navigation, and timing (PNT) applications; and education. The IGS final products are the basis for the IGS reference frame and are intended for those applications demanding high consistency and quality.

This derived product set consists of Global Navigation Satellite System Weekly Combined Station Position Earth Rotation Parameter (ERP) product (produced during the reference frame combination) from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. Analysis Centers (ACs) of the International GNSS Service (IGS) retrieve GNSS data on regular schedules to generate GNSS-based ERP products. The IGS Analysis Center Coordinator (ACC) uses these individual AC solutions to generate the official IGS final ERP product. The final products are considered the most consistent and highest quality IGS solutions; they consist of daily orbit, clock, and ERP files, generated on a weekly basis with a delay up to 13 (for the last day of the week) to 20 (for the first day of the week) days. All ERP solution files utilize the IGS ERP file format and span 24 hours from 00:00 to 23:45 UTC.

Data Access

GNSS Final Combined Station Position Solution Earth Rotation Parameter (ERP) Products (GPS and GPS+GLONASS solutions) are online:

Anonymous ftp service will be discontinued on October 31, 2020.

Append the following directory and file names to the starting directory:


as described in the table below.

Code Meaning
yy2-digit year
dday of week (0-6, 7 indicates weekly)
.Z UNIX compressed file