On 31 October 2020, anonymous ftp access will officially be discontinued at CDDIS. Beginning July 1, 2020, CDDIS will bandwidth limit ALL IPs using anonymous ftp to just 1MB/s transfer rates. CDDIS is STRONGLY recommending all users begin to transition to using alternate method of access to the CDDIS archive. Examples of alternate methods can be found at: https://cddis.nasa.gov/Data_and_Derived_Products/CDDIS_Archive_Access.html.

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Daily 30-second GNSS Observation Data


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, Daily 30-second observation data, Greenbelt, MD, USA:NASA Crustal Dynamics Data Information System (CDDIS), Accessed [[enter user data access date]] at doi:10.5067/GNSS/gnss_daily_o_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: Daily 30-second sampled GNSS observation data
  • Format: RINEX V2, 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: 2.5 Mbytes/site/day
  • Platforms: GPS, GLONASS


GNSS receivers collect the signals from orbiting satellites to determine their location in three dimensions and calculate precise time. GNSS receivers detect, decode, and process both pseudorange (code) and phase transmitted by the GNSS satellites. The satellites transmit the ranging codes on two or more radio-frequency carriers, allowing the locations of GNSS receivers to be determined with varying degrees of accuracy, depending on the receiver and post-processing of the data. The receivers also calculate current local time to high precision facilitating time synchronization applications.

This dataset consists of ground-based Global Navigation Satellite System (GNSS) Observation Data (30-second sampling, daily 24 hour files) from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS satellites 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. The daily GNSS broadcast ephemeris files contain one day of mixed GNSS navigation (30-second sampling) data in RINEX format from a global permanent network of ground-based receivers, one file per site.

Data Access

The daily 30-second GNSS observation data are online:

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

in subdirectories by year, day of year, and data type as follows:


RINEX V2 format
View format codes


RINEX V3 format
View format codes