Attention GNSS Data Users: Please review the IGSMail messages related to the "Transition to ISO-3166 Alpha-3 codes in the IGS metadata." The changes go into effect on December 4, 2024. See https://lists.igs.org/pipermail/igsmail/2024/008454.html and https://lists.igs.org/pipermail/igsmail/2024/008518.html.

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Daily 30-second data

The CDDIS archive contains GNSS data from the global network of permanent GNSS receivers supporting the IGS operating at a 30-second sampling rate and containing 24 hours of data (00:00-23:59 UTC). IGS analysis centers retrieve these data daily to produce IGS products. These products, such as the daily and weekly satellite ephemerides, station positions and velocities, satellite and station clock information, and the Earth rotation parameters, are in turn, submitted to the CDDIS.

IGS regional data collection centers forward their data holdings of these daily, 30-second GNSS data in compressed RINEX format to the CDDIS on a daily basis. At the present time, an average of more than 500 sites are archived in this fashion each day for availability to the global science community. In general, a majority of the data delivered to and archived in the CDDIS are available to the user community within a few minutes (to a few hours) after the end of the observation day.

Daily GNSS data available in RINEX V2 format use the mmmmDDD#.YYt.gz filename convention and are in gzipped format as of December 1, 2020. Files received prior to this date use the mmmmDDDH.YYt.Z filename convention and are in a Unix compressed format. Starting with data from 2016, all daily GNSS data in RINEX V3 format that use the RINEX V3 filenaming convention and the gzip compression format are archived with data in RINEX V2 format, in subdirectories in the /gnss/data/daily area.

For RINEX V2 data, the CDDIS utilizes UNAVCO's TEQC (Translation, Editing and Quality Checking) software on incoming daily 30-second files for quality checking purposes. Metadata are extracted from the TEQC output and stored in the CDDIS database. Data quality information is also maintained in daily "status" files, with filename convention YYYDDD.status, that reflect the timeliness of the data delivered as well as statistics on number of data points, cycle slips, and multipath. Users can thus obtain a snapshot of data availability and quality by viewing the contents of these "status" files. Valid data are then archived on-line in daily subdirectories by year, day, and file type within the file system in the /gnss/data/daily area. Content metadata for the RINEX V3 data are also extracted and stored in the CDDIS database. Data quality information is maintained in daily V3 "status" files with the filename convention YYDDD.V3status.

Most daily data are uploaded to the CDDIS in the Hatanaka compressed RINEX format. For RINEX V2 data, the CDDIS uses the Hatanaka compression/decompression software to create RINEX files, and both are contained in the archive. In order to save space, RINEX V3 data files are archived in the Hatanaka compressed format, and the corresponding RINEX files are not created.

RINEX V2 and RINEX V3 files are archived in the same directories.

The starting directories for the files are:

Append the following directory and file names to the starting directory using the format codes in the links below:

YYYY/DDD/YYt/mmmmDDD#.YYt.gz


YYYY/DDD/YYt/XXXXMRCCC_K_YYYYDDDHHMM_01D_30S_tt.FFF.gz

Note: The "30S" sampling rate string is optional for navigation and meteorological files and may not be included in every file name of these types.