Full-rate Satellite Laser Ranging (SLR) data holdings archived in NASA’s Crustal Dynamics Data Information System (CDDIS) include all valid satellite returns and are thus larger in volume; these data are not routinely provided by all stations in the laser tracking network. Full-rate data are useful for both engineering evaluation and scientific applications (e.g., studying the performance of retroreflectors, discerning satellite signatures, understanding the statistical nature of satellite returns, calibration of satellite targets, validating system quality of laser station co-locations, etc.). Although many of these studies are of an engineering nature, the results have an important impact on the quality of the scientific output. Full-rate data are transmitted in daily files containing all data received in the previous 24-hour period. CDDIS then updates monthly, satellite-specific files from these daily files.

As of 25-Apr-2017, the CDDIS has changed its directory structure for quarantined SLR data. CDDIS recently implemented changes to our incoming SLR data processing and archiving procedures. These changes required that we now archive quarantined SLR data (both normal points and full-rate) in subdirectories by station number, rather than subdirectories by site name; these directories are located at: https://cddis.nasa.gov/archive/slr/data/fr_crd/quarantine/

Older data will be transitioned to this new structure in the near future. EDC has used this directory convention for its quarantined data files. Please email Rivers Lamb, CDDIS manager, if you have any questions or problems with the new CDDIS archive structure.

Daily and monthly full-rate data are available from CDDIS in subdirectories by satellite and year.

Files in the Current CRD Format

The starting directory varies based on the Consolidated Laser Ranging Data (CRD) format version available. 

Append the following directory and file names to the starting directory as described in the tables below.

Files in the Former V2/V3 Format

Prior to 2012, the International Laser Ranging Service (ILRS) used the full-rate data format formerly known as the MERIT-II format, V2/V3. The starting directory is: https://cddis.nasa.gov/archive/slr/data/fr/.

Append the following directory and file names to the starting directory as described in the tables below.