Laser ranging normal points constitute the primary International Laser Ranging Service (ILRS) data product; they are generated following the conclusion of the laser pass and typically transmitted to NASA’s Crustal Dynamics Data Information System (CDDIS) within hours of the observation. SLR normal point data are transmitted in hourly and daily files where each file contains all data collected by the ILRS operations center in the previous hour or daily time period. Therefore, these daily files may contain data spanning several operating days. These daily and hourly files containing data from all satellites are available from the "allsat" subdirectory within the normal point archive area. Each day, CDDIS updates monthly satellite-specific files containing all normal point data received to date for the month. The monthly files contain all normal point data for each satellite during the month.

As of Apr 25, 2017, CDDIS has changed its directory structure for quarantined SLR data. CDDIS 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/npt_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 normal point data are available from the 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.