Full-rate data

Full-rate data 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. The 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. The 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:

ftp://cddis.nasa.gov/slr/data/npt_crd/quarantine/
ftp://cddis.nasa.gov/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 contact the CDDIS manager if you have any questions or problems with the new CDDIS archive structure.

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

Files in current CRD format

The starting directory for these files in the is:

ftp://cddis.gsfc.nasa.gov/slr/data/fr_crd/

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

SATNAME/YYYY/SATNAME_YYYYMMDD.frd.Z (daily file)

SATNAME /YYYY/SATNAME_YYYYMM.frd.Z (monthly file)

as described in the table below.

Code Meaning
SATNAME satellite name
YYYY4-digit year
MM2-digit month
DD 2-digit day
.Z UNIX compressed file

Files in former format V2/ V3

ftp://cddis.gsfc.nasa.gov/slr/data/fr/

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

SATNAME/YYYY/SATNAME_V.YYMM.Z (daily file)

SATNAME/YYYY/SATNAME_YYYYMM.frd.Z (monthly file)

as described in the table below.

Code Meaning
SATNAME satellite name
YYYY4-digit year
YY2-digit year
MM2-digit month
V version of data (a, b, c, …)
.Z UNIX compressed file