On 31 October 2020, anonymous ftp access will officially be discontinued at CDDIS. Beginning October 1, 2020, CDDIS will bandwidth limit ALL IPs using anonymous ftp to just 50KB/s and will limit simultaneous downloads to only 3 per IP address. 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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SLR product holdings

Products derived from SLR data archived in the CDDIS support scientific research in:

  • Terrestrial reference frame (center of mass and scale)
  • Improve understanding of the dynamics and modeling of GNSS orbits (one of our major users)
  • Calibration and validation of ocean and ice altimetry missions
  • Static and time-varying gravity field (low order/degree terms)
  • Plate tectonics and crustal deformation
  • Earth orientation and rotation (polar motion, length of day)
  • Total Earth mass distribution
  • Space science – satellite dynamics, etc.
  • Relativity and lunar science

The CDDIS archive of laser ranging products consists of solutions derived by analysis centers in support of the ILRS. The ILRS combination centers retrieve these solutions and produce the combined ILRS A and B solutions (generated by the primary and backup ILRS combination centers, respectively). Products derived from these SLR observations include precise satellite ephemerides, station positions and velocities of sites in the ILRS network, and EOPs (polar motion and rates, length-of-day). ILRS analysis and combination centers deliver the precise orbit and station position/EOP products to the ILRS data centers, including the CDDIS.

Spatial coverage

Temporal coverage

  • SLR station position, and EOP products since June 1976
  • SLR precise satellite orbit products since February 2016

Data formats

Related resources