SLR Analysis Center (AC) Position and ERP Product (weekly files, generated daily)

doi: 10.5067/SLR/SLR_ILRSACSNX_001

Data Center Citation

Noll, Carey E., The Crustal Dynamics Data Information System: A resource to support scientific analysis using space geodesy, Advances in Space Research, Volume 45, Issue 12, 15 June 2010, Pages 1421-1440, ISSN 0273-1177,

Data Citation

International Laser Ranging Service (ILRS), SLR Analysis Center (AC) Station Position and ERP Product, Greenbelt, MD, USA:NASA Crustal Dynamics Data Information System (CDDIS), Accessed [[enter user data access date]] at doi: 10.5067/SLR/SLR_ILRSACSNX_001.

Other standard citation formats may be used for this data set and can be found at the DOI Citation Formatter website.

More information about CDDIS data citations and acknowledgments is available.


  • Name: SLR Analysis Center (AC) Position and ERP Product
  • Format: SINEX format
  • Spatial Coverage: 90.0 to -90.0, 180.0 to -180.0
  • Temporal Coverage: 1976-01-01 to present
  • Temporal Resolution: daily
  • File Size: 30kb
  • Platforms: etalon1, etalon2, lageos1, lageos2


The CDDIS archive of laser ranging products consists of solutions derived by ILRS analysis centers in support of the ILRS. These products include station positions and velocities of sites in the ILRS network, and EOPs (polar motion and rates, length-of-day) that support the creation of the SLR and International Terrestrial Reference Frames. ILRS analysis centers deliver the station position/EOP product to the ILRS data centers, including the CDDIS. 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) which are in turn archived in the CDDIS. Prior to 2012, ILRS analysis centers generated the products on a weekly basis; today, these products are generated daily. Station positions and EOP date from 1976 through the present. SLR products are available from the CDDIS in subdirectories by year and date.

Data Access

SLR Analysis Center (AC) Position and ERP Product is online:

in subdirectories by year, month, and day as follows:


Code Meaning
YY 2-digit year
MM 2-digit month
DD 2-digit day
Bundesamt für Kartographie und Geodäesie (BKG) Germany
Deutsches Geodätisches Forschungsinstitut (DGFI) Germany
ESA/ESOC, Germany
Helmholtz Centre Potsdam German Research Centre for Geosciences (GFZ), Germany
ILRS primary combination solution
ILRS backup combination solution
Italian Space Agency, Centro di Geodesia Spaziale "G. Colombo" (ASI/CGS), Italy
Joint Center for Earth System Technology/Goddard Space Flight Center (JCET/GSFC) Greenbelt, Maryland, USA
NERC Space Geodesy Facility (NSGF) formely RGO Satellite Laser Ranging Group, United Kingdom
XXX numeric version number
gz gzipped file