NASA’s Crustal Dynamics Data Information System (CDDIS) archive of laser ranging products consists of solutions derived by analysis centers in support of the International Laser Ranging Service (ILRS). Products derived from these Satellite Laser Ranging (SLR) observations include precise satellite ephemerides, station positions and velocities of sites in the ILRS network, and Earth orientation parameters (EOPs) including polar motion and rates and length-of-day. 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 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 CDDIS in subdirectories by year and date.
Reference Frames
- ITRF2020, DOI: https://doi.org/10.5067/SLR/slr_itrf20200_repro2020_001
Product Formats
- Software INdependent EXchange (SINEX) format
The starting directory for these files is: https://cddis.nasa.gov/archive/slr/products/pos+eop/.
Append the following directory and file names to the starting directory:
YYYY/YYMMDD/ACNAME.pos+eop.YYMMDD.v###.TYP.gz
as described in the table below.
| Code | Meaning |
|---|---|
| YYYY | 4-digit year |
| YY | 2-digit year |
| MM | 2-digit month |
| DD | 2-digit day |
| ACNAME | Analysis Center Name |
| ### | version of solution |
| TYP | type of solution (SNX or SUM) |
| gz | Compressed file |
Solutions Contributed to Reference Frames
SLR Products ITRF2020: Station Positions and Earth Orientation Parameters Time Series (REPRO2020)
doi: 10.5067/SLR/slr_itrf20200_repro2020_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, http://dx.doi.org/10.1016/j.asr.2010.01.018.
Noll, C. E., Ricklefs, R., Horvath, J. et al. Information resources supporting scientific research for the international laser ranging service, Journal of Geodesy, Volume 93, Issue 11, February 2020, Pages 2211–2225, https://doi.org/10.1007/s00190-018-1207-2.
Analysis Center Citation
The individual solutions that comprise the REPRO2020 products were computed by the following official International Laser Ranging Service (ILRS) Analysis Centers (listed in alphabetical order of their acronym identifier) using the Satellite Laser Ranging (SLR) data obtained from the LAGEOS, LAGEOS-2, Etalon-1, and Etalon-2 satellites. The combined solutions of the REPRO2020 products were generated by the official ILRS Combination Center hosted by ASI and e-GEOS at CGS, Matera, Italy.
- Italian Space Agency (ASI)
- German Federal Agency for Cartography and Geodesy (BKG)
- German Geodetic Research Institute (DGFI-TUM)
- European Space Agency (ESA)
- German Research Centre for Geosciences (GFZ)
- Joint Center for Earth Systems Technology (JCET), University of Maryland Baltimore County (UMBC)
- Natural Environment Research Council (NERC) Space Geodesy Facilities (NSGF)
Data Citation
SLR product Contribution to ITRF2020: Station Positions and Earth Orientation Parameters Time Series (REPRO2020) , Greenbelt, MD, USA: NASA Crustal Dynamics Data Information System (CDDIS), Accessed [[enter user data access date]] at doi:10.5067/SLR/slr_itrf20200_repro2020_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.
Summary
- Name: SLR product Contribution to ITRF2020: Station Positions and Earth Orientation Parameters Time Series (REPRO2020)
- Format: SINEX
- Spatial Coverage: 90.0N to -90.0S, 180.0E to -180.0W
- Temporal Coverage: 1983 - 2021
- Temporal Resolution: Weekly and bi-weekly
- File Size: 50 KB
- Platforms: LAGEOS-1, LAGEOS-2, Etalon-1, Etalon-2
Description*
"The ILRS contribution to ITRF2020 consists of a pair of time series of weekly and bi-weekly station position estimates along with daily and 3-day averaged Earth Orientation Parameters (X-pole, Y-pole and excess Length-Of-Day (LOD)) estimated over 7-day arcs (1993.0 – 2021.0) and 15-day arcs for the period 1983.0-1993.0, aligned to the calendar weeks (Sunday to Saturday), starting from January 1983. Each solution is obtained through the combination of loosely constrained weekly/biweekly solutions submitted by each of the seven official ILRS Analysis Centers. Both, the individual and combined solutions have followed strict standards agreed upon within the ILRS Analysis Standing Committee (ASC) to provide ITRS products of the highest possible quality." (The ILRS contribution to ITRF2020, E. C. Pavlis (GESTAR II/UMBC & NASA Goddard 61A) and V. Luceri (e-GEOS S.p.A., ASI/CGS)) NOTE: yymmdd in the filenames refers to the last day of the week.
* Reference
- The ILRS contribution to ITRF2020, Pavlis, E. C. (GESTAR II/UMBC & NASA Goddard 61A) and Luceri, V. (e-GEOS S.p.A., ASI/CGS)
https://itrf.ign.fr/docs/solutions/itrf2020/The_ILRS_contribution_to_ITRF2020_description_2022.09.23.pdf - The ILRS ASC Contribution to ITRF2020: A Sneak Preview, Pavlis, E. C., Luceri, V., Basoni, A., Sarrocco, D., Kuzmicz-Cieslak, M., Evans, K. D., Bianco, G.
https://ui.adsabs.harvard.edu/abs/2019AGUFM.G11A..05P/abstract
Data Access
The SLR products Contributed to ITRF2020 Station Positions and Earth Orientation Parameters Time Series (REPRO2020) are online: https://cddis.nasa.gov/archive/slr/products/REPRO_SERIES/REPRO2020/
in subdirectories day of year as follows:
yymmdd/ilrsa.pos+eop. yymmdd.v40x.snx.gz
| Code | Meaning |
|---|---|
| yy | 2-digit year |
| mm | 2-digit month |
| dd | 2-digit day |
| x | part of version number, 0-9 |
| .gz | Compressed file |
The combined ILRSA solutions that contributed to the ITRF2020 realization are in subdirectories based on the year, month, and day as follows:
ac/yymmdd/ac.pos+eop.yymmdd.v40x.snx.gz
| Code | Meaning |
|---|---|
| ac | Analysis Center Code |
| yy | 2-digit year |
| mm | 2-digit month |
| dd | 2-digit day |
| x | part of version number, 0-9 |
| .gz | Compressed file |
Documentation
http://cddis.nasa.gov/Data_and_Derived_Products/SLR/Reference_frame.html
SLRF2020
doi: 10.5067/SLR/slrf2020_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, http://dx.doi.org/10.1016/j.asr.2010.01.018.
Noll, C. E., Ricklefs, R., Horvath, J. et al. Information resources supporting scientific research for the international laser ranging service, Journal of Geodesy, Volume 93, Issue 11, February 2020, Pages 2211–2225, https://doi.org/10.1007/s00190-018-1207-2.
Analysis Center Citation
The individual SLR solutions that contributed to the ITRF2020 combination product were computed by the following official International Laser Ranging Service (ILRS) Analysis Centers (listed in alphabetical order of their acronym identifier) using the Satellite Laser Ranging (SLR) data obtained from the LAGEOS, LAGEOS-2, Etalon-1, and Etalon-2 satellites. The combined solution was generated by ITRS CC/Paris including the corresponding products from the other techniques, IVS, IGS and IDS, resulting in the ITRF2020 combination product which was the basis for the development of SLRF2020. SLRF2020 was generated by the official ILRS Combination Center hosted by JCET/GSFC at Univ. of Maryland, Baltimore County (UMBC).
- Italian Space Agency (ASI)
- German Federal Agency for Cartography and Geodesy (BKG)
- German Geodetic Research Institute (DGFI-TUM)
- European Space Agency (ESA)
- German Research Centre for Geosciences (GFZ)
- Joint Center for Earth Systems Technology (JCET), University of Maryland Baltimore County (UMBC)
- Natural Environment Research Council (NERC) Space Geodesy Facilities (NSGF)
Data Citation
SLRF2020 product, Greenbelt, MD, USA: NASA Crustal Dynamics Data Information System (CDDIS), Accessed [[enter user data access date]] at doi:10.5067/SLR/slrf2020_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.
Summary
- Name: SLRF2020
- Format: SINEX (hybrid)
- Spatial Coverage: 90.0N to -90.0S, 180.0E to -180.0W
- Temporal Coverage: May 1976 to July 2023
- Temporal Resolution: N/A
- File Size: 172 KB
- Platforms: N/A
Description
Expanded set of SLR station positions and velocities in the ITRF2020 frame, includes historical sites NOT part of ITRF2020 and some very recently installed sites that came online in 2022. A small number of sites require special treatment with the addition of corrections to their "mean" positions (in this file) from the ITRS-distributed PSD model, due to "events" (e.g. earthquakes) or changes at the site. Users must apply these corrections cumulatively, to the linearly propagated positions from this file, by themselves. For more details, s/w and relevant correction files please visit the official ITRS site on ITRF2020.
Reference
- The ILRS contribution to ITRF2020, Pavlis, E. C. (GESTAR II/UMBC & NASA Goddard 61A) and Luceri, V. (e-GEOS S.p.A., ASI/CGS)
https://itrf.ign.fr/docs/solutions/itrf2020/The_ILRS_contribution_to_ITRF2020_description_2022.09.23.pdf - The ILRS ASC Contribution to ITRF2020: A Sneak Preview, Pavlis, E. C., Luceri, V., Basoni, A., Sarrocco, D., Kuzmicz-Cieslak, M., Evans, K. D., Bianco, G.
https://ui.adsabs.harvard.edu/abs/2019AGUFM.G11A..05P/abstract
Data Access
The SLRF2020 product is online: https://cddis.nasa.gov/archive/slr/products/resource/SLRF2020_POS+VEL_2023.10.02.snx
Documentation
http://cddis.nasa.gov/Data_and_Derived_Products/SLR/Reference_frame.html