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Satellite Laser Ranging (SLR) AC Station Position and ERP Product (daily files, generated daily) from NASA CDDIS

This derived product set consists of Satellite Laser Ranging Analysis Center (AC) Station Position plus ERP Product (daily files, generated daily) from the NASA Crustal Dynamics Data Information System (CDDIS). SLR provides unambiguous range measurements to mm precision that can be aggregated over the global network to provide very accurate satellite orbits, time histories of station position and motion, and many other geophysical parameters. SLR operates in the optical region and is the only space geodetic technique that measures unambiguous range directly. Analysis of SLR data contributes to the terrestrial reference frame, modeling of the spatial and temporal variations of the Earth's gravitational field, and monitoring of millimeter-level variations in the location of the center of mass of the total Earth system (solid Earth-atmosphere-oceans). In addition, SLR provides precise orbit determination for spaceborne radar altimeter missions. It provides a means for sub-nanosecond global time transfer, and a basis for special tests of the Theory of General Relativity. Analysis Centers (ACs) of the International Laser Ranging Service (ILRS) retrieve SLR data on regular schedules to produce precise station positions and velocities for stations in the ILRS network. The ACs also generate Earth Orientation Parameters from the SLR data. These individual AC solutions are used by the ILRS Analysis Center Coordinators (ACC) to generate the official ILRS final combined station position plus ERP products, as well as backup combination. The final products are considered the most consistent and highest quality ILRS solutions; they consist of daily station position/ERP files, generated on a daily basis with a typical delay of 2 days. All station position/ERP solution files utilize the Software Independent Exchange (SINEX) format and span 1 day from 00:00 to 23:45 UTC.

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