SLR ILRS Final Orbit Product: Weekly Satellite Positions and Velocities

Satellite Laser Ranging provides unambiguous range measurements with millimeter precision, the only space geodetic technique to do so directly. Analysis Centers of the International Laser Ranging Service generate these weekly combined orbit files, considered the most consistent and highest quality solutions for satellites equipped with retroreflectors. The data supports the terrestrial reference frame, gravitational field modeling, and precise orbit determination for altimeter missions.

Use Cases

• Modeling the spatial and temporal variations of Earth's gravitational field based on precise satellite orbits.
• Monitoring millimeter-level variations in Earth's center of mass (solid Earth-atmosphere-oceans) using unambiguous range measurements.
• Providing precise orbit determination for spaceborne radar altimeter missions to calibrate sea-level measurements.
• Contributing to the International Terrestrial Reference Frame by analyzing time histories of station position and motion.
• Conducting special tests of the Theory of General Relativity based on sub-nanosecond global time transfer capabilities.

Strengths

• Provides the official ILRS final combined orbit products, considered the most consistent and highest quality solutions.
• Delivers unambiguous range measurements with millimeter precision, a unique capability among space geodetic techniques.
• Files are generated on a weekly basis with a typical delay of only 3 days, indicating regular updates.

Limitations

• Column names and specific data schema are not provided in any source description, limiting immediate usability.
• One platform (datagov) describes a mail exploder (SLRMail) for community announcements, which may indicate a separate or confusingly listed resource.
• Metadata completeness is low; size, row counts, and specific authors are listed as unknown or None.

Provenance

Source

NASA Crustal Dynamics Data Information System (CDDIS), generated by International Laser Ranging Service (ILRS) Analysis Centers.

Collection Method

Derived product set generated from aggregated Satellite Laser Ranging data retrieved by ILRS Analysis Centers on regular schedules.

Time Range

Weekly files spanning 7 days from 00:00 to 23:45 UTC, generated weekly.

Freshness

2026-04-09 22:40:08.951574

Geography

Global, based on measurements from the global SLR network.