SLR ILRS Combination Center Orbit Product: Weekly Satellite Orbits

NASA CDDIS provides weekly Satellite Laser Ranging (SLR) final orbit products from the International Laser Ranging Service (ILRS) Combination Center. The data consists of weekly files generated with a typical 3-day delay, containing precise satellite positions and velocities. SLR measurements provide millimeter-precision range data used for geophysical modeling and precise orbit determination.

Use Cases

• Contributing to the International Terrestrial Reference Frame (ITRF) based on precise station position and motion data.
• Modeling Earth's gravitational field variations based on unambiguous range measurements.
• Monitoring millimeter-level variations in Earth's center of mass based on SLR tracking data.
• Providing precise orbit determination for spaceborne radar altimeter missions as mentioned in the description.
• Conducting tests of General Relativity based on sub-nanosecond time transfer capabilities.

Strengths

• Provides unambiguous range measurements with millimeter precision.
• Data is generated weekly with a typical delay of only 3 days.
• Products are the official ILRS final combined solutions, considered the most consistent and highest quality.
• Orbit files utilize the extended standard product-3 (SP3) format, a recognized standard.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count and total dataset size are unknown, which may limit suitability assessment.

Provenance

Source

NASA Crustal Dynamics Data Information System (CDDIS), International Laser Ranging Service (ILRS) Combination Center.

Collection Method

Analysis Centers (ACs) produce precise orbits from SLR data; ILRS Analysis Center Coordinators generate combined products.

Freshness

Weekly generation with typical 3-day delay.

Geography

Global network of SLR stations.