VLBI Intensive Earth Orientation Parameter Series from NASA CDDIS

Very Long Baseline Interferometry (VLBI) Intensive Earth Orientation Parameter (EOPI) solutions are derived from 1-hour experiments measuring radio signals from distant quasars. The data series provides precise measurements of Earth rotation, length of day, polar motion, and station velocities. Products are contributed by analysis centers of the International VLBI Service for Geodesy and Astrometry (IVS) and support research in solid Earth science, tides, and fundamental astronomy.

Use Cases

• Monitoring Earth rotation and length of day based on Universal Time (UT1) intensive session data.
• Analyzing polar motion and crustal motion rates derived from baseline and station velocity calculations.
• Improving VLBI technique and fundamental astronomy models using precise quasar signal time-difference measurements.
• Studying solid Earth deformation and tides using derived Earth orientation parameter solutions.

Strengths

• Data is contributed by multiple analysis centers of the International VLBI Service for Geodesy and Astrometry (IVS), suggesting a multi-institutional validation process.
• Operational EOPI products are available at IVS Data Centers within 24 hours after Intensive data become available, indicating a rapid operational pipeline.
• The dataset's presence on multiple government platforms (Data.gov, NASA Earthdata) signals its importance and established use in the scientific community.

Limitations

• Key metadata such as row count, file size, and specific column names are not provided on any platform, limiting assessment of data scale and structure.
• The license is ambiguously listed as 'other-license-specified' without further details, creating uncertainty for reuse.
• The 'last updated' dates are all in the future (April 2026), which is a conflict in factual reporting across sources.

Provenance

Source

International VLBI Service for Geodesy and Astrometry (IVS) analysis centers, archived by NASA's Crustal Dynamics Data Information System (CDDIS).

Collection Method

Derived from Very Long Baseline Interferometry (VLBI) observations of radio signals from distant quasars received at Earth-based antenna stations.

Time Range

The VLBI EOPI series includes one product for each Universal Time (UT1) intensive session with a minimum of one year of data, but the specific temporal coverage is not stated.

Freshness

The most recent 'last updated' timestamp provided is 2026-04-09 21:09:32.835405, but this date is in the future and therefore not credible.

Geography

Global, based on the network of Earth-based antenna stations used in VLBI experiments.