VLBI Daily Intensive Earth Orientation Solutions in SINEX Format

Daily Intensive solution files provide Very Long Baseline Interferometry (VLBI) analysis products for Earth orientation monitoring. These SINEX format files contain datum-free normal equations and estimates for site positions, polar motion, UT1-TAI, and Length of Day (LOD), along with covariance matrices. The products are generated by the CDDIS and are updated daily, 24 hours after each new session data becomes available.

Use Cases

• Combining VLBI solutions with other space geodetic techniques using the datum-free normal equations.
• Estimating UT1 (Universal Time) for each 1-hour Intensive session by applying a selected datum.
• Analyzing covariance matrices for parameter estimates (site positions, polar motion, UT1-TAI, LOD) provided in the SINEX files.
• Studying high-frequency variations in Earth orientation parameters derived from daily VLBI sessions.

Strengths

• Provides datum-free normal equations specifically designed for combination within IVS and with other space techniques.
• Contains a covariance matrix for all parameter estimates, enabling error analysis.
• Updated with high frequency (daily) 24 hours after each new session data is available.

Limitations

• Specific parameter estimates (site positions, polar motion, LOD) are tightly constrained to a priori values, limiting independent analysis.
• Cross-source conflict: The last updated date differs between platforms (2026-03-12 vs 2023-12-05), creating uncertainty about the most recent version.

Provenance

Source

CDDIS (Crustal Dynamics Data Information System).

Collection Method

Analysis products derived from Very Long Baseline Interferometry (VLBI) Intensive sessions.

Time Range

Daily coverage from ongoing VLBI sessions.

Freshness

Most recent platform update reported as 2026-03-12.

Geography

Global coverage from VLBI station networks.