Global Navigation Satellite System (GNSS) IGS Final Weekly Combined Earth Rotation Parameters (ERP) Product from NASA CDDIS

This derived product set consists of Global Navigation Satellite System Weekly Combined Station Position Earth Rotation Parameter (ERP) product (produced during the reference frame combination) from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. Analysis Centers (ACs) of the International GNSS Service (IGS) retrieve GNSS data on regular schedules to generate GNSS-based ERP products. The IGS Analysis Center Coordinator (ACC) uses these individual AC solutions to generate the official IGS final ERP product. The final products are considered the most consistent and highest quality IGS solutions; they consist of daily orbit, clock, and ERP files, generated on a weekly basis with a delay up to 13 (for the last day of the week) to 20 (for the first day of the week) days. All ERP solution files utilize the IGS ERP file format and span 24 hours from 00:00 to 23:45 UTC.