Description
The demise of the cold war and the development of the internet have vastly expanded international collaboration and partnership in many scientific endeavors. The science of geodesy has benefit immensely from these efforts. Significant advancements in space and terrestrial measurement systems such as the Global Navigation Satellite Systems (GNSS), Very Land Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR) and Doppler Orbitography and Radio Positioning Integrated by Satellite (DORIS), have greatly improved our knowledge of earth orientation parameters including the knowledge of the location of Earth geocenter, Polar Wobble (Chandler Wobble) and tectonic plate velocities. National geodetic surveying and mapping agencies along with government and academic research institutes from across the globe now share vast amounts of positioning information with the International Earth Rotation and Reference System Service (IERS) headquartered in Paris, France. Periodically the IERS releases updated positional and velocity information for the network of stations providing this foundational information. From this network national organizations can ensure that their respective geodetic reference frames are kept up to date and consistent with the most current understanding of the motions of the planet. This class will review the efforts of the IERS and how NGS and the National Geospatial-Intelligence Agency (NGA) ensure the integrity of NAD 83 and WGS 84.
Learning Objectives
- Introduction to the IERS and the ITRF
- Integration of measurement systems and services into the ITRF
- Relationship of NAD 83, WGS 84 and ITRF
- Evolution of realizations of WGS 84
- Importance of metadata
