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NGS Publishes Technical Report on New Geoid Monitoring Service (GeMS)

Friday, November 15, 2019

For more than 200 years, NGS has provided access to the National Spatial Reference System (NSRS), a consistent coordinate system that defines latitude, longitude, height, scale, gravity, and orientation throughout the United States. The datums that define this positioning framework are currently fixed with respect to time. However the Earth is not a static object, and we now have the scientific and observing capabilities to understand many physical changes and incorporate them into a time-dependent, dynamic NSRS that uses a gravity-based vertical reference system to measure heights. NGS has published a new technical report that describes the current state of knowledge and outlines the next steps required to define this time-dependent geopotential datum. Long-term NGS goals regarding time-dependent geopotential datum have been incorporated into a project called the "Geoid Monitoring Service," or GeMS. This report presents a roadmap of options for how NGS could realize a time-dependent geopotential datum.

For more information, contact: Kevin Algren