The National Geodetic Survey (NGS), an office of NOAA's National Ocean Service, manages a network of Continuously Operating Reference Stations (CORS) that provide Global Navigation Satellite System (GNSS) data consisting of carrier phase and code range measurements in support of three dimensional positioning, meteorology, space weather, and geophysical applications throughout the United States, its territories, and a few foreign countries. This is called the NOAA CORS Network (NCN) Surveyors, GIS users, engineers, scientists, and the public at large that collect GPS or GNSS data can use NOAA's CORS data to improve the precision of their positions. CORS enhanced post-processed coordinates approach a few centimeters relative to the National Spatial Reference System, both horizontally and vertically. The NCN network is a multi-purpose cooperative endeavor involving government, academic, and private organizations. The sites are independently owned and operated. Each agency shares their data with NGS, and NGS in turn analyzes and distributes the data free of charge. As of November 2021, the NCN provides data from more than 2,000 active sites. NCN data holdings to include decommissioned stations, comes to a total of 2,820 sites. These sites are contributed by over 230 different organizations, and the network continues to expand.

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In Gauss' words, the geoid is "the mathematical figure of the Earth". This figure is an equipotential surface coincident with the idealized mean sea surface. The geoid can be computed from the geodetic boundary value problems that use gravity data as its boundary value. A geoid model computed using gravity data is called a gravimetric geoid. On the other hand, geoid height at bench marks can also be computed using data from spirit leveling and the Global Positioning System (GPS). A geoid model that is fixed to the GPS/leveling data is called a hybrid geoid. Both geoid models can serve as the zero-height-surface of a country's height system by selection. To satisfy this need, National Geodetic Survey has published a series of geoid models (https://geodesy.noaa.gov/GEOID). The vast majority of navigation and positioning applications utilize a hybrid geoid model with the latest model being GEOID18 for CONUS and Puerto Rico/U.S. Virgin Islands and GEOID12B for all other states and territories of the United States. The corresponding gravimetric geoid for these regions is xGEOID19B and USGG2012, respectively. All models are provided at 1 arc-minute resolution.

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This dataset includes GDA94 and GDA2020 coordinates derived in different ways: - GDA94 coordinates from the Victorian Survey Control Network Adjustment - GDA2020 coordinates from the National Adjustment - GDA2020 coordinates derived by applying the conformal grid to the GDA94 coordinates - GDA2020 coordinates derived by applying the distortion + conformal grid to the GDA94 coordinates - GDA2020 coordinates derived by applying the 7 parameter transformation to the GDA94 coordinates