National Geodetic Survey (NGS) New CORS Coordinates and Absolute Antenna Calibration Pages

National Geodetic Survey (NGS) Releases New CORS Coordinates and Absolute Antenna Calibration Pages

NAD83(2011,MA11,PA11) epoch 2010.00 Coordinates

On September 6, 2011, NGS updated the National Spatial Reference System NAD 83 (CORS96, MARP00, PACP00) positions and velocities for all CORS sites, to NAD 83 (2011, MA11, PA11). The NAD 83 (2011) frame, which is relative to the fixed North American plate, is used to define the coordinates for sites located in the CONterminous United States (CONUS), Alaska and US territories in the Caribbean.

The NAD 83 (MA11) frame is realized with respect to the fixed Marianas plate and is used to define coordinates in the Marianas. The NAD 83 (PA11) is a Pacific plate fixed frame and is used to define coordinates in Hawaii, American Samoa, the Marshall Islands and other US territories residing on the Pacific Plate. For informative articles about NAD 83 see Snay and Soler, 2000, Snay, 2003.

The new realization of NAD 83 involves no datum change, which means that, the origin, scale and orientation of NAD 83(2011) are identical to those of NAD 83(CORS96), and the same for the two other frames. The coordinates are not the same in the old and new realizations for multiple factors including the switch to absolute antenna calibrations, new/revised processing algorithms, improved discontinuity identification, several years of additional GPS data, change in reference epoch, and an improved definition of the global reference frame, IGS08.

For a description of how NAD 83 is related to the global reference frame see Craymer et al., 1999, Snay and Soler, 1999. Users working in Canada should consult Craymer , 2006 for a review of how NAD 83 is implemented in Canada. Concisely, the two biggest changes are caused by the change in reference epoch and the move from relative to absolute antenna calibrations.

RELEASED NEW CORS COORDINATES and ABSOLUTE ANTENNA CALIBRATION PAGES

New CORS coordinates have been released today Tuesday, 6 September 2011. These coordinates are in:

• IGS08 epoch 2005.00
• NAD 83 (2011,MA11,PA11) epoch 2010.00
• These coordinates are from a stacked solution including data from 1 January 1994 to 16 April 2011.
• 60-day and long-term plots are available
• Absolute antenna calibrations have been released in both ANTINFO and ANTEX format older relative antenna calibration remain available in ANTINFO format
• OPUS-S and OPUS-RS support obtaining solutions in either new reference frames as listed above and in older reference frames ITRF00 epoch 1997.0 and NAD83 (CORS96, MARP00, PACP00) epoch 2002.00
• UFCORS only provides coordinates in the old frame, but will by next week also have the new coordinates as an additional file.

National Geodetic Survey (NGS) CORS Coordinates

A detailed description of the new coordinates with a comparison of results to previous reference frames, and an FAQ is available:

• http://geodesy.noaa.gov/CORS/coords.shtml

Professional Land Surveyor Source