Transforming Positions and Velocities between the International Terrestrial Reference Frame of 2000 and North American Datum of 1983

Abstract

In December 2001, Natural Resources Canada and the U.S. National Geodetic Survey ~NGS! jointly adopted values for a set of 14 parameters for transforming positional coordinates and velocities between the International Terrestrial Reference Frame of 2000 ~ITRF00! and the North American Datum of 1983 ~NAD 83!. Seven of these parameters characterize the variation with respect to time of the standard seven parameters ~three shifts, three rotations, and a differential scale !. In March 2002, the NGS updated the NAD 83 positional coordinates for all continuously operating reference stations to be consistent with their corresponding ITRF00 coordinates at an epoch date of 2002.00. Also, the NGS has incorporated these adopted values for the 14 transformation parameters into software packages, such as HTDP ~horizontal time dependent positioning! for transforming positional coordinates across time and between reference frames, and OPUS ~On-line Positioning User Service! for processing global positioning system data. Both HTDP and OPUS are available through the NGS Tool Kit ~http://www.ngs.noaa.gov/TOOLS/!.