NAD-83: The base station coordinates are provided in the NAD-83 datum, which is the recommended datum for Atqasuk GPS users who are not sure what datum to report their data in. Use of NAD-83 allows for the direct application of the Geoid-99 geoid model to determine elevations relative to sea level. NAD-83, which holds the North American tectonic plate fixed, coincides with the original version of WGS-84.
Base coordinates in NAD-83:
70° 28' 19.3285" N
157° 24' 28.2019" W
27.498m HAE
WGS-84: There are several versions of WGS-84, as it is periodically re-defined due to global tectonic plate motion. As a result, just specifying WGS-84 without also specifying the version, is un-precise as the various versions differ by several centimeters.
ITRF: For precise geodesy, the ITRF reference frame is used. Unlike NAD-83, WGS-84, and other datums, ITRF also incorporates tectonic plate velocities. Therefore, when referring to ITRF coordinates, one must also provide the date that the coordinates refer to. The Atqasuk base station coordinates were initally processed in the ITRF-00 reference frame based on data collected on June 14 2006. These coordinates were then transformed to the NAD-83 datum for general use. The following ITRF coordinates are provided for users who prefer to work with ITRF coordinates, or who want to transform the coordinates to another reference frame.
Base coordinates in ITRF-00, June 14, 2006:
70° 28' 19.3199" N
157° 24' 28.3269" W
28.077m HAE
See the on-line NGS calculator for reference frame transformations.
Last modified: 2019-12-24 02:12:47 America/Denver