Modernization of the North American reference frame

Abstract

The North American Datum of 1983 (NAD 83) witnessed over the past few decades major transformation in order to satisfy users need in terms of accuracy and reliability. Such transformation evolved in multi-phase modernization program that left users anxious about tools and procedures that they needed to implement in order to catch up with such changes. Today, users of NAD83 have to deal with different versions of the datum such as NAD83/86, NAD83/HARN, NAD83/CORS(96), and the latest adjustment of NAD83/NSRS2007. The subsequent versions added confusion and discrepancies in the product delivered over the years. The North American Vertical Datum of 1988 (NAVD88) went through similar evolution each time a new geoid model is published. The panel addresses users concerns and shed the light on the latest efforts lead by the National Geodetic Survey (NGS) to modernize the datums to coincide with the more reliable and globally maintained, the International Terrestrial Reference System (ITRS) realized by a set of reference points coordinates denoted by the International Terrestrial Reference Frame (ITRF).