Abstract
Orthometric Heighting with GPS
Track: Geodesy
Authors: Thomas Meyer
Recent advances in gravity modeling and the Global Positioning System (GPS) have made it possible to determine Helmert orthometric heights at centimeter-level accuracy without spirit leveling. This workshop will explain the theory, the technology and the best practices based on NGS guidelines to educate the audience about how to use this powerful technology effectively. This workshop has two parts. The first contains an introduction to physical geodesy, explaining how gravity is the key concept in heighting, developing an understanding of the geoid, explaining why the mean sea surface is not the mean sea level, and discussing of all the major heighting systems in use in the U.S. and abroad. The second part of the workshop is pragmatic, giving a short overview of GPS, a discussion of the GPS error budget with particular emphasis on "do-es" and "don'ts" necessary for obtaining the desired accuracy from the GPS orthometric heighting, a presentation of NGS observation planning and occupation guidelines, and an actual example.