The geoid and receiver measurements tutorial
http://www.unavco.org/edu_outreach/tutorial/geoidcorr.html

UNAVCO


This web page explains how differences in the gravity at different places on Earth requires GPS receivers use additional corrections to find the true elevation of places on Earth's surface. The method uses the reference ellipsoid surface (a smooth average of sea level) and the reference geoid surface (the actual "bumpy" sea level surface).


Subject: Geoscience:Geology:Geophysics:Geodesy, Geography:Geospatial
Resource Type: Scientific Resources:Overview/Reference Work