Completion of the GPS constellation, improved receiver quality and a steady reduction of environmental errors have pushed GPS geodesy to levels few had foreseen even five years ago. While the discipline has attained a measure of maturity, progress continues on many fronts, including atmospheric and higher order ionospheric calibration, GPS orbit modeling, AS mitigation and network estimation techniques. At the millennium we will see cheaper receivers with still better performance (particularly under AS), a vast permanent global network supporting dozens of regional arrays, 10-cm GPS orbits, and daily solutions for absolute geocentric site positions accurate to better than 1 cm.
Acknowledgments. I thank all those who provided valuable inputs to and comments on this overview. This report was prepared at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.