The Global Positioning System Geodesy Odyssey

ABSTRACT: Fundamental to GPS operation and application are the computational developments that have led to accurate user positioning. This paper reviews some of these developments from a historical perspective. The developmental odyssey begins with the events leading to initial GPS operation. Early developments in satellite geodesy, which led to the development of the GPS constellation, are briefly reviewed. A chronology of the incremental improvements in satellite orbit determination is presented. Contributions basic to GPS operation and accuracy, including coordinate frame definition and software development for user absolute and differential/kinematic positioning, are reviewed. Applications are also discussed, including surveying and mapping, geodynamics, and spaceborne geodesy, which have motivated the most stringent accuracy requirements for GPS. The paper ends with a discussion of expected future geodetic capabilities and then a summary of the impact of GPS geodesy contributions on the user community.