| It is fair to say that the Navigation Satellite Timing And Ranging (NAVSTAR) Global Positioning System (GPS) has revolutionized many, if not most, geodetic applications. Today, GPS has already joined VLBI and SLR to become a vital part of global geodynamics studies and almost all precise positioning applications of different magnitudes and purposes such as geodetic control, crustal motion monitoring, aerophotogrammetry without ground control, land surveying, and navigation are utilizing GPS in an unprecedented scale and speed as a powerful and reliable resource.;Among the many scientific uses of GPS, high-precision orbit determination of the GPS satellites is an important ingredient of GPS-based space geodesy. Accurate GPS baseline estimates with relative precisions of one to few parts in 10;It is the objective of this dissertation research to attack the two most important topics in today's GPS development, namely, high-precision orbit determination and precise kinematic positioning, with optimally developed measurement modeling techniques. This dissertation therefore is divided into two major parts. The first part is devoted to efficient orbit estimation--using the measurement triple differencing technique to achieve high-precision GPS orbit determination without going through the time consuming data editing procedure, and in the meantime, automate the entire computation process to eliminate any need of human interaction. The second part concentrates on precise kinematic positioning--using the forward and smoother filters that operate on single-differenced measurements and incorporating a newly developed spatial stochastic model of differential ionospheric effects. Analyses of results are presented. |
