Robust and fuzzy techniques for parameter estimation and quality assessment in GPS

Since the first satellites of the Global Positioning System were launched in 1978, many novel and exciting applications of GPS have evolved. Frequently, applications to geodesy and engineering require positioning at the centimeter and even at the millimeter Ievel. Today, these accuracies are obtainable because many of the problems which originally limited the positioning and timing accuracy are now well understood und can be adequately solved. However, in engineering applications, obstacles in the vicinity of a GPS antenna may not be avoidable. The resulting signal distortions degrade the quality of the positioning results substantially if they are not properly taken into account. In this thesis, different approaches to the detection and compensation of signal distortion effects are developed with the goal of fully automatic operation. These approaches rely mainly on robust estimation, and on fuzzy set theory.