PRECISION, VOLUME AND EIGENSPECTRA FOR GPS AMBIGUITY ESTIMATION BASEDON THE TIME-AVERAGED SATELLITE GEOMETRY

In this contribution we consider the time-averaged GPS single-baseline model and study in a qualitative sense its relation with the geometry -free model and the geometry-based model. The least-squares estimators of the model are derived and their properties discussed. Special atte ntion is given to the ambiguity search spacer since it plays such a cr ucial role in the problem of integer ambiguity estimation and validati on. Easy-to-evaluate, closed-form expressions are presented for the vo lumes of the ambiguity search spaces that belong to the geometry-free model, the single-epoch geometry-based model and the time-averaged mod el. By means of an eigenvalue analysis, the geometry of the ambiguity search spaces is revealed and its impact on the search for the integer least-squares ambiguities discussed.