A CANONICAL THEORY FOR SHORT GPS BASE-LINES .1. THE BASE-LINE PRECISION

The present contribution is the first of four parts. It considers the precision of the floated and the fixed baseline. A measure is introduc ed for the gain in baseline precision which is experienced when the ca rrier phase double-differenced ambiguities are treated as integers ins tead of as reals. The properties of this measure are analyzed, and it is shown by means of principal angles how it relates to the change ove r time of the relative receiver-satellite geometry. We also present ca nonical forms of the baseline variance matrices for different measurem ent scenarios. These canonical forms make the relation between the var ious variance matrices transparent and thus present a simple way of st udying their relative merits.