Local datum definition and geodetic network positioning using global navigation satellite systems

The problem of datum definition as applied to local-area geodetic networks is investigated using data collected from global navigation satellite systems (GNSS). It is shown that the process of double differencing makes the model more sensitive to computational errors that reduce the ability of the satellites alone to control the translation component of the datum definition, and as a result additional regularization is required. Traditionally, datum definition has been accomplished by constraining one station to set coordinates. Alternative regularization strategies are analysed in terms of their effects on positioning and ambiguity resolution. In doing so, processing strategies are developed which can improve the quality of global positioning system (GPS)-based position solutions in geodetic network applications of limited spatial extent, such as high-precision engineering and deformation monitoring networks.