Stochastic Modelling for Network-Based GPS Positioning

Over the past few years the concept of network-based positioning has been developed in support of longer baseline processing compared with 'traditional' single reference station positioning. In fact network-based positioning enables the generation of so-called ‘virtual measurements’ which can significantly improve positioning results. Even though the virtual measurements are generated from the stochastic network estimates, their propagation into the user position solution has not been investigated in any detail. The aim is to understand how the unique stochastic properties of the network corrections propagate into the uncertainties of the estimated parameters. A better understanding of the stochastic properties of this virtual measurement will make the estimation result more realistic and hence ensure faster and more reliable ambiguity resolution.