Impact of the Combined GPS + Galileo Satellite Geometry on Positioning Precision

摘要

The improvement in positioning precision that can be expected from extending the GPS constellation with Galileo satellites will be treated in this paper. The influence of the pure geometric aspect, i.e. the effect of having more available satellites, will be assessed, while the effect of the availability of new signals will be ignored. From this point of view, two scenarios have been studied: (1) the case of stand-alone positioning, typically based on code observables, and (2) the case of relative positioning, typically based on double difference carrier phase observables. The results show that the use of the additional Galileo constellation improves absolute positioning with about 40% in terms of formal errors when simulating urban conditions. For relative positioning, the concept of Relative Dilution of Precision (RDOP) allowed to demonstrate that using GPS+Galileo only half the observation time is sufficient to get similar precisions as with GPS only.