Testing the test satellites: the Galileo IOV measurement accuracy

The European GNSS, Galileo, is currently in its In-Orbit Validation (IOV) phase where four satellites are finally available for computing the user position. In this phase, the analysis of the measurements obtained from the IOV satellites can provide insight on the performance and potentialities of the Galileo system. In this paper, a methodology based on the use of precise orbits and ionospheric corrections is suggested for the analysis of the Galileo IOV pseudorange and pseudorange rate errors. Several hours of data were collected using a Septentrio PolarRxS receiver and used to determine figures of merits such as RMS and maximum errors of the Galileo observables. From the analysis it emerges that Galileo measurements have accuracies comparable with those of GPS. The benefits of combined GPS-Galileo positioning are also highlighted and results relative to the computation of a Galileo-only navigation solution based on broadcast ephemerides are provided.