A proposed fault detection and exclusion method applied to multi-GNSS single-frequency PPP

In the last few years, Precise Point Positioning (PPP) has become widespread as a standalone positioning technique. Unlike classical GNSS point positioning, which uses the pseudorange observables from four or more visible satellites and the broadcast ephemeris to obtain the user instantaneous position, PPP takes the advantage of the more precise carrier phase measurements, attempting to account for all the GNSS errors and biases. PPP is able to provide accuracy level comparable to differential positioning. In particular, the single-frequency (SF) PPP technique is attracting great interest, since SF GNSS devices are widely used for most positioning and navigation applications. For this aim, the paper proposes a SF-PPP approach based on the use of code and single-frequency ionosphere-free linear observables combination, collected from GPS and Galileo systems. In addition, an integrity monitoring algorithm is modified to be applied to SF-PPP for the detection, isolation and the removal of faulty measurement sources. The proposed strategy is tested using real and simulated data gathered in static mode. Results demonstrate the effectiveness of the proposed integrity monitoring algorithm, applied to SF-PPP.