Estimation of Galileo Uncalibrated Hardware Delays for Ambiguity-fixed Precise Point Positioning

Ambiguity fixing in Precise Point Positioning (PPP) has been extensively studied in recent years. The provision of uncalibrated hardware delays (UHDs) to the PPP algorithm, on top of precise orbits and clocks, allows the recovery of the integer values of the carrier-phase ambiguities. Experimental results show that integer ambiguity resolution increases the accuracy in the position domain. Most of the research so far has been done on GPS, where the wide- and narrow-lane approach for ambiguity resolution has proven successful. In the context of multi-GNSS PPP, the aim of this study is to extend the method to Galileo. Initial results for UHD estimation for Galileo satellites are presented. The contribution of ambiguity-fixing to GPS+Galileo PPP is assessed.