On Maximum Tolerable Multipath for Successful Meta-signal Subcarrier Ambiguity Fixing

The prospect of GNSS meta-signal tracking promises the synergy of both code reliability and the high-precision of sub-carrier observations. The latter has the advantage, in comparison to carrier-phase observations, of having wavelengths in the order of a few meters instead of cm-level. This realizes the possibility of resolving sub-carrier phase ambiguities without the need of a reference station providing positioning solutions with a sub-meter level accuracy. In the frame of the HANDS-CD project led by IGASPIN GmbH, a synthetic meta-signal observation formed from Galileo E5a and E5b signals using the widelaning concept will be demonstrated in this contribution. This analysis is performed based on a simulated kinematic trajectory. The synthetic meta-signal observations are fed into an Extended Kalman Filter-based positioning engine (M-SiPE-tool), which applies the LAMBDA ambiguity fixing method to resolve the sub-carrier ambiguities. To assess the robustness of the positioning filter against signal impairments, the observations of many Galileo satellites are synthetically contaminated by multipath reflection with different amplitudes. The outcome of the positioning engine exhibits successful sub-carrier ambiguity fixing and provides a sub-decimeter positioning accuracy for a code multipath amplitude of less than 30 meters, or for sub-carrier multipath amplitude of less than 0.5 meters.