Precise point positioning with multiple Galileo frequencies

Precise point positioning is analysed with new ionosphere-free mixed code-carrier combinations of satellite-satellite single difference (SD) measurements. The large wavelength of 3.215 m and the low noise level of 3.76 cm of an L1-E5 linear combination enable reliable fixing of ambiguities with a sequential bootstrapping and an integer decorrelation transformation. This linear combination suppresses the L1 code noise and multipath by 23.5 dB. The bias estimation accuracy is improved by an additional ionosphere-free L1-E5 linear combination of time-differenced measurements that is uncorrelated with respect to the first linear combination. The SD biases of the discrimination maximizing linear combination are determined at a single reference station with an accuracy between a few millimeters and 1 cm within 5 min. These biases refer to a geometry-preserving linear combination and are directly applicable at the mobile receiver. Moreover, the SD phase and code biases on L1 and E5 are determined separately by subdividing the Galileo E5 band into the E5a, E5b and E5c band whereas the latter one corresponds to the central lobe between E5a and E5b.