First results of mixed GPS+GIOVE single-frequency RTK in Australia

First results are presented for precise (mm/cm-level) short-baseline RTK positioning based on single-frequency GPS data combined with data of GIOVE-A/B, the two experimental Galileo satellites, collected in Australia. The paper first focuses on the model of GPS+Galileo observation equations and addresses the issues that arise when combining data of both systems, in particular the inter-system biases (ISBs). Our results indicate that the differential ISBs are quite stable in time, potentially enabling calibration and a priori correction of the Galileo phase and code observations. Based on ISB-corrected data, the reliability of single-frequency GPS+GIOVE ambiguity resolution is significantly improved, when compared to GPS only.