Reliable positioning with the next generation global navigation satellite systems

Improved reliability is one of the key aspects to enable security-related applications. In this contribution it will be shown how a new carrier-phase ambiguity resolution approach improves the accuracy and reliability of the final position solution based on experimental results. Of course, the reliability will also be improved thanks to the future Galileo system and a third GPS frequency. A quantification of the improvements is given here by showing the impact of the frequency choice on the performance of ambiguity resolution in terms of success rates. For that purpose realistic models for locations at different latitudes are used. The variation of the success rate during one day are analyzed for all possible frequency combinations, including those of combined GPS-Galileo. It will be shown that improved performance as compared to the current GPS is to be expected from Galileo. As expected, the highest success rates will be obtained with combined GPS-Galileo. But what is interesting, is that using three frequencies from either one or two systems does not guarantee a significant improvement as compared to using only two.