A Study of Hybrid Modernized GPS and Galileo Positioning in Japan

The modernization of the GPS and the advent of the European Galileo will enhance the capability of quickly and correctly resolving the integer cycle carrier phase ambiguities in precise differential positioning. In this paper the performances of hybrid modernized GPS and Galileo positioning are analyzed for different scenarios by using the LAMBDA method in Japan. The scenarios include modernized GPS system, future Galileo system and combined GPS and Galileo system over different baselines. The results show that extending a present dual frequency GPS system to hybrid modernized GPS and Galileo system in future will significantly improve the capability of Real-Time Kinematic (RTK) positioning. On the short baseline very high ambiguity success rate can be easily obtained, even with a single epoch of data. On the medium baseline the ambiguity success rate could increase by the increased number of satellites and the improved satellite geometry. On the long baseline, for which differential atmospheric delays have to be dealt with, reliable instantaneous ambiguity resolution is feasible only if a stringent condition is met on either the code measurement accuracy or on the accuracy of atmospheric correction information.