Abstract:

This paper discusses different frequency combination observations of Galileo/GPS systems. Firstly, the author analyses the research significance of combination observations in different GNSS. Secondly, the author analyses the present study status of combination observations in internal and external. Thirdly, the author points out the main problems presently. Fourthly, the author proved the feasibility of different frequency observations in different GNSS. Lastly, some valuable conclusions are drawn.

Key words: Galileo/GPS, combination observation, error analysis, ambiguity resolution