Global Positioning System Reference
In-Depth Information
(a)
(b)
Fig. 4. Navigation data bits at the output of the inphase Prompt correlator both for GPS (a)
and Galileo (b) signals
The stream of data bits must be decoded to recover the message broadcast by the satellite. The
navigation data follow the scheme defined in the GPS Interface Control Document (Arinc
Research Corporation, 1991) in case of GPS, while all the information regarding the navigation
message of the Galileo Open Service can be found in (European Commission, 2010).
Since the navigation format is out of scope of this chapter we will give just an introduction
to the argument by showing the general structure both of the GPS and Galileo message. In
Fig. 5 the overall navigation data in case of GPS L1 C/A code is depicted.
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