In a direct contract with ESA (European Space Agency) AUDENS ACT supported the agency in the definition of the Galileo signal structure that is compatible with preliminary requirements as indicated in a Communication by the European Commission from February 3, 1999. Hereby, many different aspects were analysed.

For that purpose, the modernisation of the GPS signal structure has been summarised and the properties of the new proposed spreading codes have been verified.

Furthermore, the allocation of frequency bands for the different Galileo services was illuminated. The pro’s and con’s of the application of a spread ‘pilot’ signal have been discussed as well as the type of multiplex between the spread ‘pilot’ and the data signal.

Finally, a baseline signal and message structure has been derived and its performance was investigated with respect to code phase acquisition and tracking, carrier phase tracking and mean-time-to-loose-lock, and bit/word error rates.