Galileo's Availability in Urban Areas

With the first of the thirty Galileo satellite launched, it is still unclear to me on own much improvement in availability it will have over GPS. Apparently even with better behavior, Galileo will not solve all the problems in dense urban areas. In 2004, the European Union and the United States clinched a deal last year on making Galileo compatible with the GPS that should provide a full super-constellation to improve availability and accuracy in city centers.

Galileo Performance: GPS Interoperability and Discriminators for Urban and Indoor Environments concludes with:

Analysis of the potential for Galileo to serve mass-market users in high mask angle environments indicates that Galileo has a slightly better availability over Europe than GPS, but neither system alone provides reliable visibility of satellites.

and advocatates for GPS and Galileo interoperability:

System performance predictions suggest that an interoperable GPS/Galileo can offer significantly improved accuracy and availability over GPS alone, particularly in urban areas.