What are the advantages and disadvantages of the GALILEO system compare to GPS system?

One advantage will be finally, that Galileo will use a constellation, which is allowing better coverage of Earth, but requires more satellites.

Also, it will start with Hydrogen-Maser-clocks, while GPS is slowly phasing this technology into the system when satellites get replaced.

Next, Galileo will provide a better coverage of the polar regions, because all satellites operate at a higher inclination as GPS.

Disadvantages are simpler: It is not 100% compatible to GPS and it will take a while until it is ready. It will also cost money for more than the basic services, but these high quality service are harder to get for GPS.

And another disadvantage: It is not yet decided who will really operate Galileo. In the worst case, it is a European consortium of these companies who are already responsible for delaying the program.

Personaly, I think that the advantage of having the Galileo project active is that the future of the GPS won't only rest on the shoulder of the US Departement of Defense.

We, non-US citizens, often forget that we have, for years, enjoyed freely the GPS system that is paid for by the American tax-payers. It's about time that we share the maintenance of this beautiful tool.

The Galileo satellites are not different but complementary to the GPS. The Russians have also the Glonass system but it is not compatible.

The best east-west collaboration was probably the joint COSPAR-SARSAT satellite project which are the satellites receiving your distress signals if you have a ELT (aviation) or a EPIRB (maritime) beacon. Since I sail and fly ... I have both! :-)