Galileo is Europe's alternative to GPS which is US owned and built. It promises to be far more accurate. It was built and financed by the European Union. We are leaving the EU, so we won’t be part of the project anymore.
The European Space Agency, which we will remain part of after brexit, was the contractor tasked with launching the satellites. Their job is now completed, all the parts of Galileo are now in space.
So basically, by opting out of the EU, we have opted out of the benefits of this new system.
I assume the UK Government will have to pay to use it, and UK Telecoms will pay more to license its use than their EU rivals.
We have quit the club so we don’t get to use its facilities for free anymore.