One part says
The Royal Navy said GPS services would be unavailable for limited periods during training in parts of Scotland's west coast.
So presumably with the cooperation of the USA they're switching something off so they can test how their equipment performs without GPS.
But how do they narrow the outage to such a specific area? As I understand it, each GPS satellite is broadcasting to a pretty wide area (33 satellites covering the planet according to Wikipedia). To switch off those covering the west coast of Scotland would surely wipe out coverage to a huge area?
Scott.