Comment GPS (Score 2, Interesting) 457
1. In the UK NOTAMs ( Notice to airmen) are issued on a regular basis for GPS jamming trials. They take place over several weeks, and are, I believe, carried out by the army. I am not sure if their intention is to remove the possibility of soldiers on exercise using GPS rather than other means to navigate, or for some other reason.
I fly gliders and have a GPS unit on board which is used as a navigation aid. I also carry a chart (as required by air law) which serves as primary aid for navigation.
2. I would be pretty confident that all airliners currently in service have GPS capability
3. Radar is useful for seeing where everyone else is, GPS is for finding yourself. While transmitting location/vector information from an airbourne GPS to a ground station would enable collision avoidance, this feature is currently available through transponders. These are a requirement for any aircraft wanting to transit class A airspace.
