GPS is used for all these things. It's even used for automated landing systems: http://www.freeflightsystems.com/gps_landing.htm http://www.freeflightsystems.co

GPS is used for all these things. It's even used for automated landing systems: http://www.freeflightsystems.com/gps_landing.htm http://www.freeflightsystems.com/gps_landing.htm