On+the+ground
131Ground-Based Midcourse Defense — (GMD) is a component of the national missile defense strategy of the United States administered by the U.S. Missile Defense Agency. Previously known as National Missile Defense (NMD), the name was changed in 2002 to differentiate it from other… …
132Ground proximity warning system — (GPWS) is a system designed to alert pilots if their aircraft is in immediate danger of flying into the ground or an obstacle. Another common name for such a system is ground collision warning system (GCWS). Commercial aircraft The system… …
