Plain English Meaning

The tools and signals a pilot uses to know where the aircraft is and how to get where it's going, especially when the ground can't be seen.

Full Definition

The collective set of equipment, signals, and procedures used by an aircraft to determine its position, track, and progress along an intended route. In instrument flying, navigation systems include ground-based aids (such as VOR, NDB, DME, and ILS), satellite-based systems (such as GPS), and onboard equipment (such as inertial reference units and flight management systems) that work together to guide the aircraft from departure to destination.