Guidance, navigation, and control

Guidance, navigation and control (abbreviated GNC, GN&C, or G&C) is a branch of engineering dealing with the design of systems to control the movement of vehicles, especially, automobiles, ships, aircraft, and spacecraft.

However, because of the speed of, for example, a rocket's dynamics, human reaction time is too slow to control this movement.

Even in cases where humans can perform these functions, it is often the case that GNC systems provide benefits such as alleviating operator work load, smoothing turbulence, fuel savings, etc.

In addition, sophisticated applications of GNC enable automatic or remote control.

Guidance, navigation, and control systems consist of 3 essential parts: navigation which tracks current location, guidance which leverages navigation data and target information to direct flight control "where to go", and control which accepts guidance commands to affect change in aerodynamic and/or engine controls.