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. In many cases these functions can be performed by trained humans. However, because of the speed of, for example, a rocket's dynamics, human reaction time is too slow to control this movement. Therefore, systems—now almost exclusively digital electronic—are used for such control. 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.