Before revision: Navigation systems may be entirely on board a vehicle or vessel (for example, on the ship's bridge) , or they may be located elsewhereand communicate via radio or other signals with a vehicle or vessel , or they may use .
After revision: Nthevigation systems may be entirely on board a vehicle or vessel (for example, on the ship's bridge) or located elsewhere, making use of radio or other signal transmission to control the vehicle or vessel that the system is controlling .