A navigation system is a (usually electronic) system that aids in navigation. Navigation systems may be entirely on board a vehicle or vessel (on the ships bridge, or they may be located elsewhere and communicate via radio or other signals with a vehicle or vessel, or they may use a combination of these methods.
Navigation systems may be capable of:
containing maps, which may be displayed in human readable format via text or in a graphical format
determining a vehicle or vessel's location via sensors, maps, or information from external sources
providing suggested directions to a human in charge of a vehicle or vessel via text or speech
providing directions directly to an autonomous vehicle such as a robotic probe or guided missile
providing information on nearby vehicles or vessels, or other hazards or obstacles
providing information on traffic conditions and suggesting alternative directions