Navigation is the process of determining a vehicle's position and directing its movement. Navigation is used chiefly to guide airplanes, ships, and spacecraft, but it also can be used for vehicles that travel on land. The word navigate comes from two Latin words meaning ship and to drive. Navigation involves many sciences, including astronomy, mathematics, and physics, and a variety of equipment.

Basic navigation aids include a chart and a compass. A chart shows the physical characteristics of an area and is used to plot a vehicle's course and position. An aeronautical chart provides such information as the location of airports, the height of mountains, and the location of radio transmitters that aid navigation. A nautical chart provides the depth of the water, the location of buoys and lighthouses, and other sailing information. A navigator uses either a magnetic compass or a more complex electronic instrument called a gyrocompass. Gyrocompasses are more precise than magnetic compasses.

Vehicles also have such basic navigation aids as an extremely accurate timepiece called a chronometer and a device to determine speed. The speed gauge of a plane is known as an air-speed indicator. The one on a ship is a log and on a land vehicle is a speedometer.

There are five primary methods of navigation: (1) dead reckoning, (2) piloting, (3) celestial navigation, (4) electronic navigation, and (5) inertial guidance. A navigator uses one or more of these methods, depending on such factors as the type of vehicle and the weather.