A system of navigation that consists of a computer, a gyroscope for detecting rotational motion, and an accelerometer, i.e. a device for measuring acceleration. Thus from the knowledge of the initial position, velocity, direction of travel, and rotation of an object it is possible to determine all subsequent motion of the object being guided, including its position at any time. Inertial guidance has been used for rockets and other guided missiles, ships, aircraft, submarines, and spacecraft.