inertial guidance

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Guidance of an aircraft or spacecraft in which gyroscopic and accelerometer data are used by a computer to maintain a predetermined course.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An automated system which directs a craft or missile, continually calculating its position from its measured acceleration.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a method of controlling the flight of a missile by devices that respond to inertial forces