How an Inertial Navigation System Operates
Many methods of navigation, including piloting, radio navigation and celestial navigation, rely on external objects or sources of information such as landmarks, celestial objects, satellites or transmitters. Inertial navigation is a self-referential method by which a system may track its own position, orientation and velocity (once given initial values for these parameters) without the need for such external references.
EMCORE FOG-based Inertial Navigation System
If the acceleration of an object is known, it is possible to use mathematical integration to calculate the velocity. Thus, accelerometers are required in an inertial navigation system, or INS.
Inertial navigation also requires that the direction in which the system’s accelerometers are pointing is known. This can be kept track of using gyroscopes, which measure the inertial navigation system’s rotational motion.
A typical inertial measurement unit, or IMU, thus usually incorporates three accelerometers, mounted orthogonally to each other, and three gyroscopes, also mounted orthogonally. More complex IMUs may contain more than three of each sensor. A navigation computer then processes the signals given out by the system’s sensors to continuously calculate the position, orientation and velocity of the system.