Uses
IMUs are used in vehicle-installed inertial guidance systems. Today almost every commercial or military water-going vessel has one. Most aircraft are also equipped with IMUs.
IMUs are also used alone on air- and spacecraft, in order to report inertial measurements to a pilot (whether he is in the cockpit or piloting by remote control). They are critical during space missions to maneuver manned or unmanned landers and other craft.
IMUs can, besides navigational purposes, serve as orientation sensors in the human field of motion. They are frequently used for sports technology (technique training), and animation applications. They are a competing technology for use in motion capture technology. An IMU is at the heart of the balancing technology used in the Segway Personal Transporter.
When used in orientation sensors, IMUs are often (wrongly) used synonymously for Attitude and heading reference systems. However, an Attitude and heading reference system includes an IMU but additionally -and that is the key difference- a processing system which calculates the relative orientation in space.
Read more about this topic: Inertial Measurement Unit