Inertial reference systems use gyroscopes, accelerometers and electronics to provide precise attitude, velocity and navigation information so an aircraft can determine how its moving through the airspace.  More specifically, these systems provide data on linear and angular acceleration, linear and angular velocity, position, attitude (roll, pitch), platform azimuth, magnetic and true heading, altitude, body angular rates and more.

The inertial reference system is a key component to an aircraft’s inertial navigation system which is usually combined with a GPS receiver and sensor fusion software to show pilots and flight crew where the plane is at any given moment even when GPS signals are not available.