Inertial measurement unit and method for improving its measurement accuracy

摘要

An inertial measurement unit is provided which includes a core inertial measurement unit (13) having accelerometers (19, 21, 23) and gyroscopes (25, 27, 29) aligned along x, y and z axes to provide signals to an onboard computer (39) to determine position of the vehicle upon which they are mounted while in movement. A fourth accelerometer (35) is pivoted perpendicular to the direction of the gravitational field for measuring the gravitational field about the axis upon which it is mounted to provide a reference set of data to an onboard computer prior to movement of the vehicle upon which the system is mounted.