An inertial measurement unit includes a base having a plurality of physically distinct sectors, upon which are positioned thereon three groups of orthogonally oriented angle rate sensors, each group positioned on a different sector of the base. Three high-G orthogonally oriented accelerometers are also positioned on the base, as well as three low-G orthogonally oriented accelerometers. A processor is positioned on the base having software resident thereon for receiving signals from the three groups of angle rate sensors and the three high-G and three low-G accelerometers. Software is also resident on the processor for calculating from the received signals one or more of the following: a change in attitude, a change in position, a change in angular rate, a change in velocity, and a change in acceleration of the unit over a plurality of finite time increments. Preferably, each gyro is subjected to oversampling, temperature and bias compensation, and bias offset compensation.