For the high performance motion control system using the MEMSinertial measurement unit (IMU) in the feedback loop, the error of the sensor alignment is often one of the key considerations. For gyroscope in IMU, sensor alignment error describes the angle difference between gyro's rotation axis and system defined "inertial reference frame" (also known as "global coordinate system"). In order to control the effect of alignment error on sensor accuracy, special encapsulation and special assembly process may be needed, and even complex inertia test is needed in final configuration. All these things can have a significant impact on the important indicators of project management, such as planning, investment, and the total cost related to IMU in each system. Therefore, at the early stage of design cycle, when there is time to define the system architecture to achieve the most effective solution, it is necessary to consider the alignment error of sensors.