Accuracy Evaluation Method of Inertial Measurement Unit Using Optical Motion Capture System

Abstract

This paper proposes a method for evaluating the attitude accuracy of an inertial measurement unit (IMU) using an optical motion capture system. The most valuable feature of this method is that it can evaluate the accuracy of the IMU in a free-fall condition. Two independent coordinate systems, i.e., the reference coordinate systems of the IMU and the motion capture system, are made to correspond using a rotation matrix that is obtained through a static pretest. Two types of accuracy evaluation methods are displayed. One is the difference of Euler angles in each component, and the other is the difference of measured three-dimensional attitudes, which is calculated using Rodrigues' rotation formula. The demonstration result indicates that the proposed method can evaluate the accuracy of the IMU in free-fall conditions effectively.