Orientation tracking of a moving object has a wide variety of applications, including but not limited to military, surgical aid, navigation systems, mobile robots, gaming, virtual reality, and gesture recognition. In this article, a novel algorithm is presented to automatically track and quantify change of direction (COD) incident angles or heading angles (i.e. turning angles) of a moving athlete using the inertial sensor signals from a microtechnology unit (an inertia measurement unit (IMU))