This document discusses using MEMS gyroscopes and accelerometers for motion tracking in gaming applications. It describes how gyroscopes measure angular velocity and accelerometers measure acceleration. Integration of gyroscope data causes drift over time, while accelerometer and magnetometer data can be fused to estimate orientation. The document proposes a method using a modified Kalman filter to fuse the sensor data and estimate orientation without boundless drift. Simulation results show the method accurately tracks motion while overcoming noise and drift issues better than a standard Kalman filter.