Abstract
Accelerometers nowadays have been widely used in mobile devices. Many applications on mobile devices rely on accelerometers for information of the motions, tilt, and states of the devices to provide advanced and interesting functionalities. Most accelerometers are used in conjunction with the gravity, which provides an absolution reference for the accelerated variations of the accelerometers. Without gravitational information, applications need extra devices like magnetic sensors, gyroscopes, and GPS to measure the horizontal rotation. However, these additional devices are much bigger, more expensive, and more easily affected by environment, which are unsuitable for mobile devices. To overcome these constraints, in this thesis, we propose a simple and low-cost method to estimate horizontal rotations of mobile devices by using dual triaxial accelerometers separated by a known and fixed distance. With two triaxial accelerometers, acceleration signals were obtained to estimate the angular displacement by physical equations. Experiments were conducted to evaluate and compare the accuracy of our approach and that of a magnetic sensor.