UniCoor: A Smartphone Unified Coordinate System for ITS Applications

Using smartphones in intelligent transportation systems (ITS) is gaining an increasing interest among researchers and developers. Typically, the set of sensors that come with smartphones are utilized to develop tools and services in order to enhance safety and driving experience. GPS, cameras, Bluetooth and inertial sensors are used to detect and analyze drivers' behavior and vehicles' motion. Given that inertial sensors reading are in reference to the device local coordinate system, one of the main challenges in processing the inertial sensors in vehicles is to translate the sensors reading values to the vehicle movement context (i.e., vehicle coordinate system). In this work we develop and evaluate a framework to map the inertial sensors readings from the device coordinate to the vehicle coordinate. The proposed framework in this paper performs better than the existing methods and it enhances the accuracy of tracking and analyzing various vehicle dynamics such as vehicle's stops, lane changes and accurate vehicle speed calculation that, in turn, it will enable development of new ITS applications and services.