No abstract

The accident of vehicles carrying hazardous materials occurring in downtown area has a possibility of secondary damage due to the hazardous material spill even after the primary damage of accident, and therefore incurs huge losses in economic and social aspects considering the extent and spread of damage. For minimizing the loss incurred by the accident of vehicles carrying hazardous materials, it is necessary to quickly detect and take action against the accident of vehicles carrying hazardous materials. A large vehicle carrying hazardous materials consists of tractor and trailer. To effectively and promptly detect the accident occurrence, the precise relative position, relative velocity, and attitude information between the tractor and trailer are required. In general, the GPS and INS are mainly used to obtain the position information and attitude

The conventional global positioning system (GPS) can often fail to provide position determination for a mobile user in indoor and urban environments. To cope with GPS failure in such environments, a new navigation system which utilizes a terrestrial digital multimedia broadcasting (T-DMB) signal to obtain the mobile user's position is presented. Since the T-DMB transmitters in Korea construct a single frequency network (SFN), which forces the transmitters to be synchronized, the mobile user can measure a time difference of arrival (TDOA) for all audible T-DMB transmitter pairs. The time difference between T-DMB transmitters is converted to a distance difference by multiplying the time difference by the speed of light. Using these measurements and a TDOA positioning method, the mobile user position can be estimated. An experiment with a T-DMB receiver and a data acquisition (DAQ) board is performed in Seoul to analyze the error characteristic of TDOA measurements. It is certified that the measurement error is bounded under 300 m and can be used to determine the mobile user's position with a small standard deviation.