Research On Active Safety Warning Mechanism Based On BDS

With the development of vehicle transportation industry, the demand for themonitoring and intelligent management of vehicles becomes increasingly urgent.Meanwhile, traffic safety has been a critical problem that threatens people’s lives andproperties. The traditional passive safety equipment, such as safety belts and air bags,cannot meet people’s demands, and the active safety rises in response to the propertime and conditions. However, the price of active safety equipment in the car before itappears on the market is very expensive. And currently, the function of vehicleterminals in the market is quite simple. Active safety techniques have not been usedwidely. If vehicle terminals combine with the active safety techniques, it will providea new type of terminal with high performance and low cost, which can meet thepublic demands. This paper aims to design an active-safety early-warning system usedin vehicle positioning terminals. The BDS/GPS dual mode positioning terminals arealso employed to provide high positioning accuracy.The vehicle terminals should have these functions, such as positioning,navigation and real-time monitoring, to realize vehicles management. It contains thefollowing modules: positioning module, communication module, MCU, and on-lineservice platform. The positioning module is responsible for receiving, resolving,dispatching, and storing of the positioning data. The communication module isresponsible for GPRS transmission to realize the data interaction between vehicleterminals and on-line service platform. MCU includes CPU, Flash, clock circuit, etc.It controls peripheral functional modules via different interfaces, acting as the centralcontrol unit of the vehicle terminals. On-line service platform is responsible fordisplaying and monitoring the real-time position of vehicles.The active-safety early-warning mechanism this paper raises mainly refers toforward-anti-collision function, drivers’ behavior monitoring function and vehiclespotential malfunction detection function. To implement these early-warning functions,microwave ranging radar, Hall speed sensor, CCD camera and CAN bus data acquisition module are needed to install on the vehicle terminals. Picture processing,calculation of early-warning safety distance, and processing of CAN bus faultinformation functions should be added to MCU module. CAN protocol specificationsof different automobile manufacturers and vehicles fault codes database should beadded to on-line service platform.According to the actual vehicle braking process, the braking distances of vehicleterminal owner’s car and front car can be obtained, and the active-safety distancemodel can be established. With the distance and relative speed from the front cargetting from the microwave ranging radar, and speed information of vehicle terminalowner’s car getting from Hall speed sensor, the early-warning safety distanced wcanbe calculated by MCU module. When the distance from the front car is less than,an audible warning will be triggered automatically to alert the driver to slow down.And the forward-anti-collision function is implemented.To implement the drivers’ behavior monitoring function, a CCD camera isneeded to install in the cab to collect drivers’ real-time facial images. After the imagedenoising, light compensation, grayscale conversion, and binarization processing,employ the spatial matching filter algorithm to implement the template matching offacial feature organs. Then match the eye with opening-template and closed-templateand process the PERCLOS fatigue detection. When PERCLOS is over15%and lastsmore than3seconds, a fatigue-driving warning will be triggered automatically. Andthe drivers’ behavior monitoring function is implemented.The implementation of the vehicles potential malfunction detection is mainlybased on CAN bus data acquisition module and on-line service platform. CAN busdata acquisition module implements the collection of vehicles CAN bus statusinformation. On-line service platform invokes the CAN protocol specificationsdatabase and vehicles fault codes database to match the CAN protocol and resolve theCAN packets and fault codes, then sends messages back to the vehicle terminal. Theterminal triggers a malfunction warning if a potential malfunction is confirmed.Although many technological areas are involved in this active-safety early-warning mechanism, it makes full use of the existing vehicle terminal techniqueresources, and reduces the cost of active-safety technique. If this system can beconverted to market application, it will improve the traffic safety coefficientenormously and drive the service transformation of transportation industry.