Study On Techniques Of Sensor Network Oriented To Road Traffic Information Acquisition

In the road traffic control system, the importance of acquisition for the road traffic information is increasing day by day. At present, the acquisition for the road traffic information is usually taken single detector as the main information acquisition unit and the line-wire as the communication method, which causes the cost of detectors to be high in the information acquisition and deployment of the detectors lacks of flexibility. Thus the detectors can only be deployed in minority of the road section, and there are massive information acquisition scotomas in the road network. The wireless sensor network technology takes entire sensing network as the main unit for the information acquisition, which reduces the cost of the information acquisition communication through wireless communication between nodes and information fusion in the network and provides the condition for the application of road traffic information acquisition technology in wider range. How to apply the wireless sensor network technology in the process of road traffic information acquisition is the main question in the resrarch of this paper.The main task in this article includes:(1) The wireless sensor network to apply in the road traffic information acquisition (RTISN) is defined. Through the analysis of the demand of the application of the road traffic information acquisition, a series of characteristics of the RTISN can be obtained, which includes the general character characteristic inherited from the wireless sensor network and the sole characteristic distinguished from the classics application of the wireless sensor network.(2) The meaning of nodes in the application of the acqusition of the road traffic information are described from four points, including the nodes types, the information types which the nodes provide, the deployment positions of the nodes and the action sphere of the nodes. The code of different nodes in RTISN is designed through the classification of different node for the information acquisition application. Referring to the corresponding national standards, the information type code in RTISN is designed to describe each kind of information type obtained in the road traffic information acquisition. The code of the nodes positions in RTISN is designed to substitute for conventional the GPS positions which describe the deployment position and the action sphere of the nodes in the road network. (3) According to the layered demand of the road traffic information acquisition, the structure of communication network in RTISN, the communication address structure, the communication frame structure in RTISN, the commnication methods of the upper tree network and the lower detection network are designed. Based on the gain of the link communication cost and the optimization of the topology of the sensing network, the organization steps of the upper tree network and the lower detection network in the RTISN are designed separately. Through the analysis of the road environment for the wireless communication, the reliable communication mechanism between the nodes under road surface and the roadside nodes is designed.(4) According to the layered demand of the road traffic information acquisition, the hierarchical structure of the fusion in the information characteristic level in RTISN is defined. The characteristic level fusion and the lossless fusion in RTISN are contrasted. The strategy of the information characteristic fusion is designed to satisfy the monitoring and the research demand in the road traffic information acquisition.