车联网专用短程通信和定位技术的研究与应用

发布时间：2018-11-13 15:50

【摘要】：随着人们出行需求的增加,交通问题逐渐成为了人们关注的焦点。车联网将道路、车辆等因素作为一个有机的整体加以考虑,是当下智能交通领域的研究热点。国内的车联网研究还停留在感知层,在通信层尚未形成统一标准,也缺乏相关的应用。本文研究了车联网中的专用短程通信技术和定位技术,并在二者的基础上实现了车路协同和路口预警的应用。首先,本文分析了Wi-Fi协议栈结构及驱动机制,在Wi-Fi的协议及状态机基础上,主要进行了车载环境下的快速接入和短消息协议设计,包括数据收发、信道切换以及用户和内核通信方式的设计,并与Wi-Fi进行了性能上的对比。然后将伪距差分定位技术与专用短程通信技术结合,使用短消息协议封装差分改正数,完成差分数据编解码,提高了车辆的定位精度,降低了系统成本。车路协同的功能是实现道路管理者和出行者间的双向通信,能够定时发布交通服务信息、上传车辆数据、维持连接状态。程序设计采用了多线程技术及多路复用技术,提高了数据并行处理能力。路口防撞预警通过路侧设备收集并广播车辆信息,避免了车辆较多时带来的信道争用问题。预警系统收到车辆信息后判断可能发生的碰撞类型,减少了不必要的预警所造成的系统开销,并对直线和侧面碰撞分别采用不同的预警方法。设置预警参数时,考虑了不同碰撞环境下的安全因素以及实际驾驶状况,并通过离线测试证明了预警系统在实际环境下的可靠性。最后,本文对将前几章所设计的内容集成,介绍了集成系统的层次结构及硬件组成,并完成了实际应用场景下的测试。全文的测试结果表明,本文设计的专用短程通信技术及差分定位技术具有良好的性能,在通信延迟、定位精度等多方面达到了技术指标,设计的应用可以用在实际的交通环境中。
[Abstract]:With the increase of people's travel demand, traffic problem has gradually become the focus of attention. It is a research hotspot in the field of intelligent transportation to consider the road, vehicle and other factors as an organic whole in vehicle networking. Domestic research on vehicle networking is still in the perception layer, communication layer has not yet formed a unified standard, and lack of related applications. In this paper, the special short-range communication technology and positioning technology in vehicle networking are studied, and the application of vehicle-road coordination and intersection warning is realized on the basis of the two technologies. Firstly, this paper analyzes the structure of Wi-Fi protocol stack and its driving mechanism. On the basis of Wi-Fi protocol and state machine, it mainly designs the fast access protocol and short message protocol under vehicle environment, including data receiving and sending. The design of channel switching and communication between user and kernel is compared with that of Wi-Fi. Then, the pseudo-range differential location technology is combined with the special short-range communication technology, and the differential correction is encapsulated by using the short message protocol to complete the differential data coding and decoding, which improves the positioning accuracy of the vehicle and reduces the system cost. The function of vehicle-road cooperation is to realize the two-way communication between the road manager and the traveller, to release the traffic service information regularly, to upload the vehicle data, and to maintain the connection state. Multithread technology and multiplexing technology are adopted in the program design, which improves the ability of data parallel processing. Intersection collision warning collects and broadcasts vehicle information through road side equipment, which avoids the channel contention problem when there are more vehicles. After receiving the vehicle information, the early warning system judges the possible collision type, reduces the system overhead caused by unnecessary early warning, and uses different warning methods for straight and side collisions. When setting early warning parameters, the safety factors and actual driving conditions in different collision environments are considered, and the reliability of the early warning system in actual environment is proved by off-line test. Finally, this paper introduces the hierarchical structure and hardware structure of the integrated system, and completes the testing of the practical application scenario. The test results show that the special short-range communication technology and differential positioning technology designed in this paper have good performance, and achieve the technical targets in communication delay, positioning accuracy and so on. The application of the design can be used in the actual traffic environment.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U495

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