现代有轨电车车地无线通信关键技术研究

发布时间：2019-06-13 08:18

【摘要】：目前,中国城市交通工具中汽车仍占主要地位,大量的汽车易造成城市交通拥堵、环境污染严重等问题。为了应对这些问题,现代有轨电车凭借载客量大、安全舒适、节能环保、快速便捷等优点,在全世界范围内得到广泛使用。车地无线通信系统作为现代有轨电车运营控制系统中的重要组成部分,直接关系着行车安全与行车效率,运营监控中心必须准确可靠的获取车辆实时运行状态,才能完成对车辆的运行状况全程追踪及故障告警和预警等任务。所以,对现代有轨电车车地无线通信关键技术进行研究,建立一套实时、可靠、稳定的车地无线通信系统有着重要意义。本文针对现代有轨电车数据传输的实时性与可靠性,研究了车地无线通信系统的框架,实现了基于GPRS公共网络和TCP协议的无线通信,以及制定了保障数据可靠性传输的机制。首先,文章分析了目前常见的现代有轨电车车地无线通信系统所使用的网络接入方案,对比后选取更符合本系统需求的GPRS网络,在此基础上构建通信系统的总体框架。其次,对车载通信平台和地面通信平台的硬件和软件进行分析与设计。车载设备由控制单元、无线通信模块、定位模块、存储模块、显示模块等构成,地面通信平台由一个基于TCP协议的Socket通信服务器端软件和WEB网站等构成。为了进一步提高数据传输的可靠性与实时性,从通信过程中的多个阶段提出了可靠性保障机制:根据私有协议制定数据包格式;使用两个SIM900A模块与TCP服务器端软件建立两个TCP连接的双机冗余方式;制定不同情况下的传输应答机制;传输数据使用TCP Socket、HTTP POST的主备方式,在TCP服务器端软件出现故障时,WEB网站中的一个PHP页面作为接口接收数据。最后,对系统运行进行了测试分析,结果表明数据传输稳定可靠,出错概率和延时都在允许范围内,使用的数据可靠性传输机制有效提高了车地通信的可靠性与实时性。
[Abstract]:At present, cars still play a major role in urban transportation in China, a large number of cars are easy to cause urban traffic congestion, serious environmental pollution and other problems. In order to deal with these problems, modern tram has been widely used all over the world because of its large passenger capacity, safety and comfort, energy saving and environmental protection, fast and convenient and so on. As an important part of modern tram operation and control system, vehicle-ground wireless communication system is directly related to driving safety and driving efficiency. The operation monitoring center must obtain the real-time running state of the vehicle accurately and reliably in order to complete the tasks of tracking the whole running condition of the vehicle, fault alarm and early warning. Therefore, it is of great significance to study the key technologies of modern tram wireless communication and to establish a set of real-time, reliable and stable vehicle-ground wireless communication system. Aiming at the real-time and reliability of modern tram data transmission, this paper studies the framework of vehicle-ground wireless communication system, realizes wireless communication based on GPRS public network and TCP protocol, and formulates the mechanism to ensure data reliability transmission. First of all, this paper analyzes the network access scheme used in the modern tram ground wireless communication system, and then selects the GPRS network which is more in line with the needs of the system, on the basis of which the overall framework of the communication system is constructed. Secondly, the hardware and software of vehicle communication platform and ground communication platform are analyzed and designed. The vehicle equipment is composed of control unit, wireless communication module, positioning module, storage module, display module and so on. The ground communication platform is composed of a Socket communication server software based on TCP protocol and WEB website. In order to further improve the reliability and real-time performance of data transmission, a reliability guarantee mechanism is proposed from several stages in the communication process: making packet format according to private protocol, using two SIM900A modules and TCP server-side software to establish two TCP connections, establishing transmission response mechanism under different conditions. When the TCP server software fails, a PHP page in the WEB website receives the data as an interface. Finally, the operation of the system is tested and analyzed. The results show that the data transmission is stable and reliable, and the error probability and delay are within the allowable range. The data reliability transmission mechanism effectively improves the reliability and real-time performance of vehicle-ground communication.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U482.1;TN929.532

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