【作者】 惠希云；

【导师】 蔡伯根；

【作者基本信息】 北京交通大学 ， 交通信息工程及控制， 2009， 硕士

【摘要】 应答器在欧洲列车控制系统(ETCS-European Train Control System)和中国列车控制系统(CTCS-Chinese Train Control System)中都是主要的定位设备。为了提高定位精度,应答器必须高密度地布设在轨道上,增加了系统的建设成本和后期维护量。列车运行控制系统是典型的安全苛求系统,在列车高速行驶时,由于环境等外部因素的影响会导致应答器故障,无法保证列车运行的安全性。因此,如何保证列车运行的安全性、提高列车定位的精度对列车运行控制系统具有重要的现实意义。随着全球导航定位系统GNSS(Global Navigation Satellite System)的发展,国内外纷纷开展基于GNSS技术来实现列车定位。为了与ETCS系统相兼容,GNSS定位子系统必须输出与ETCS规范相符合的格式的信息,因此国际铁路联盟(UIC)提出了基于GNSS技术的虚拟应答器(Virtual Balise-VB)的概念,即采用GNSS接收机和相关软件实现应答器的功能,用于模拟一个真正放置在轨道上的应答器。虚拟应答器主要依靠执行程序来完成定位功能,其内部主要有三个模块组成:定位单元模块、安全判别模块、虚拟应答器捕获和报文生成模块。论文对虚拟应答器的系统结构和功能需求进行了分析,在此基础上进行了虚拟应答器系统框架设计。本文主要工作包括以下两点。第一:实现了虚拟应答器报文的编码,虚拟应答器需要输出和实际的应答器一样格式的报文信息,因此虚拟应答器报文的编码策略和实际应答器的报文的编码策略是一样的。论文首先通过用户数据表得到830比特的用户数据,然后通过编码策略实现了虚拟应答器报文的编码。第二:提出了虚拟应答器捕获半径的设置方法,详细推导了其数学公式,设计了虚拟应答器的捕获算法。通过设置仿真场景,对捕获半径为变量和常量的捕获率和捕获精度进行了比较分析,同时对捕获率、捕获精度在不同的列车行驶速度及不同的接收机输出频率时进行了分析,得出捕获半径为变量时更能适应列车高速、变速行驶的需要,在列车高速行驶时,如果对捕获精度的要求高,仅仅将捕获半径设为变量并不能满足要求,还需要提高接收机的输出频率,最后通过实验验证了仿真结论的正确性。更多还原

【Abstract】 Balise is the main positioning device both in European Train Control System and Chinese Train Control System. In order to improve train positioning accuracy, massively developed balises will increase system construction and maintenance cost. Train control system is a safety-critical system, due to external factors such as the environment, the safety of the train operation can not be guaranteed caused by the failure of the balise for high-speed train. It has realistic significance to improve train position accuracy and the safety of the train operation.With the development of Global Navigation Satellite System (GNSS),the research about the train position with GNSS technology has been begun in some countries. For achieving interoperability with ETCS, the location subsystem must translate the positioning information given by the GNSS based locator unit to ETCS message specification. For this purpose the concept of virtual balise has been proposed by the UIC. A virtual balise is a software element that emulates the functionality of a single balise or a balise group via convenient processing of navigation data. The virtual balise sub-system is a modular structure. It has three modules: locator unit module, safety qualifier module, the virtual balise capture and messaging module. On the basis of analyzing VB system architecture and functional requirement, the virtual balise system framework is designed. This thesis includes the following two aspects.First, the virtual balise coding is realized. The virtual balise shall output a virtual balise telegram as specified in ETCS class 1 messages specification. Therefore, this thesis uses Eurobalise coding strategy to realize virtual balise coding. First of all, 830 user bits is got through user data table, then, virtual balise message coding is realized by using coding strategy.Second, this thesis presents a virtual balise capture radius setting method, and designs the virtual balise capture algorithms. Detailed mathematical algorithms are deduced in this thesis. A simulation has been carried out to verify the algorithms. The thesis analyses the relationship among the locator fix rate, the train speed, the capture ratio and the capture precision. Finally, the conclusion that defining the capture zone of a VB as a function of the static speed profile of the line can meet the requirement of the train is given. Also, an experiment has been carried out to verify the correctness of the conclusion of the simulation.更多还原