【作者】 周晔；

【导师】 郑正奇；

【作者基本信息】 华东师范大学 ， 通信与信息系统， 2007， 硕士

【摘要】 智能交通系统是目前城市规划的一个重要方面,车流量检测作为系统中非常重要的一个环节,它的工作方式也由原先的单一的接触式线圈向混合型的非接触式的方式转化,车流量雷达检测系统作为智能交通系统用于获取路面信息的一种方式,具有非常广阔的应用前景。车流量检测系统由雷达前端,中频电路板,数字电路板,计算机操作界面等部分组成。本文的主要工作是研究车流量检测系统的后端(数字板部分),重点探讨如何利用DSP芯片来对雷达信号进行处理的原理和方法。本文分析了调频连续波雷达的工作原理,介绍了德州仪器公司TMS320VC5416芯片的特点和开发的平台,讨论了数字信号处理器在雷达信号处理中的应用,设计完成了基于VC5416的车流量检测器的数字电路板,以满足智能交通发展的需要。文章最后,对现场实验数据结果进行比较分析,’对系统的数字部分进行总结和展望。数字板硬件主要由以下电路和模块组成:电源管理模块,为各器件提供直流电源;时钟电路,为DSP芯片提供工作时钟;ADC转换电路,对雷达的中频信号进行连续采样,将模拟信号转换成数字信号;DSP模块,实现车流量检测雷达的信号处理算法,控制外围相关芯片,并与计算机通信;存储器模块,一块Flash用来存储交通信息数据,另一块Flash用来存储程序代码,在DSP芯片上电时,片内ROM内固化的Bootloader程序自动将程序代码加载到DSP片内RAM执行;串口通信电路,与计算机通信;三角波产生电路,利用多通道缓冲串口和DAC产生,给压控振荡器提供电压;RTC电路,记录实时时间;CPLD,实现逻辑控制功能。软件部分是在TI公司推出的针对标准TMS320调试接口的集成开发环境CCS2下开发完成的,程序的主线为:先对中频信号采集和存储,即将ADC采样数据后存放在DSP片内RAM中,采集到一定量数据后利用快速傅立叶变换进行频谱分析,运用自适应算法确定门限,并根据车流量检测相关原理和经验计算,统计出车流量信息。更多还原

【Abstract】 Intelligent Traffic System (ITS) is a key aspect of urban planning. The vehicle flow detector is a very import part in the system, and it has been changed from a single contact loop to a mixed non-contact mode. Vehicle flow detection radar system as one of accesses for road information will have broad application prospects in ITS .The Whole system conists: radar, cutting intermediate frequency circuit board, digital signal circuit board and computer operation interface. This paper mainly studies the end part of vehicle flow detector (digital part), focused on how to using DSP chip to realize the principles and methods of vehicle flow detecting with the radar signal. This paper analysis the work principle of radar: FMCW(Frequency Modulated Continuous Wave) , introduces the characteristics and development platform of TMS320VC5416 from Texas Instruments Company, then an application of the digital signal processor in this radar sigal processing is presented in this paper. We designed the digital circuit board of Microwave vehicle detector based on TMS320VC5416 to fulfill the requirement of ITS. Finally, the data got from experiment is compared and analysed and summary and prospects of system is presented.The digital circuit board of Microwave vehicle detector mainly consists the following modules: Power management module circuits, it provides DC power supply for various devices; Clock generating circuits, it generate DSP core clock; The AD converter circuit, it is continuously sampling the IF signal and changing analog signals to digital signals; The DSP module, it executes radar signal processing algorithms, also contrals other related devices, communicates with PC; Memory module, it uses two NOR Flash, The one is used to store code of traffic flow detecting, the code will be loaded to RAM by bootloader program in ROM when the system is powered then excuted in RAM of DSP , the other is used to store data of traffic information; Serial communication circuit, it is responsible for changing parallel data to serial data and communicate with computer; Triangular wave circuit, triangular wave is created by McBSP of DSP and a serial DAC,and it is sent to VCO(Voltage Controlled Oscillator); RTC circuit, which is used to record real-time; CPLD is used to achieve circuit logic contral.The software is developed under the Integrated Development Environment CCS2, which aimed at the Ti’s TMS320 Debug Interface standards, Software realizes main process as follows: collect and store IF signal, that is, put sampled data from ADC into RAM of DSP chip; After a certain amount of data is collected, using fast Fourier transform to have spectrum analysis,and using adaptive thresholding algorithm to calculate thresholds; then get statistic result about vehicle flow information according to the theory and experience of vehicle flow.更多还原