单双基SAR高速数据采集系统的研究与实现

【作者】 徐进；

【导师】 吕幼新；

【作者基本信息】 电子科技大学 ， 信号与信息处理， 2007， 硕士

【摘要】 合成孔径雷达(SAR)具有全天时、全天候、高分辨率的特点,在军事和民用领域得到了广泛的应用。在SAR系统中,需要对正交两路(I/Q)雷达回波信号需要被连续采样,并同时连续高速实时地存入硬盘等存储介质中。由于SAR系统采集的数据量大,速度快,而现有存储设备存储速度较低,所以很难实现将所有的回波数据全部录入。为实现数据长时间连续存储,本文采用了记录有效回波信号的方法。所以在单基与双基SAR中,需要确定有效回波的位置。文中使用了一种基于滑窗的纽曼-皮尔逊的检测方案,并设计和实现了一种应用于单基及双基SAR、基于SATA硬盘的高速数据采集和存储系统中的采集部分。采用Xilinx公司的FPGA实现采集系统工作时序与采集与存储部分的相互通信等。存储部分的SMT387板块完成FAT32文件系统下的数据格式转换和对硬盘的操作。其特点是采用了计算机在存储时使用的FAT32文件系统,便于数据的读取和后期处理。存储设备使用了实时记录平均速度达到40MB/s的高速SATA I硬盘。采集与存储板块之间的数据传输使用了速率有240MB/s的SHB数据传输总线。本文主要工作:1.完成了采集系统软硬件工作:电路板设计实现、基于FPGA的系统总体时序控制和系统工作流程的设计与实现,并实现了通过对SHB数据传输总线的控制进行采集与存储板块的通信。2.共同讨论制定系统实现方案,全面介绍了单基及双基SAR数据采集与存储系统的组成结构及设计原理,分别对单基和双基SAR的各模块从工作原理到实现过程进行了详细地介绍。3.配合后端存储模块实现了基于滑窗的对雷达回波信号中有效回波的的检测,从系统测试结果和实际外场试验使用对其进行了验证。4.完成了对采集系统各部分工作性能的测试与分析,结果表明,系统工作性能可靠,稳定度高,满足系统设计要求。并且参与了实际外场试验,通过后期成像结果表明,系统是稳定有效的。更多还原

【Abstract】 Synthetic Aperture Radar recently is used in military and civilian because of its excellent performance in complex weather and high resolving power. In SAR system, the in-phase and quadrate radar echoes must be sampled simultaneity and stored in the recorders for a long-time. Only the available echoes can be stored because of the speed limitation of hardware. The receiver needs to detect the position of available echoes in bistatic SAR. In this paper, a method to detect the position of available echoes in the integrity period based on slide-window was used. A high-speed data acquisition and storing system, which is based on SATA disks and used in bistatic and monostatic SAR, is introduced in this dissertation. The FPGA which is produced by Xilinx is used to control the system’s working time and communication between acquisition module and storage module. The SMT387 module changes the data’s format into FAT32 file system and controls the SATA disk. The character of this system is that the data is stored in FAT32 file system, which is generally used in computers and makes the recorded data can be easily read and processed by computers. The SATA disk whose average recording speed arrives at 40 MB/s is chosen to be storage, and the data communication between acquisition module and storage module is finished by SHB whose speed is 240 MB/sThe primary work in this dissertation:A method was present to detect the radar echoes based on slide-window and proved both by theory and experiment result. The system’s construction and design proposal was introduced from every part of it.The central controlling and system working flow was completed, the controlling of SHB bus was realized.The system was validated in the car’s and plane’s experiments.更多还原