低截获混合扩频接收机设计及FPGA实现-空间信息科学技术专业论文.docxVIP

万方数据 万方数据 摘 要 宽带、高速跳频和直接序列扩频相结合的混合扩频系统具有较强的抗截获能 力和抗干扰能力。本文给出了一种截获概率很低的混合式扩频通信系统接收机方 案，进行了硬件结构设计，完成了相关模块的 FPGA 实现，具体工作如下： 1. 针对系统的突发性和低截获性，本文提出了一种长码实时捕获方案；设计 了一种基于循环码移键控(CCSK)的高阶 M 元解扩和迟早环同步跟踪方案；给出了 系统相关接口。 2. 完成了相关模块的 FPGA 实现，包括：基于部分匹配滤波-FFT 算法的长码 捕获模块、基于延迟锁定环的同步跟踪模块、基于高阶 M 元扩频系统 FFT 快速相 关解扩模块以及 FPGA 控制 FX2 芯片 Slave FIFO 模式的数据接口模块。通过波形 仿真测试，验证了这些 FPGA 模块功能的正确性。 3. 选定了系统器件，完成了接收机的硬件平台设计。 4. 完成了接收机的测试。测试结果表明接收机的性能可以达到设计指标。 关键词：长码捕获 高阶 M 元解扩 Slave FIFO 模式 FPGA Abstract A hybrid spectrum spreading communication system, which combines broadband high-speed frequency-hopping and direct sequence spectrum spreading, possesses strong ability in anti-interception and anti-jamming. This paper proposed a receiver scheme in a hybrid spectrum spreading communication system, which possess very low probability of interception; and designed its hardware structure, as well as finished its related FPGA implementation. The main contributions are as follows: According to the requirement of burstiness and low probability of interception, a synchronization acquisition of long PN code in real time is proposed. A high-order M-ary spectrum spreading system based on CCSK and a synchronization tracking approach based on delay locked loop are both designed. In addition, the corresponding interface is presented. FPGA implementations of the related modules are realized, including long code acquisition module based on part-matched-filter-FFT algorithm, synchronization tracking module based on delay lock loop algorithm, the FFT-based fast correlation despreading module for high-order M-ary spectrum spreading signals and data interface module in FX2’s Slave FIFO mode. Finally, the designed FPGA modules are tested through wave simulation, their function has been verified. Devices are selected to finish the hardware platform of the receiver. The prototype receiver has been tested. And the test result shows that the performance of the receiver meets the designed targets. Keywords: long code ca