超高速平台圆轨迹SAR信号处理系统设计和实现

Design and Implementation of Circular SAR Signal Processing System Based on Ultra-high-speed Platform

首先讨论了超高速平台的应用背景,研究了圆轨迹合成孔径雷达(SAR)成像的基本原理,并做了仿真研究。同时,讨论了系统脉冲重复频率的选取要素,并根据平台运动特点,研究了SAR实时成像算法,推导了圆轨迹SAR运动参数。根据超高速运动平台的特点与成像处理机的处理能力,分析了实时处理的具体要求,设计了雷达信号处理模块。由于系统对处理速度的要求高(32 K点脉压通过率为1.4 GB/s),在系统设计时利用现场可编程门阵列(FPGA)完成了脉压、快速傅里叶变换、徙动校正和矩阵转置等流水处理,保证了系统的实时性要求;利用数字信号处理器完成了运动参数估计,FPGA运算参数配置工作。最后,文中的处理方法利用实测数据进行了验证,验证结果表明,处理方法满足系统要求。基于超高速平台的圆弧SAR成像,具有实际应用价值,已经成功应用于雷达工程实现中。

The application background of ultra-high-speed platform is discussed in the article firstly; the basic principle of circular SAR is researched and simulated. The factor of selected system PRF is discussed on the basis, according to the platform characteris- tics, the SAR real-time algorithm is researched and the motion parameters of circular SAR are deduced. The specific requirements are analyzed and radar signal processors are designed according to the characteristics of ultra-high-speed platform and the ability of signal processor, Because the system requires high processing speed （ the data rate of pulse compression need achieve 1.4 GB/s ） , the pipeline processing, such as pulse compression, FFT, migration correction and matrix transpose, are completed by FPGA in the system design. The estimation of motion parameter and FPGA parameter configuration are completed by DSP. In the last, the process- ing method is verified by measured data, the processing result indicates that this method fulfills the system requirements. The circular SAR based on ultra-high-speed platform has practical application value and is already applied successfully in radar system.