基于GPU的长轨SAR实时成像算法

GPU-Based Real-Time Imaging Algorithm for Long-Track SAR

为了满足长轨道超高分辨W波段合成孔径雷达(Synthetic aperture radar,SAR)的快速成像需求,本文提出了一种基于图形处理器(Graphics processing unit,GPU)的ω-K实时成像算法,该算法采用并行架构和双流多线程的处理方式。默认流沿着物理原理的方向进行数据处理,首先对距离补偿、误差校正和补零等操作进行并行化处理,然后采用一层嵌套的插值方式,通过维持上下层的依赖关系和同步管理就能达到约30的加速比。阻塞流与默认流同时启动,生成默认流所需的参数和函数,并在执行前将其存入显存,极大地缩小了算法的运行时间,同时通过在默认流上设置事件以保持双流的同步并行执行。实验结果表明,算法总的加速比可达13左右,幅值和相位相对误差趋近0,不仅具有良好的实时性、聚焦性,还保持了良好的成像效果。

To meet the fast imaging requirements of long-orbit ultra-high resolution W-band synthetic aperture radar(SAR),this paper proposes a graphics processing unit(GPU)-based ω-K real-time imaging algorithm which adopts parallel architecture and double stream multithreading processing.The default stream processes data along the direction of the physical principle.Firstly,it parallelizes the rang compensation,error correction,zero filling and other operations,and then adopts one-layer nested interpolation method.By maintaining the upper and lower dependencies and synchronization management,it can achieve a speed ratio of about 30.The blocking stream starts at the same time as the default stream,generates the parameters and functions required by the default stream,and stores them into video memory before execution,which can greatly reduce the running time of the algorithm.Meanwhile,by setting events on the default stream,the two streams can be executed synchronously in parallel.Experimental results show that the total acceleration ratio of the algorithm can reach about 13,and the relative errors of amplitude and phase are close to 0,which not only has good real-time performance and focusing performance,but also maintains good imaging effect.