基于广义Keystone变换的机载雷达舰船目标ISAR成像  

Airborne radar ISAR imaging of ship target based on generalized Keystone transform

作　　者：贺小慧[1] 张龙[1] 

机构地区：[1]西安工程大学电子信息学院,陕西西安710048

出　　处：《西北大学学报（自然科学版）》2013年第6期885-889,923,共6页Journal of Northwest University（Natural Science Edition）

基　　金：陕西省自然科学基础研究计划基金资助项目(2012JM8015);陕西省教育厅专项计划基金资助项目(12JK0530;12JK0557);西安工程大学博士科研启动基金资助项目(BS1119)

摘　　要：克服对传统ISAR成像算法在低信(杂)比下,无法在长相干积累时间内对舰船目标进行高分辨成像。提出一种基于广义二阶Keystone变换的机载雷达对舰船目标成像算法。首先,该方法对距离压缩后的回波数据进行广义二阶Keystone变换,去除由于目标与雷达的相对运动高次项产生的距离弯曲,然后利用Radon-Ambiguity变换估计方位向调频率并对方位二次项进行补偿,接着再次利用广义二阶Keystone变换校正剩余的距离走动,最后用Relax方法估计散射点参数并获得目标的高分辨ISAR像。在长相干积累时间内对舰船目标可获得高分辨ISAR像。仿真与实测数据的处理结果验证了该方法的有效性。The conventional ISAR imaging method is unable to obtain the high resolution image of ship target in low SCNR condition when long coherent integration time is needed. To overcome this problem, in this paper a novel ap- proach is proposed for imaging the ship target by airborne radar. First, applying the second-order generalized key- stone formatting to compensate for the range curvature induced by long integration time. Second, the quadratic term of slow time is removed by estimating the target motion parameter using Radon-Ambiguity Transform （RAT）. Next, using the second-order Keystone formatting method again to eliminate the residual linear range walk. At last, the high resolution image of ship is obtained by employing the Relax technique. Both the results of the simulation and real data confirm the validity of the proposed algorithm.

关 键 词：ISAR成像 广义Keystone变换 模糊Radon变换 RELAX算法 

分 类 号：TN957.51[电子电信—信号与信息处理]