摘要
针对现有运动目标聚焦方法存在的对多普勒模糊敏感、信噪比要求高、不能较好地实现无模糊运动参数估计的问题,提出一种严重方位模糊下的合成孔径雷达微弱运动目标聚焦与参数估计方法。首先,构造方位谱压缩函数压缩目标方位谱带宽;其次,应用二阶Keystone变换补偿距离弯曲;随后,通过所构造的距离走动补偿函数与吕氏分布变换(LVD)完成剩余距离徙动和多普勒徙动的补偿,进而实现目标能量聚焦;最后,结合参数粗估计结果,设计一种LVD域的无模糊参数精估计准则。仿真结果表明:该方法不受方位多普勒谱分裂与LVD域多普勒模糊的影响,具有较强的抗噪性,与Radon分数阶傅里叶变换的方法和基于非线性变换的方法相比,信噪比损失分别降低了约2dB和15dB。
A method for weak moving target focusing and parameter estimation of synthetic aperture radars is proposed to solve the problems that existing moving target focusing methods are sensitive to Doppler ambiguity, require high signal-to-noise ratio (SNR) and cannot estimate unambiguous parameter. Firstly, an azimuth spectrum compression function is constructed to compress the azimuth spectrum bandwidth of a target. Secondly, the second-order Keystone transform is applied to correct the range curvature. Then, the residual rang migration and Doppler migration are eliminated by a proposed range walk compensation function and the Lv’s distribution (LVD), and the moving target energy focus is finally achieved. Meanwhile, a precise estimation criterion of unambiguous parameters in LVD domain is designed by combining rough parameter estimation results. Simulation results show that the proposed method works well in the presence of Doppler spectrum splitting and Doppler ambiguity in LVD domain and has good anti-noise performance. Comparisons with the Radon fractional Fourier transform method and the nonlinear transform-based method show that the proposed method reduces the loss of SNR by 2 dB and 15 dB, respectively.
作者
万俊
周宇
张林让
陈展野
WAN Jun;ZHOU Yu;ZHANG Linrang;CHEN Zhanye(National Laboratory of Radar Signal Processing,Xidian University,Xi’an 710071,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2019年第6期85-91,108,共8页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(61871305,61671361,61731023)
关键词
合成孔径雷达
微弱运动目标聚焦
无模糊参数估计
多普勒谱分裂
距离徙动
多普勒徙动
synthetic aperture radar
weak moving target focusing
unambiguous parameter estimation
Doppler spectrum split
rang migration
Doppler migration
作者简介
万俊(1991-),男,博士生;通信作者:周宇,男,副教授.
