基于太赫兹ViSAR的无源干扰物成像  

Terahertz-ViSAR-based Imaging of Passive Jamming Objects

作　　者：范磊[1] 杨琪 王宏强[1] 易俊 FAN Lei;YANG Qi;WANG Hongqiang;YI Jun(College of Electronic Science and Technology,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学电子科学学院,长沙410073

出　　处：《雷达学报(中英文)》2025年第2期486-500,共15页Journal of Radars

基　　金：国家自然科学基金(62201591,62035014);湖南省科技创新计划项目(2024RC3143)。

摘　　要：无源干扰物的成像一直是雷达成像/对抗研究中的热点问题,直接影响着雷达目标检测和识别性能。然而,在微波频段下,为达到期望的方位分辨率,通常需要较长的驻留时间来形成单幅图像,这使得无源干扰物难以通过成像直接区分,并缺乏时间维的分辨能力。相比之下,太赫兹频段成像系统在实现相同方位分辨率时所需的合成孔径更短,从而更容易获得低延迟、高分辨、高帧率的成像结果。因此,太赫兹雷达在视频合成孔径雷达(ViSAR)技术中具有重要潜力。首先,对机载太赫兹ViSAR的孔径划分及其成像系统指标进行简要分析。随后,静止无源干扰物以角反阵和伪装网为例,探索它们运动补偿前后的成像结果及成像特性,并首次实验验证了具有上下起伏网格结构的伪装网在太赫兹频段将表现出粗糙特性,展现出该频段下特殊的目标特性。接下来,运动无源干扰物以旋转角反为例,分析了旋转角反成像所形成的压制性成像干扰。考虑到静止场景在相邻子孔径下类似,在完成帧间成像结果图像和幅度校准后,可直接在图像域内基于非相干相减实现旋转角反检测,从而提取感兴趣信号并实施非参数化补偿。目前关于太赫兹频段下对无源干扰物的外场成像实验验证甚少。该研究开展了太赫兹频段公里级机载外场试验,有效验证了太赫兹ViSAR具备对无源干扰物良好的高分辨与高帧率成像能力。Imaging of passive jamming objects has been a hot topic in radar imaging and countermeasures research,which directly affects the detection and recognition capabilities of radar targets.In the microwave band,the long dwell time required to generate a single image with desired azimuthal resolution makes it difficult to directly distinguish passive jamming objects based on imaging results.In addition,there is a lack of time-dimensional resolution.In comparison,terahertz imaging systems require a shorter synthetic aperture to achieve the same azimuthal resolution,making it easier to obtain low-latency,high-resolution,and high-framerate imaging results.Hence,terahertz radar has considerable potential in Video Synthetic Aperture Radar(ViSAR)technology.First,the aperture division and imaging resolutions of airborne terahertz ViSAR are briefly analyzed.Subsequently,imaging results and characteristics of stationary passive jamming objects,such as corner reflector arrays and camouflage mats,are explored before and after motion compensation.Further,the phenomenon that camouflage mats with fluctuating grids exhibit roughness in the terahertz band is demonstrated,exhibiting the special scattering characteristics of the terahertz band.Next,considering rotating corner reflectors as an example of moving passive jamming objects,their characteristics regarding suppressive interference are analyzed.Considering that stationary scenes feature similarity under adjacent apertures,rotating corner reflectors can be directly detected by incoherent image subtraction after inter-frame image and amplitude registrations,followed by the extraction of signals of interest and non-parametrical compensation.Currently,few field experiments regarding the imaging of passive jamming objects using terahertz ViSAR are being reported.Airborne field experiments have been performed to effectively demonstrate the high-resolution and high-frame-rate imaging capabilities of terahertz ViSAR.

关 键 词：太赫兹ViSAR 无源干扰物 微动目标成像 非参数化补偿 机载试验探索 

分 类 号：TN957.91[电子电信—信号与信息处理]