基于涡旋电磁波新体制的雷达前视三维成像  

Novel Forward-looking Three-dimensional Imaging Based on Vortex Electromagnetic Wave Radar

作　　者：潘浩然 马晖 胡敦法 刘宏伟[1] PAN Haoran;MA Hui;HU Dunfa;LIU Hongwei(National Key Laboratory of Radar Signal Processing,Xidian University,Xi’an 710071,China)

机构地区：[1]西安电子科技大学雷达信号处理全国重点实验室,西安710071

出　　处：《雷达学报（中英文）》2024年第5期1109-1122,共14页Journal of Radars

基　　金：国家重点研发计划(2022YFB3902400);国家自然科学基金面上基金(62471362);国家自然基金青年基金(61901344);博士后创新人才支持计划(BX20180239);博士后基金(2019M653562);高等学校学科创新引智计划(B18039)。

摘　　要：涡旋电磁波具有独特的波前相位调制特性,其作为一种新的雷达发射端分集模式,可实现目标雷达截面积(RCS)分集、提升信号与信息处理维度和性能,其探测与成像性能在多种雷达体制中得到了验证。该文针对前视雷达成像的应用背景,基于均匀圆阵发射与圆阵中心单天线接收的收发体制,在建立了电磁涡旋前视雷达信号模型与成像模型的基础上,提出了一种分时多模态扫描的成像方法,利用多模态涡旋电磁波在不同俯仰角的幅度差异性和在不同方位角的相位差异性,以及雷达与目标相对运动产生的多普勒效应,提出了改进的后向投影-距离多普勒算法,实现了目标三维成像。由于涡旋电磁波的能量发散特点,随着俯仰角增大,高模态方向图增益急剧下降,该文所提方法通过对多个模态在空域能量分布的有效利用,在较大视场角下具有较高的稳定性。基于点目标成像结果,验证了在多模态涡旋波覆盖的较大视场范围内,目标成像结果的归一化等效增益在低俯仰角与高俯仰角处基本相当。所提方法通过对飞机目标的实验验证,根据成像结果可较为准确地重构目标的三维结构。Vortex Electromagnetic Waves(VEMWs)have unique wavefront phase modulation characteristics.As a new degree of freedom in the diversity of radar transmitters,the VEMW Radar(VEMWR)provides Radar Cross-Section(RCS)diversity and improves signal and information processing dimensions and performances.The detection and imaging performances of VEMWR have been verified in various radar systems.This article focuses on the applying background of forward-looking radar imaging and proposes a time-division multiplemode scanning imaging method based on a Uniform Circular Array(UCA)system with multiple transmitters and a single receiver at the UCA center.First,we establish the forward-looking VEMWR imaging mode and corresponding signal mode.Next,an improved three-Dimensional(3D)back-projection and range-Doppler algorithm is proposed,which utilizes the magnitude difference at various elevation angles of multimode VEMW,phase difference at different azimuth angles,and Doppler effect resulting from the relative motion of the radar and target to achieve 3D imaging of the target.As the elevation angle increases,the beam pattern gain of the high-mode VEMW decreases sharply due to the energy divergence of the VEMW.The proposed method can maintain stability at low or high elevation angles using the energy distribution of multiple modes in the spatial domain.Imaging results of point targets revealed that the normalized gain of target-imaging results is equivalent either at low or high elevation angles within the multimode VEMW field of view.The proposed method is validated through experiments with an aircraft target.Based on the imaging results,it is verified that the proposed method can accurately reconstruct the 3D structure of complex targets.

关 键 词：涡旋电磁波雷达 前视三维成像 分时多模态 后向投影算法 距离多普勒 

分 类 号：TN95[电子电信—信号与信息处理]