基于单脉冲雷达和差通道多普勒估计的前视成像  

Forward-looking Imaging via Doppler Estimates of Sum-difference Measurements in Scanning Monopulse Radar

作　　者：李悦丽 马萌恩 赵崇辉 周智敏[1] LI Yueli;MA Meng’en;ZHAO Chonghui;ZHOU Zhimin(College of Electronic Science and Technology,National University of Defense Technology,Changsha 410073,China;Science and Technology on Millimeter-wave Laboratory,Beijing 100854,China)

机构地区：[1]国防科技大学电子科学学院,长沙410073 [2]毫米波遥感技术重点实验室,北京100854

出　　处：《雷达学报（中英文）》2021年第1期131-142,共12页Journal of Radars

基　　金：国家部委基金(61404150103,61425020604)。

摘　　要：单脉冲测角技术用于扫描雷达前视成像可有效提高图像的清晰度,但单个脉冲对同分辨单元多目标测角时会发生角闪烁现象,造成图像模糊。该文提出了一种基于单脉冲雷达和差通道多普勒估计的前视成像算法,利用目标和平台之间相对运动引起的多普勒梯度差异实现同分辨单元内不同方向目标的分离,然后在多普勒域采用和差比幅测角(SDAC)技术测量目标的方位角,完成能量投影。为提高测角精度,进一步提出了采用调频Z变换(CZT)重建和差多普勒估计并进行比幅测角的算法。点目标仿真实验结果表明,所提出的算法在前斜视方向具有分离多目标的能力,对实测数据成像结果验证了基于CZT的成像算法相比传统算法能显著提高对场景成像的轮廓清晰度。Monopulse technique is used in scanning radar systems to improve image quality in the forwardlooking area.However,monopulse measurements fail to resolve multiple targets in the same resolution cell because of angular glint which often results to image blurring.In response to this,we propose a monopulse forward-looking imaging method utilizing Doppler estimates of sum-difference measurements.First,target multiplicity is resolved by exploiting the different Doppler shifts caused by the relative motion between the platform and the targets at different directions.High azimuthal angle measurement accuracy of the Doppler estimates is then obtained using the Sum-Difference Amplitude-Comparison(SDAC)monopulse technique.Subsequently,the intensity of the sum channel estimates is projected onto the image plane according to the range and angle measurements.To further improve the precision of angle measurements,a Chirp-Z Transform(CZT)-based algorithm is proposed for the reconstruction of the Doppler estimates of the sum-difference channels.Simulation results demonstrate the capability of the proposed methods in resolving multiple targets at high squint angles in a large scanning field.Real data experiments show significant improvement of image profiles using the CZT-based algorithm compared to that of the conventional monopulse imaging method.

关 键 词：单脉冲雷达 前视成像 和差比幅测角 调频Z变换 

分 类 号：TN958.4[电子电信—信号与信息处理]