【作者】 金光虎；

【导师】 陈永光； 黎湘；

【作者基本信息】 国防科学技术大学 ， 信息与通信工程， 2009， 博士

【摘要】 研究中段弹道目标宽带雷达信息处理对弹道导弹防御系统中区分弹头及诱饵具有重要的实际意义。论文围绕基于宽带信息的中段弹道目标ISAR成像及物理特性反演问题进行研究,重点开展中段弹道目标ISAR成像、几何特性反演、运动特性反演三个方面的研究工作。在中段目标ISAR成像中,对目标高速运动补偿、相位自聚焦、回波分离、图像定标等问题进行了研究。文章首先分析了高速运动对距离像和ISAR像的影响,借助chirplet分解实现了目标径向速度估计,实现了中段目标高速运动补偿;针对ISAR成像中的相位自聚焦问题,利用初像加窗分离了散射点,构建了扩展距离像序列,进而根据扩展距离像的多普勒中心跟踪实现了相位高精度补偿;针对目标尾附体和主体信号分离问题,本文根据LFM特点构建了单频信号回波,根据两者多普勒差异,采用chirplet分解实现了信号的分离,提高了目标主体成像的清晰度;最后对ISAR像的定标问题进行了研究,分析了中段目标的成像特点,提出了基于图像配准的横向定标方法。在中段目标几何特性反演中,研究了目标径向长度、实际长度、目标纵截面积等几何特性的反演方法。首先研究了基于单幅距离像的目标径向长度反演,综合利用FFT算法和超分辨算法的优点,实现了目标径向长度的高精度估计;文章进一步研究了基于多幅距离像的目标实际长度反演方法,结合中段目标进动的特点,建立了径向长度统计模型,提出了实际长度的最大似然估计方法;最后对基于ISAR图像的几何特性反演进行研究,采用边缘提取、图像分割分离了背景和噪声,采用聚类算法得到了目标的散射中心位置,实现了横向长度、纵向长度、最大长度、目标纵截面积等几何特性的反演。在中段目标运动特性反演中,研究了目标进动参数反演方法。根据目标空间姿态和目标距离像、ISAR像的关系,提出了基于距离像相关特性和ISAR图像配准的进动参数反演方法;根据进动下目标径向长度变化特性,提出了基于极大极小值的进动角估计方法;根据特显点在距离像序列和ISAR像序列中的运动轨迹,提出了基于宽带像中散射点移动曲线的进动参数反演方法。本文提出的各种方法分别采用了仿真、暗室或实测数据进行了验证,实验结果验证了算法的有效性。论文针对中段弹道目标识别中存在的实际问题进行研究,在导弹防御中具有较强的现实意义,希望能够为未来的导弹防御系统建设服务,为导弹突防手段的提高提供帮助。更多还原

【Abstract】 Researching on the wideband radar signal processing of midcourse target has practical significance for discriminating warheads from decoys. The dissertation focused on the research of the ISAR imaging and physical feature extraction based on wideband radar. Three main subjects have been researched in this dissertation, which are ISAR imaging, geometry feature extraction and micro-motion feature extraction.In the research of ISAR imaging of midcourse target, four issues are studied including high velocity compensation, phase auto focus, signal decomposition and cross scaling of ISAR image. Firstly, the dissertation analyzes the effect of high velocity on the HRRP and ISAR image. With the aid of chirplet presentation, the radius velocity is estimated and the phase item caused by high velocity is compensated. For phase auto focus, scattering centers are separated based on windowed rough ISAR image and expanded HRRP is constructed to get more stable Doppler center. The phase error is compensated based on expanded HRRP. For the appendix part and body part signal decomposition, single frequency radar echo is constructed. Based on the Doppler difference, the dissertation separates the echo of body and appendix by chirplet decomposition. And the ISAR image clarity of ballistic target body is improved. Lastly, the ISAR image cross scaling problem is studied. According to the ISAR image characteristic of midcourse target, a new cross scaling method based on image registration is proposed.In the geometry feature extraction, radius length, actual length, cross section area feature extraction are studied. The dissertation studies the radius length extraction based on single HRRP firstly. By the advantage of FFT algorithm and super resolution algorithm, radius length is estimated with high precision. Furthermore, the dissertation studied the actual length extraction method based on HRRP series. According to the precession effect on the HRRP, the statistical model of radius length is constructed. And an actual length estimation based on ML algorithm is raised. Lastly, the geometry feature extraction based on ISAR image is studied. The target and background is separated based on edge extraction and image segmentation. And the scattering centers are extracted based on clustering algorithm. The cross length, radius length and target cross section area are extracted.In the micro-motion feature extraction of midcourse target, the dissertation studies the precession feature extraction. According to the relation between target posture and HRRP or ISAR image, the dissertation proposes two kinds of precession feature extraction methods based on the HRRP coefficients and ISAR image registration. According to the radius length change under the precession, the dissertation proposes an algorithm based on the minimum and maximum radius length. Lastly, according to the dominant scattering centers motion, the paper proposes two new algorithms based on HRRP series and ISAR image series. All approaches and algorithms put forward in the dissertation have been tested with simulated data, compressed field data or measured data. And experiment results show the validity.The dissertation focuses on the practical problems in the midcourse ballistic target recognition, which have great significance in ballistic missile defense. The writer hopes that the researching results are helpful for constitution of the missile defense systems and improvement of the ability of missile penetration in the future.更多还原