雷达关联成像技术研究

发布时间：2018-01-13 15:13

本文关键词：雷达关联成像技术研究　出处：《国防科学技术大学》2014年博士论文　论文类型：学位论文

【摘要】：关联成像是光学领域研究前沿的新兴热点问题之一,能够实现非定域性成像,一经提出就引起了广泛的讨论和研究。本文借鉴光学关联成像的基本原理,基于波前随机调制、波束内超分辨的创新构思,探索一种不依赖、且不受限于目标相对运动的雷达关联成像技术,与SAR/ISAR成像形成互补,为现有雷达成像技术中对静止\准静止目标以及非合作目标成像等瓶颈问题提供崭新的视角和解决思路。论文围绕雷达关联成像展开研究,对成像过程和理论实现、数学模型建立、成像算法以及模型失配条件下的图像重构等问题进行了研究。本文首先研究了雷达关联成像的基本理论,对关联成像应用于微波雷达系统的基本结构、信号波形以及波束内超分辨原理等基础问题进行了研究。具体内容包括:1)分析了热光关联成像原理,从雷达信号处理的角度得出关联成像实现的前提条件;2)提出采用时空不相关的探测信号实现雷达关联成像的方式。对比了雷达关联成像和热光关联成像的差异,并分析了二者在成像根本原理上的一致性;3)提出了阵列结构发射正交-时间不相关信号的波前调制方法,推导证明了这种方法能够在探测区域产生具有时空不相关特征的雷达信号覆盖;4)对比了雷达关联成像与传统SAR/ISAR以及阵列雷达成像方法,进一步诠释了雷达关联成像不依赖于多普勒频率的波束内超分辨原理。结合数值模拟实验说明了雷达关联成像利用单脉冲回波能够获得静止、合作以及非合作目标的清晰图像。第三章研究了雷达关联成像的空间模糊函数,对名义分辨率、波形设计、阵列构型和抗干扰性能进行了分析。具体内容包括:1)给出了雷达关联成像的空间模糊函数,推导了名义分辨率的解析表达式,阐明了雷达系统参数与分辨能力之间的关系;2)给出了零载频假设下的分辨率表示,从而量化评估阵列构型对分辨率的影响;3)提出了噪声调制波形和混沌调制波形,该种波形能够天然地满足雷达关联成像对正交性和时间不相关性的要求;4)针对典型的雷达成像干扰形式,分析了雷达关联成像的抗干扰性,理论和实验都说明由于采用了具有时空不相关特征的探测信号,这种成像技术具有突出的抗干扰性能。第四章研究了基于参数化模型的图像重构方法。由于探测信号的空间不相关特征受到微波系统条件限制,热光关联成像中基本的相关重构法并不能在雷达关联成像中获得高分辨率。本章由此提出了参数化模型下的重构方法,对成像方程的构造和重构条件进行了分析,并提出了分步式重构方法以降低计算复杂度。重点分析了在三维区域构造时空不相关探测信号的条件,由此在参数化模型下研究了雷达关联成像的三维图像重构。第五章对模型失配条件下的成像算法展开了研究,具体内容包括:1)分析了模型失配的产生原因,即目标运动和初始网格失配;2)研究了模型失配条件下的信号模型,给出了其主要影响因素:目标运动速率、初始网格偏移、探测信号的时空不相关特征以及目标散射系数矢量;3)分析了现有算法在模型失配条件下的局限性,给出了图像重构的两种方案;4)针对运动目标引起的模型失配,研究了基于稀疏恢复的图像重构算法。针对高速运动目标给出了基于参数估计和基于多维参数联合估计的成像方案;5)分析了雷达关联成像中初始网格失配效应的特殊性,并分析了现有网格优化算法的局限性,从而提出了相关-参数化联合重构算法,在保证分辨率的同时有效增强了模型失配条件下算法的稳健性。并且,提出了基于匹配滤波的联合重构算法,将传统雷达成像与关联成像初步结合,在提高算法效率的同时,能够为模型失配条件下的误差估计提供有效先验信息,提高图像重构质量。第六章对全文进行总结,并指出下一步可能的研究工作。
[Abstract]:Correlated imaging is one of the emerging hotspot frontier in the field of optics, can realize the nonlocality of imaging, once proposed have aroused extensive discussion and research. Referring to the principle of optical image correlation, wavefront random modulation based on innovative ideas in the beam of super resolution, explore a do not rely on, and is not limited radar image correlation technology in target relative motion, and complementary to existing SAR/ISAR imaging, radar imaging of stationary quasi stationary targets and non cooperative target imaging problem provides a new perspective and ideas to solve. This thesis focuses on the research of correlated imaging radar, imaging process and theory, the mathematical model is established, the problem of imaging the model and algorithm of image reconstruction with loss conditions were studied. This paper firstly studies the basic theory of association of association of imaging radar, imaging applied to The basic structure of microwave radar system, signal waveform and beam in super resolution principle are studied. The specific contents include: 1) analysis of thermal correlated imaging principle, the premise of correlated imaging realized from the angle of radar signal processing; 2) mining association with imaging radar detection signal is not relevant time and space. The comparison between radar correlated imaging and correlated imaging with thermal light, and analyzes the two fundamental principle of consistency in imaging; 3) wavefront modulation method is proposed to transmit orthogonal array structure - time uncorrelated signals, it is proved that this method can generate radar signal coverage both in time and space related characteristics in the detecting area; 4) compared with the traditional SAR/ISAR and the associated radar imaging array radar imaging method, further interpretation of the related imaging radar does not depend on the frequency of Doppler Beam in super resolution principle. Based on the numerical simulation experiment indicates that the single pulse echo can be obtained using the static correlation imaging radar, clear images of cooperation and non cooperative target. The third chapter studies the correlation of imaging radar ambiguity function of space, name resolution, waveform design, array configuration and anti-jamming performance is analyzed. The specific contents include 1) gives the association space imaging radar ambiguity function, the analytical expression of the nominal resolution is deduced, the relationship between the radar system parameters and resolution; 2) gives zero frequency resolution under the assumption that, in order to quantify the effects of array configuration on the assessment resolution; 3) noise modulation waveform and chaotic modulation put forward the waveform, waveform can satisfy the natural image correlation radar correlation on the orthogonality and time requirements; 4) for typical ray reach like shape interference Type analysis of interference correlation imaging radar, the theory and the experiment shows that the detection signal both in time and space characteristics, has the anti-jamming performance highlight of this imaging technique. The fourth chapter studies the image reconstruction method based on parametric models. The detection signal space characteristics by microwave the system limit, related basic reconstruction method can not in thermal correlated imaging and obtain high resolution radar image correlation. In this chapter the reconstruction method of parametric model, structure and reconstruction on the imaging equation are analyzed, and puts forward the step-by-step reconstruction method to reduce the computational complexity is analyzed. In the three-dimensional space and time correlation detection signal of regional tectonic conditions, resulting in the parametric model of 3D image reconstruction imaging radar. The fifth chapter related to the model mismatch With the condition of imaging algorithm is studied, the specific contents include: 1) analysis of the causes of model mismatch, i.e. the target motion and the initial mesh mismatch; 2) signal model to study the model mismatch conditions, are the main influencing factors: the rate of target motion, the initial mesh offset, space-time detection signal irrelevant features and target scattering coefficient vector; 3) analysis of the limitations of the existing algorithms with loss conditions in the model, gives two kinds of scheme of image reconstruction; 4) for moving targets caused by model mismatch, the image reconstruction algorithm based on sparse recovery. For the high speed moving target parameters is presented. Estimation and estimation based on multi parameter imaging scheme based on the analysis of the particularity; 5) the initial mesh mismatch effect between imaging radar, and analyzes the limitations of the existing grid optimization algorithm, and puts forward relevant Parametric joint reconstruction algorithm, in ensuring the resolution and effectively enhance the model mismatch conditions with algorithm robustness. And proposed joint reconstruction algorithm based on matched filtering, the preliminary combination of traditional radar imaging and image correlation, in improve the efficiency of the algorithm at the same time, to the model mismatch conditions provide estimates of error effective prior information, improve the quality of image reconstruction. The sixth chapter summarizes the full text, and points out that the research work may be the next step.

【学位授予单位】：国防科学技术大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN957.52

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