【作者】 常宇亮；

【导师】 王雪松；

【作者基本信息】 国防科学技术大学 ， 信息与通信工程， 2010， 博士

【摘要】 利用极化信息提高雷达的检测、抗干扰和识别等能力是当前新体制雷达发展的趋势之一。瞬态极化概念及相关理论的提出为时变、宽带和动态极化信息的表征与处理提供了有力的理论工具,促进了全极化新体制雷达的研制和发展。采用瞬态极化信息处理理论和技术进行信息处理的同时全极化测量体制雷达,可称为瞬态极化雷达。由于瞬态极化雷达可通过单次观测获取目标极化散射矩阵的全部信息,且可对极化散射矩阵进行瞬态极化信息处理,因此其极化信息获取与处理能力更强,与传统极化雷达相比在目标检测、抗干扰和目标识别等方面具有较大优势。在瞬态极化雷达系统研制和发展需求的牵引下,本文对极化测量、极化校准、极化检测和极化抗干扰等瞬态极化雷达关键技术进行了研究,并通过瞬态极化雷达实验系统开展的内、外场试验对部分研究成果进行了验证。第一章,概述了雷达极化学的研究内容和发展历程,以及极化雷达测量体制和关键技术的研究现状和发展趋势;介绍了瞬态极化雷达的概念,归纳了瞬态极化雷达系统发展和应用中待解决的部分技术问题;简要阐述了论文的主要研究内容。第二章,研究了瞬态极化雷达的目标极化散射特性测量问题。针对极化雷达研制阶段发射信号的波形选择和参数设计问题,提出了基于瞬态极化模糊函数矩阵的发射信号极化测量性能评估方法,为极化雷达发射信号的波形选择和参数设计提供了理论基础;针对传统极化测量方法对发射信号的正交性约束在工程中难以实现的问题,提出了基于瞬态极化模糊函数矩阵的极化测量新方法,有效消除了因发射信号非正交性引入的测量误差;最后介绍了瞬态极化模糊函数矩阵的参数估计方法。第三章,研究了瞬态极化雷达的测量校准问题。针对传统极化校准方法忽略天线空域极化特性、工程实施难度较大等缺陷,提出了基于金属球和标准信号源的极化校准新方法,在充分考虑天线空域极化特性的前提下实现了极化测量校准,降低了校准实施难度,提高了校准精度;针对极化雷达天线空域极化特性引入的与来波极化相关的测向误差,研究了测向误差与极化测量误差间的耦合关系,发现了该耦合误差的产生机理,并提出了相应的误差消除方法。第四章,研究了瞬态极化雷达的目标检测问题。针对经典极化检测算法假定极化雷达接收信号对应的目标极化散射矩阵测量值满足互易性,而实际接收信号会因天线空域极化特性产生互易性偏离现象的问题,在考虑天线空域极化特性影响的前提下,推导了高斯噪声条件下确定性目标的最佳检测算法,提出了相应的准最佳极化检测实现方法,研究了高斯噪声条件下起伏目标、非高斯噪声条件下确定性目标的最佳极化检测方法,利用非互易性条件下的交叉极化信息提高了极化雷达的目标检测性能。第五章,研究了瞬态极化雷达的抗干扰问题。针对干扰极化变化造成传统极化抗干扰方法性能下降的问题,提出了瞬态极化滤波方法,实现了目标回波时、频域内干扰信号的极化检测、估计和抑制,提高了变极化干扰的抑制性能;针对极化周期调制干扰,以弹载干扰机为研究对象,提出了干扰极化跟踪滤波方法,与传统的固定极化滤波器相比具有更好的极化抑制性能;针对具备目标极化散射矩阵模拟能力的全极化复杂调制假目标干扰,提出了相应的假目标极化鉴别方法,提高了极化雷达的假目标鉴别能力。更多还原

【Abstract】 As one of the development tendencies of current new radar system, the polarizationinformation is used to improve the radar abilities, such as detection, anti-jamming andrecognition, etc. The conception and theory of instantaneous polarization provides a pow-erful theory tool to represent and process the variable, wideband and dynamic polarizationinformation. It also motivates the manufacture and development of new full-polarimetricradar system. The simultaneous full-polarization measurement radar, which uses the in-stantaneous polarization theory and technology to process the information, can be calledinstantaneous polarization radar (IPR). Because the IPR can achieve the measurment ofentire polarization scattering matrix (PSM) through one observation and process the PSMusing instantaneous polarization theory, it is more powerful in measurement and process-ing of the polarizatoin information. Therefore, it has the obvious advantage in target de-tection, anti-jamming and target reorganization comparing with traditional polarimetricradar. Motivated by the development of the IPR system, this dissertation focused on themethodsofpolarimetricmeasurement,polarimetriccalibration,polarimetricdetectionandpolarimetric interference suppression. Part of the research results was testified by the out-door tests.Chapter 1 summarizes the development of the polarimetric radar theory, the polar-ization measurement system and the key techniques of polarimetric radar. The conceptof IPR is given; the unresolved problems in the IPR development are listed. The majorresearch topics of this dissertation are summarized.In Chapter 2, the PSM measurement method for IPR is studied. To resolve the prob-lem of signal selection and parameter design of IPR’s transmitting signals, the evaluationmethodofPSMmeasurementperformanceofthetransmittingsignalsisprovidedbasedonthe instantaneous polarimetric ambiguity function matrix (IP-AFM), which provides thetheory foundation of the signal selection and parameter design for polarimetric radar. Tosuppress the measurement error that is produced by the cross-correlation between twoorthogonally polarized transmitting signals exists in the traditional PSM measurementmethod, the new PSM measurement method based on IP-AFM is proposed. To achievethe new PSM measurement, the IP-AFM estimation method is introduced.In Chapter 3, the calibration method for IPR is studied. Because the spatial polar-ization characteristics of antenna are neglected by the traditional polarimetric calibrationmethod, the new polarimetric calibration methods based on mental sphere or standard signal transmitter are introduced. With consideration of the spatial polarization charac-teristics of antenna, the PSM measurement error is calibrated by the new methods. Thecalibration difficulties are reduced, the calibration precision is improved. By studying theangle of arriving (AOA) measurement error, which is associated with the polarization ofthe received signals, the causation of the coupling measurement error between polariza-tion and AOA is analyzed. The calibration method for this coupling measurement error isintroduced.In Chapter 4, the target detection method for IPR is studied. The PSM measure-ment result of the received signals is assumed to be reciprocity in the traditional detectionmethod. Because of the influence of the spatial polarization characteristics of antenna,this assumption can not be satisfied in practice. With consideration of this influence, theoptimal polarimetric detection algorithm of stable target in Gaussian noise is studied, theengineering realization method of this algorithm is given. The optimal detection methodsof fluctuant target in Gaussian noise and stable target in non-Gaussian noise are also stud-ied. The detection performance is improved because of the usage of the cross-polarizationsignals under the non-reciprocity assumption.In Chapter5,theanti-jammingmethodforIPRisstudied. Toresolvetheproblemthatthe performance of traditional polarimetric filter is dropped when the jamming polariza-tion is changing, the instantaneous polarimetric filter (InPol-filter) is introduced. ThroughInPol-filter, theinterferencethatpresentsinthetime-frequencyareaofthetargetbackscat-tering can be detected and suppressed automatically after the polarization estimation. Andthesuppressionperformanceofthevariablypolarizedjammingisimproved. ThePSMes-timation method based on the outputs processed by polarimetric filter is given. Take thejamming in midcourse of missile trajectory as the typical example, the polarization track-ing filter to suppress the polarization modulation jamming is introduced. The jammingsuppression performance is improved by the polarization tracking filter comparing withthe traditional polarization filter with invariable receiving polarization. The decoy distin-guishmethodoffull-polarimetricmodulationdecoyarealsostudied,thedecoydistinguishability of IPR is improved.更多还原