低频段外辐射源雷达信号处理若干关键技术研究

发布时间：2018-06-26 18:29

  本文选题：低频段 + 外辐射源雷达　； 参考：《武汉大学》2016年博士论文

【摘要】：外辐射源雷达因具有绿色环保、抗隐身特性、抗辐射摧毁、低成本易部署等诸多优点引起了国内外学者的关注而成为近十年来的研究热点。随着国内外研究机构对外辐射源雷达深入而广泛的研究,当前在理论研究和技术实现上已出现不少突破性进展。与此同时,新的应用场景的不断出现也带来了许多新的研究课题,亟待解决。围绕着特定应用场景中如何实现阵列排布的最优化、如何对直达波干扰进行有效抑制、如何实现信号的实时处理,本文就阵列信号处理若干关键技术进行了讨论与研究,具体工作如下：(1)针对常规阵型在外辐射源雷达特定应用场景中适应性差的问题,提出了适用于最远探测距离的方向性系数最优准则,以及适用于全方位最小定向误差的峰值旁瓣比(PSLR)准则,论证了阵列方向性系数与阵元坐标的关系、一维阵列间距微小扰动与旁瓣电平的关系,解决了两类典型场景中限定阵元数量情况下的外辐射源雷达阵列排布最优化问题。(2)基于DRM数字调幅广播的特点,提出了一种利用直达波频率导频信号的高频外辐射源雷达接收阵列幅相一致性校正新方法。首先介绍了DRM广播的信号结构,分析了其导频信号作为校正源的可行性,考虑到高频段电磁环境和传播环境的时变非平稳特性,接着提出了一种基于平移不变阵元偶在时间上优选直达波校正数据的方法,最后结合地波模式和天波传播模式高频外辐射源雷达实测多通道数据,比较了该方法与其他辅助定标源方法用于接收阵列校正的效果,分析结果证实了该方法的有效性。(3)针对常规自适应波束形成技术在外辐射源雷达强直达波干扰下效果差的问题,提出了基于线性约束最小方差(LCMV)的直达波零陷静态波束形成方案,以及利用协方差矩阵锥化(CMT)技术进行直达波零陷展宽的稳健自适应波束形成方案,在仿真分析基础上对该方案进行了实测数据处理验证,实现了外辐射源雷达对直达波干扰的有效抑制、降低了杂波谱功率、提高了系统目标检测性能。(4)针对单调频广播外辐射源雷达面临的带宽时变及RCS闪烁等问题,提出了多调频信号联合探测的实验方案,并利用武汉大学研制的多调频外辐射源雷达系统开展了外场实验验证。首先阐述了多调频广播外辐射源雷达的工作原理,在信号特性统计分析的基础上论证了多调频信号联合探测的必要性和优越性,推导了调频信号数量与目标检测概率的关系,最后展示了实测数据处理结果并对结果进行统计分析。(5)针对外辐射源雷达在使用较大带宽信号引起的处理难度增加问题,提出了基于GPU并行计算以实现DTMB信号实时处理的解决方案,分析了CUDA架构下的信号重构、杂波抑制、匹配滤波等算法的并行化处理流程,开发了模块化的程序软件,通过对不同时段多场连续数据的测试,实现8 MHz带宽信号了实时处理。
[Abstract]:External emitter radar has attracted the attention of scholars at home and abroad because of its advantages of green environment protection, anti-stealth, anti-radiation destruction, low cost and easy deployment, and has become a research hotspot in recent ten years. With the deep and extensive research of external emitter radar at home and abroad, there have been many breakthroughs in theoretical research and technical realization. At the same time, the emergence of new application scenes has brought many new research topics to be solved. Focusing on how to optimize array arrangement, how to suppress direct wave interference effectively, and how to realize real-time signal processing in a specific application scenario, this paper discusses and studies some key technologies of array signal processing. The main works are as follows: (1) aiming at the problem of poor adaptability in the specific application scene of conventional array external emitter radar, an optimal criterion of directivity coefficient suitable for the farthest detection range is proposed. And the peak sidelobe ratio (PSLR) criterion, which is suitable for the omnidirectional minimum orientation error, is discussed. The relationship between array directivity coefficient and array element coordinates, the relation between one-dimensional array spacing tiny disturbance and sidelobe level is proved. In this paper, we solve the problem of optimizing the array arrangement of external emitter radar in the case of limiting the number of array elements in two typical scenarios. (2) based on the characteristics of DRM digital AM broadcasting, A new method for correcting amplitude and phase coherence of high frequency external emitter radar receiving array using direct wave frequency pilot signal is proposed. Firstly, the signal structure of DRM broadcasting is introduced, and the feasibility of using the pilot signal as the correction source is analyzed. The time-varying non-stationary characteristics of the electromagnetic and propagation environments in the high frequency range are considered. Then a method based on the translational invariant array element pair to select the direct wave correction data in time is proposed. Finally, combined with the ground wave mode and the sky-wave propagation mode, the multi-channel data of the high-frequency external emitter radar are measured. The effectiveness of this method in receiving array correction is compared with that of other auxiliary calibration methods. The results show that the method is effective. (3) the conventional adaptive beamforming technique has poor effect under strong direct wave interference of external emitter radar. A direct zero trapping static beamforming scheme based on linear constrained minimum variance (LCMV) is proposed, and a robust adaptive beamforming scheme based on covariance matrix conization (CMT) is proposed. On the basis of simulation and analysis, the method is verified by practical data processing, which realizes the effective suppression of direct wave interference by external emitter radar, and reduces the power of clutter spectrum. The performance of system target detection is improved. (4) aiming at the problems of time-varying bandwidth and RCS scintillation in the external emitter radar with single FM broadcast, the experimental scheme of joint detection of multi-frequency modulation signals is proposed. The field experiments are carried out using the multi-FM external emitter radar system developed by Wuhan University. At first, the working principle of external emitter radar with multi-frequency modulation broadcasting is expounded, and the necessity and superiority of joint detection of multi-frequency modulation signals are demonstrated on the basis of statistical analysis of signal characteristics, and the relationship between the number of FM signals and the probability of target detection is deduced. Finally, the processing results of the measured data are shown and the results are statistically analyzed. (5) aiming at the problem of increasing the processing difficulty caused by the use of large bandwidth signals in the external emitter radar, This paper presents a solution to realize DTMB signal real-time processing based on GPU parallel computing, analyzes the parallel processing flow of signal reconstruction, clutter suppression, matched filtering and other algorithms under CUDA architecture, and develops a modularized program software. The 8 MHz bandwidth signal is processed in real time by testing the continuous data of different time periods.
【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN957.51
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本文编号：2071006