天波超视距雷达干扰与杂波信号处理技术研究

发布时间：2017-12-31 16:18

本文关键词：天波超视距雷达干扰与杂波信号处理技术研究　出处：《西安电子科技大学》2016年博士论文　论文类型：学位论文

【摘要】：雷达在电子战中扮演了重要的角色,其担负着预警、探测、跟踪、识别、制导等许多重要的任务,因此被称为是战场中的“千里眼”。随着科技的发展和信号处理手段的提高,现代雷达朝着多元化和多体制的方向发展。在不同体制的雷达中,天波超视距雷达(Over-the-Horizon Radar,OTHR)以其独特的超视距探测优势引起国内外学者的关注。作为一种复杂的雷达系统,天波超视距雷达工作在高频段(3~30 MHz),通过利用电离层对高频电磁波的折射实现对舰船、飞机、导弹等目标的远距离探测,从而用于早期的预警功能,同时天波超视距雷达还具有反隐身、超低空探测、对抗反辐射导弹探测、综合情报监测等优点。尽管天波超视距雷达具有上述诸多优势,但同时也面临着很多挑战。天波超视距雷达的性能受外界环境因素影响较大,因此其信号处理过程也较普通微波雷达复杂的多。瞬态干扰抑制和杂波背景下舰船目标检测一直是天波超视距雷达信号处理中的重点和难点,许多学者运用现代信号处理方法对上述问题进行研究,并取得了一定的成效。近年来,低秩矩阵恢复理论得到了广泛的研究与发展,并在图像信号处理、雷达信号处理等领域得到了成功的应用。本文主要将低秩矩阵恢复理论引入到天波超视距雷达信号处理中,研究和探讨了低秩矩阵恢复理论在瞬态干扰抑制、杂波抑制、舰船目标检测等方面的应用,文中最后还探讨了利用现代信号处理方法中的盲信号处理技术对舰船目标进行检测。归纳起来,主要包括以下几个部分:第一部分主要是对低秩矩阵恢复理论进行了分析,低秩矩阵恢复包括了低秩矩阵填充(Matrix Completion,MC)、低秩矩阵表示(Low-rank Representation,LRR)以及鲁棒主成分分析(Robust Principal Component Analysis,RPCA)三个方面,文中主要围绕RPCA理论展开讨论,并详细介绍了几种典型的RPCA算法。第二部分对天波超视距雷达中瞬态干扰抑制方法进行了讨论。通过对瞬态干扰的类型和特点进行分析可知,其在慢时间域上表现为能量强,持续时间短。将回波信号某一距离单元的信号构造为Hankel矩阵,在Hankel矩阵中,瞬态干扰信号则具有一定的稀疏性;根据回波信号模型,目标和杂波信号在Hankel矩阵中具有低秩性的特点。因此本文提出了将低秩矩阵恢复模型应用到瞬态干扰抑制问题上,并提出了一种基于复数条件下RPCA的瞬态干扰抑制方法。该方法的优点是无需对瞬态干扰信号的位置进行定位,同时还可以避免对缺损信号进行数据重构,能够实现对回波信号中多个瞬态干扰信号或能量较弱的干扰信号信号进行抑制;此外算法还提高了回波信号的信噪比,可以改善OTHR中弱小目标的检测性能。第三部分主要讨论了天波超视距雷达中短相干积累条件下杂波抑制问题。对于舰船等慢速目标来说,其多普勒频率往往比较低,而天波超视距雷达回波信号中包含了强大的分布于零频附近杂波信号,因此目标信号很容易被杂波信号湮没,在对这类目标进行检测时通常需要对强大的杂波进行抑制。一种方法是通过增加相干积累时间提高频率分辨率的方法实现杂波和信号的分离,但提高相干积累时间会带来其他的诸如电离层扰动概率增大等问题。考虑到回波信号中相邻距离单元上杂波信号表现出很强的相关性的特点,本文提出了一种基于RPCA的短相干积累条件下杂波抑制方法。利用相邻距离单元的回波信号构造距离-扫频信号矩阵,在该信号矩阵中,杂波信号表现出一定的低秩性;目标信号往往存在于一到两个距离单元,因此在矩阵中表现出一定的稀疏性;采用低秩分解的方法对低秩的杂波信号与稀疏的目标信号进行分离,从而实现对杂波信号的抑制。第四部分首先对非连续采样导致数据缺失的OTHR目标检测问题进行了探讨,目前针对这类问题的研究比较少,本文在前人的研究基础上,提出了一种基于矩阵填充的目标检测方法,利用目标和杂波信号在重构的Hankel矩阵中具有低秩性的特点,在时域上对缺失的数据进行补全,从而实现对回波谱的重构并完成目标的检测,与传统的基于压缩感知方法相比具有更好的检测效果。接着研究了利用盲信号处理技术对回波信号中杂波、目标信号进行分离,从而实现杂波背景下目标的检测。考虑到目标信号和杂波信号源个数未知,且目标信号与杂波信号在时域和频域均可能存在交叠的问题,传统的盲信号处理方法效果并不理想,因此本文提出了一种基于张量正则分解的时频混叠盲信号处理方法,利用该方法对天波超视距雷达中的回波信号进行处理,实现对目标信号的检测。
[Abstract]:The radar plays an important role in electronic warfare, which bears a warning, detection, tracking, recognition, guidance and many other important tasks, so it is called the battle of the "TeleEye". With the development of science and technology and signal processing methods improve modern radar toward pluralistic and multi system the direction of development. In different radar OTHR (Over-the-Horizon, Radar, OTHR) with its unique advantages over the horizon detection by domestic and foreign scholars. As a kind of complex radar system, OTHR working in high frequency band (3~30 MHz), by using the ionospheric of ships, aircraft the refraction of high-frequency electromagnetic waves, long-range missile target detection, which can be used early warning function, at the same time OTHR also has anti stealth, low altitude detection, anti radiation missile detection, comprehensive information monitoring etc. Despite the advantages. The OTHR has many advantages, but also faces many challenges. The larger influence the performance of OTHR is affected by environmental factors, so the signal processing is more complex than ordinary microwave radar ship target. The transient suppression and clutter background detection has been the focus and difficulty over the horizon radar signal processing, many scholars use modern signal processing methods to study the above problems, and achieved certain results. In recent years, the recovery of low rank matrix theory has been extensive research and development, and in image signal processing, radar signal processing has been successfully applied in this paper. The low rank matrix recovery theory into the sky wave over the horizon radar signal processing, study and discuss the recovery of low rank matrix theory in suppressing transient interference, clutter suppression, ship The application of ship target detection, this paper finally discusses blind signal processing technology with modern signal processing method to detect ship targets. To sum up, mainly includes the following parts: the first part is mainly on the recovery of low rank matrix theory are analyzed, including the recovery of low rank matrix low rank matrix filling (Matrix Completion MC), said the low rank matrix (Low-rank Representation, LRR) and robust principal component analysis (Robust Principal Component Analysis, RPCA) three aspects, this paper mainly focuses on the theory of RPCA is discussed, and introduced several typical RPCA algorithm are discussed. The transient suppression method of second part on the horizon skywave radar. Analysis shows the types and characteristics of transient interference, the slow time domain showed strong energy, short duration. The echo signal of a The distance signal tectonic unit for the Hankel matrix, Hankel matrix, the transient interference signal has a certain sparseness; according to the echo signal model, the characteristics of target and clutter signals with low rank of the Hankel matrix. This paper presents low rank matrix recovery model is applied to the transient suppression problem, and a method was proposed to suppress the transient interference of complex conditions based on RPCA. The advantage of this method is no need to locate the position of transient interference signal, but also can avoid the data reconstruction of the defect signal can suppress interference signals to achieve echo signal in multiple transient interference signal or weak energy; in addition the algorithm also improves the signal to noise ratio can improve the OTHR detection performance of weak and small targets. The third part mainly discusses the OTHR in short coherent conditions Under the clutter suppression problem. For the ship slow target, the Doppler frequency is relatively low, and the sky wave over the horizon radar echo signal contains strong clutter signal distribution in near zero frequency, so the target signal can easily be clutter annihilation, in this category standard detection is usually required to inhibit in the strong clutter. One method is to separate the clutter signal and the method to improve the frequency resolution by increasing the coherent time, but increase the coherent time will bring other ionospheric disturbances such as probability problem. Considering the adjacent signal distance unit clutter signal shows the characteristics of a strong correlation the paper presents a short coherence clutter suppression method based on RPCA accumulation conditions. By constructing the signal from the adjacent distance unit of the sweep signal in the matrix. The signal matrix, the clutter signal shows a low rank of the target signal; often exists in a distance to two units, so as to show a certain sparseness in the matrix; the target signal clutter signal and sparse low rank method using low rank decomposition of the separation, suppression of the clutter signal from the first part of the fourth. And the realization of non continuous sampling OTHR target detection problems lead to missing data are discussed, current research on this problem is relatively small, on the basis of previous research, proposed a target detection method based on the characteristics of the matrix, target and clutter signals with low rank in the Hankel matrix reconstruction of the missing data in the time domain to complete, so as to realize the reconstruction of the echo spectrum and target detection, and the traditional compressed sensing method based on contrast detection has better Results. Then study the use of blind signal processing of echo signal in clutter, target signal separation, so as to realize the target detection in clutter background. Considering the target signal and the clutter signal source number is unknown, and the target signal and the clutter signal can exist overlapping problem in both time domain and frequency domain. The traditional methods of blind signal processing effect is not ideal, so this paper proposes a blind signal processing method based on frequency tensor canonical decomposition, using the method of echo signal of OTHR in processing, realize the target detection signal.

【学位授予单位】：西安电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN957.51

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