高频雷达杂波背景下的舰船检测方法研究
发布时间：2019-01-16 02:09
【摘要】：天波超视距雷达(OTHR)是一种特殊的雷达体制,利用电离层对雷达信号的反射作用进行目标探测。OTHR作用距离远,覆盖范围大,具有很高的国防和军事价值。但是目前天波超视距雷达短相干积累条件下的舰船检测比较困难,这主要是因为舰船和海杂波的多普勒频率接近,雷达回波谱中舰船目标容易被海杂波一阶回波遮蔽。本文主要研究OTHR的舰船检测问题,各章节的主要工作如下:说明了天波雷达的工作原理和军事价值,结合其发展历史和现状介绍了OHTR舰船检测的研究意义和存在的问题。阐述了OTHR的信号处理流程,介绍了时域、空域和多普勒域的处理方法;分析了高频雷达海洋回波谱的特性,基于Barrick导出的散射强度公式模拟了海洋回波谱,介绍了海态、雷达工作参数和电离层等因素对回波谱的影响。目前工程上解决海杂波遮蔽问题的方法主要有两类,一类是海杂波循环对消法,通过减去正弦信号的方法抑制海杂波;另一类是高分辨谱估计方法,通过较高的频率分辨率在多普勒域将目标和海杂波区分开。本文首先研究了海杂波循环对消法的理论知识和实现方法,分别使用Root法,FFT相位分析法和APES方法进行海杂波对消,实现了海杂波的抑制。然后介绍了两种超分辨谱估计方法,即Capon和MUSIC算法,通过仿真和实测数据的处理分别验证了两种算法的有效性并对其性能做了简要的分析。某些情况下,电离层的层次性分布会导致多模传播的发生,使得一个距离单元内的多普勒谱中存在多对Bragg峰,传统方法海杂波对消和高分辨谱估计方法均无法将目标和多个海杂波一阶谱峰区分开来。本文针对多模传播的情况,研究一种基于杂波统计特性的一阶峰匹配算法,该算法利用同一传播模式下的正负一阶峰多普勒频率差恒定的特性对海杂波一阶谱峰配对从而区分舰船目标和海杂波一阶谱峰,实现舰船目标的检测。仿真和实测数据的处理验证了该算法的有效性。
[Abstract]:Sky-wave over-the-horizon radar (OTHR) is a special radar system, which detects targets by ionospheric reflection of radar signals. The OTHR has a long range and a wide coverage, which has high national defense and military value. However, it is difficult to detect ship under the condition of short coherent integration of sky wave over-the-horizon radar. This is mainly due to the fact that the Doppler frequency of ship and sea clutter is close, and the ship target in radar echo spectrum is easy to be obscured by the first order echo of sea clutter. This paper mainly studies the ship detection of OTHR. The main work of each chapter is as follows: the working principle and military value of sky-wave radar are explained, and the research significance and existing problems of OHTR ship detection are introduced according to its development history and present situation. The signal processing flow of OTHR is described, and the processing methods of time domain, spatial domain and Doppler domain are introduced. The characteristics of ocean echo spectrum of high frequency radar are analyzed. The scattering intensity formula derived by Barrick is used to simulate the ocean echo spectrum. The influence of sea state, radar operating parameters and ionosphere on the echo spectrum is introduced. At present, there are two kinds of methods to solve the sea clutter masking problem. One is the sea clutter cyclic pair elimination method, which can suppress the sea clutter by subtracting sinusoidal signals. The other is the high-resolution spectral estimation method, which distinguishes the target from the sea clutter in the Doppler domain by high frequency resolution. In this paper, the theoretical knowledge and implementation method of sea clutter cyclic pair cancellation method are studied. Root method, FFT phase analysis method and APES method are used to eliminate sea clutter, respectively, and the suppression of sea clutter is realized. Then two super-resolution spectral estimation methods, Capon and MUSIC, are introduced. The effectiveness of the two algorithms is verified by the processing of simulation and measured data, and their performance is analyzed briefly. In some cases, the hierarchical distribution of the ionosphere will lead to the occurrence of multimode propagation, resulting in the existence of multiple pairs of Bragg peaks in the Doppler spectrum of a distance unit. The traditional methods, such as sea clutter cancellation and high resolution spectral estimation, can not distinguish the first order spectral peaks between targets and multiple sea clutter. In this paper, a first-order peak matching algorithm based on the statistical characteristics of clutter is proposed for multimode propagation. The algorithm makes use of the constant Doppler frequency difference between positive and negative first order peaks in the same propagation mode to match the first order spectral peaks of sea clutter to distinguish the ship targets from the first order spectral peaks of sea clutter and to realize the detection of ship targets. The validity of the algorithm is verified by simulation and the processing of measured data.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：E925.6;TN958.93
本文编号：2409353
[Abstract]:Sky-wave over-the-horizon radar (OTHR) is a special radar system, which detects targets by ionospheric reflection of radar signals. The OTHR has a long range and a wide coverage, which has high national defense and military value. However, it is difficult to detect ship under the condition of short coherent integration of sky wave over-the-horizon radar. This is mainly due to the fact that the Doppler frequency of ship and sea clutter is close, and the ship target in radar echo spectrum is easy to be obscured by the first order echo of sea clutter. This paper mainly studies the ship detection of OTHR. The main work of each chapter is as follows: the working principle and military value of sky-wave radar are explained, and the research significance and existing problems of OHTR ship detection are introduced according to its development history and present situation. The signal processing flow of OTHR is described, and the processing methods of time domain, spatial domain and Doppler domain are introduced. The characteristics of ocean echo spectrum of high frequency radar are analyzed. The scattering intensity formula derived by Barrick is used to simulate the ocean echo spectrum. The influence of sea state, radar operating parameters and ionosphere on the echo spectrum is introduced. At present, there are two kinds of methods to solve the sea clutter masking problem. One is the sea clutter cyclic pair elimination method, which can suppress the sea clutter by subtracting sinusoidal signals. The other is the high-resolution spectral estimation method, which distinguishes the target from the sea clutter in the Doppler domain by high frequency resolution. In this paper, the theoretical knowledge and implementation method of sea clutter cyclic pair cancellation method are studied. Root method, FFT phase analysis method and APES method are used to eliminate sea clutter, respectively, and the suppression of sea clutter is realized. Then two super-resolution spectral estimation methods, Capon and MUSIC, are introduced. The effectiveness of the two algorithms is verified by the processing of simulation and measured data, and their performance is analyzed briefly. In some cases, the hierarchical distribution of the ionosphere will lead to the occurrence of multimode propagation, resulting in the existence of multiple pairs of Bragg peaks in the Doppler spectrum of a distance unit. The traditional methods, such as sea clutter cancellation and high resolution spectral estimation, can not distinguish the first order spectral peaks between targets and multiple sea clutter. In this paper, a first-order peak matching algorithm based on the statistical characteristics of clutter is proposed for multimode propagation. The algorithm makes use of the constant Doppler frequency difference between positive and negative first order peaks in the same propagation mode to match the first order spectral peaks of sea clutter to distinguish the ship targets from the first order spectral peaks of sea clutter and to realize the detection of ship targets. The validity of the algorithm is verified by simulation and the processing of measured data.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：E925.6;TN958.93
【参考文献】
相关硕士学位论文 前1条
1 邵昕;天波超视距雷达（OTHR）抗瞬态干扰及海杂波抑制研究[D];电子科技大学;2007年
，本文编号：2409353
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