船载高频地波雷达一阶海洋回波分析与处理

发布时间：2018-03-20 15:15

本文选题：船载高频地波雷达　切入点：一阶海洋回波　出处：《武汉大学》2017年硕士论文　论文类型：学位论文

【摘要】：高频地波雷达能够对特定海域实现超视距、大范围、全天时的海洋环境监测,是进行海洋表面风、浪、流参数提取,以及对船舶、低空飞机进行目标检测和跟踪的良好选择。与采用大口径相控阵天线的高频地波雷达系统相比,便携式系统具有结构简洁、占地面小、安装维护方便的特点,利用超分辨率算法也能达到媲美大型阵列的角度分辨能力。根据架设位置不同,高频地波雷达分为岸基与船载两种形式,船载模式继承了岸基雷达的特性,附加了灵活探测的优点,同时相对地提高了雷达探测范围和环境适应能力。因此船载便携式高频地波雷达在军民两用上具有强大的优势与广阔的应用前景。武汉大学雷达与信号处理实验室于2013年在广西防城港海域进行了船载高频地波雷达的探测性试验,旨在研究回波特性、海洋参数提取和目标检测的性能。本文基于此次试验,对船载模式下的一阶海洋回波的展宽机理、海面径向流场与风向的反演、展宽回波的抑制,进行了理论研究与实测数据处理,取得了一定的成果。主要的研究工作包括:1)通过构建走航条件下的探测模型,分析了船速、海流、风向和探测张角对一阶海洋回波谱形态的影响,解释了船载试验实测多普勒谱区别于岸基情况的原因。2)分析船载雷达反演径向流场可行性,详述各处理步骤的原理与结果,流速及方位角分布情况符合理论模型,最终给出径向流场的反演结果;基于多普勒谱随风向发生形态变化的特点,提出一种风向估计的新方法,解决了单基地雷达的风向模糊问题,估计结果与实际风向较吻合。3)研究了船载雷达中单根单极子交叉环天线进行空时自适应处理抑制海杂波的性能,基于空间分解的原理,提出一种海杂波抑制方法。该方法能够抑制展宽的海洋回波并凸显目标,但会使目标方位角发生变化,为此提出了添加调整系数,补偿导向矢量和增加天线阵元的办法来消除此影响。
[Abstract]:High frequency ground wave radar can be used to monitor the marine environment in a wide range and all day in a certain sea area. It is used to extract the parameters of wind, wave and current on the ocean surface, as well as to extract the parameters of the ship. Compared with the high frequency ground wave radar system with large aperture phased array antenna, the portable system has the advantages of simple structure, small ground occupation, convenient installation and maintenance. The super-resolution algorithm can also achieve angular resolution comparable to large array. According to the different position, the HF ground wave radar can be divided into shore-based and shipborne, and the shipborne mode inherits the characteristics of shore-based radar. With the advantage of flexible detection, Therefore, shipborne portable HF ground wave radar has strong advantages and broad application prospects in both military and civilian applications. Wuhan University Radar and signal processing experiment. On 2013, the laboratory conducted the detectability test of shipborne HF ground wave radar in Fangchenggang, Guangxi. The purpose of this paper is to study the characteristics of echo, the performance of ocean parameter extraction and target detection. Based on this experiment, the broadening mechanism of the first order ocean echo, the inversion of the radial current field and wind direction of the sea surface, and the suppression of the broadening echo are studied in this paper. Theoretical research and practical data processing have been carried out, and some achievements have been made. The main research work includes: 1) the ship velocity and current are analyzed by constructing the detection model under the condition of sailing. The influence of wind direction and detecting angle on the first order ocean echo spectrum morphology is explained. The reason why the measured Doppler spectrum of shipboard test differs from the condition of shore base is explained. The feasibility of ship borne radar inversion of radial flow field is analyzed. The principle and results of each processing step are described in detail. The distribution of velocity and azimuth is in accordance with the theoretical model. Finally, the inversion results of radial flow field are given, and a new method of wind direction estimation is proposed based on the characteristics of Doppler spectrum changing with wind direction. The fuzzy problem of wind direction of mono-static radar is solved. The estimated results are in good agreement with the actual wind direction. 3) the performance of space-time adaptive processing and suppression of sea clutter by single monopole cross loop antenna in shipborne radar is studied, based on the principle of spatial decomposition. In this paper, a sea clutter suppression method is proposed, which can suppress the wide ocean echo and highlight the target, but it can change the azimuth of the target. Compensate the guidance vector and increase the antenna element to eliminate this effect.
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN957.51

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