机载雷达模式下海杂波模型及洋流估计方法研究

With the more importance of the radar detecting the sea, the difference between the sea clutter and ground clutter is necessary to study deeply. The radar echo is affected by the moving of both the platform and the sea clutter under airborne radar, so the target detection and the sea information extraction under sea condition are more difficult. In the mode of the airborne radar observing the sea, this project focuses on the sea clutter model and the estimation of the sea surface current in the observation area. This project mainly includes three aspects. (1) A method of combining multi goodness of fit indexes is proposed. The amplitude distribution models of the sea clutter under the airborne radar for different beam sights are studied with this method, which provides the basis for the obtainment of the target detection threshold. (2) Extract the variant orbital velocity component which affects the radar clutter spectrum from many velocity components. Combining with the amplitude distribution model of the sea clutter, the multi-channel space time signal model including sea clutter moving is established. Then the effect of the sea clutter on the performance of the target detection is analyzed. (3) Under the circular scanning model, the amplitude distribution model of the sea clutter is used to choose the sea clutter data with good coherence. By the variation curve of the Doppler center shifts with the scan angles, the magnitude and direction of the current velocity can be exactly acquired. The study of this project can provide theoretical basis and technology support for the obtainment of the target and sea information of the sea-surveillance radar.

随着雷达对海探测的重要性日益凸显，海杂波不同于地杂波的特性有待深入研究。机载雷达模式下，雷达回波同时受到平台与海杂波运动的影响，导致海洋背景下的目标检测及海洋信息提取更加困难。针对机载雷达对海观测模式，本项目重点研究海杂波模型及观测区海面洋流估计问题，主要包括三个方面：（1）提出一种结合使用多种拟合度指标的方法，研究机载雷达下海杂波在不同波束视线下的幅度分布模型，给后续目标检测门限的确定提供依据；（2）在诸多海面运动速度中，提取影响雷达杂波谱的时变轨道速度分量，结合海杂波幅度分布模型，建立考虑海杂波运动的多通道空时信号模型，进而分析海杂波对目标检测性能的影响；（3）采用环视雷达扫描模式，借助海杂波幅度分布模型挑选一致性较好的海杂波数据，利用多普勒谱中心偏移随扫描角的变化曲线，准确求取洋流速度的大小和方向。本项目研究可为海洋监视雷达获取目标和海洋信息提供一定的理论基础和技术支持。

围绕着雷达对海探测的重点问题，本项目聚焦了海杂波的相关性质并建立了海杂波模型。本项目围绕机载雷达海杂波数据，提出了直方图拟合度结合图形拟合度的幅度分布模型判定方法，确定了中等擦地角下海杂波的幅度分布模型。建立了基于确定海杂波速度的多通道空时信号模型并分析其谱特性及处理性能，并提出了利用增益权处理共形阵海杂波的方法。利用分布模型辅助估计海面洋流速度大小与方向，并用实测数据进行了验证。本项目执行期间，在国内外重要刊物和会议上发表论文7篇，其中SCI检索3篇，EI检索4篇，申请专利6项，多次参加相关领域知名学术交流与学术会议。本项目对于运动平台下的对海探测有重大意义，对于实际系统中的海杂波处理和海面目标检测有比较广阔的应用前景。