基于MIMO雷达的海面场景成像模拟及海浪信息反演方法

Sea surface imaging simulation and sea wave retrieval method based on MIMO radar

多输入多输出(multiple input multiple output,MIMO)雷达作为一种新型的雷达体制,其成像兼具高分辨率与实时性的优点,为海面成像观测提供了一种新的技术平台.基于MIMO雷达的海面成像技术目前还处于探索性研究阶段,若干关键问题需要进一步解决和完善.针对这一问题,本文从MIMO雷达海面场景模拟和基于MIMO雷达图像的海流与海浪信息反演两个方面展开了研究.在MIMO雷达海面场景成像模拟方面,针对目前利用MIMO雷达对海面进行成像的外场实验条件尚不具备的问题,提出一种基于双尺度模型的MIMO雷达海面场景成像模拟方法.利用曲率修正的双尺度方法和阴影效应构建海面的后向散射截面分布模型,以此为目标采用舰载MIMO雷达成像系统与反向投影成像算法对其作成像处理.在海流与海浪信息反演方面,利用所得的MIMO雷达图像反演海表面流速与海浪参数.反演海流时,采用加权最小二乘法,在海浪参数反演时,利用成像模拟仿真实验确定了MIMO雷达的调制传递函数,在此基础上获得了海浪谱与海浪参数反演结果.相比于航海导航雷达,基于MIMO雷达的有效波高,主波波向与上跨零周期反演都具有更高的精度.仿真实验验证了基于MIMO雷达的海面成像以及海流海浪信息反演相较于航海导航雷达的优越性.

Multiple-input-multiple-output（MIMO） radar is an emerging radar system that has significant potential. MIMO radar can provide a higher resolution real-time imaging solution than traditional phased-array radar schemes and is well suited for the imaging of complex sea surfaces. MIMO radar imaging of sea scenes is still in the exploratory stage and several key issues need to be resolved and improved further. With the objective of achieving sea surface monitoring using MIMO radar, some basic research work on MIMO radar imaging simulation of sea surfaces, and MIMO radar sea current and wave information retrieval were conducted in this study.In order to analyze the feasibility and advantages inherent in MIMO radar imaging simulation of sea surfaces,ocean surface imaging based on MIMO radar was carried out via computer simulation. The curvature-modified two-scale method and shadowing modulation were used to build a back scatter section distribution model of a sea surface, which is taken as the object of MIMO radar imaging. In terms of sea current and wave information retrieval from MIMO radar images, the weighted least square method was used to fully explore the advantages of MIMO radar surface imaging. While retrieving the wave spectrum and wave parameters, the modulation transfer function of MIMO radar was determined via imaging simulation experiments. The retrieved significant wave height, main wave direction, and cross-zero cycle from MIMO radar images were found to be more precise than those from navigation radar images. The simulation results obtained also showed that MIMO radar sea surface imaging and parameter retrieval are superior to and more effective than marine radar.