基于MIMO-SAR的宽幅大覆盖海流反演方法研究

Sea-surface currents can impose influences and constraints on oceanic physical, chemical and biological processes, and thus measurement of sea currents and understanding of laws of currents are of great significance be it for the oceanography research or for fisheries, shipping, pollution discharge, etc. Spaceborne synthetic aperture radar (SAR) systems, capable of providing all-weather, day and night remote sensing of the ocean surfaces, have proven to be an excellent candidate for the ocean dynamical environment surveillance. However, the conventional current retrieval methods (e.g., the SAR along-track interferometry method) can only measure the radial velocity component of currents, having some difficulties in measuring the azimuthal velocity component. Besides, because the baseline of the existing spaceborne SAR systems is rather short, the potential to further improve the accuracy of sea-surface current retrieval is confined. Another drawback of the existing current-retrieval methods is that the range coverage is very limited. In this research, we attempt to design a suitable multiple-input multiple-output SAR (MIMO-SAR) system that can retrieve 2-D vector sea-current fields with wide-swath coverage and high precision. The algorithm for the retrieval of the 2-D current vector linked to the proposed MIMO-SAR system is also developed. By these studies, this project is expected to make breakthrough in some crucial theories and approaches, and further the application of MIMO SAR to ocean dynamical environment surveillance.

海流对海洋中多种生物过程、化学过程和物理过程都有制约作用，掌握全球范围的海洋流场的信息和规律无论是对于海洋学本身的研究，还是与海洋密切相关的渔业、航运等都有重要意义。星载合成孔径雷达（SAR）由于具有全天候全天时的特点，可以很好地对海洋动力环境进行遥感探测。然而，传统SAR海流反演方法（如SAR干涉法）通常只能反演海流的径向速度而很难得到方位向速度。现有的星载干涉SAR系统的基线长度较短，因此进一步提高这些星载系统的流场反演精度往往受到限制。再者，现有的星载SAR系统的距离向覆盖范围还不能满足实际应用的需求。本研究试图设计一种MIMO-SAR系统（多输入多输出SAR）使之能够实现宽幅大覆盖条件下的流场高精度反演，并提出相应的算法，突破一些关键性的理论和方法，进一步推进海洋环境探测理论与技术的发展。

海流对海洋中多种生物过程、化学过程和物理过程都有制约作用，掌握全球范围的海洋流场的信息和规律无论是对于海洋学本身的研究，还是与海洋密切相关的渔业、航运等都有重要意义。星载合成孔径雷达（SAR）由于具有全天候全天时的特点，可以很好地对海洋动力环境进行遥感探测。然而，传统SAR海流反演方法（如SAR干涉法）通常只能反演海流的径向速度而很难得到方位向速度。再者，现有的星载SAR系统的距离向覆盖范围还不能满足实际应用的需求。本研究设计了一种MIMO-SAR系统（多输入多输出SAR）使之能够实现宽幅大覆盖条件下的流场高精度反演，并且我们提出一种新算法，用于顺轨干涉SAR测量非均匀场景的海表面流时（例如沿海水域或河流）抑制方位模糊，突破一些关键性的理论和方法，进一步推进海洋环境探测理论与技术的发展。