基于数据融合的星载分布式综合孔径微波辐射测量方法研究

To improve the spatial resolution of the passive microwave remote sensing, the ideal that "aperture synthesis" was introduced, and the microwave aperture synthesis radiometers (ASRs) were proposed, which forms a large equivalent aperture antenna by a thinned array with many small-aperture antennas. However, ASRs have the performance of imaging with high resolution at the expense of the complexity of the system hardware and signal processing, and their spatial resolution are not completely meet the demand of practical applications. To further improve the spatial resolution, a measurement method of space-borne distributed ASRs based on data assimilation is proposed in this project, which refers to the ideal of the data assimilations in the combined active and passive microwave remote sensing and uses the technology of the small satellite formation. This method makes use of the distributed small satellites in the same orbit as the platforms of the ASRs, which is composed of many small scale ASRs. In this method, the satellite attitudes are adjusted to make the original grid on Earth of the brightness temperature of the small scale ASRs as certain rules overlap. Finally, a higher spatial resolution is obtained by a data assimilation method. The proposed method in this project provides a new method for passive microwave remote sensing of the Earth with high resolution.

为了提高被动微波遥感的空间分辨率，“综合孔径”的思想被引入被动微波遥感中，提出了综合孔径微波辐射计，其是通过稀疏的小口径天线阵列合成一个等效的大口径天线；然而，其是以系统硬件和信号处理复杂度为代价的，且其空间分辨率还无法完全满足实际应用需求。为了进一步提高被动微波遥感的空间分辨率，本项目提出了基于数据融合的星载分布式综合孔径微波辐射测量方法。该方法借鉴了主被动数据融合的思想，利用小卫星编队技术，充分利用各自的优点，以同一轨道上的小卫星编队作为分布式综合孔径微波辐射系统的平台，该系统由多个小型综合孔径微波辐射计组成，通过调整卫星的姿态使得小型综合孔径微波辐射计在地面的亮温原始网格按照一定的规则重叠，最终利用数据融合方法获取更高的空间分辨率。本项目提出的微波辐射测量方法可为高分辨率对地被动微波遥感提供一种新途径。

目前，高分辨率是空间被动微波遥感研究的重点之一，其是目前满足被动微波遥感各种应用需求的关键。尽管近二三十年发展起来的综合孔径微波辐射测量技术能提高被动微波遥感的分辨率，但是以系统硬件和信号处理复杂度为代价的，且其空间分辨率还无法完全满足实际应用需求。.本项目针对高分辨率被动微波遥感的需求提出了基于数据融合的星载分布式综合孔径微波辐射测量方法。该方法核心思想是以多个小卫星搭载多个小型综合孔径微波辐射计系统，利用数据融合方法获取更高的空间分辨率。本项目从测量原理和模型、关键性能与阵列优化排布、误差分析与校正以及数据融合等方面进行研究，建立了基于数据融合的星载分布式综合孔径微波辐射测量模型，分析了其关键性能指标、提出了基于基线权重的天线阵列优化算法、在轨外定标方法和数据融合算法，实验验证了基于数据融合算法的可行性。研究结果表明，提出基于数据融合的星载分布式综合孔径微波辐射测量方法是可行性的，其为高分辨率对地被动微波遥感提供一种新途径。.在本项目研究的启发下，提出了基于空间拼接的星载分布式综合孔径微波辐射计测量技术；同时，为了拓展高分辨率微波辐射测量技术的应用，提出了将高分辨率微波辐射测量技术应用于海面目标探测，建立了海面目标微波辐射被动探测理论，分析了复杂天气及海况对目标探测性能的影响，提出了一种基于亮温图像的海面目标探测算法，并利用其它项目提供的机会开展了机载验证实验，验证了海面目标微波辐射被动探测相关理论和技术的可行性，其可为海面目标全天时、全天候、广域隐蔽性探测跟踪与识别提供一种新的技术途径。