林下隐目标极化干涉相干探测方法研究

The detection of obscured targets hidden underneath forest is not only crucial for strategic decisions of both battle sides, but also in the fight against illegal activities of terrorism. However, it is difficult to accurately detecting obscured targets only by reducing the operating frequency. The model of obscured targets hidden underneath forest is established based on polarimetric SAR interferometry (POLINSAR), then clutter suppression of scene and the effective detection methods of obscured man-made targets are proposed to achieve the goal. The project will do the followings: the research is based on the polarimetric and interferometric experimental data of forest vegetation, soil and typical man-made targets. The geometric model and the electromagnetic scattering model of them are established. Through the maximum scattering ratio of soil and forest vegetation calculated by interferometric coherence, a filter is designed to suppress the clutter of forest vegetation. Polarization coherence of pixel element projected on two polarization vectors with small difference of scattering mechanism is used as detector. The obscured targets hidden underneath forest are detected with the constant false alarm probability (CFAR) method. Through constructing the POLINSAR hard-in-loop measurement system in an anechoic chamber, the model and methods will be validated. This project will help lay an academic foundation for the application of POLINSAR to the detection of obscured target hidden underneath forest.

森林覆盖下隐藏人造目标探测不仅对于作战双方的战略决策至关重要，在打击恐怖主义非法活动方面也具有重大意义。仅通过降低频率的方法难以实现林下隐目标的准确探测。本项目以极化干涉合成孔径雷达（SAR）为应用背景，提出场景的杂波抑制和隐藏人造目标有效检测方法，从而实现林下隐目标的探测。具体方法是：以森林植被、土壤及典型人造目标的后向散射实验数据为研究基础，建立极化干涉SAR林下隐目标探测场景的几何模型和电磁散射模型。通过干涉相干系数计算地表与森林植被回波幅度比的最大值，设计滤波器消除森林植被的杂波干扰。提出利用散射机制具有微小差异的两组极化向量，将像素元在两组极化向量上投影的极化相干系数作为检测器，结合雷达目标的恒虚警率检测方法，有效检测出隐藏人造目标。通过在微波暗室内构建极化干涉SAR半实物仿真系统，对模型及方法进行试验验证。本项目的研究将为极化干涉SAR在林下隐目标探测方面的应用奠定理论基础。

森林覆盖下隐藏人造目标探测不仅对于作战双方的战略决策至关重要，在打击恐怖主义非法活动方面也具有重大意义。仅通过降低频率的方法难以实现林下隐目标的准确探测。本项目以极化干涉合成孔径雷达（SAR）为应用背景，提出场景的杂波抑制和隐藏人造目标有效检测方法，从而实现林下隐目标的探测。项目主要研究了以下内容：以森林植被、土壤及典型人造目标的后向散射实验数据为研究基础，建立极化干涉SAR林下隐目标探测场景的几何模型和电磁散射模型。通过在微波暗室内构建极化干涉SAR半实物测试系统，对模型及方法进行试验验证。本项目的研究将为极化干涉SAR在林下隐目标探测方面的应用奠定理论基础。