移变双基前视合成孔径雷达空变运动补偿方法研究

Translational Variant Bistatic Forward-Looking Synthetic Aperture Radar (TV-BFSAR) is a new radar system of which the transmitter and receiver are placed on different platforms with different velocities. The receiver works in forward-looking mode. TV-BFSAR is of great importance in the application of remote sensing, such as aircraft autonomous landing and autonomous navigation. However, there is large range migration and strong azimuth variance for the echo of TV-BFSAR due to forward-looking mode and the velocity difference between transmitter and receiver, large range migration and strong azimuth space variance exist in the echo of TV-BFSAR. Hence, the existed motion compensation methods cannot be applied in TV-BFSAR, which brings difficulty to high resolution imaging of forward-looking terrain. Focused on characteristics of large range migration and strong azimuth space variance, this project will study space variant motion compensation of TV-BFSAR. By building the complex motion error model and introducing the theory and methods, such as Keystone transform, nonlinear chirp scaling and optimization, a breakthrough in the key technologies of forward-looking space variant range migration correction and space variant high-order Doppler parameter equalization will be achieved. Hence, the methods of TV-BFSAR space variant motion compensation with independent intellectual property rights will be formed. All these work will lay theoretical and technical basis for promoting the development and application of TV-BFSAR.

移变双基前视合成孔径雷达（Translational Variant Bistatic Forward-Looking SAR, 简写TV-BFSAR），是一种收发站分置于不同平台且平台速度不同，接收站波束前视照射的新体制雷达，在飞行器自主着陆、自主导航等遥感领域具有重要的应用价值。然而，由于接收波束前视照射及收发平台速度差异，回波规律呈现大距离徙动、强方位空变特点，致使现有运动补偿不再适用，高分辨前视成像存在困难。 本项目将围绕TV-BFSAR回波大距离徙动、强方位空变特点，研究TV-BFSAR空变运动补偿，引入Keystone变换、非线性调频变标及最优化等理论与方法，构建TV-BFSAR复杂运动误差模型，突破前视空变距离徙动校正、空变高阶多普勒参数均衡等关键技术，形成拥有自主知识产权的TV-BFSAR空变运动补偿方法，为推动TV-BFSAR系统的研制与应用奠定理论与技术基础。

本项目针对高分辨前视对地成像应用需求，开展了移变双基前视合成孔径雷达空变运动补偿研究，主要研究内容包括：建立了移变双基前视SAR回波时频域模型，剖析了回波信号的距离徙动规律、徙动空变规律、多普勒变化规律、误差空变规律，仿真了运动误差影响，导出了运动误差和空变约束条件，提出了基于Keystone变换的空变距离徙动迭代校正方法、基于最小熵的双基前视SAR自聚焦技术、三阶空变运动补偿方案等，形成了具有自主知识产权的双基前视合成孔径雷达空变运动补偿体系，为推动双基前视SAR系统在飞行器自主着陆、自主导航及前视侦察等方面的应用，提供了运动补偿方面的理论与方法储备。