前视阵列SAR回波稀疏采样及其三维成像方法

针对高分辨前视阵列SAR三维成像系统面临的距离采样率高和回波数据量大的问题，本文利用地面散射源在三维空间中的稀疏性，提出距离频域和沿航向时域二维稀疏采样并稀疏重构地面三维图像的方法.从前视阵列SAR角度观察三维地面，地面散射源在距离向和沿航向二维空间中是稀疏的，在该二维方向上联合稀疏采样有望实现最佳的稀疏采样效果.为避免距离向时域稀疏采样造成的三维成像复杂化，提出利用子脉冲结合距离频域稀疏采样的方法来实现距离向稀疏采样.同时，结合地面散射源连续性特点，提出低信噪比情况下稳健的信号重构方法.与传统三维匹配滤波成像方法相比，本方法降低了距离采样率和回波数据量，并直接重构地面散射源信息以实现三维成像.

The Method on Echo Sparse Sampling and Three-Dimensional Imaging for Forward-Looking Array SAR

For the problem of high slant-range sampling ratio and huge echo data volume in the high-resolution three-dimensional imaging system of forward-looking array SAR,the joint two-dimensional sparse sampling method in the domain of slant-range frequency and along-track time and its sparse reconstruction method for the three-dimensional imaging of the scene is presented,which is based on the sparse property of the scatterers in the three-dimensional space.From the perspective of forward-looking array SAR to observe the three-dimensional ground,the scatterers in the ground are sparse in the joint space of the slant-range direction and the along-track direction.To avoid the effect of the sparse sampling in the slant-range direction on the three-dimensional imaging,the solution of sub-pulse technique and the sparse sampling in the slant-range frequency is presented to accomplish the sparse sampling in the slant-range direction.Also,the sparse reconstruction method,which is combined with the continuity of the scatterers,is proposed to increase the robustness in the situation of low signalto-noise ratio.Compared to the traditional imaging method with three-dimensional matched filtering,the method in this paper reduces the slant-range sampling ratio and the echo data volume,and the three-dimensional image can be directly reconstructed using the recovered scatterers.