基于四阶累积量的机载多基线SAR谱估计解叠掩方法

Solution to Layover Problemin Airborne Multi-baseline SAR Based on Spectrum Estimation with Fourth-order Cumulant

叠掩问题是SAR成像处理的一个技术难点,在机载多基线SAR系统中,传统的谱估计解叠掩方法受到非均匀基线和基线数目少的限制,使得其在解叠掩过程中的散射点高度向测量误差大、分辨性能差。针对以上问题,该文将4阶累积量统计特性用于传统的谱估计解叠掩方法中,利用4阶累积量的盲高斯性和非均匀阵列的虚拟阵列扩展性能,结合传统的Capon, MUSIC谱估计方法,能在有效去除高斯噪声的同时,提高叠掩处各散射点的高度向测量精度及分辨率。仿真和实测数据实验证明了该文方法的有效性。

Layover is a difficult problem in SAR imaging technology.Airborne multi-baseline SAR systems are constrained by non-uniform baselines that are also few in number,which means the measured scattering point height is characterized by unacceptable error and poor resolution when using traditional spectrum estimation methods.To solve these problems,in this paper,we combine fourth-order cumulant statistical properties with traditional spectrum estimation methods.With its blind Gaussian noise characteristic,non-uniform virtual array extension of the fourth-order cumulant,and traditional Capon and MUSIC spectrum estimation approaches,the proposed method can effectively remove the Gaussian noise,while also improving the measurement accuracy and resolution of the scattering point heights.The simulation and real-data experimental results validate the effectiveness of our proposal.