基于一维距离像的墙壁参数估计方法

合成孔径雷达穿墙成像中的关键问题是对墙壁影响的补偿.而墙壁参数通常为先验未知量,获得其值后才能进行成像补偿.本文建立了正侧视条带工作模式的SAR信号穿墙传播的数学模型,研究解决了电磁波的折射和传播路径等问题.在分析回波时域结构的基础上,提出了一种基于高分辨一维距离像的墙壁参数估计新方法.通过对目标各部分回波延时的提取,采用方程数值解算和搜索曲线交汇的方法实现了对墙壁厚度和介电常数的准确估计.基于估计的参数值采用后向投影(BP)算法,得到对墙体的折射和延时作用补偿后的聚焦图像,仿真结果验证了理论分析和估计方法的正确性与有效性.

Estimation of wall parameters based on range profiles

Compensation of effects of wall on SAR through-wall imaging is of main concern.Wall parameters are essential for the compensation,which are normally not known a priori.A model of SAR works in sidelooking strip mode for through-wall imaging is established,considering the path of signal due to refraction.After analysis of echo configuration in time domain,a new procedure for estimating wall parameters is provided which making use of high range resolution profiles.Based on extraction of time delay of target counterpart,thickness and permittivity of wall are figured out exactly by employing numerical equation method and searching curves intersecting.With the estimated parameters,focused image of targets in a room is acquired after wall effects are compensated in imaging processing with back projection algorithm.Simulation results verify the validity of the theoretical analysis and imaging algorithm.