基于步进频连续波的远程三维穿墙成像方法研究

Research on Standoff 3D Through-Wall Imaging Method Based on Stepped Frequency Continuous Wave

摘要: 步进频连续波以其高分辨率和高灵敏度在穿墙成像领域表现出色。针对墙后目标信噪比过低的问题，该文通过32端口矢量网络分析仪作为信号收发装置，构建了一套MIMO架构的步进频连续波远程三维穿墙成像系统，提出了一种适用于强杂散环境的叠加采样信号提取算法，利用不同时刻多个独立的接收信号叠加降噪，有效抑制系统噪声和多径干扰，突出墙后隐藏目标的微弱信号特征，解决墙后目标信号易被噪声所淹没的问题；同时，通过对超宽带对数周期天线准确的相位中心估计和幅度相位误差校准，进一步提升了成像的质量和准确度。实测数据结果证明该系统可以通过远程探测的方式对墙后的人体目标进行三维成像。

Abstract: The stepped frequency continuous wave technology excels in wall-penetrating imaging with its high resolution and sensitivity. In response to the low signal-to-noise ratio of targets behind walls, a 32-port vector network analyzer is utilized as the signal transmitter and receiver device to establish a MIMO-structured stepped frequency continuous wave standoff 3D through-wall imaging system in this paper. The proposed superimposed sampling signal extraction algorithm is suitable for strong cluttered environments. This algorithm leverages the summation and noise reduction of multiple independent received signals at different time points to effectively suppress system noise and multipath interference. Besides, it highlights faint signal characteristics of targets hidden behind walls and mitigates the issue of target signals being overwhelmed by noise easily. Additionally, the imaging quality and accuracy were further enhanced by accurately estimating the phase center of ultra-wideband logarithmic periodic antennas and calibrating amplitude-phase errors. Experimental data confirms that this system is capable of producing 3D images of human targets behind walls using standoff detection methods.