基于空间特征的MIMO穿墙雷达墙杂波抑制

摘要

In Through-the Wall Imaging (TWI), wall reflections are often stronger than the target, hence they make great interference on the imaging and detection of the target. Spatial filtering based on single input and single output is a traditional method for wall-clutter mitigation, whereas it is not applicable to MIMO Through-the-Wall Radar (TWR). In this paper, the spatial signatures of wall and target from MIMO TWR measurements are analyzed respectively. The results based on parametric models show that the wall reflections not only have no relations with positions of antenna array, but also have symmetry properties, whereas the target reflections do not. According to the above difference, a new method called symmetry subtraction for suppressing wall reflections is introduced. Simulation results indicate that the proposed method can suppress efficiently the wall reflections without affecting target signal.%在穿墙成像中，墙体反射波相对于目标回波具有很强的能量，因此对目标的成像及检测造成严重干扰。传统的空域滤波方法基于单发单收阵列体制，利用墙体空间特征不变性有效地抑制墙体杂波。随着MIMO技术越来越多的应用于穿墙雷达，墙体空间特征发生变化，该方法不再适用于MIMO穿墙雷达回波。为解决这一问题，该文分析了MIMO穿墙雷达回波中墙体与目标回波的空间特征，参数化建模结果表明，墙体回波的空间特征与天线阵列的位置无关且具有对称性，而目标回波不具有该特性。根据两者的这一差异，该文提出对称消去法来消除墙体回波。仿真结果表明该方法能够有效地消除墙体杂波，且能够保留目标的全部信息。