Change Detection Analysis of Humans Moving Behind Walls

In this paper, we consider the problem of detection of humans behind walls and inside enclosed structures using radars. We use change detection techniques to mitigate the heavy clutter caused by strong reflections from exterior and interior walls. To improve spatial resolution, we apply multiple-input multiple-output (MIMO) configurations to moving target indication (MTI). We examine change detection formulation and performance when clutter removal is performed pre- and postbeamforming. Using signal multiplexing from two transmitters and several receiver positions, we show that the virtual array (coarray) implementing the prebeamforming change detection MIMO scheme permits enhanced clutter rejection and improvement in imaging resolution of moving targets without increasing the physical aperture. Laboratory experiments are conducted to validate the proposed approaches with targets walking behind walls.