Autofocus for coherent through-the-wall imaging with multiple antenna arrays

We consider the problem of coherent through-the-wall imaging with spatially distributed antenna arrays. A compact antenna array with wide bandwidth can be used to provide snapshots of a scene at high range resolution. The physical size of the antenna aperture limits the cross-range resolution of the array. Multiple arrays at spatially diverse locations can increase cross-range resolution, however coherent operation requires precise knowledge of the array locations and distortions caused by the wall propagation. We present a method for spatially-variant autofocus for distributed arrays by maximizing the coherence between the images provided by the individual arrays interrogating a common scene. Examples with measured data illustrate the effectiveness of the distributed array approach to coherent through-the-wall imaging.