Estimating moving targets behind reinforced walls using radar

We addressed the important problem in urban warfare of estimating moving targets such as personnel behind a reinforced wall using radar measurements. First, we considered the case in which the reinforced wall is completely unknown. We coherently added measured electric fields to estimate the wall thickness and concrete permittivity, independently. We applied beamforming to estimate the number and locations of the targets. The algorithm proved robust and performed satisfactorily in the case in which the bar parameters are unknown. We also analyzed the problem in which the characteristics of the metallic grid are known. We improved the estimation significantly by modeling the waveform distortion due to the bars. The resulting images are focused and represent the contours of the targets. In addition, the minimal necessary SNR is lower compared with the case in which the influence of the bars on the signal shape is ignored.