Effect of Wall Parameters on Ultra-Wideband Synthetic Aperture Through-the-Wall Radar Imaging

Synthetic aperture radar (SAR) and ultra-wideband (UWB) waveforms have recently been considered for through-the-wall surveillance to enhance its imaging and detection performance. The performance of UWB SAR through-the-wall imaging is analyzed here. A time-domain back-projection focus algorithm is used for SAR image formation. The target shift in the focused image and the detection performance are formulated as functions of the wall parameters. The target shift is corrected using a waveform propagation path estimation method, and the relevant estimation errors are analyzed. The two popular UWB modulations, time modulation (TM) and spread spectrum (SS), are investigated in these analyses, and their robustness to wall parameters is evaluated. Results show that SS is preferable to TM for through-the-wall SAR imaging due to its robustness to wall parameter estimation errors and its superior range sidelobe suppression performance.