Fully polarimetric UWB imaging demonstrator for group screening

This paper presents the demonstrator of a fully polarimetric ultra-wideband (UWB) multistatic imaging system for screening of groups of walking people in public areas. The system is working in the FCC UWB frequency band from 3.6 GHz to 10.6 GHz. The low frequency range is chosen to reduce the influence and clutter of clothes to a minimum. This is important for the screening in public places because the scanner needs to identify threats even under thick and heavy jackets with a low false alarm rate. Furthermore, the effect of motion blurring in the reconstructed radar images is enormously reduced. To further improve the detection of threats a fully polarimetric radar frontend was chosen for the imaging system. Radar polarimetry is a well-established technique in remote sensing to characterize di erent scattering mechanisms like single and double bounce or volumetric scattering. This offers the opportunity to classify different terrain properties or manmade objects in remote sensing. The investigated antenna arrangement is a roof-like geometry which can be installed on ceilings or archways in public areas. This approach doesn't disturb the flow of walking persons and even could enable a hidden installation of the screening device. Furthermore, this arrangement reduces shadowing risks, i.e. that a terrorist hides himself between closely walking neighbors. The paper discusses the applied signal processing and the polarimetric evaluation. Results are demonstrated for static and dynamic scenarios.