Polarimetric 3D SAR imaging and analysis of polarization signatures for enhanced subsurface detection

The detection of buried objects with GPR poses a significant challenge in many sectors, including utilities, military operations and humanitarian efforts. It is a difficult task partly due to the presence of clutter and the strong signal attenuation presented by many soil types. This paper seeks to improve the detection of buried objects using the combination of Synthetic Aperture Radar (SAR) and Polarimetry (PolSAR). In this study a Stepped Frequency Continuous Wave (SFCW) air-coupled radar is used to acquire polarimetric measurements of buried metallic and dielectric objects between the frequency range of 1 - 6.5 GHz. A 3D Synthetic Aperture Radar (SAR) algorithm is developed and following a polarimetric calibration procedure the SAR algorithm is used to create sub-surface images of each polarization channel. Using polarimetric decompositions, the dominant scattering mechanisms are identified and used to synthesize polarization signatures of the buried objects. Analysis is conducted to determine the optimal polarization state for sub-surface detection, enhancing target identification and discrimination capabilities.