Dependence of landmine radar signature on aspect angle

Antipersonnel landmines have been indiscriminately used since World War II, and their longterm persistence in the ground creates a barrier to development in a large number of countries, forcing people to live in constant fear. Therefore, there is a growing demand for reliable landmine inspection systems that could achieve an exhaustive detection to and return the land to its normal use. Due to its ability of detecting both metallic and non-metallic objects, Ground Penetrating Radar (GPR) has successfully been demonstrated to be a meaningful method for detecting landmines, allowing faster and safer operations. Most landmines may be considered as multiple layered dielectric cylinders, which each interface causes a reflection, properties that are hardly expected in other commonly encountered clutter objects. Considering that these features have their own angular pattern and will respond differently to different illumination, landmines are expected to produce signatures that present some discriminant features that could be used for reducing the false alarm rate of GPR equipment. In this paper, a set of measurements of three inert landmines has been acquired to study and characterise landmine signatures as a function of the antenna orientation relative to the landmine and target aspect angle.