Contents I. Introduction
The challenging task of structural health monitoring (SHM) calls for new inspection paradigms and analytic tools to enable efficient and timely maintenance operations. In this context, non-destructive technologies (NDTs) are crucial, and ground penetrating radar (GPR) should be taken into account for ad hoc, high-resolution subsurface surveys [1] . Even though GPR is a validated technique, commercially available systems typically operate in close proximity to the structure being tested, and it is challenging to employ moving platform-mounted GPR systems to evaluate vertical structures. In this study, a compact radar prototype that can conduct contactless surveys of elongated, horizontal, and vertical structures is designed. The radar prototype is light enough to deploy on portable platforms with a small payload mass, such as mini-Unmanned Aerial Vehicles (UAVs). Mini-UAVs provide significant benefits in terms of adaptability, usability, affordability, and human capital risk reduction [2] . The constructed prototype is offered here, along with a discussion of the design principles. In addition, a performance analysis is given by taking into account simulated data and early tests conducted under controlled circumstances.
