Software defined radio for stepped-frequency, ground-penetrating radar

Abstract

This research explores the potential of software defined radio (SDR) as a platform for ground-penetrating radar (GPR). SDR is a rapidly developing technology that implements signal processing components partially or completely in software, providing enhanced design flexibility over traditional hardware radio. The stepped-frequency GPR method is used to detect and locate metallic and non-metallic subsurface objects. A multi-tone signal allows the 500-5000 MHz band to be scanned 150 MHz at-a-time. This system is extended to isolate and process the reflections of modulated scatterers. A demonstration prototype is developed, consisting of a transmitting antenna and a receiving antenna, each pointed at the ground and connected via coaxial cable to an off-the-shelf SDR unit. This SDR unit is connected via ethernet cable to a host computer, which controls the system using open- source software libraries. SDR is typically designed for communications applications, so special consideration is necessary for remote sensing. Initial design challenges are weighed against potential advantages of design flexibility and hardware versatility.