A Highly Digital Multiantenna Ground-Penetrating Radar (GPR) System

Ground-penetrating radar (GPR) is a widely popular sensing method with broad applications in nondestructive subsurface imaging. This article presents a multistatic GPR for vehicle-mounted roadway and utility monitoring applications that employ several methods to improve performance compared with the state of the art. The proposed system illuminates the subsurface with pseudorandom codes (m-sequences) that have near-ideal autocorrelation properties. As a result, the received signal can be matched-filtered to provide pulse compression, which improves both range resolution and depth of scan compared with impulse-based GPRs. It also uses a highly digital transmit and receive architecture based on direct FPGA-based transmit pulse generation and direct radio frequency (RF) sampling of the received echoes. Furthermore, the analog front end uses an 8 x 8 multistatic antenna array design with broadband antipodal Vivaldi elements to provide spatial diversity, which leads to the improved object localization and reduced drift between scans. Experimental results from indoor and outdoor test beds confirm the functionality of the proposed GPR system.