An FPGA-based Flexible and MIMO-capable GPR System

Ground penetrating radar (GPR) has broad applications in non-destructive subsurface imaging. Most GPRs on the market are bistatic devices that illuminate the buried objects using analog pulses with simple Gaussian-like shapes. These GPRs suffer from drift in the scan results and have either a low-resolution or a low depth of scan, which limits their application. High resolution along with an increased depth of scan can be achieved by transmitting maximal length pseudorandom sequences (m-sequences) which enable pulse compression due to their near-ideal autocorrelation properties. In addition, improved object localization and reduced drift can be obtained with the spatial diversity offered by a MIMO transceiver. This paper discusses the design and implementation of a 8 × 8 MIMO-capable impulse-based GPR that transmits m-sequences generated on a low-cost FPGA platform, performs a quadrature transform on the received signal to reduce computation, and implements subsampling to sample the quadrature-converted signals using low-speed ADCs. Preliminary experimental results are also presented.