Ground penetrating radar inspection of asphalt pavement with an off-ground antenna array

In our previous publication, we have designed a ground penetrating radar (GPR) system with and antenna array for in-situ estimation of the thickness and dielectric permittivity of the asphalt pavement. In this paper, we change the work mode of the GPR antenna array from the ground-coupled mode to the off-ground one, accelerating the data acquisition speed required for highway inspection. The GPR antenna array consists of one transmitting antenna and five receiving antennas. We determine the phase-center location of the employed Vivaldi antenna for calibration and simply the antennas as point sources in the following process. Velocity spectrum analysis is applied to robustly estimate the dielectric constant from the time delay of re ection signal recorded in different channels. We show one of the laboratory experiment results in Figure 1. The thickness estimation error of the asphalt pavement layer is 14mm (7.0%); and the velocity estimation error of the asphalt pavement layer is 0.016 m/ns (9.2%). With the off-ground antenna array, the proposed GPR system has a vast potential in pavement inspection.