in situ measurement of pavement thickness and dielectric permittivity by GPR using an antenna array

•We design a common-source GPR antenna array using six Vivaldi antennas.•We calibrate the antenna array by locating the antenna phase center.•We estimate the pavement thickness and dielectric permittivity.•The error of the in situ estimation of pavement thickness is less than 6 mm (10%).

We present a ground penetrating radar (GPR) system, which uses an antenna array for in situ measurements of the thickness and dielectric permittivity of an asphalt pavement layer. We calibrated the antenna array by considering the antenna phase center and the antenna offset. The results of the laboratory measurements demonstrate that the proposed calibration method can greatly improve the accuracy of the velocity and thickness estimations when compared with the conventional method. A field measurement conducted on a highway pavement shows that the error of the thickness estimation of the asphalt layer is less than 6 mm (10%).