Super-resolution of 3-d GPR signals to estimate thin asphalt overlay thickness using the XCMP method

The extended common midpoint (XCMP) method can be used on multichannel 3-D ground-penetrating radar (GPR) to estimate the asphalt pavement thickness and dielectric constant without the need for calibration by taking cores. The XCMP method requires accurate time delay determination of pavement reflection. However, for thin asphalt overlay, the range resolution of 3-D GPR signal is insufficient to resolve the overlapped pulses of asphalt concrete (AC). The objective of this paper is to use multiple signal classification (MUSIC) algorithm to increase the resolution of 3-D GPR signals, such that thin asphalt overlay thickness can be accurately estimated. An evaluation of the MUSIC algorithm at a full-scale test section and a comparison with regularized deconvolution algorithm showed the MUSIC algorithm is an effective approach for increasing the 3-D GPR signal range resolution when the XCMP method is applied on thin AC overlay.