Improving FMCW GPR Precision through the CZT Algorithm for Pavement Thickness Measurements

Abstract

Ground Penetrating Radar (GPR) application in road surface detection has been greatly developed in the past few decades, which enables rapid and economical estimation of pavement thickness and other physical properties in non-destructive testing (NDT) and non-contact testing (NCT). In recent years, with the rapid development of microwave and millimeter-wave solid-state devices and digital signal processors, the cost of Frequency-Modulated Continuous-Wave (FMCW) radar has dropped significantly, with smaller size and lighter weight. Thereafter, FMCW GPR is considered to be applied during pavement inspection. To improve the precision of FMCW GPR for NDT and NCT of pavement thickness, a Chirp Z-transform (CZT) algorithm is introduced to FMCW GPR and investigated in this paper. A FMCW + CZT GPR at 2.5 GHz with a bandwidth of 1 GHz was built, and laboratory and field experiments were carried out. The experimental results demonstrate that the FMCW + CZT GPR radar can obtain the sample thickness with low error and recognize subtle thickness variations. This method realizes the high precision thickness measurement of shallow asphalt pavement by FMCW radar with a narrow bandwidth pulse signal and would provide a promising low-cost measurement solution for GPR.

Soil Water Content Estimation Over Plantation Area Using FMCW Radar

“…Considering that these layers are approximated as a dielectric medium, Γ s in Equation ( 28) can then be written as Equation (29).…”

“…FMCW radar transmits electromagnetic waves continuously from low frequency to high frequency, which increases linearly [23]. FMCW radar detects targets by identifying the change in the frequency beat or the change in phase between the transmitted signal and received signal [24,29]. This research proposes an FMCW radar at 24 GHz frequency to estimate the SWC in tea plantation areas.…”