CONCRETE DIELECTRIC CONSTANT ESTIMATION BASED ON ANALYTIC SIGNAL PEAK RATIO OF GPR RESPONSE FOR NON-DESTRUCTIVE INSPECTION

Imaging of the internal concrete is important for a quantitative building health assessment. Ground penetrating radar can be employed to do this mission. However, to make an accurate image, the dielectric constant information of the concrete is needed. In order to provide a simple and accurate estimation method, this paper proposes a new signal processing technique focusing on the air-coupled configuration to estimate the concrete dielectric constant. The proposed method employs the peak ratio between the analytic representation of the ground surface reflection and antenna direct coupling signal. This ratio has a strong and reliable correlation to the concrete permittivity. To accommodate the different model of correlation within different antenna configurations, we propose a simple look-up table and interpolation techniques to the pre-recorded data. Based on the numerical analysis on the simulated flat surface concrete, the method is able to estimate accurately. Moreover, this method is stable enough facing of vary incident pulse waveforms. Thus, this method is promising enough to be explored further aiming the real applications.