Joint Time-Frequency Analysis of Ground Penetrating Radar Data over Layered Sequences

Ground-penetrating radar (GPR) is widely used for interpretation of sedimentary deposits, where beds often occur in layered sequences and are often too thin to be individually resolved. Guha et al. (2005) showed that GPR traces over laminated sequences shift toward higher frequencies, and spectral analysis can be used to detect thin beds. In that study, very fi nely laminated sequences (well below the tuning thickness, 1/250 of dominant wavelength) were considered, and the radar frequency response was obtained using the Fourier transform. Estimating frequency response through the Fourier transform, however, does not provide information regarding the variation of frequency with time. On the other hand, joint time-frequency analysis, or JTFA, is a processing method that captures energy localization of a signal with time and allows representation of variations in spectral content of a signal in both the time and frequency domains.