Effective source wavelet determination

For the imaging of ground-penetrating radar (GPR) data, the form of the radar wavelet is usually not taken into account, because the behaviour of actual source and receiver antennas, that have a large influence on the wavelet, is rather complex. Nevertheless, knowledge of the wavelet has the potential to improve the imaging and interpretation of GPR data. An efficient way to deal with the wavelet is proposed by introducing an effective wavelet that incorporates the influence of the finite-length antennas. To obtain this effective wavelet, the impulse response for a point source-receiver antenna system is calculated using the medium properties, that are obtained from the isolated air- and ground-waves observed on the actual CMP data. The deconvolution of this impulse response with the actual CMP data, yields an effective wavelet. Together with the well-known radiation characteristics of dipole antennas in a dielectric halfspace, the propagation of the electromagnetic waves emitted a finite-length source-receiver antenna system can be effectively described. We demonstrate that propertiesof the shallow subsurface can be extracted from the ground-wave with reasonable accuracy. An effective wavelet determined from numerical data calculated for a finite-length source-receiver antenna system shows an effective wavelet that is less minimum phase than the effective wavelet calculated from the electric field generated by a point source-receiver antenna system.