Abstract:

Layered medium attenuation algorithm using constant Q model for ground penetrating radar (GPR) signal processing is introduced. Comparing with traditional GPR method in which it used single Q-factor to describe the attenuation of medium, moreover, the Q-factor of layered medium is determined by getting mean square root Q value using the spectral ratio method. At the same time, the step can be described as follow: the theory of wavefield downward continuation is applied to GPR signals to process the inverse Q filtering data. First, it assumes the underground Q model with multilayer constant Q structure. For each constant Q-layer, the surface wavefield records are directly extended to the top of the current layer. And then in the wavefield extended of the constant Q-layer, the signals are inverse Q filtered through generalized S transform in time-frequency domain. And then the generalized S inverse transform is done on the results of the filtering to obtain the time-domain signal of the inverse Q filtering. Finally, using this method, the amplitude and phase of three-layer GPR signals attenuation which are synthesized and two-layer GPR signals’ attenuation which are gained though test are compensated, and the result shows that the algorithm is correct and valid in inverse Q filtering of GPR signals.

Key words: signal processing, layered media, spectral ratio method, inverse Q filtering, wavefield downward continuation, generalized S transform