FFT implementation of Kirchhoff´s migration for ground penetrating radar image focussing

GROUND-penetrating radar (GPR) is a mature remote sensing technique employed by engineers and scientists to obtain information from subsurface structures. It is often advantageous to estimate the ground surface topography from radar returns. In this letter, we propose a method to solve the diffraction problem and improve the accuracy of surface topography. A modified version of Kirchhoff´s migration technique is introduced to refocus the diffraction waves before searching for the brightest pixel. Experimental data have been used to display the effects of diffraction waves and test the method. The result shows that the method can dramatically estimate accurate surface topography even in the sharp variable surface area. We have proved our algorithm on both simulated as well as experimental data.