On polar sampling of GPR for tunneling boring machine

Forward looking imaging system with data acquisition over 2D aperture is studied. Theoretical analysis for polar sampling at the aperture is performed and the sampling constraints based on polar Fourier transform are determined. From the analysis, it can be seen that polar sampling requires equi-arc-length and uniform samplings respectively in azimuthal and radial directions to avoid the spatial spectra aliasing. Finally, numerical simulations demonstrate the validity of the analysis.