Impact of the wave number estimation in Underground Focusing SAR images

This work studies the impact estimating soil wave number in Underground Focusing SAR imaging for tunnel detection applications. It is demonstrated that poor underground imaging results when wave refraction at the ground surface is neglected, but that incorporating refraction with sufficiently high estimates of soil dielectric constant produce clear target images. Using a wrong wave number for the soil incorrectly predicts the tunnel´s depth, but gives positive identification of its transverse and extent.