High resolution imaging techniques in step-frequency subsurface radars

Imaging of buried objects with subsurface radars is affected by the resolution limits imposed by the constraints in bandwidth and antenna beamwidth. In this contribution, the step-frequency radar capabilities are exploited through the application of various signal processing methods that alleviate the resolution problem. Depth resolution is improved with a high-resolution technique based on signal extrapolation. Horizontal resolution is achieved via migration techniques similar to those used in seismic sounding, that exploit the peculiar characteristics of a step-frequency system. Selected examples are included to illustrate the improvements