High Precision Surface Reconstruction Based on Coherent Near Field Synthetic Aperture Radar Scans

This paper describes the development of a method using the phase information of an 80 GHz 3D synthetic aperture radar for high precision surface reconstruction. At first, an introduction of theory of phase unwrapping methods is given. Furthermore, the chosen unwrapping algorithm is discussed and applied to one range bin of a complex valued data cube, generated by an 80 GHz 3D synthetic aperture radar with a bandwidth of 25 GHz. Additionally, a method for phase unwrapping is proposed in case of objects crossing several range bins. The impact of diffraction and refraction on the reconstructed surface is discussed. To evaluate the resolution limits, the height profile is extracted and analyzed, resulting in a range resolution better than 50 μm. Finally, material imaging results are shown to underline the potential of the presented method for commercial radar imaging systems.