Three-dimensional SAR from curvilinear apertures

The 3D information content in data taken from a curved SAR aperture path is significant if sizable areas are produced when the data are projected in three orthogonal directions. Such an undersampled data space does not generate visually acceptable 3D images by straight forward Fourier transformation however. The high sidelobes present in such images may be larger than the main response of other significant scatterers thus veiling their appearance. Also such sidelobes block visual lines of sight to remote scatterers for all but very simple images. A coherent adaptation of the CLEAN algorithm is shown to be effective in eliminating sidelobes in such images allowing the target to be effectively visualized in 3D. Clean images of a target consisting of eight corner reflectors show moderate dependence upon aperture subsets taken from a parent dataset. The algorithm appeared to work well to the limits of the dynamic range of the data set. Initial results indicate the possibility of forming high resolution 3D images of targets from SAR data taken along curvilinear aperture paths in operational situations.