Three-dimensional tomographic imaging for foliage penetration using multiple-pass spotlight-mode SAR

In this paper we demonstrate how spotlight-mode synthetic aperture radar (SAR) imagery can be collected and processed using tomographic techniques to produce three-dimensional images. The technique is particularly useful for the application of foliage penetration (FOPEN), wherein it is desired to separate the radar returns corresponding to tree leaves and branches from the objects of interest that may lie beneath them. We present a mathematical framework for spotlight-mode SAR three-dimensional tomographic imaging and show with real Ku-band SAR data collections the effectiveness of the technique for "seeing" beneath trees.