Tomographic Profiling (TP) - a scheme for vertical backscatter profiling of biogeophysical targets at constant incidence angles

Tomographic Profiling (TP) is a new imaging technique which provides a vertical profile of the backscatter through a volume. Data is collected as for normal SAR imaging, but with the antennas aligned along-track. The real antenna provides a wide beam in the along-track direction, which is sharpened by addition of the elemental measurements across a synthetic sub-aperture. A novelty of the scheme is the ability to produce an image transect in which the incidence angle is constant at every point. This is accomplished by incrementally sliding the sub-aperture across the full aperture, and utilising the appropriate sub-aperture to provide the necessary viewing geometry at each pixel. By suitable phasing between the sub-aperture elements, the synthesized beam can be steered in angle within the wide angular extent of the real beam, allowing post-measurement retrieval of the backscattering properties of the scene over a continuous range of incidence angles from a single scan.