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

Abstract

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.

Mapping Subsurface Archaeology with SAR

“…The microwave RF subsystem is based around a HP8719ES radar unit. The measurements utilized the new tomographic profiling (TP) imaging scheme (Morrison and Bennett, ). A linear scanner mounted above a 4 m ( l ) × 1 ( w ) × 0.9 m ( h ) trough filled with kiln‐dried sand was used to collect 3‐m‐long TP transects.…”

“…Tomographic profiling offers the opportunity to directly measure the vertical backscattering through a volume without the problems of large data‐capture requirements or model ambiguities. Using a single‐pass acquisition along a single aperture, it simultaneously captures detail on the vertical backscattering through a target volume over a range of incidence angles (Morrison and Bennett, ). In addition, each pixel within an image transect is viewed at the same incidence angle.…”