A fast spotlight-mode synthetic aperture radar imaging system

The author reformulates the standard spotlight mode synthetic aperture radar (SAR) problem as a (τ,p) Radon transform. This results in a new algorithm for SAR that uses a linear chirp FM source signal that is a function of the geometry between the source and the object. While the close relation between computer-aided-tomography (CAT) and SAR has been understood for over a decade, no accompanying computational advantages could be realized. Recently, Kelley and Madisetti (1991), have proposed a new approach to image reconstruction from projections using the so-called fast Radon transform (FRT). He derives, in the (τ,p) domain, a FRT-based solution to the SAR problem. The FRT offers implicit interpolation and parallel processing advantages not found in conventional back projection operations. He proposes its efficient application in the computationally intensive problems in telecommunications and remote sensing, especially in military applications