Geometric invariance for synthetic aperture radar (SAR) sensors

Synthetic Aperture Radar (SAR) sensors have many advantages over electro-optical sensors (EO) for target recognition applications, such as range-independent resolution and superior poor weather performance. However, the relative unavailability of SAR data to the basic research community has retarded analysis of the fundamental invariant properties of SAR sensors relative to the extensive invariant literature for EO, and in particular photographic sensors. This paper develops the basic geometric imaging transformation associated with SAR from first principles, and then gives an existence proof for several geometric scatter configurations which give rise to SAR image invariants.