Smear signature morphology of surface targets with arbitrary motion in spotlight synthetic aperture radar imagery

This study develops a methodology for analytically predicting the detailed smear signature morphology of surface targets with arbitrary motion in spotlight synthetic aperture radar (SAR) imagery. The radar sensor is assumed to move with constant speed and heading on a level flight path with broadside imaging geometry. Cases of uniform target motion exhibit morphology of simply curved smear shapes, as has been reported previously. However, the present analysis shows that non-uniform target motion can cause complicated smear shapes in spotlight SAR imagery. Specifically, the method of stationary phase is applied to local subaperture SAR images to yield analytic non-parametric expressions for the morphology of smear signatures within spotlight SAR imagery for surface targets with arbitrary motion trajectories. This predictive capability offers the potential of extracting some characteristics of true target motion based upon the induced SAR smear signatures alone.