The node equation approach to wide band SAR image reconstruction

Abstract

As opposed to Fourier and associated integral methods for SAR processing, the paper discusses a method, based on the numerical unfolding of a differential equation along the synthetic aperture path. The method is a particular case of a general approach, which also may be applied to other synthetic aperture techniques, such as ISAR and btstatic imaging. The integration process may be termed cumulative, since a low resolution image available at a certain time along the synthetic aperture, together with the data registered at this moment of time, form the basis for constructing an image of successively improved resolution. The approach seems suitable for real time imaging, motion compensation, adaptive radar, and whenever continuous control over the imaging process is required. The paper considers application of the method to the extreme situation of ultra wide band, low frequency SAR. It is not as yet known how the method compares to the more conventional correlation methods, in the case of narrow band microwave SAR. The method is demonstrated by several numerical tests.