Numerical SAR Processing Scheme for Generic Very-High Resolution Spotlight Acquisitions

Abstract

The assumption of hyperbolical range histories is at the core of many conventional SAR image formation schemes. The model however breaks down in usual very-high resolution SAR cases, be it monostatic or bistatic. Whereas the accommodation of non-hyperbolical range histories has been sufficiently addressed in the literature on bistatic SAR, the handling of time and frequency folding has been paid far less attention. We put forward a purely numerical, yet efficient, SAR processing scheme for generic very-high resolution spotlight acquisitions based on SPECAN. The algorithm is basically composed of two distinct steps: a) a numerical range-variant SAR image formation kernel, and b) a numerical subaperture handler. Residual geometrical corrections may be reduced to a minimum with the use of the suggested methodology. The validity of the approach is demonstrated by showing results on simulated orbital raw data of a monostatic PAZ, and a bistatic TanDEM-X staring spotlight acquisition.