An improved wide swath imaging algorithm based on series reversion in GEO SAR

In geosynchronous (GEO) synthetic aperture radar (SAR), the synthetic aperture time (SAT) is very long and the trajectory mode should be considered as curve. This paper mainly analyzes the impacts of target azimuth position displacement on GEO SAR image formation. Because GEO SAR imaging need be based on the curved trajectory, targets´ azimuth position displacement on GEO SAR image formation can affect targets´ defocusing. This point will be analyzed by comparing two-dimensional (2-D) spectrum in GEO SAR and low earth orbit (LEO) SAR and some simulations. In the imaging formulation, to focusing a large scene, we present an improved secondary range compression (SRC) algorithm. In this proposed SRC algorithm, the azimuth compression function can adapt itself by changing the azimuth displacement. Finally, a large scene´s imaging under the long SAT is realized.