Abstract:

When applying the phase gradient autofocusing (PGA) algorithm to high resolution inverse synthetic aperture radar (ISAR) imaging of non-cooperative targets, the byproduct of Doppler bias effect hampers the following rotational motion compensation process, and thus undermines the quality of the imaging result. This paper shows how Doppler bias effect appears in the PGA process from the perspective of the principle of PGA. Then, the paper illustrates how the Doppler bias effect affects the range migration compensation of scattering centers. Accordingly, an imaging quality evaluation based method for Doppler bias effect estimation and compensation is proposed. Finally, experiments with both numerical simulation and some real ISAR data are provided to illustrate the effectiveness of the proposed method.