Sparse aperture inverse synthetic aperture radar imaging of manoeuvring targets with compensation of migration through range cells

Abstract

In inverse synthetic aperture radar (ISAR) imaging of a target with significant manoeuvres, severe migration through range cells (MTRCs) and time-varying Doppler usually involve in the echoed signal. Both of them may challenge the conventional motion compensation and imaging methods, which are usually based on the assumption of small rotational angle with short coherent time duration. Moreover, for a multi-functional ISAR, full aperture (FA) data collection might be unachievable because of the conflict with other radar activities, resulting in sparse aperture (SA) data. In this study, an ISAR imaging method of manoeuvring targets with SA data is proposed, where MTRC compensation and time-varying Doppler are well accounted. By using a sparse chirp-Fourier basis with first-order range–azimuth coupling term, an improved orthogonal match pursuit algorithm is implemented to solve the sparsity-driven optimisation for FA data reconstruction from SA-ISAR measurements. As a primary item, MTRC compensation is seamlessly embedded into the FA signal reconstruction for ISAR imaging of manoeuvring targets. Both simulated and real data are utilised to confirm the effectiveness of the proposed method.