Azimuth Super-resolution Imaging using Photonics-based Inverse Synthetic Aperture Radar

Photonics-based inverse synthetic aperture radars can enable wide operation bandwidth and high range resolution. To improve the azimuth resolution, a large coherent accumulation angle or a sufficient observation time duration is required, which is difficult to achieve in practical applications. To overcome the sparse aperture problem of a photonics-based ISAR, azimuth super-resolution imaging is demonstrated in this paper, in which the sparse representation method is applied to implement sparse azimuth data extrapolation or fusion. In the experiment, the photonics-based radar has a bandwidth of 8 GHz, and ISAR echoes from a full observation aperture are selected to imitate the short-aperture detection and sparse aperture detection, respectively. Performance of the sparse-representation-based azimuth super resolution imaging method is investigated. Experimental results show that the azimuth resolution of a photonics-based ISAR can be greatly improved to get well focused images in which small targets can be well distinguished.