Forward-looking Imaging via Iterative Super-resolution Estimation in Airborne Multi-channel Radar

Abstract

The direction of arrival estimation algorithm can overcome the Rayleigh limit, effectively separate multiple targets within the main lobe, and improve the azimuth resolution when applied to forward-looking imaging in airborne multi-channel radar. However, the limited antenna beam coverage and rapid scanning result in a scarcity of data samples available for covariance matrix estimation, leading to direction and amplitude estimation errors. Herein, we propose a forward-looking imaging algorithm based on single-snapshot iterative super-resolution estimation. The algorithm performs single-snapshot iterative spectral estimation to accurately determine the azimuth and amplitude of the target. Subsequently, a high-resolution image is achieved through non-coherent accumulation. Simulation and experimental data processing results show that the proposed algorithm can resolve multiple targets, significantly improving the azimuth resolution of the forward-looking image compared with traditional forward-looking imaging algorithms. Moreover, it ensures the accurate reconstruction of point targets and contour reconstruction of area targets.

Keywords

• doa estimation
• forward-looking imaging
• single snapshot
• iterative super-resolution
• iterative minimum mean square error