Constrained adaptive beamforming for electromagnetic interference cancellation for a synthetic aperture radar

Imaging capability of a Synthetic Aperture Radar (SAR) could be seriously limited or denied by an electromagnetic interference signal impinging on the antenna array during imaging. The use of antenna nulling techniques shall cancel the effects of interferences over the collected SAR data. Despite the greater Signal to Interference plus Noise Ratio (SINR) obtainable using an antenna nulling interference cancellation technique, nulling the antenna pattern in the direction of arrival of the disturbance could modify the antenna main lobe gain during the synthetic aperture, resulting in a distorted focused image even after interference cancellation. Thus, forming a SAR image while suppressing an interference can potentially destroy large regions of the image. In this paper we analyse several constrained spatial techniques aiming to reduce the interference level without significantly affecting the image quality.