Interference covariance matrix estimation for a Multi-Channel Synthetic Aperture Radar

Abstract:
The imaging capability of a SAR could be seriously limited by electromagnetic interferences. A Multi-channel SAR, exploiting antenna nulling techniques, is able to cancel the effects of interferences. The adaptive nulling (beamforming) requires the estimation of the disturbance covariance matrix from multi-channel data, where only disturbance is present. For space-based high-PRF SAR these samples might not be available at any range, therefore we propose to estimate the matrix by avoiding the transmission of specific sets of radar pulses during the synthetic aperture. Several approaches to select transmissions to skip and their impact on both the SAR impulse response and the interference cancellation capability are analyzed and compared.