BIAS Corrected PSD Estimation with an Interference Canceling Array

Adaptive interference canceling beamformers are known to suffer from beampattern distortion, particularly when interferers approach the nominal mainlobe. In some applications such as radio astronomy, even small pattern variations can be problematic. We address the issue of computing power spectral density (PSD) estimates at the output of a beamforming array in the presence of strong moving interference. A bias corrected PSD estimation algorithm is introduced which uses subspace projection methods to cancel interference at the beamformer. A correction step eliminates both pattern-distortion-induced PSD bias and spatial response errors over the long-term PSD averaging window.