Experimental results for adaptive sidelobe cancellation techniques applied to an HF array

The authors describe an experimental analysis of adaptive array processing techniques conducted using a 16-element high frequency (HF) array. The results demonstrate the ability of these techniques to cancel both narrow-bandwidth interference and wide-bandwidth noise. The effects of calibration errors and the nonstationary HF channel on beamforming and constrained adaptive processing are discussed. The HF channel will support both beamforming and constrained processing over short time intervals. However, for longer periods robust adaptive array processing techniques may be required. Two robust methods are described, the diagonal loading algorithm and a principal components projection method. It is shown that adaptive array processing algorithms can be used in conjunction with a matched filter to extract a spread-spectrum signal from interference.>