Adaptive beamforming with interpolated arrays for multiple coherent interferers

The spatial smoothing technique is effective in decorrelating multiple coherent interferers for an adaptive beamformer. However, it requires a configuration with identical subarrays. This paper presents an interpolation scheme to synthesize multiple virtual subarrays allowing for the use of spatial smoothing from a real array of arbitrary geometry. After interpolation, the optimum spatially smoothed subarray beamformer is constructed. A dimension recovery transformation can then be implemented to calculate the weights of the full array which will retain the interference nulls of the subarray beamformer. The efficacy of the proposed scheme is assessed through simulation. (C) 1997 Elsevier Science B.V.