Adaptive beamforming for coherent interference suppression

Adaptive beamforming in a coherent interference environment is considered. An eigenanalysis based two-step adaptive method is proposed for uniform linear arrays. In the first step, an optimum subarray weight vector is obtained via eigenanalysis techniques. In the second, the adaptive array response is optimized by employing unused degrees of freedom. Two optimization criteria are minimization of white noise power and matching a desired response. The authors deals with coherent interference suppression using a sensor array of arbitrary geometry and introduce a novel concept called split-polarity transformation (SPT) which is incorporated into the conventional linearly constrained minimum variance (LCMV) beamformer to decorrelate the desired signal from interference. With the aid of SPT processing, the signal cancellation due to correlation between the desired signal and interference is almost eliminated. Numerical results are presented to demonstrate the effectiveness of the proposed methods in a coherent interference environment.<>