A new approach to robust beamforming in the presence of steering vector errors

This correspondence presents a new approach to array beamforming in the presence of steering vector errors, such as steering angle and carrier frequency errors. The basic idea is based on the principle that the output power of an optimized beamformer achieves a local maximum if the steering vector coincides with that of the desired signal. The proposed approach iteratively searches for the correct steering vector by maximizing the array mean output power using a first-order Taylor series approximation of the steering vector in terms of the steering errors. This method has the advantages of easy implementation and suffers no loss in the degrees of freedom for interference rejection. Furthermore, the method is independent of the choice of the phase center coordinate origin contrary to derivative constraint methods. Conditions for the existence of a solution using the proposed method are also established