Robust adaptive beamforming with near-field scatterers

Near-field scattering which causes steering vector mismatch with array received data suffers severe performance degradation with beamforming. A new robust adaptive beamforming algorithm based on the steering vector uncertainty set is proposed to utilize the near-field scattering signal to improve the beamforming output signal-to-noise ratio. The properties of the far-field direct-path signal and near-field signal are incorporated. The large uncertainty set is divided into two small ones describing the far-field and near-field steering vectors, respectively. The far-field steering vectors and the near-field scattering coefficient with a transform matrix are evaluated by convex optimization. Simulation examples demonstrate that the algorithm is correct and effective.