Digital extrapolation beamforming

More sensors are usually required in order to enhance the resolution of a beamformer and to improve its beam pattern. Due to physical and/or economical constraints this requirement cannot be met. This paper presents the results of an analytical and experimental study of the use of a signal extrapolation method in order to "synthetically" (without adding more physical sensors) enhance the beamformer resolution. A simple model for the extrapolation error has been obtained experimentally. The beam pattern has been extensively improved. Further improvements can be achieved by combining other techniques such as windowing, temporal interpolation, etc. to the spatial extrapolation.