Beamforming with aperture extrapolation (APEX): Performance in practice

Linear predictive extrapolation of line-array sensor data coupled with conventional beamforming is examined with respect to the performance gains that can be realized when applied to real underwater acoustic measurements. The gain in signal-to-noise ratio as a result of extrapolation is shown in general to outweigh any loss associated with increased beampower variance. Data-domain extrapolation is argued to be preferred to a covariance-domain implementation for a number of practical reasons. Results are compared with those for the MUSIC algorithm operating on a relatively dynamic signal field.