A method for enhancing the bearing resolution obtained by conventional beamforming is described. Using the beamformer power outputs, the beam response functions, and optionally a background-noise spatial power spectral density (PSD) as input, the method gives a point-mass estimate of the signal PSD as function of bearing. The estimate is defined from the solution of a semiinfinite linear optimization problem and can be computed efficiently by solving a sequence of linear programs obtained by discretization using adaptive mesh refinement. In theory the estimate can achieve arbitrary resolution of the bearings of distinct plane-wave signals in stationary noise. For actual hydroacoustic data, it has been shown to yield a significant improvement of the resolution obtained by traditional beamforming. Some results obtained with simulated data and with actual data from a hydroacoustic application are presented. >
['Ilkka Karasalo']
A high-resolution postbeamforming method based on semiinfinite linear optimization