Sensitivity constrained optimum endfire array gain

The problem considered is that of designing endfire line array shadings which provide a useful amount of supergain without extreme sensitivity to random errors. Optimum shading weights are obtained subject to a constraint on the gain against uncorrelated noise. The results of optimum array gain versus white noise gain constraint are presented parametrically for arrays of different inter-element spacings, and different noise fields. Results are presented for spherically and cylindrically isotropic noise and other wave-number limited noise fields, used in modeling ocean ambient noise. It is found that nearly optimum performance can be obtained in a simple delay and sum beamformer by shading to reduce sidelobes and modest oversteering to reduce main-lobe width without too large a reduction in main lobe sensitivity.