Correlation due to inter-element coupling in line arrays

In spite of the fact that inter-element coupling in a receiving array markedly affects the amplitude of the output signals when the beam is deflected from its normal axis, and also introduces correlation into otherwise-uncorrelated noise outputs from the various elements, yet its effect on signal/noise performance and on the beam-steering itself is small and usually negligible. The correlation introduced by inter-element coupling and the way it adds to correlation already existing in the acoustic field is examined and discussed in more detail. It is shown that it has important implications for a class of sonar systems in which signal and noise are distinguished by their inter-element correlation.