Array Design for Measuring Source Depth in a Horizontal Waveguide

The signal-to-noise ratio of received radiation is enhanced by properly combining the outputs from a collection of sensors which are connected as an array. In an infinite homogeneous medium, such as a deep ocean layer, the array is matched to the incoming signal by adjusting the phases or time delays of the sensor outputs so that the signals may be added coherently. Beamforming, however, is inappropriate if the waveguide boundaries significantly effect the radiation field. The maximum information array design for estimating source depth in an infinite homogeneous horizontal waveguide is shown to be horizontal, and thus a horizontal array can be used to obtain source depth as well as bearing in a shallow waveguide.