Design of hydrophone arrays for multipath environments

Energy arriving at a receiving site, from multiple elevation angles at a single azimuth, places constraints on array design which are nearly independent of other phenomena. Methods are developed to determine the constraints and to produce approximate design equations and curves for collinear and planar arrays. The approximate methods are compared to exact calculations for a few exemplary cases to establish the validity of the approximations. Curves and equations for the collinear array give the maximum attainable gain for a given arrival geometry and the length and number of hydrophones required to achieve a specified gain. For planar arrays, equations are presented which allow calculation of required dimensions and number of hydrophones. Although the design equations do not give details of hydrophone placement, or account for other propagation phenomena, they provide useful preliminary estimates as a basis for more detailed design.