A method for obtaining sensor array manifold using sound field calculation

In this paper, a new method for obtaining the array manifold in sensor array beampattern design and optimization is proposed. The basic idea behind the proposed method is replacing the theoretical obtained or experimentally measured array manifold by the calculated one, which is obtained by calculating the sound field at each element positions in the array. The acoustical boundary element method is used to calculate the sound field and the array manifold is obtained by accumulating the values at all sensor in all interested directions. By doing so, the effects of the array supporting structure or baffle can be included so as to yield a result which is more approaching the practical situation, and at the same time, avoids the tedious work of practical measurements. A conformal array with 27 sensors was designed and built and analyzed by the proposed method. The calculated sensor directivity by the proposed method has a similar tendency with that measured in an anechoic watertank, and the design requirements of beampatterns which use the optimized weighting coefficient obtained from the array manifold calculated by the proposed method are well met in practical system. The simulation results have verified the effectiveness and feasibility of the proposed method.