Estimation of underwater sound power using linear array beamforming

A linear array sound intensity scaling method is proposed to estimate the partial area sound power of underwater vehicle noise source. The method establishes a conversion relationship between the linear array beamforming output and the radiated power of the sound source. The numerical simulation results for an underwater monopole point sound source show that the sound power estimation error does not exceed 0.2dB when the test distance is larger than the array diameter. The existing sound intensity scaling methods are based on the condition that the incident direction of sound source to be tested equals to the broadside direction. Significant errors can exist in the estimation results when the direction of the sound source is different significantly from the broadside direction. By using theoretical derivation and simulation, the variation of estimation error for the single monopole point source in different locations is investigated with various frequency and amplitude. The results indicate that the error is only related to the sound source location rather than the intensity information of the sound source. The corresponding error correction method is proposed accordingly. The present methodology provides a simple and effective way to measure the radiated power of underwater sound sources.