Investigation On Acoustic Holography Technique For Underwater Sound Source Identification And Position By Continuously Scanning Sound Field

Generally, in acoustic holography experiment, the sound pressure data on holograms is usually obtained by step scanning the sound filed. In each step of the measurement process, the data can't be measured until the hydrophone array is still, in order to minimize the measurement error. Therefore, the experiment time will be very long. The acoustic holography technique for sound source identification and position by the method of continuously scanning improves the previous acoustic holography experiment. The hydrophone array is moving continuously while scanning the sound field, so the experimental time is shortened greatly.Based on the formula of Kirchhoff's retarded potential and boundary element method(BEM), the continuously scanning acoustic holography reconstruction expressions of the particle normal velocity on sound source surface and the sound pressure in the sound field at different time have been established. If the relative moving speed between the sound source and the hydrophone is very low, the two situations, in which the sound source is moving and the hydrophone array is still, or otherwise, are equivalent. Therefore, the first situation is adopted in the paper. This method has been verified by numerical simulation with the model of a spherical sound source, and good results have been obtained. The simulation results show that the relative moving speed of sound source and array must be measured accurately and the Doppler effect of the sound pressure should be eliminated. The effect of measurement parameters, such as the moving distance of source, the distance between the source moving plane and array, etc, on sound field reconstruction error has been analyzed in the paper. And the double arrays are suggested to be adopted in order to decrease the moving distance of source and improve the accuracy of sound field reconstruction.