Analysis on acoustic longitudinal horizontal correlation of air-to-water transmission

Spatial correlation is an important characteristic of underwater sound field, which is relevant to the detection of aerial targets from underwater. But compared with waterborne sources there are few researches about airborne sources. In order to perform further analysis on the air-to-water sound transmission in shallow water, State Key Laboratory of Acoustics, Institute of Acoustics, conducted an experiment in the South China Sea in March, 2013. During the experiment, multi-frequency signals transmitted by a hooter hung on a research ship were received by a horizontal line array (HLA) which laid on the seabottom, and signals far from 9.8 km were received successfully. Based on data recorded in the experiment, the longitudinal horizontal correlation coefficients of underwater sound field excited by airborne source at different distances with the frequency is 128 Hz are obtained, which have evident oscillation structure as horizontal spacing increases. The mathematical expression is derived based on the normal mode theory and gives a better physical explanation for the oscillatory behavior of the experimental longitudinal horizontal correlation. Spatial correlation is an important characteristic of underwater sound field, which is relevant to the detection of aerial targets from underwater. But compared with waterborne sources there are few researches about airborne sources. In order to perform further analysis on the air-to-water sound transmission in shallow water, State Key Laboratory of Acoustics, Institute of Acoustics, conducted an experiment in the South China Sea in March, 2013. During the experiment, multi-frequency signals transmitted by a hooter hung on a research ship were received by a horizontal line array (HLA) which laid on the seabottom, and signals far from 9.8 km were received successfully. Based on data recorded in the experiment, the longitudinal horizontal correlation coefficients of underwater sound field excited by airborne source at different distances with the frequency is 128 Hz are obtained, which have evident oscillation structure as horizontal spacing increases. The mathematical expression is derived based on the nor...