Target dimension is important information in underwater target classification. An intrinsic mode characteristic extraction method in underwater cylindrical shell acoustic radiation was studied in this paper based on t...Target dimension is important information in underwater target classification. An intrinsic mode characteristic extraction method in underwater cylindrical shell acoustic radiation was studied in this paper based on the mechanism of shell vibration to gain the information about its dimension instead of accurate inversion processing. The underwater cylindrical shell vibration and acoustic radiation were first analyzed using mode decomposition to solve the wave equation. The characteristic of acoustic radiation was studied with different cylindrical shell lengths, radii, thickness, excitation points and fine structures. Simulation results show that the intrinsic mode in acoustic radiation spectrum correlates closely with the geometry dimensions of cylindrical shells. Through multifaceted analysis, the strongest intrinsic mode characteristic extracted from underwater shell acoustic radiated signal was most likely relevant to the radiated source radius. Then, partial information about unknown source dimension could be gained from intrinsic mode characteristic in passive sonar applications for underwater target classification. Experimental data processing results verified the effectiveness of the method in this paper.展开更多
To overcome the performance limitation of multipath time-delay estimation posed by underwater acoustic sinusoidal signals, an approach incorporating the frequency-domain weighting of the highly oscillatory Nonlinear L...To overcome the performance limitation of multipath time-delay estimation posed by underwater acoustic sinusoidal signals, an approach incorporating the frequency-domain weighting of the highly oscillatory Nonlinear Least Squares （NLS） cost function with the evolu- tionary optimization was proposed to facilitate the accurate estimation of the multipath timedelay of sinusoidal signals. In the described method, the number of the effective multipath signals, which is included into the parameter model as well as the multipath time-delay and amplitude factor, can be estimated simultaneously thus avoiding the requirement of additional computation. The experimental results performed with numerical simulation and sea-trial data are provided, demonstrating the effectiveness and precision enhancement of the proposed algorithm.展开更多
基金supported by the Project of the Key Laboratory of Science and Technology on Underwater Test and Control(Grant No.9140C260505120C26104)the National Natural Science Foundation of China(Grant No. 11104029)
文摘Target dimension is important information in underwater target classification. An intrinsic mode characteristic extraction method in underwater cylindrical shell acoustic radiation was studied in this paper based on the mechanism of shell vibration to gain the information about its dimension instead of accurate inversion processing. The underwater cylindrical shell vibration and acoustic radiation were first analyzed using mode decomposition to solve the wave equation. The characteristic of acoustic radiation was studied with different cylindrical shell lengths, radii, thickness, excitation points and fine structures. Simulation results show that the intrinsic mode in acoustic radiation spectrum correlates closely with the geometry dimensions of cylindrical shells. Through multifaceted analysis, the strongest intrinsic mode characteristic extracted from underwater shell acoustic radiated signal was most likely relevant to the radiated source radius. Then, partial information about unknown source dimension could be gained from intrinsic mode characteristic in passive sonar applications for underwater target classification. Experimental data processing results verified the effectiveness of the method in this paper.
基金supported by the National Nature Science Foundation of China (10704063)the 863 project (2006AA09Z108)the Nature Science Foundation of Fujian Province (D0610019).
文摘To overcome the performance limitation of multipath time-delay estimation posed by underwater acoustic sinusoidal signals, an approach incorporating the frequency-domain weighting of the highly oscillatory Nonlinear Least Squares （NLS） cost function with the evolu- tionary optimization was proposed to facilitate the accurate estimation of the multipath timedelay of sinusoidal signals. In the described method, the number of the effective multipath signals, which is included into the parameter model as well as the multipath time-delay and amplitude factor, can be estimated simultaneously thus avoiding the requirement of additional computation. The experimental results performed with numerical simulation and sea-trial data are provided, demonstrating the effectiveness and precision enhancement of the proposed algorithm.
