Research On Inversion Of Seafloor Parameter

In recent years, the inversion of seafloor acoustic parameter has already become a hot topic of underwater acoustic. In traveling through the sea, an underwater acoustic signal is affected by many factors and takes much information of the ocean. By analyzing and processing the underwater acoustic signals received on the array, the inversion technique of underwater acoustic can get the needed parameters of ocean bottom. Compared with traditional methods of direct point measurement, the inversion technique has obvious advantages, such as simplicity and effectivity. By using the inversion technique, it can continuously monitor ocean environment in a large area for a long time.Building a proper sound propagation model and researching a kind of efficient algorithm of optimization are necessary to the inversion of seafloor parameters. Then the observed acoustic field data can be correlated with the synthetic data through a cost function, to realize the searching procedure of seafloor parameter.In this dissertation, the sound field was computed with Gaussian ray bundle method which based on ray theory. The Gaussian ray bundle is an improvement of Gaussian beam. In the Gaussian beam approach, every ray of beam correlated with the intensity profile of Gaussian vertical to the ray, the width of the beam is determined by integrating an extra pair of differential equations along with the ray equations. The Gaussian ray bundle is similar to Gaussian beam, except that it uses a simpler method to arrive at the width of the Gaussian. A set of programs for sound ray calculating have accomplished by using Gaussian ray bundle approach, which can calculate the traces and the sound field. A friendly interface has been developed, and the program has perfect performance in computation speed.In parameter optimization, the particle swarm optimization approach was introduced. The particle swarm optimization is a kind of swarm intelligence...