Research On The Method Of Measuring The Tidal Currents Based On Ocean Acoustic Tomography

Ocean is rich in energy,biological resources and mineral resources,which is the main venue of human life in future.In recent years,shallow sea acoustic problems have become the focus of marine acoustic research,due to human activities and the gradual development of coastal waters demand.The shallow water environment is affected by tide.One of important parameters in ocean is ocean current velocity.Grasping the current distribution and flow pattern can effectively serve the various maritime activities.In this thesis,aiming at the characteristics of sea currents in the shallow sea,the acoustic propagation model in the moving media is established using ray theory.Then the local sea tidal current velocity is inversed based on the two-way acoustic propagation delay difference.Basing this inversion method,the effect of number of array elements,spacing of array elements,and horizontal range on the inversion precision are analyzed through numerical results.The results show that this method can accurately inverse the current velocity,and the time parameter used for inversion is sensitive to the change of current velocity.The higher the flow velocity is,the higher the inversion precision is.Moreover,this inversion model is validated for long-range measurements in shallow sea environments.Finally,the ocean experiment data was analyzed using the inversion method presented in this thesis,and the inversion current is in accordance with the measurement current.