A MATLAB GUI for ocean acoustic propagation

A MATLAB-based MAP graphical user interface (GUI) is described for accessing bathymetry and sound speed databases and using them to predict ocean acoustic transmission and to display the results. MATLAB scripts have been developed to estimate a field of view from a single transducer and to compute transmission losses between a source and receiver using one of several standard propagation codes. The GUI called MAP is described and several test cases are presented. The MAP GUI supports three simple functions that display database information; an image of bathymetry for a user-specified area may be plotted, a sound speed profile (SSP) at a user-selected location may be plotted, and bathymetry and SSP along a geodesic between a transmitter and receiver may be plotted. The MAP GUI supports two types of algorithms modeling acoustic transmission loss. The first is computation of the acoustic field between two points. External propagation codes written by other agencies are used to do the basic simulation. MATLAB accesses database information, writes input files for the simulations, runs them, and plots results. Currently five external simulations are supported; (1) EIGENRAY, (2) RAY, (3) CASS, (4) UMPE, and (5) RAM. The first three simulations are ray-based models, and the last two are parabolic expansion models. The second type of algorithm is mapping a "field of view" for a transducer (a "shadow" plot). Horizontal rays are propagated from the instruments and the range at which acoustic propagation fails is displayed. Two algorithms are supported. One accesses a database of sound channel depths along with bathymetry information and uses heuristics to estimate propagation along the horizontal rays. The other accesses the Levitis SSP database and uses Weston's Ray Invariant to identify ray elevations "interrupted" by bathymetry or (if specified by the user) by the surface.