Interference of Echo Signals from Spherical Scatterers Located Near the Bottom

Abstract—The influence of the bottom on an echo signal from spherical scatterers is studied. The bottom is modeled by a liquid absorbing half-space. The emitter/receiver is located in the aqueous half-space. The distance between the emitter/receiver and scatterer is assumed to be large compared to the acoustic wavelengths in the water and bottom. Numerical results are obtained for acoustically rigid spherical scatterers with the same radius. The interaction between scatterers is not taken into account. The echo signal from one sphere in a wide frequency range is calculated using the method proposed in papers by R.H. Hackman and G.S. Sammelmann, an important step in the implementation of which is calculation of the scattering coefficients of the sphere. To calculate them, the authors use asymptotic formulas obtained with the saddle point method. The resulting asymptotic expressions for the scattering coefficients of the sphere make it possible to significantly reduce the number of terms in the formula for the echo signal form function.