ESTIMATION METHOD FOR SCATTERING COEFFICIENT

PROBLEM TO BE SOLVED: To obtain an estimation method in which a surface-of-sea scattering coefficient, a bottom-of-sea scattering coefficient and a volume scattering coefficient are estimated in a shallow sea area. SOLUTION: The product of a transmitting-receiving directivity is integrated by a transmitting-receiving-sensitivity-product computing device 5 so as to find a transmitting- receiving-directivity product. A transmitting-receiving-sensitivity product at an angle of elevation required for a computation is found by interpolating the output of the transmitting- receiving-sensitivity-product computing device 5 by an interpolator 6. By using an environmental condition and by using the transmitting-receiving-sensitivity product, at the angle of elevation found by the interpolator 6, a by-route propagation characteristic in a surface-of-sea scattering route and a bottom-of-sea scattering route and a propagation characteristic which corresponds to a volume scattering are found. On the basis of the initial value α0 of a parameter vector α found by the updater 9 of the parameter vector α and on the basis of the propagation characteristic, an estimated value in the time series of a reverberation and a partial differential by a parameter at the initial value of the estimated value are found. A wave- receiving array output in the time series of the reverberation is squared and smoothed, and a reverberation power time series is found by a reverberation-observed-value generation device 7. A matrix A and a matrix B are found by a matrix and vector computing device 11, and Δα is computed by a Δα estimator 12. A convergence is judged by a convergence judger 13.