Channel distortion on target scattering amplitude in shallow water

Bistatic acoustic scattering uses echo returns from a target to estimate the scattered intensity or amplitude as a function of angle and frequency (acoustic color) for target classification. In a shallow water waveguide, the echo return from a target at a distance, such as a mine, is modified by the waveguide and deviates significantly from that at close range or in free space. The channel effect or distortion on the echo return is studied using simulated data. A simple frequency domain signal processing method is proposed to equalize the channel effect. The frequency and angle distribution of the estimated scattering function is compared with that of the original function. It is found to be an adequate representation of the original function with a high correlation coefficient (∼0.88).