Improved acoustic detection and identification of gillnets

A study of the acoustic backscattering produced by an array of scattering spheres fixed to a fishing net is reported. The system enhances net detection and also allows net identification by using a method in which the echogram is arranged to resemble a commercial bar-code. A simplified theoretical model has been developed to study the interference due to echo formation. This model establishes the relations between system geometry (target dimensions, scatterer separation and net depth) and sonar performance (directivity, pulse length, pulse repetition rate, wavelength, and ship speed), getting a better system response. Experimental tests have been realized in a water tank in good agreement with bar code gillnet identification provided by the theoretical model.