Sea experimental detection of an array of hollow spheres

A stu~$~ o/the acoustic backxatteringproduced by m army of scattering spheresfixed to ajishing net is reported. The System enhances net detection and also allows net identijcation by using a method in which the echogram is arranged to resemble a commercial bar-code. A simplijied theoretical model has been developed to shrdy the inlerference due to echo formation. This model establishes the relations behveen .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 vstem response. Experimental tests have been reolized in D water tank in good agreement with bar code gillnet identijication provided by the theoretical model. A sea survey in the Mediterranean sea has been carried out. II has been placed a gillnet with an array ofplastic hollow spheres attached at the headline of the net. Several measurements were taken with o side scan sonar to detect the net and identify the associated bar code.