A method of localization and identification of a solid elastic cylinder

A cylinder is immersed in water and insonified at large ka (k = wave-number, a = radius of the target) in the backscattering geometry. We describe a method for determining the distance of the transducer to the target, the radius of the cylinder, and the material of the cylinder from ultrasonic mesurements. The measured arrival times of four received echoes provide us a way of approximating the distance, the radius, and the velocities of the bulk waves in the solid. We present a formula that gives the maximum of the measurement error allowing a degree of accuracy on the estimated values of the velocities that is compatible to the proper identification of the material of the cylinder. In those eases when the value of this maximal measurement error would be too little to be realistic, we evaluate the density of the solid from the measurement of the amplitudes of two different echoes.