Experimental procedure for target strength measurement in a small water tank using cumulative energy method

Abstract

This study proposes a precise experimental procedure based on the cumulative energy method to measure the target strength (TS) of arbitrary underwater targets in a small water tank. The proposed procedure aims to overcome environmental variability and the high costs associated with large scale experiments. The specific methodology involves: 1) determining optimal underwater acoustic sensor positions using the Image Source Method (ISM) to separate direct and reflected signals, and 2) evaluating signal energy using the cumulative energy method to minimize noise effects. The validity of the procedure was verified through experiments on a spherical target under both far-field and near-field conditions. The results demonstrated that the experimental TS values agreed with numerical results within $1\text{dB}$ over the frequency range of $80-90\text{kHz}$, confirming the effectiveness of the proposed procedure in small water tank environments. Numerical results were obtained using the backscattering analysis software SYSCOS with a near-field model based on spherical projection.