Acoustic compact test range system for large-scale target characteristic testing in a shorter distance

Abstract

In the acoustic scattering and characteristic tests of large targets and large-scale transducers, in order to meet the plane wave conditions, the larger test distance is often required. It is a greater difficulty for the testing laboratories with limited space. In order to compact the testing distance and solve the problem of requiring a long distance for large-scale target scattering and large-scale transducer testing, based on the principle and application of microwave compact test rang system and the approximation of electromagnetic wave and acoustic wave, an underwater acoustic compact range test system (ACTRS) is proposed. The developed ACTRS uses a parabolic main reflector to obtain a plane wave at a short distance. Compared to the traditional underwater acoustic test system, the space distance is effectively compacted and the conversion process is reduced. Moreover, as the main device in the proposed ACTRS, the air-cavity with resin honeycomb structure was selected as the basic unit cell of the main reflector for the good underwater acoustic reflection performance. In addition, the edge sawtooth structure was selected to reduce the interference of edge diffraction in the quiet zone. Subsequently, the main reflector was simulated, trial-produced and measured. The measurement result shows good agreement with the simulation result. Finally, based on the proposed main reflector, the ACRTS was constructed for the object scattering and transducer directivity measurements. The test results were consistent with the simulation and the manufacturer’s manual data. Overall, the designed ACTRS can be used for large-scale target scattering and transducer directivity testing, providing a new reference for exploration of acoustic measurement methods.