Antenna design and performance assessment for fast high resolution sonar imaging using high bandwidth transducers and frequency domain compounding

Abstract

In this work, we present the design and performance assessment of a Multi Beam Echo Sounder (MBES) antenna for fast high resolution sonar imaging as a follow up to a previously presented concept based on high bandwidth transducers and frequency compound imaging. The antenna configuration consists of a modified mills-cross set-up of two linear array transducers with 128 elements each with a center frequency of 1.0 MHz. The elements of the antennas are set-up in a special geometrical assembly for ideal acoustic directivity. Each element consists of the acoustic sandwich optimized for sensitivity and bandwidth on a carrier for highly precise positioning and safe and simple electrical connection. The antenna performance was tested by means of water tank measurements on test targets. Channel data acquisition was performed using a digital acoustic research platform and beamforming was performed according to the concept presented earlier. The achieved spatial resolution and sensitivity correspond well with the theoretical expectations.