Dolphin-inspired sonar provides underwater clarity

Developed by a team from the National University of Singapore (NUS) Tropical Marine Science Institute (TMSI), the sonar is said to incorporate information on the sparsity of objects, which helps interpret sound echoes better. This processing method is based on the hypothesis that dolphins use prior information about their environment, apart from broadband sound pulses, to interpret their echoes.

Compared to similar sonars, the NUS sonar is claimed to provide a better trade-off between sonar-image clarity, the number of sensors and the size of the sensor array used. The study has been published in Communications Engineering.

The scientists observed that dolphins were able to acoustically scan objects underwater and pick matching objects visually. This demonstrated that a dolphin’s sound echoes emitted off an object contained information of the object’s shape. They then recorded dolphin echoes emitted when scanning an object underwater.

Based on their observations, the team built a biomimetic sonar that replicated a dolphin’s sonar. The sonar is designed to emit sharp, impulsive click sounds similar to a dolphin’s echolocation. Three transmitters are used to send sounds from different directions. The researchers then processed the sounds from the dolphin and their sonar to visualise what the echoes revealed about the object shape.