ABSTRACT
This chapter describes the biomimetic model for a bat’s echolocation and echo sounder system using the dolphin-like broadband signal. Bats and dolphins can use echolocation, which is called “biosonar.” Dolphins make use of similar information when using broadband sonar signals to detect and pursue their prey. Behavioral experiments have found that bottlenose dolphins can determine the size, material, and shape of a target, as well as the object characteristics. The broadband split-beam echo sounder using a dolphin-like signal has been constructed to estimate fish abundance. Acoustic surveys have been carried out for the estimation of fisheries resources. Narrowband ultrasound signals have been used for these surveys. Fish densities are typically estimated using measurements of echo amplitudes, that is, volume-backscattering strength of aggregations encountered directly the survey vessel. A broadband split-beam echo sounder includes some receiving points in order to estimate the direction of each fish by using the time difference of arrival.
