The biosonar of the Mediterranean Bottlenose dolphins: analysis and modelling of echolocation signals

The biosonar of the Mediterranean Bottlenose dolphins: analysis and modelling of echolocation signals

For access to this article, please select a purchase option:

Buy chapter PDF
(plus tax if applicable)

IET members benefit from discounts to all IET publications and free access to E&T Magazine. If you are an IET member, log in to your account and the discounts will automatically be applied.

Learn more about IET membership 

Recommend to library

You must fill out fields marked with: *

Librarian details
Your details
Why are you recommending this title?
Select reason:
Biologically-Inspired Radar and Sonar: Lessons from nature — Recommend this title to your library

Thank you

Your recommendation has been sent to your librarian.

In this chapter, we described the analysis carried out on the sonar clicks emitted by Mediterranean Bottlenose dolphins in both audio and ultrasonic bands. We found that most of the sonar clicks emitted when the dolphin is in front of the hydrophone can be modelled by exponential or by Gaussian broadband multicomponent signals. The parameters of these two models have been estimated. The components characterizing each pulse are generally the first or the first two most powerful ones and the fitting with the data seems to be very good in both audio and ultrasonic band. Actually, the meaning of the sonar clicks in the audio band signals is not clear. Maybe, as reported by Zimmer [20], they can be “machinery noise”, that is noise produced by dolphins in emitting the ultrasonic pulses used for the echolocation. In ultrasonic band the most powerful frequency component is located around 24 kHz, almost four octaves under the frequency peak measured for the Oceanic Bottlenose dolphins. This phenomenon can be mainly due to the differences in the Oceanic and Mediterranean environments. However, the efficiency of the dolphin sonar is not only due to the broadband characteristic of the sonar click signals, then to the very high range resolution. Dolphins are able to use as well a multi-perspective, multi-waveforms approach to sense the targets, moving around their preys and changing their trajectories [21], the power and the Pulse Repetition Frequency (PRF) based upon what they have learned from the previous sonar clicks [11,22]. Finally, they use their trained brain to control the whole biosonar process allowing for versatility and continuous learning [4]. It is, of course, not trivial to build a technological sonar similar to that of the marine mammals but the idea of cognitive radars (and so sonars) has been already proposed in 2006 by Haykin in [23] and some progress has been made since then along that path.

Chapter Contents:

  • 9.1 Introduction
  • 9.2 Data acquisition
  • 9.2.1 The hydrophone
  • 9.2.2 The amplifier
  • 9.2.3 Digital card
  • 9.3 Biosonar model
  • 9.4 Signal estimation
  • 9.4.1 Exponential pulse
  • 9.4.2 Gaussian pulse
  • 9.5 Estimation results
  • 9.5.1 Exponential pulse
  • 9.5.2 Gaussian pulse
  • 9.5.3 Audio band
  • 9.6 Conclusions
  • References

Inspec keywords: signal processing; bioacoustics; biology computing; zoology; biological techniques; hydrophones

Other keywords: audio band signals; marine mammals; sonar click signals; pulse repetition frequency; echolocation signal modelling; biosonar; hydrophone; frequency 24 kHz; ultrasonic pulses; cognitive radars; ultrasonic band; echolocation signal analysis; Gaussian broadband multicomponent signals; brain; Oceanic Bottlenose dolphins; machinery noise; Mediterranean Bottlenose dolphins

Subjects: Biology and medical computing; Biophysical instrumentation and techniques; Mechano- and chemio-ceptions; Digital signal processing; Signal processing and detection

Preview this chapter:
Zoom in

The biosonar of the Mediterranean Bottlenose dolphins: analysis and modelling of echolocation signals, Page 1 of 2

| /docserver/preview/fulltext/books/ra/sbra514e/SBRA514E_ch9-1.gif /docserver/preview/fulltext/books/ra/sbra514e/SBRA514E_ch9-2.gif

Related content

This is a required field
Please enter a valid email address