Author: Ben Coxworth [Gizmag]
Chances are, you know that dolphins use sonar to locate and stun prey underwater. You might also know that they create “bubble nets,” in which they trap fish inside a ring of air bubbles that they blow while swimming in a circle. With all those distracting bubbles suspended in the water, though, their sonar needs to work in a special way in order to pick out the fish. Scientists have copied that sonar system, to create a type of radar that could differentiate between ordinary objects and things like explosive devices.
Prof. Tim Leighton, of the University of Southampton in the UK, led the research. His team started out by developing a dolphin-inspired system known as twin inverted pulse sonar, or TWIPS, which we covered in 2010.
In this system, two sonar pulses are sent out in quick succession. Those pulses are identical to one another, except for the fact that they’re phase-inverted. When those pulses hit a solid target, it scatters the reflected sound in a linear pattern. Bubbles, on the other hand, produce non-linear scattering. By suppressing the non-linear return signals, TWIPS is therefore able to locate underwater targets amidst bubbles.
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