Use of clicks resembling those of the Atlantic bottlenose dolphin (Tursiops truncatus) to improve target discrimination in bubbly water with biased pulse summation sonar

Chua, Gim Hwa; White, P.R.; Leighton, Timothy G.

doi:10.1049/iet-rsn.2011.0199

Cited by 13 publications

(10 citation statements)

References 40 publications

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“…In addition, each mobile is also operated at three different states: switched on (labelled as 'on' in figures 6-8); switched off (labelled as 'off' in figures 6-8) and switched on with an out-of-date SIM card inserted (labelled as 'simcard' in figures [6][7][8]. Given that mobile phones might contain multiple resonances and are themselves active sources through their communications with their base stations, this is a look-see experiment rather than a comprehensive study.…”

Section: Resultsmentioning

confidence: 99%

“…Let the pulses be related by a relationship of the form ψ 2 (t) = Γ ψ 1 (t), where Γ is a scalar. The difference in amplitude will mean that two echoes from a linear scatterer only differ by the scaling factor Γ , whereas echoes from a nonlinear scatterer will not be related in that simple manner [6,7]. The efficacy of a general form of Γ is yet to be experimentally tested for radar, and TWIPR exploits the particular case of Γ = −1.…”

Section: Introductionmentioning

confidence: 99%

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Radar clutter suppression and target discrimination using twin inverted pulses

et al. 2013

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The proposition that the use of twin inverted pulses could enhance radar is tested. This twin inverted pulse radar (TWIPR) is applied to five targets. A representative target of interest (a dipole with a diode across its feedpoint) is typical of covert circuitry one might wish to detect (e.g. in devices associated with covert communications, espionage or explosives), and then distinguish from other metal (‘garbage’ or ‘clutter’), here represented by an aluminium plate and a rusty bench clamp. In addition, two models of mobile phones are tested to see whether TWIPR can distinguish whether each is off, on or whether it contains a valid SIM card. Given that a small, inexpensive, lightweight device requiring no batteries can produce a signal that is 50 dB above clutter in this test, the options are discussed for using such technology for animal tagging or to allow the location and identification of buried personnel who opt to carry them (rescue workers, skiers in avalanche areas, miners, etc.). The results offer the possibility that buried catastrophe victims not carrying such tags might still be located by TWIPR scattering from their mobile phones, even when the phones are turned off or the batteries have no charge remaining.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Radar clutter suppression and target discrimination using twin inverted pulses

et al. 2013

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“…As with TWIPS (Leighton et al 2010(Leighton et al , 2011, such effectiveness at discrimination is seen as its primary advantage, an enhancement of the ability to detect the target in the first place (prior to classifying it) being a secondary, lesser advantage. Figure 8 compares the ROC curve for BiaPSS processing of this dolphin-like pulse for tank data (figure 8a) and for simulation (figure 8b) (using the simulation method described by Chua et al (2012)). In the simulation, the losses during transmission to and from the bubble cloud are imposed by applying the attenuation that would be given by linear bubble pulsations (Commander & Prosperetti 1989), the attenuation of water (Francois & Garrison 1982a,b) and geometric losses.…”

Section: (A) Results For Dolphin-like Pulsesmentioning

confidence: 99%

Do dolphins benefit from nonlinear mathematics when processing their sonar returns?

2012

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Dolphins have been observed to blow bubble nets when hunting prey. Such bubble nets would confound the best man-made sonar because the strong scattering by the bubbles generates 'clutter' in the sonar image, which cannot be distinguished from the true target. The engineering specification of dolphin sonar is not superior to the best man-made sonar. A logical deduction from this is that, in blowing bubble nets, either dolphins are 'blinding' their echolocation sense when hunting or they have a facility absent in man-made sonar. Here we use nonlinear mathematical functions to process the echoes of dolphin-like pulses from targets immersed in bubble clouds. Dolphins emit sequences of clicks, and, within such a sequence, the amplitude of the clicks varies. Here such variation in amplitude between clicks is exploited to enhance sonar performance. While standard sonar processing is not able to distinguish the targets from the bubble clutter, this nonlinear processing can. Although this does not conclusively prove that dolphins do use such nonlinear processing, it demonstrates that humans can detect and classify targets in bubbly water using dolphin-like sonar pulses, raising intriguing possibilities for dolphin sonar when they make bubble nets.

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“…The simulation method is described by Chua et al (2012). A train of pulses is emitted, such that the interval between each pulse pair is 0.5 s. The separation between the pulses in each pulse pair is kept at 15 ms. Every other pulse is as shown in Figure 2(a), but between them are pulses which have the same form as that of Figure 2(a) but with the amplitudes all scaled down by approximately 30%.…”

Section: Methodsmentioning

confidence: 99%

Use of dolphin-like pulses to enhance target discrimination and reduce clutter

Leighton¹,

Chua²,

White³

2013

Proceedings of Meetings on Acoustics

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Building on the earlier success of using twin inverted pulses to supress bubble scatter and so reduce clutter when detecting targets in bubbly water (proven in ship wakes in field trials), the same nonlinear processing scheme is generalized to make use of dolphin-like pulses. Their performance in reducing clutter and enhancing target discrimination is demonstrated in the laboratory, and the opportunities for using the same scheme to improve the detection of hidden electronic devices or semiconductor devices by radar are discussed.

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Use of clicks resembling those of the Atlantic bottlenose dolphin (Tursiops truncatus) to improve target discrimination in bubbly water with biased pulse summation sonar

Cited by 13 publications

References 40 publications

Radar clutter suppression and target discrimination using twin inverted pulses

Radar clutter suppression and target discrimination using twin inverted pulses

Do dolphins benefit from nonlinear mathematics when processing their sonar returns?

Use of dolphin-like pulses to enhance target discrimination and reduce clutter

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