Analysis and classification of broadband echoes using bio-inspired dolphin pulses

Proceedings of Meetings on Acoustics

2013

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In this paper we present the results of MCM trials using a Biosonar system mounted on the AUV (autonomous underwater vehicle) REMUS 100. The trials were run in Lochearnhead in Scotland. Two mine-like objects were put on the seafloor. The first one was a aluminium cylinder (150 cm long and 40 cm diameter) and the second object was a truncated cone shaped aluminium shell (Manta mine like target). The REMUS 100 was equipped with a standard Marine Sonics sidescan sonar. The Biosonar payload was in a side-looking configuration. Data were gathered using both sensors simultaneously. A first set of runs covered the delimited search area using lawnmower pattern. The AUV then returned to the interesting detected objects and reacquired them following a dolphin-like spiral to obtain further data giving a range of views of the objects. The data supplied have demonstrated that the wideband sonar system is very effective at identifying seafloor objects.

“…The classification was performed using the distance metric Eq. 2 in a controlled environment [5]. The correct identification rate was greater than 90%.…”

Section: Object Identification Via Broadband Echoesmentioning

confidence: 80%

“…In Ref. [5] Pailhas and al. proved that the localisation of the notches are stable features for identification.…”

Section: Object Identification Via Broadband Echoesmentioning

confidence: 99%

MCM trials with Biosonar system

Pailhas¹,

Capus²,

Proceedings of Meetings on Acoustics

2013

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“…The identification of the landmarks is based on the work done by Pailhas et al in [35], which proves that the localisation of the notches are stable features for identification.…”

Section: Characteristic Coded Artificial Landmarksmentioning

confidence: 99%

Design of artificial landmarks for underwater simultaneous localisation and mapping

Pailhas

Capus

IET Radar, Sonar & Navigation

et al. 2013

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The use of autonomous underwater vehicles for a variety of purposes is set to increase in the future. A key issue is accurate navigation, especially for survey applications large cumulative error are introduced by the various position sensors: accelerometer; Doppler velocity log; compass; inertial navigation sensors. Algorithms such as simultaneous localisation and mapping rely on accurate landmark recognition in order to correct the vehicle position. This study proposes a solution based on broadband sonar and passive artificial coded landmarks to improve the navigation. Through resolution of the wave equation for acoustic propagation in a multilayer concentric sphere, it is shown that there is a great diversity in the echo spectrum with only small changes in internal structure. This enables the design of a set of passive landmarks, which can be identified unambiguously, since each has a characteristic signature or spectral code when insonified with a broadband sonar.

“…This delay between elements of a single click follows the analyses from real dolphin clicks: the higher frequency chirp is always delayed relative to the lower frequency one. In total, a series of six bio-mimetic pulses were created and named DCn with n [ [1,6] to cover the six click types detailed in Table 1.…”

Section: Dolphin-like Pulsesmentioning

confidence: 99%

Dolphin-inspired sonar system and its performance

Pailhas

Capus

IET Radar, Sonar &Amp; Navigation

2012

The sonar of dolphins has developed over millions of years of evolution and has achieved excellent performance levels. Using the excellent performance of the dolphins sonar as an inspiration, bio-inspired wideband acoustic sensing methods for underwater target detection and tracking are being developed. In this study the authors explore what they expect to gain from such a wideband sonar. The systems wideband sensors are based on bottlenose dolphins sonar, covering a frequency band from around 30 to 150 kHz and having a frequency dependent beamwidth considerably larger than that of conventional imaging sonars. The system can be made relatively compact and is suitable for mounting on a variety of platforms including small-scale autonomous underwater vehicles to allow the sonar to operate in a similar way to that used by dolphins. In contrast to high-resolution image processing techniques, detection and classification in the wideband system are based on pattern recognition methods applied to the echo spectra. The authors highlight the properties of the transducers needed for such a system indicating how these properties may be exploited to give improved sonar performance. The results obtained from such a system are presented to illustrate the effectiveness of this approach.