Performance of an enhanced passive sonar reflector SonarBell: A practical technology for underwater positioning

Islas-Cital, Alan; Atkins, P.; Gardner, Simon; Tiltman, Carl

doi:10.3723/ut.31.113

Cited by 8 publications

(4 citation statements)

References 11 publications

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“…Only the reflectors show up because their peak pattern remains constant and can be detected repeatedly in the IRs of the environment. Comparing the reflector designs proposed here with the underwater reflector designs referred to above, we note again that for airborne sonar we cannot make use of multiple internal layers of materials with different reflective properties to generate a characteristic echo pattern (13,15) because of the large mismatch between acoustic impedances of air and solid materials. Virtually no sound will penetrate into the reflector, and thus the approach of layers of different reflective properties cannot be used for sonar landmarks on land.…”

Section: Discussionmentioning

confidence: 87%

“…For radar sensors, multiple trihedral reflectors proved useful in autonomous straddle-carrier systems (10,11) and could improve their localization efficacy. To aid underwater robot navigation, sonar landmarks (12), information encoding sonar markers (13,14), and even commercially available sonar targets exist (15). Surprisingly, airborne sonar systems have not used synthetic markers so far, even though nearly every autonomous vehicle is equipped with sonar sensors and several studies showed that such sensors are capable of 3-dimensional (3D) localization and classification of objects in complex environments (16)(17)(18)(19)(20)(21).…”

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confidence: 99%

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Bioinspired sonar reflectors as guiding beacons for autonomous navigation

Simon

Rupitsch

Baumann

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Sonar sensors are universally applied in autonomous vehicles such as robots and driverless cars as they are inexpensive, energy-efficient, and provide accurate range measurements; however, they have some limitations. Their measurements can lead to ambiguous estimates and echo clutter can hamper target detection. In nature, echolocating bats experience similar problems when searching for food, especially if their food source is close to vegetation, as is the case for gleaning bats and nectar-feeding bats. However, nature has come up with solutions to overcome clutter problems and acoustically guide bats. Several bat-pollinated plants have evolved specially shaped floral parts that act as sonar reflectors, making the plants acoustically conspicuous. Here we show that artificial sonar beacons inspired by floral shapes streamline the navigation efficacy of sonar-guided robot systems. We developed floral-inspired reflector forms and demonstrate their functionality in 2 proof-of-principle experiments. First we show that the reflectors are easily recognized among dense clutter, and second we show that it is possible to discern different reflector shapes and use this identification to guide a robot through an unfamiliar environment. Bioinspired sonar reflectors could have a wide range of applications that could significantly advance sonar-guided systems.

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Section: Discussionmentioning

confidence: 87%

mentioning

confidence: 99%

Bioinspired sonar reflectors as guiding beacons for autonomous navigation

Simon

Rupitsch

Baumann

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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“…The SonarBell is a kind of passive sonar reflector, and can be designed beforehand to have a frequency response for single or multiple peaks. 16) In this trial, we designated the frequency response of each target to have a single peak of 80 or 160 kHz, and each diameter was 275 mm. The angle corresponding to the diameter of the target arranged at the range of 15 m is about 1°, as shown in Fig.…”

mentioning

confidence: 99%

“…Then, it is possible to designate the second echo to have a peculiar frequency response. 16) The power spectra of the target echo and silent sound were calculated by 2048points fast Fourier transform (FFT) and smoothing with 10-points Median filter to reject line spectra of internal noises in measurement equipment. As shown in the mid panel of Fig.…”

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confidence: 99%

Expression with red–green–blue additive color mixing for frequency-dependent targets in the third sea trial of ambient noise imaging with acoustic lens in 2016

Mori

Kawahara

Ogasawara

et al. 2018

Jpn. J. Appl. Phys.

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In November 2016 in Uchiura Bay, the third sea trial of ambient noise imaging with an acoustic lens was carried out to detect two targets having frequency response peaks of 80 and 160 kHz. Here, the received frequency band was divided into three parts, and the band levels of low, mid, and high frequencies were assigned to red (R), green (G), and blue (B) colors, respectively. Then, the target images created with RGB additive color mixing successfully expressed the frequency dependences of both targets, in which the red and blue spots corresponded to the targets of 80 and 160 kHz, respectively.

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