Fast Bistatic Signal-to-Reverberation-Ratio Calculation

Harrison, Chris H.

doi:10.1142/s0218396x05002669

Cited by 26 publications

(15 citation statements)

References 30 publications

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“…These have been justified and favorably compared with the model BiStaR ͑LePage and Harrison, 2003;Harrison, 2005c͒. As is apparent from the original definition, a variable ␣ can also be accommodated as part of the effective depth integral, so the original term in the exponent ␣ s 2 ͐ dr / H͑r͒ 3 becomes s 2 ͐ ␣͑r͒dr / H͑r͒ 3 ͑see also Holland, 2006͒ and we define a modified effective depth eff ͑r͒ = H s 2 H͑r͒ 2 r ͵ 0 r ␣͑r͒dr/H͑r͒ 3 ͑30͒…”

Section: A Range-dependencementioning

confidence: 90%

Separability of seabed reflection and scattering properties in reverberation inversion

Harrison

Nielsen

2007

The Journal of the Acoustical Society of America

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Separation of scattering properties ͑Lambert's ͒ from reflection properties ͑the reflection loss' angle derivative ␣͒ presents difficulties in the geoacoustic inversion of long range reverberation in isovelocity water, and here it is shown that there is still a problem in a refracting environment. An alternative technique is proposed where reverberation is modified by altering the source or receiver beam pattern, for instance, using a triplet array or ring source, to provide a dipole and monopole pattern. Combinations of these two measures of reverberation then conveniently determine ␣ and independently of other unknown quantities from long ͑or short͒ range data, in fact even from a single range. In addition the short range ratio of the two quantities determines the critical angle independently. The effects of refraction and other source or receiver beam patterns, including a horizontal beam and a tilted beam, are investigated by using analytical techniques. To enhance the credibility of these findings and demonstrate the benefits of the approach an example is posed as a standard inversion problem using a cost function based on both types of reverberation. Finally the technique is applied to some experimental data by forming simultaneous monopole and dipole beams in the vertical plane.

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Section: A Range-dependencementioning

confidence: 90%

Separability of seabed reflection and scattering properties in reverberation inversion

Harrison

Nielsen

2007

The Journal of the Acoustical Society of America

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“…[6][7][8][13][14][15][16] Due to its simplicity and intuitive nature, the energy flux method has further been developed and widely used for SW reverberation calculations, 17-30 mainly due to works by Harrison,Holland and Ainslie. 18,20,21,[23][24][25][26][27][28][29][30] All the closed-form expressions in isovelocity shallow water, derived by Zhou, 6 Harrison, 18 Ainslie 27,30 and Holland, 24 are almost identical, having only minor differences in constant coefficients. In this paper, Zhou's closed-form expressions for reverberation in isovelocity water are used to extract the frequency and angular dependence of the BBS at LF&LGA from long-range reverberation data.…”

Section: The Closed-form Expressions For Ocean Reverberation Intementioning

confidence: 97%

Low frequency seabed scattering at low grazing angles

Zhou

Zhang

2012

The Journal of the Acoustical Society of America

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Low-frequency (LF) seabed scattering at low grazing angles (LGA) is almost impossible to directly measure in shallow water (SW), except through inversion from reverberation. The energy flux method for SW reverberation is briefly introduced in this paper. The closed-form expressions of reverberation in an isovelocity waveguide, derived from this method, indicate that in the three-halves law range interval multimode/ray sea bottom scattering with different incident and scattering angles in forming the reverberation may equivalently be represented by the bottom backscattering at a single range-dependent angle. This equivalent relationship is used to derive the bottom backscattering strength (BBS) as a function of angle and frequency. The LF&LGA BBS is derived in a frequency band of 200-2500 Hz and in a grazing angle range of 1.1°-14.0° from reverberation measurements at three sites with sandy bottoms. This is based on three previous works: (1) The closed-form expressions of SW reverberation [Zhou, (Chinese) Acta Acustica 5, 86-99 (1980)]; (2) the effective geo-acoustic model of sandy bottoms that follows the Biot model [Zhou et al., J. Acoust. Soc. Am. 125, 2847-2866 (2009)] and (3) A quality database of wideband reverberation level normalized to source level [Zhou and Zhang, IEEE J. Oceanic Eng. 30, 832-842 (2005)].

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“…An acoustic model [22] is used to estimate the SNR of the contacts associated to the track; the SNR is then used to compute the acoustic measurement uncertainties (on bearing and on arrival time) which are needed to compute the bistatic measurement error [23]. …”

Section: B Track Scoringmentioning

confidence: 99%

Towards fully autonomous underwater vehicles in ASW scenarios: An adaptive, data driven AUV mission management layer

Ferri

Goldhahn

LePage

2015

OCEANS 2015 - Genova

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We present an adaptive, data driven Mission Management Layer (MML) to manage the phases (surveillance, track prosecution and target reacquisition) of the mission of AUVs operating as receiver nodes in a multistatic network for littoral surveillance. Among the tracks produced by the on board tracker, the MML selects those which are likely originated by a target. The MML then issues commands to the vehicle Control Layer to trigger data-driven optimization behaviours to prosecute these candidate tracks.Selecting few candidate tracks is indeed crucial since the addressed scenario usually presents many tracks hence resulting challenging from the tracking point of view. To select the candidate tracks, a metric is introduced to quantify their quality. It is based on the kinematic features of the target, on an acoustic model and on the quality of measurement-totrack associations. By selecting a limited subset of produced tracks, the MML can improve the benefits of using datadriven behaviours activating them only on interesting cues and reducing the time wasted to optimize tracks not related to a target. This aims at achieving a balance between the surveillance of the area of interest and exploitation of target cues (tracks). These features are essential for improving the overall mission performance and for an effective AUV decision making in realistic conditions. We present results from sea trials demonstrating the effectiveness of our approach and how the proposed MML can represent a step forward towards the full autonomy of our system. These results represent one of the first examples of AUVs autonomously taking decisions in a realistic and complex littoral surveillance scenario.

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Fast Bistatic Signal-to-Reverberation-Ratio Calculation

Cited by 26 publications

References 30 publications

Separability of seabed reflection and scattering properties in reverberation inversion

Separability of seabed reflection and scattering properties in reverberation inversion

Low frequency seabed scattering at low grazing angles

Towards fully autonomous underwater vehicles in ASW scenarios: An adaptive, data driven AUV mission management layer

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