Maximum directivity proof for three-dimensional arrays

Parsons, A.T.

doi:10.1121/1.395561

Cited by 31 publications

(10 citation statements)

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“…As the frequency tends to 0, the DFs will approach the limit values expressed by Eqs. (10) and (11). Figure 3 shows the plot of the SF evaluated using Eqs.…”

Section: Simulationsmentioning

confidence: 99%

“…It has been theoretically proved that the directivity factor (DF) of a spherical array can approach N 2 (Refs. 7 and 8) and the endfire DF of a linear array can also reach M 2 , 9,10 where N and M are the mode number and element number, respectively. However, this theoretical performance cannot be achieved easily in practice because of the high sensitivity of errors 11 from characteristics of actual sensors, array configuration, imprecision of the model, etc.…”

Section: Introductionmentioning

confidence: 99%

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Robust high-order superdirectivity of circular sensor arrays

Wang

Yang

et al. 2014

The Journal of the Acoustical Society of America

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This paper presents a detailed study of the high-order superdirectivity of circular sensor arrays, which is aimed at completing the authors' recently proposed analytical superdirectivity model. From the limit expression of the maximum directivity factor, it is shown that the circular arrays possess good potential for directivity improvement. It is found that the sensitivity function used as a robustness measurement can also be accurately decomposed into a series of closed-form sensitivity functions of eigenbeams, similar to the optimal beampattern and its corresponding directivity factor. Moreover, the performance of eigenbeams can be regarded as an indicator of error sensitivity, and the robustness constraint parameters can be estimated easily. Two specific approaches are proposed for obtaining robust superdirectivity on the basis of robustness analyses, and their performance is demonstrated experimentally.

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“…As the frequency tends to 0, the DFs will approach the limit values expressed by Eqs. (10) and (11). Figure 3 shows the plot of the SF evaluated using Eqs.…”

Section: Simulationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Robust high-order superdirectivity of circular sensor arrays

Wang

Yang

et al. 2014

The Journal of the Acoustical Society of America

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“…berke.gur@eng.bahcesehir.edu.tr arrays steered to the endfire direction (Weston, 1986;Parsons, 1987). Several optimum differential array design methods based on maximizing various performance metrics exist.…”

Section: Introductionmentioning

confidence: 99%

Particle velocity gradient based acoustic mode beamforming for short linear vector sensor arrays

Gur

2014

The Journal of the Acoustical Society of America

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In this paper, a subtractive beamforming algorithm for short linear arrays of two-dimensional particle velocity sensors is described. The proposed method extracts the highly directional acoustic modes from the spatial gradients of the particle velocity field measured at closely spaced sensors along the array. The number of sensors in the array limits the highest order of modes that can be extracted. Theoretical analysis and numerical simulations indicate that the acoustic mode beamformer achieves directivity comparable to the maximum directivity that can be obtained with differential microphone arrays of equivalent aperture. When compared to conventional delay-and-sum beamformers for pressure sensor arrays, the proposed method achieves comparable directivity with 70%-85% shorter apertures. Moreover, the proposed method has additional capabilities such as high front-back (port-starboard) discrimination, frequency and steer direction independent response, and robustness to correlated ambient noise. Small inter-sensor spacing that results in very compact apertures makes the proposed beamformer suitable for space constrained applications such as hearing aids and short towed arrays for autonomous underwater platforms.

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“…Superdirectivity refers to the phenomenon that a small sensor array can outperform its conventional delay-and-sum beamforming with a much higher directivity [2]. Various researches have been performed to explore the superdirectivity both theoretically and practically [3][4][5][6][7][8][9]. Specifically, circular arrays superdirective beamforming can achieve better directivity pattern and DI than conventional beamforming, especially at low frequencies [10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…The proposed beamforming technique has been applied to acoustic source detection and localization. For any given directivity pattern and its expansion form, Parsons [5] in his paper gave a general method to calculate the maximum DI.…”

Section: Introductionmentioning

confidence: 99%

Phase modes circular array superdirective beamforming

Liu

2012

2012 Oceans

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Circular arrays are widely used in underwater acoustics array signal processing due to their two dimensional symmetrical characteristics. In this paper a new method to analytically calculate the superdirective mode coefficients of the phase modes circular array beamforming is proposed. The maximum Directivity Index (DI) achievable for phase modes circular array beamforming is also derived. Computer simulation is held for a circular array composed of 12 separate hydrophones mounted on either open sphere or rigid sphere. The calculated DI achieved by the proposed superdirective beamforming corresponds to the theoretical maximum DI for up to the 5 th order. The proposed method to calculate the superdirective mode coefficients is also applicable for calculating mode coefficients for arrays of any shape and any kind of expansion, indicating its wide range of applications in superdirectivity beamforming.

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Maximum directivity proof for three-dimensional arrays

Cited by 31 publications

References 0 publications

Robust high-order superdirectivity of circular sensor arrays

Robust high-order superdirectivity of circular sensor arrays

Particle velocity gradient based acoustic mode beamforming for short linear vector sensor arrays

Phase modes circular array superdirective beamforming

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