Steering vector sensor array elements with linear cardioids and nonlinear hippioids

Smith, Kevin B.; Leijen, A. Vincent van

doi:10.1121/1.2722054

Cited by 14 publications

(7 citation statements)

References 3 publications

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“…Besides the figure-8 sensor, other directional sensors could be investigated by the interested reader, e.g., the "cardioids" 35 or the "hypioids." 36…”

Section: Discussionmentioning

confidence: 99%

A higher-order “figure-8” sensor and an isotropic sensor—For azimuth-elevation bivariate direction finding

Muaz

Yu-hua

Wong

et al. 2018

The Journal of the Acoustical Society of America

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A "p-u probe" (also known as a "p-v probe") comprises one pressure-sensor (which is isotropic) and one uni-axial particle-velocity sensor (which has a "figure-8" bi-directional spatial directivity). This p-u probe may be generalized, by allowing the figure-8 bi-directional sensor to have a higher order of directivity. This higher-order p-u probe has not previously been investigated anywhere in the open literature (to the best knowledge of the present authors). For such a sensing system, this paper is first (1) to develop closed-form eigen-based signal-processing algorithms for azimuth-elevation direction finding; (2) to analytically derive the associated Cramér-Rao lower bounds (CRB), which are expressed explicitly in terms of the two constituent sensors' spatial geometry and in terms of the figure-8 sensor's directivity order; (3) to verify (via Monte Carlo simulations) the proposed direction-of-arrival estimators' efficacy and closeness to the respective CRB. Here, the higher-order p-u probe's two constituent sensors may be spatially displaced.

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“…Besides the figure-8 sensor, other directional sensors could be investigated by the interested reader, e.g., the "cardioids" 35 or the "hypioids." 36…”

Section: Discussionmentioning

confidence: 99%

A higher-order “figure-8” sensor and an isotropic sensor—For azimuth-elevation bivariate direction finding

Muaz

Yu-hua

Wong

et al. 2018

The Journal of the Acoustical Society of America

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“…The additive combination of pressure and particle velocity measurements is optimal to improve low SNR signals, which is the case of reflections from deep bottom layers in seismic applications. These combinations are particular cases of the wellknown super directive beamformers [12] and VS combinations discussed in [26].…”

Section: Combinations Of Pressure and Particle Velocitymentioning

confidence: 99%

Acoustic Pressure and Particle Velocity for Spatial Filtering of Bottom Arrivals

Felisberto

Santos

Jesus

2019

IEEE J. Oceanic Eng.

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This paper discusses the advantages of using a combination of acoustic pressure and particle velocity motion for filtering bottom arrivals. A possible area of application is reflection seismology where, traditionally, the seismic image is extracted from the bottom-reflected broadband acoustic signals received on hydrophones. Since hydrophones are omnidirectional in nature, the received bottom returns are often contaminated by waterborne signals, sea surface reflections, and noise. A substantial part of the processing of the data is dedicated to filtering out these unwanted signals. Today, vector sensors allow us to measure both acoustic pressure and particle velocity motion in a single and compact sensor. The combination of pressure and particle velocity measured at a single location or particle velocity and particle velocity gradient at closely spaced locations allows for spatial beam steering to predetermined directions and filter out unwanted replicas from other directions. Moreover, this can be done at the sensor level, dramatically decreasing the offline processing. The spatial filtering capabilities of various pressure-pressure, particle velocity-particle velocity, and pressure-particle velocity combinations are analyzed in view of filtering the bottom arrivals. It is shown that the combination of pressure and vertical particle velocity and, particularly, the combination of vertical particle velocity and particle velocity gradient enhance bottom arrivals. Moreover, a simple steering procedure combining pressure and particle velocity components of a triaxial sensor allows us to determine the tridimensional structure of the acoustic field and the separation of the bottom reflections. The spatial selectivity of the various sensor combinations is shown with simulations and verified with experimental data acquired with 10 cm separated vector sensors in the 800-1250-Hz band, during the Makai 2005 sea trial, off Kauai Island, HI, USA.

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“…A major conclusion is that linear AVS arrays, albeit equipped with more measurement channels, provide a directivity improvement of up to 5 dB compared to conventional arrays of equal aperture lengths. More recently, Smith and Van Leijen (2007) proposed a beamformer by extending on the cardioid pattern of a single AVS in the array. In the method proposed by the authors, the cardioid response of a single AVS is raised to integer powers, resulting in a more directional single sensor response.…”

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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Steering vector sensor array elements with linear cardioids and nonlinear hippioids

Cited by 14 publications

References 3 publications

A higher-order “figure-8” sensor and an isotropic sensor—For azimuth-elevation bivariate direction finding

A higher-order “figure-8” sensor and an isotropic sensor—For azimuth-elevation bivariate direction finding

Acoustic Pressure and Particle Velocity for Spatial Filtering of Bottom Arrivals

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

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