VLF source localization with a freely drifting acoustic sensor array

Chen, G.C.; Hodgkiss, William S.

doi:10.1109/joe.1993.236359

Cited by 12 publications

(2 citation statements)

References 52 publications

(34 reference statements)

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“…Several passive methods have been developed. Array processing techniques are generally used to estimate the source azimuth; for narrow-band signals, the tracking of line spectrum or more geometrical methods are used [23][24] [25]. The receivers form antennae which are linear or nonlinear, moving or fixed.…”

Section: Introductionmentioning

confidence: 99%

Passive tracking in underwater acoustic

Xerri¹,

Cavassilas²,

Borloz³

2002

Signal Processing

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This paper provides a novel passive underwater acoustic method to track a moving object called source or target, with the following constraints: the sensors location is fixed and imposed, and classical array processing techniques cannot be applied. The method proposed has been successfully used to track a surface vessel (2D problem) or an underwater target (3D problem). All the results presented have been obtained with real signals. The localization of the target requires the estimation of propagation delays, that means the duration between the instant of the signal emission and its reception on each receiver. The cross-correlation function is a suitable tool when the target is motionless, but needs to be extended to the ambiguity function when it is moving. The signal to noise ratio, the uniformity of power spectral density and the integration time are determining factors for the accuracy of the localization. We show that a whitening method and a Doppler compensation are necessary, and we propose a way to eliminate the significant problem of the reflected signals. Furthermore, a new configuration of the receivers is proposed, based on the idea of coupling receivers whose distance is chosen from experiment derived results. Furthermore, the algorithm proposed is susceptible to parallel implementation, thereby facilitating real-time uses. Experimental results with real time domain data are presented and compared to trajectories obtained by an active method. RésuméCet article présente une nouvelle méthode d'écoute passive destinée à trajectographier un objet en mouvement appelé la "source" ou la "cible", avec les contraintes suivantes : le réseau de capteurs est fixe et imposé, et les méthodes classiques de traitement d'antenne ne peuvent pas s'appliquer. La méthode proposée ici a été utilisée avec succès pour trajectographier un bâtiment de surface (problème à deux dimensions) ou une cible sous-marine (problème à trois dimensions). Tous les résultats présentés ont été obtenus sur des signaux réels. Le calcul de la position de la cible nécessite l'estimation des temps de propagation, c'est-à-dire du temps écoulé entre l'instant d'émission du signal et sa réception sur chaque capteur. La fonction d'intercorrélation est un outil opportun lorsque la cible est immobile mais elle doit être étendue à la notion d'ambiguïté quand la source est en mouvement. Le rapport signal à bruit, l'uniformité de la densité spectrale de puissance et la durée d'intégration sont des facteurs déterminants pour la précision de la localisation. Nous montrons qu'une méthode de blanchiment et une compensation de l'effet Doppler sont nécessaires et nous proposons un moyen d'éliminer le problème des trajets multiples. Par ailleurs, une nouvelle configuration des capteurs est proposée, fondée sur l'idée d'associer des hydrophones séparés d'une distance déterminée de manière expérimentale. Des résultats de trajectographies sont présentés et comparés aux trajectoires obtenues par une méthode active.

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Section: Introductionmentioning

confidence: 99%

Passive tracking in underwater acoustic

Xerri¹,

Cavassilas²,

Borloz³

2002

Signal Processing

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“…They increase the signal gain by maximizing the output SNR and have increased detection range. This technique is useful but the sensor arrays are expensive and cumbersome to deploy [6], [7], [8].…”

mentioning

confidence: 99%

Passive Acoustic Vessel Localization

Suwal¹

2000

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On the potential of recording earthquakes for global seismic tomography by low‐cost autonomous instruments in the oceans

Simons¹,

Nolet²,

Georgief³

et al. 2009

J. Geophys. Res.

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[1] We describe the development and testing of an autonomous device designed to revolutionize Earth structure determination via global seismic tomography by detecting earthquakes at teleseismic distances in the oceans. One prototype MERMAID, short for Mobile Earthquake Recording in Marine Areas by Independent Divers, was constructed and tested at sea. The instrument combines two readily available, relatively low-cost but state-of-the-art components: a Sounding Oceanographic Lagrangian Observer, or SOLO float, and an off-the-shelf hydrophone, with custom-built data logging hardware. We report on the development of efficient wavelet-based algorithms for the detection and discrimination of seismic events and analyze three time series of acoustic pressure collected at a depth of 700 m in pilot experiments conducted offshore San Diego, CA. In these tests, over 120 hours of data were gathered, and five earthquakes, of which one was teleseismic, were recorded and identified. Quantitative estimates based on these results suggest that instruments of the MERMAID type may collect up to a hundred tomographically useful teleseismic events per year. The final design will also incorporate a Global Positioning System receiver, onboard signal processing software optimized for low-power chips, and high-throughput satellite communication equipment for telemetered data transfer. With these improvements, we hope to realize our vision of a global array of autonomous floating sensors for whole-earth seismic tomography.

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VLF source localization with a freely drifting acoustic sensor array

Cited by 12 publications

References 52 publications

Passive tracking in underwater acoustic

Passive tracking in underwater acoustic

Passive Acoustic Vessel Localization

On the potential of recording earthquakes for global seismic tomography by low‐cost autonomous instruments in the oceans

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