Acoustic vector-sensor processing in the presence of a reflecting boundary

We consider the passive direction-of-arrival (DOA) estimation problem using arrays of acoustic vector sensors located in a fluid at or near a reflecting boundary. We formulate a general measurement model applicable to any planar surface, derive an expression for the Cramer-Rao bound (CRB) on the azimuth and elevation of a single source, and obtain a bound on the mean-square angular error (MSAE). We then examine two applications of great practical interest: hull-mounted and seabed arrays. For the former, we use three models for the hull: an ideal rigid surface for high frequency, an ideal pressure-release surface for low frequency, and a more complex, realistic layered model. For the seabed scenario, we model the ocean floor as an absorptive liquid layer. For each application, we use the CRB, MSAE bound, and beam patterns to quantify the advantages of using velocity and/or vector sensors instead of pressure sensors. For the hull-mounted application, we show that normal component velocity sensors overcome the well-known, low-frequency problem of small pressure signals without the need for an undesirable "stand-off" distance. For the seabed scenario, we also derive a fast wideband estimator of the source location using a single vector sensor.

[1]  Michael D. Zoltowski,et al.  Extended-aperture underwater acoustic multisource azimuth/elevation direction-finding using uniformly but sparsely spaced vector hydrophones , 1997 .

[2]  A. Pierce.  An Introduction to its Physical Principles and Applications , 1981 .

[3]  Marilyn Berliner,et al.  Acoustic particle velocity sensors; design, performance, and applications, Mystic CT. September 1995 , 1996 .

[4]  Allan D. Pierce,et al.  Acoustics , 1989 .

[5]  Murray Hodgson,et al.  Development and evaluation of equivalent-fluid approximations for sea-bottom sound reflection , 1998 .

[6]  Michael D. Zoltowski,et al.  Root-MUSIC-based azimuth-elevation angle-of-arrival estimation with uniformly spaced but arbitrarily oriented velocity hydrophones , 1999, IEEE Trans. Signal Process..

[7]  W.S. Hodgkiss,et al.  A Vertical Array Of Directional Acoustic Sensors , 1992, OCEANS 92 Proceedings@m_Mastering the Oceans Through Technology.

[8]  K. F. Sander,et al.  Transmission and Propagation of Electromagnetic Waves , 1986 .

[9]  J. E. Piercy,et al.  Outdoor sound propagation over ground of finite impedance , 1976 .

[10]  Sung H. Ko,et al.  Signal pressure received by a hydrophone placed on a plate backed with a compliant baffle , 1988 .

[11]  G.L. Edmonds,et al.  Initial Analysis Of The Data From The Vertical DIFAR Array , 1992, OCEANS 92 Proceedings@m_Mastering the Oceans Through Technology.

[12]  Arye Nehorai,et al.  Battlefield Target Localization Using Acoustic Vector Sensors and Distributed Processing , 1999 .

[13]  F. N. Frenkiel,et al.  Waves In Layered Media , 1960 .

[14]  Gerald C. Lauchle,et al.  Flow‐induced noise on pressure gradient hydrophones , 1996 .

[15]  A. Yariv,et al.  Modelocked pulses from semiconductor lasers at greater than 100 GHz repetition rates , 1991, LEOS 1991 Summer Topical Meetings on Spaceborne Photonics: Aerospace Applications of Lasers and Electro-Optics, Optical Millimeter-Wave Interactions: Measurements, Generation, Transmission and Control.

[16]  Michael D. Zoltowski,et al.  Closed-form underwater acoustic direction-finding with arbitrarily spaced vector hydrophones at unknown locations , 1997 .

[17]  J. P. Hartley,et al.  Monitoring the Occurrence of Large Whales Off North and West Scotland Using Passive Acoustic Arrays , 1997 .

[18]  S. Ko,et al.  Flow noise reduction techniques for a planar array of hydrophones , 1991 .

[19]  J. Wait,et al.  Waves in layered media, 2nd edition , 1981, IEEE Antennas and Propagation Society Newsletter.

[20]  Arye Nehorai,et al.  Vector-sensor array processing for electromagnetic source localization , 1994, IEEE Trans. Signal Process..

[21]  T. Ferguson.  A Course in Large Sample Theory , 1996 .

[22]  Arye Nehorai,et al.  Performance bounds for estimating vector systems , 2000, IEEE Trans. Signal Process..

[23]  Michael D. Zoltowski,et al.  Self-initiating velocity-field beamspace MUSIC for underwater acoustic direction-finding with irregularly spaced vector-hydrophones , 1997, Proceedings of 1997 IEEE International Symposium on Circuits and Systems. Circuits and Systems in the Information Age ISCAS '97.

[24]  J. D. Irish,et al.  Trawl resistant bottom mounted instrumentation: developments and results to date , 1996, OCEANS 96 MTS/IEEE Conference Proceedings. The Coastal Ocean - Prospects for the 21st Century.

[25]  A. Nehorai,et al.  Surface-mounted acoustic vector-sensor array processing , 1996, 1996 IEEE International Conference on Acoustics, Speech, and Signal Processing Conference Proceedings.

[26]  Arye Nehorai,et al.  Effects of sensor placement on acoustic vector-sensor array performance , 1999 .

[27]  S. Timoshenko,et al.  Theory of Elasticity (3rd ed.) , 1970 .

[28]  Arye Nehorai,et al.  Acoustic vector-sensor correlations in ambient noise , 2001 .

[29]  Arye Nehorai,et al.  Acoustic vector-sensor beamforming and Capon direction estimation , 1995, 1995 International Conference on Acoustics, Speech, and Signal Processing.

[30]  Michael D. Zoltowski,et al.  Closed-form underwater acoustic direction-finding with arbitrarily spaced vector-hydrophones at unknown locations , 1997, Proceedings of 1997 IEEE International Symposium on Circuits and Systems. Circuits and Systems in the Information Age ISCAS '97.