Extended-aperture underwater acoustic multisource azimuth/elevation direction-finding using uniformly but sparsely spaced vector hydrophones

Kainam Thomas Wong, Michael D. Zoltowski

Research output: Journal article publicationJournal articleAcademic researchpeer-review

155 Citations (Scopus)


Aperture extension is achieved in this novel ESPRIT-based two-dimensional angle estimation scheme using a uniform rectangular array of vector hydrophones spaced much farther apart than a half-wavelength. A vector hydrophone comprises two or three spatially co-located, orthogonally oriented identical velocity hydrophones (each of which measures one Cartesian component of the underwater acoustical particle velocity vector-field) plus an optional pressure hydrophone. Each incident source's directions-of-arrival are determined from the source's acoustical particle velocity components, which are extracted by decoupling the data covariance matrix's signal-subspace eigenvectors using the lower dimensional eigenvectors obtainable by ESPRIT. These direction-cosine estimates are unambiguous but have high variance; they are used as coarse references to disambiguate the cyclic phase ambiguities in ESPRIT's eigenvalues when the intervector-hydrophone spacing exceeds a half-wavelength. In one simulation scenario, the estimation standard deviation decreases with increasing intervector-hydrophone spacing up to 12 wavelengths, effecting a 97% reduction in the estimation standard deviation relative to the half-wavelength case. This proposed scheme and the attendant vector-hydrophone array outperform a uniform half-wavelength spaced pressure-hydrophone array with the same aperture and slightly greater number of component hydrophones by an order of magnitude in estimation standard deviation. Other simulations demonstrate how this proposed method improves underwater acoustic communications link performance. The virtual array interpolation technique would allow this proposed algorithm to be used with irregular array geometries.
Original languageEnglish
Pages (from-to)659-671
Number of pages13
JournalIEEE Journal of Oceanic Engineering
Issue number4
Publication statusPublished - 1 Oct 1997
Externally publishedYes


  • Array signal processing
  • Direction of arrival estimation
  • Eigenfunctions/eigenvalues
  • Intelligent sensors
  • Sonar arrays
  • Sonar position measurement
  • Sonar signal processing
  • Underwater acoustics arrays

ASJC Scopus subject areas

  • Ocean Engineering
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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