Skip Navigation

ICES Journal of Marine Science: Journal du Conseil 2005 62(8):1636-1646; doi:10.1016/j.icesjms.2005.06.008
This Article
Right arrow Full Text Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Conti, S. G.
Right arrow Articles by Conti, J. H.E.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Conti, S. G.
Right arrow Articles by Conti, J. H.E.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2005 International Council for the Exploration of the Sea

An improved multiple-frequency method for measuring in situ target strengths

Stéphane G. Contia,*, David A. Demera, Michael A. Souleb and Jean H.E. Contic

a Southwest Fisheries Science Center 8604 La Jolla Shores Drive, La Jolla, CA 92037, USA
b Fisheries Resource Surveys PO Box 31306, Tokai 7966, Cape Town, South Africa
c 69 Voie Antique, 69126, Brindas, France

*Correspondence to S. G. Conti: tel: +1 858 534 7792; fax: +1 858 546 5652. e-mail: sconti{at}ucsd.edu.

Refinements have been made to the multiple-frequency method for rejecting overlapping echoes when making target-strength measurements with split-beam echosounders described in Demer et al. (1999). The technique requires that echoes, simultaneously detected with two or more adjacent split-beam transducers of different frequencies, pass multiple-target rejection algorithms at each frequency, and characterize virtually identical three-dimensional target coordinates. To translate the coordinates into a common reference system for comparison, the previous method only considered relative transducer positions and assumed that the beam axes of the transducers were parallel. The method was improved by first, optimizing the accuracy and precision of the range and angular measurements of the individual frequency detections; and second, precisely determining acoustically the relative positions and angular orientations of the transducers, thus completely describing the reference-system transformation(s). Algorithms are presented for accurately and precisely estimating the transformation parameters, and efficiently rejecting multiple targets while retaining measurements of most single targets. These improvements are demonstrated through simulations, controlled test-tank experiments, and shipboard measurements using 38- and 120-kHz split-beam transducers. The results indicate that the improved multiple-frequency TS method can reject more than 97% of multiple targets, while allowing 99% of the resolvable single targets to be measured.

Keywords: split-beam, target strength, three-dimensional reference transformation

Received 14 February 2005; accepted 1 June 2005.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 ICES J. Mar. Sci.Home page
D. A. Demer, G. R. Cutter, J. S. Renfree, and J. L. Butler
A statistical-spectral method for echo classification
ICES J. Mar. Sci., July 1, 2009; 66(6): 1081 - 1090.
[Abstract] [Full Text] [PDF]

Home page
 ICES J. Mar. Sci.Home page
G. Pedersen and R. J. Korneliussen
The relative frequency response derived from individually separated targets of northeast Arctic cod (Gadus morhua), saithe (Pollachius virens), and Norway pout (Trisopterus esmarkii)
ICES J. Mar. Sci., July 1, 2009; 66(6): 1149 - 1154.
[Abstract] [Full Text] [PDF]

Home page
 ICES J. Mar. Sci.Home page
L. Berger, C. Poncelet, and V. M. Trenkel
A method for reducing uncertainty in estimates of fish-school frequency response using data from multifrequency and multibeam echosounders
ICES J. Mar. Sci., July 1, 2009; 66(6): 1155 - 1161.
[Abstract] [Full Text] [PDF]

Home page
 ICES J. Mar. Sci.Home page
C. S. Reiss, A. M. Cossio, V. Loeb, and D. A. Demer
Variations in the biomass of Antarctic krill (Euphausia superba) around the South Shetland Islands, 1996-2006
ICES J. Mar. Sci., May 1, 2008; 65(4): 497 - 508.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.