dc.contributor.author | Ona, Egil | |
dc.date.accessioned | 2010-10-22T14:02:08Z | |
dc.date.available | 2010-10-22T14:02:08Z | |
dc.date.issued | 1990 | |
dc.identifier.citation | This report is not to be quoted without prior consultation with the General Secretary. | en_US |
dc.identifier.uri | http://hdl.handle.net/11250/102081 | |
dc.description.abstract | Precise in situ target strength estimates of fish can only be made when the effect of the transducer directivity is totally removed from the recorded target amplitudes. By guiding a standard calibration target through the acoustic beam while simultaneously recording the amplitudes and angular positions of the target, a precise reconstruction of product of transducer transmit and receiving directivity can be made. From several thousand point measurements taken in a cross section through the acoustic beam, the recorded data have been fitted to a generalized three dimensional model by the use of non-linear estimation. The suggested model functions yield very low residual beam correction error with 95% of the data within ± 0.5 dB. within the half power points of the beam, the residual beam correction error is close to the observed ping to ping system stability of ± 0.1 dB. The precision and repeatability of the method is demonstrated through data from four split beam transducers mounted on four different research vessels. These are three ES-400 transducers and one EK-500 transducer, all working on 38 kHz. | en_US |
dc.language.iso | eng | en_US |
dc.publisher | ICES | en_US |
dc.relation.ispartofseries | ICES CM Documents;1990/B:30 | |
dc.subject | echo sounder | en_US |
dc.subject | ekkolodd | en_US |
dc.subject | sonar calibration | en_US |
dc.subject | sonar kalibrering | en_US |
dc.title | Optimal acoustic beam pattern corrections for split beam transducers | en_US |
dc.type | Working paper | en_US |
dc.subject.nsi | VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fisheries technology: 924 | en_US |
dc.source.pagenumber | 12 s. | en_US |