Blar i ICES CM documents authored by IMR scientists (1949-2011) på emneord "echo sounder"
Viser treff 21-35 av 35
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New towed transducer concept
(ICES CM Documents;1988/B:59, Working paper, 1988)The history of towed transducer applications at the Institute of Marine Research, Bergen, is reviewed. Advantages and disadvantages of several designs are summarized. To improve performance significantly, a new system ... -
Nominal performance measures for two 710-kHz transducers
(ICES CM Documents;1992/B:9, Working paper, 1992)Two new transducers have been designed by SIMRAD for the EK500 echo sounding system. The nominal operating frequency is 710 kHz. Each transducer is composed of a single, circular, active element, with diameter of 25 or ... -
Note on the measurement of target strength of fish at sea
(ICES CM Documents;1966/F:9, Working paper, 1966) -
Observed avoidance behaviour in herring in relation to passage of an echo survey vessel.
(ICES CM Documents;1979/B:18, Working paper, 1979) -
On subjectivity in the judging of acoustic records; comparison of degree of homogenity in allocation of echo values by different teams
(ICES CM Documents;1993/B:21, Working paper, 1993)On four fish abundance estimation surveys in the Barents Sea, january-february 1993, the acoustic records were judged by two independent teams. We have analyzed the degree of homogenity in allocation of echo values to ... -
On the shape, size and density of North Sea herring schools as mapped by echo integration and accurate sonar projection
(ICES CM Documents;1993/B:16, Working paper, 1993)The shape and horizontal extent of herring schools in the North Sea have been mapped by a naval sonar (SIMRAD SA 950) with narrow horizontal beam width. The density of schools that were passed over was measured by the ... -
Optimal acoustic beam pattern corrections for split beam transducers
(ICES CM Documents;1990/B:30, Working paper, 1990)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 ... -
Report of the PGNAPES Scrutiny of Echograms Workshop (WKECHOSCRU) [16–18 February 2009 Bergen, Norway]
(ICES CM documents;2009/RMC:02, Working paper, 2009) -
Report on echo-integrator surveys for sprat undertaken in the North Sea during the 1981 -82 winter season.
(ICES CM Documents;1982/H:13, Working paper, 1982) -
Simple calibration of a split-beam echo-sounder
(ICES CM Documents;1986/B:8, Working paper, 1986) -
Simulating echograms
(ICES CM Documents;1989/B:6, Working paper, 1989)Simulation of echo data can be useful for verifying echo integrators realized in computer software. A model is presented which associates distinct stochastic processes with each of the following: bottom depth; number, ... -
Some pitfalls of short-range standard-target calibration
(ICES CM Documents;1996/B:36, Working paper, 1996)Often it is necessary or desirable to perform a standard-target calibration at rather short range, for example, because of shallow water or interest in measuring animals at short range. A number of general range-dependent ... -
Target strengths of Antartic krill (Euphausia superba)
(ICES CM Documents;1988/B:6, Working paper, 1988)Encaged aggregations of swimming krill have been measured at 38 and 120 kHz. The results indicate that the target strength values are substantially lower than previously assumed. -
Three-in-one transducer design for a triple-frequencey echo sounder
(ICES CM Documents;1989/B:8, Working paper, 1989)A design is outlined in which three different kinds of transducer elements are arranged concentrically and in near proximity. It will be possible to drive the elements simultaneously, thus forming three coaxial beams at ... -
Trial of a New, Split-beam Echo Sounder
(ICES CM Documents;1984/B:21, Working paper, 1984)The first at-sea trial of a new, split-beam echo sounder, the SIMRAD ES380 system, is described following a review of the split-beam principle, outline of its realization in hardware and software, and description of ...