Blar i Articles på emneord "sonar"
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Acoustic sampling volume of a bistatic sonar
(Others, 2005) -
Averaging of fish target strength functions
(Journal article; Peer reviewed, 1980)A general model for averaging the acoustic target strength functions of fish is stated in calculable form. It accounts for the influences of the distribution of generally coupled spatial and orientation states of fish, ... -
Bat sonar and the role of frequency diversity
(Others, 2006) -
Calibration sphere for low-frequency parametric sonars
(Journal article; Peer reviewed, 2007)The problem of calibrating parametric sonar systems at low difference frequencies used in backscattering applications is addressed. A particular parametric sonar is considered: the Simrad TOPAS PS18 Parametric Sub-bottom ... -
Coincidence echo statistics
(Journal article; Peer reviewed, 1996)Two scatterers at similar range give an echo which may appear to be due to a single scatterer. Methods for determining target strength that depend on resolving single scatterers may fail in this instance. Statistics ... -
First data from sea trials with the new MS70 multibeam sonar
(Journal article; Peer reviewed, 2006) -
Fish target strengths for use in echo integrator surveys
(Journal article; Peer reviewed, 1987)In situ measurements of fish target strength are selected for use in echo integrator surveys at 38 kHz. The results are expressed through equations in which the mean target strength TS is regressed on the mean fish length ... -
Herring tilt angles, measured through target tracking
(Report / Alaska Sea Grant College Program, Chapter, 2001)The target strength of herring in captivity was monitored experimentally at three frequencies (18, 38, and 120 kHz) over a period of 3 years using split-beam echo sounders. One of the fundamental parameters of a target ... -
Influence of Different Factors on Abundance Estimates Obtained from Simultaneous Sonar and Echo Sounder Recordings
(Journal article; Peer reviewed, 2011-12-28)Use of horizontal guided sonar in addition to vertical echo sounder may improve biomass estimation of pelagic fish schooling near the surface. But proportions of horizontal guided sonar to vertical echo integration estimates ... -
Measurement of fish target strength with a split-beam echo sounder
(Journal article; Peer reviewed, 1986)Data derived with a 38-kHz split-beam echo sounder have been analyzed to yield target strengths suitable for use with echo integrators. This has required compensation for both thresholding and saturation, since these ... -
Observing individual fish behavior in fish aggregations: Tracking in dense fish aggregations using a split-beam echosounder
(Journal article; Peer reviewed, 2007)Acoustic instruments are important tools for observing the behavior of aquatic organisms. This paper presents a simple but efficient method for improving the tracking of closely spaced targets using a split-beam echosounder. ... -
Observing the behavioral response of herring exposed to mid-frequency sonar signals. (A)
(Conference object, 2010-03)There is general concern on how mid-frequency military sonars might affect aquatic animals. Approaches used to investigate possible effects on Norwegian spring spawning herring (Clupea harengus) are presented. Experiments ... -
Optimizing copper spheres for precision calibration of hydroacoustic equipment
(Journal article; Peer reviewed, 1982)n operational definition of backscattering cross section is developed for the wideband reception of finite echoes. This is supported by relative measurements on a set of copper spheres by each of four echo sounders operating ... -
Postprocessing system for echo sounder data
(Journal article; Peer reviewed, 1991)Echo sounding is a powerful and widely used technique for remote sensing of the marine environment. In order to enhance the power of the echo sounder, a postprocessing system has been designed and realized in standard ... -
Probing the deep: Acoustic characterization of the Mid-Atlantic Ridge ecosystem
(Journal article; Peer reviewed, 2006) -
Spheres for calibrating high-frequency broadband echo sounders
(Others, 1999)