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Side-scan uses a sonar device that emits conical or fan-shaped pulses down toward the seafloor across a wide angle perpendicular to the path of the sensor through the water, which may be towed from a surface vessel or submarine (called a “towfish”), or mounted on the ship's hull.
Side Scan Sonar systems produce images by forming angular “beams”. Beam width is determined by length of the sonar array, narrower beams resolve finer detail. Longer arrays with narrower beams provide finer spatial resolution.
Given that side scan sonar, with its across-track fan-shaped swath of insonification, had successfully exploited the cross-track variation in echo amplitudes, to achieve high quality images of the seabed, it seemed a natural progression that the fan-shaped across-track pattern of insonification associated with the new monotone higher frequency ...
The side-scan sonar is useful for scientists as it is a quick and efficient way of collecting imagery of the sea floor, but it cannot measure other factors, such as depth. [ 11 ] [ 12 ] Therefore, other depth measuring sonar devices are typically accompanied with the side-scan sonar to generate a more detailed survey.
Area coverage with a traditional side-scan sonar depends on range and at what range the resolution gets too low for the target goal of the scan. Area coverage with a synthetic-aperture sonar, with an across-track resolution that is constant all the way until the end of the range, is practically closer to the instantaneous area coverage.
An important general rule for side-scan sonar searches, regardless of what search pattern is used, is to orient the long dimension of the search area so that it is approximately parallel with the depth contours, which minimizes the need to make changes of the towfish altitude to maintain a reasonably consistent altitude (height above the bottom ...
Three main applications are used: single beam echo sounding is generally used for depth measurement below the vessel, side-scan sonar produces images showing the shape of underwater objects well, but is not very accurate for depth measurement, and multibeam echosounders provide fairly accurate three dimensional positions for a swath of points ...
Side-scan sonar is used to efficiently create images of large areas of the sea floor, as seen from the point of view of the transducer. Seismic sources such as sparkers and boomers are used in seismic reflection profiling, using sound pulse frequencies that effectively penetrate the solid seabed and are partially reflected by changes in ...