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New Generation Multibeam Sweeping Echosounders for Surveying, Object Search; Greater Resolution; Higher Accuracy; Flexible
The shallow-water survey system Atlas Fansweep 20/Atlas Hydromap represents a new standard in shallow-water multibeam sweeping echosounder technology. When the system was being developed, work was done not only to improve the technical parameters compared to the predecessor Atlas Fansweep but due to new technologies, the Atlas Fansweep 20 has much better performance.
In addition to spatial resolution, an important criterion in application of a multibeam sweeping echosounder is system productivity. In general, productivity is measured by the size of the area which can be surveyed in 10 hours using the maximum possible coverage at a speed of 6 knots (class 1: survey speed limited to 6 knots in accordance with "Hydrographic Manual EM 0-2-1003") in water depth of 10 meters. For Atlas Fansweep 20, it is about 45 square kilometers (this corresponds to a theoretical surveying performance of more than 1.2 square meters/second) and is thus up to eight times larger than the area which can be surveyed in the same time by means of a conventional multibeam sweeping echosounder.
About six years ago, Atlas Elektronik launched one of the first shallowwater multibeam sweeping echosounders on the international market, the Atlas Fansweep. Since then, the multibeam sweeping echosounder method has achieved wide acceptance, particularly in the surveying of coastal waters, rivers, and inland waterways.
This acceptance has mainly been due to the possibility of mobile use (good portability) and to the simplicity and speed with which the complete system can be installed on various vessels, including very small boats. In addition, it became possible to achieve high coverage combined with good accuracy, even for the outer beams, and a large number of depth values at points situated only short distance apart.
Technology
Conventional systems to date use either the principle of beamforming, sometimes combined with phase measurement, or the interferometric phase measurement principle. The basis for both methods is a signal processing procedure which measures sound-traveling times and transmitting or receiving angles relative to a hydroacoustic transducer and determines from these the depth and position of a point on the seafloor, doing so relative to the normal to the transducer. Both conventional methods have their special characteristics.
In the...