Using the FLOWBEC seabed frame to understand underwater interactions between diving seabirds, prey, hydrodynamics and MREDs
Benjamin J. WilliamsonPhilippe BlondelJames J. WaggittShaun FraserChris HallEric ArmstrongPaul S. BellBeth Scott
1
Citation
0
Reference
20
Related Paper
Citation Trend
Keywords:
Seabed
Cite
Since 1969 the Canadian Forces Auxiliary Vessel QUEST has been the primary research vessel of the Defence Research Establishment Atlantic in Dartmouth, Nova Scotia. This 2200 ton ship is used primarily as a platform for underwater acoustics experiments, and was specifically designed and constructed for this purpose. The features, and in particular the acoustic features which make it one of the quietest research vessels afloat today, are described.
Research vessel
Nova scotia
Cite
Citations (2)
Physics process of underwater explosion is introduced. Based on characters of sound wave produced by underwater explosion, a feasible sound pressure measurement method is proposed. In addition, with detection of some reared marine organism near the explosion site, underwater explosion ’s effect on marine organism is analyzed, which provide a reference for balancing the ocean exploitation and marine fishing.
Underwater explosion
Cite
Citations (0)
Гидроакустические навигационные системы большой дальности действия (ГАНС БД) предназначены для высокоточного определения местоположения АНПА, выполняющих длительные миссии при значительных удалениях (до 500 км) от приемопередающих устройств. Создание таких систем связано с выбором структуры сложных сигналов при использовании гидроакустических маяков или излучателей, стационарно размещенных в прибрежной полосе вдали от района нахождения объекта навигации. На основе классического уравнения дальности гидроакустики решается оптимизационная задача, состоящая в определении точностных и энергетических характеристик М-последовательностей различной длины и отношении сигнал∕шум в зависимости от уровня излучения сигналов. Путем сравнительного анализа известных методов построения дальномерных навигационных систем большой дальности получены оценки достижимых отношений сигнал∕шум при различных вариантах построения схемы обработки для М-последовательностей различной длины. По экспериментальным данным рассчитываются отношения сигнал∕шум в точке приема сигналов при различных дальностях и типах сигналов. Показано, что оптимизация энергетических характеристик ГАНС БД, а также трактов приема и обработки сигналов достигается при использовании М-последовательностей средней длины (М = 127). Long-range underwater acoustic navigation systems (LR UANS) are used for high-precision positioning of AUVs during longstanding missions at significant distances (up to 500 km) from reference transceiver devices. The development of such systems involves the selection of the structure of composite signals when using underwater acoustic beacons or transceivers stationary located in a coastal zone far apart from the object of navigation. Based on the classic equation of the underwater acoustic range, it is possible to solve an optimization task, which involves accuracy and energy characterization of M-sequences of differents lengths and evaluation of signal-to-noise ratio with respect to emitting signals level. By comparative analysis of the known approaches to the design of long-range circular navigation systems, some estimates of achievable signal-to-noise ratio values were acquired for different techniques of processing the M-sequences of different lengths. According to the experimental data, signal-to-noise ratios in the reception point were calculated for different ranges and signal types. It is shown that the optimization of energetic characteristics of LR UANS along with paths circuits of signal reception and processing is achieved when using M-sequences of medium length (M = 127).
Underwater acoustic communication
SIGNAL (programming language)
Beacon
Navigation System
Transceiver
Underwater Acoustics
Cite
Citations (0)