scholarly journals Nonlinear control of autonomous underwater vehicle in shallow water environment

2008 ◽  
Author(s):  
Shu Yong Liu
Author(s):  
William J. Marr ◽  
Anthony J. Healey

Advances in Autonomous Underwater Vehicles (AUVs) using acoustic communications to transfer relatively high rate downloads of mission information are crucial to future Navy objectives, particularly in Very Shallow Water Mine Countermeasures (VSW MCM). Present understanding is primarily based on fixed node experiments rather than quantified by vehicles working in the real environment. This paper reports on the demonstrated limits of high speed asymmetric acoustic data transfer using an AUV in an adverse very shallow water environment. A comprehensive series of studies in multiple channel geometries was completed using a “state of the art” commercially available modem system installed on the NPS ARIES autonomous underwater vehicle. The maximum operating range for effective high speed data transfer in very shallow water from a dynamic AUV with all integrated systems active was about 300 meters in the horizontal plane with nearly 100% reliability, at bit rates up to a maximum of 800 bits/second.


2011 ◽  
Vol 45 (3) ◽  
pp. 69-76 ◽  
Author(s):  
Tom Fedenczuk ◽  
Eva-Marie Nosal

AbstractShallow water acoustics provide a means for monitoring and surveillance of near-shore environments. This paper describes the current and future capabilities of the low- to high-frequency Hawaii Experimental Acoustics Range (HEAR) that was designed to facilitate a wide range of different shallow water acoustics experiments and allow researchers from various institutions to test various array components and configurations. HEAR is a portable facility that consists of multiple hydrophones (12‐16) cabled independently to a common central node. The design allows for variable array configurations and deployments in three modes: experimental (off boats and piers), autonomous, and cabled. An application of HEAR is illustrated by the results from a deployment at Makai Research Pier, Oahu, Hawaii. In this deployment, HEAR was configured as a long-baseline range of two volumetric subarrays to study passive acoustic tracking capabilities in a shallow water environment.


2008 ◽  
Vol 124 (3) ◽  
pp. EL157-EL162 ◽  
Author(s):  
D. P. Knobles ◽  
S. M. Joshi ◽  
R. D. Gaul ◽  
H. C. Graber ◽  
N. J. Williams

1995 ◽  
Vol 69 (2) ◽  
pp. 376-380 ◽  
Author(s):  
Daniel B. Blake ◽  
Keith Sturgeon

Aldebarania arenitea (Astropectinidae; Asteroidea; Echinodermata) is described from the Rocky Point Member of the Maastrichtian (Upper Cretaceous) Peedee Formation of North Carolina. A turbulent, shallow-water environment is suggested by sedimentary features, a diverse marine fauna, and the morphology of Aldebarania. Aldebarania appears to be a partial ecological equivalent of living Astropecten and Luidia; however, phylogenetic relationships within the Astropectinidae are unstudied and the origin of similarities is unknown.


Author(s):  
Zhiyi Zhou ◽  
Gongzheng Yin ◽  
Ronald P. Tripp

ABSTRACTTwenty-seven species assigned to 20 genera of trilobites are described from Feilaishi in Guizhou Province, the type section of the Shihtzupu Formation in S W China. They occur in association with a sparse graptolite fauna including Glyptograptus teretiusculus. Eleven taxa are recorded here for the first time. Much new morphological information is provided regarding previously known species and 3 lectotypes are selected. The trilobites are largely endemic and indicate a quiet and comparatively shallow water environment


2016 ◽  
Author(s):  
Mirko Mustonen ◽  
Aleksander Klauson ◽  
Janek Laanearu ◽  
Madis Ratassepp ◽  
Thomas Folegot ◽  
...  

Energies ◽  
2017 ◽  
Vol 10 (9) ◽  
pp. 1414 ◽  
Author(s):  
Umberta Tinivella ◽  
Michela Giustiniani ◽  
Ivan Vargas-Cordero

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