A tomographic ocean sound speed profile from a long veritcal acoustic array
Njeru, James Murwanthanje
MetadataShow full item record
LocationNortheast Pacific Ocean
An average sound speed profile over a 1000 km section of the northeast Pacific ocean is obtained using Ocean Acoustic Tomography, from data acquired during the 1987 SVLA experiment on a long (900 m) 120 hydrophone vertical acoustic array. In particular, we pulse compress the received signal with a phase-only matched filter. The signal, centered at 80Hz, is phase-modulated by a maximal length sequence. A fast m-sequence cross-correlation algorithm based on the Hadamard transform is used. In addition, wide band Doppler correction and coherent averaging of repetitions of the signal are performed. The tomographic inversion is initialized from a range averaged climatological profile. Multipaths are identified from ray theory. The identified arrivals are inverted for a range-independent sound speed profile change estimate. Estimates of source and array position error are also obtained. For the limited data set used, the sound speed change estimate is found to be insignificant, and a significant instrument position estimate is obtained.
Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 1992
Showing items related by title, author, creator and subject.
Mikhalevsky, Peter N.; Sagen, Hanne; Worcester, Peter F.; Baggeroer, Arthur B.; Orcutt, John A.; Moore, Sue E.; Lee, Craig M.; Vigness-Raposa, Kathleen J.; Freitag, Lee E.; Arrott, Matthew; Atakan, Kuvvet; Beszczynska-Moller, Agnieszka; Duda, Timothy F.; Dushaw, Brian D.; Gascard, Jean-Claude; Gavrilov, Alexander N.; Keers, Henk; Morozov, Andrey K.; Munk, Walter H.; Rixen, Michel; Sandven, Stein; Skarsoulis, Emmanuel; Stafford, Kathleen M.; Vernon, Frank L.; Yuen, Mo Yan (Arctic Institute of North America, 2015)The dramatic reduction of sea ice in the Arctic Ocean will increase human activities in the coming years. This activity will be driven by increased demand for energy and the marine resources of an Arctic Ocean accessible ...
Slavinsky, Mark; Bogolubov, Boris; Alelekov, Igor; Pigalov, Konstantin; Spiesberger, John L.; Boutin, Paul (Woods Hole Oceanographic Institution, 1993-02)A compact electromagnetic monopole source, requiring pressure equalization, was evaluated at the Naval Underwater Systems Center at Lake Seneca during July 1992 by scientists from the Institute of Applied Physics of the ...
Physically constrained maximum likelihood (PCML) mode filtering and its application as a pre-processing method for underwater acoustic communication Papp, Joseph C. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2009-09)Mode filtering is most commonly implemented using the sampled mode shape or pseudoinverse algorithms. Buck et al placed these techniques in the context of a broader maximum a posteriori (MAP) framework. However, the MAP ...