Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Engineering
Modeling Broadband Ocean Acoustic Transmissions With Time-Varying Sea Surfaces, Martin Siderius, Michael B. Porter
Modeling Broadband Ocean Acoustic Transmissions With Time-Varying Sea Surfaces, Martin Siderius, Michael B. Porter
Electrical and Computer Engineering Faculty Publications and Presentations
Solutions to ocean acoustic scattering problems are often formulated in the frequency domain, which implies that the surface is "frozen" in time. This may be reasonable for short duration signals but breaks down if the surface changes appreciably over the transmission time. Frequency domain solutions are also impractical for source-receiver ranges and frequency bands typical for applications such as acoustic communications (e.g. hundreds to thousands of meters, 1-50 kHz band). In addition, a driving factor in the performance of certain acoustic systems is the Doppler spread, which is often introduced from sea-surface movement. The time-varying nature of the sea surface …
Bottom Profiling By Correlating Beam-Steered Noise Sequences, Chris H. Harrison, Martin Siderius
Bottom Profiling By Correlating Beam-Steered Noise Sequences, Chris H. Harrison, Martin Siderius
Electrical and Computer Engineering Faculty Publications and Presentations
It has already been established that by cross-correlating ambient noisetime series received on the upward and downward steered beams of a drifting vertical array one can obtain a subbottom layer profile. Strictly, the time differential of the cross correlation is the impulse response of the seabed. Here it is shown theoretically and by simulation that completely uncorrelated surfacenoise results in a layer profile with predictable amplitudes proportional to those of an equivalent echo sounder at the same depth as the array. The phenomenon is simulated by representing the sound sources as multiple random time sequences emitted from random locations in …