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A distributed networked underwater sensor (DNUS) system can provide ocean measurements over a wide area with a large number of sensors. This paper studies the estimation of the ocean current field observed by a DNUS system. Considering that the current field is correlated in time and space, we present a statistically-based acoustic travel time difference tomography method based on a Kalman filter...
A propagation model-based correction method for sound transmission loss error caused by hydrophone depth fluctuation is proposed. The motivation for the correction is to obtain laws of transmission loss over range with the hydrophone in fixed depth. Firstly, we show that the effect of hydrophone depth fluctuation on sound transmission loss in shallow water environment is significant through simulation...
Acoustic Doppler current profiler (ADCP) is designed to measure the velocity profile within the water column, whilst the ability of ADCP to measure the suspended sediment concentration has been investigated for a long time. The key of the measurement is to analyze multi-frequency backscattering intensity, and to extract suspended sediment information using acoustic inversion algorithms. To investigate...
This paper presents a method to estimate the sound velocity profile (SVP) of the water column along with the bathymetry using overlapping swaths obtained from a multi-beam system. The method exploits the terrain deviations in the overlapped regions of different survey tracks. Such deviation is closely related to the SVP errors, and hence by minimizing the deviations, the SVP can be updated from the...
Model-based signal processing methods, such as matched-field processing, are concerned with exploiting the combination of the sound propagation physics in an ocean waveguide and the observation data. As such, they require accurate knowledge of the ocean acoustic environment. This paper presents an approach of environmental inversion via acoustic data assimilation (ADA), intended specifically to reconstruct...
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