Acoustic Characterization of Impulsive Underwater Noise Present in Port Facilities: Practical Case in the Port of Cartagena

Abstract

The data recording of underwater noise is a key aspect for the prevention and improvement of management systems of maritime spaces. Thus, due to the presence of activities potentially generating impulsive noise, ports deserve special attention. This article describes and shows the results of the spatial monitoring of both the basal noise and impulsive noise sources present in port facilities. A vessel was equipped with a smart digital hydrophone with a working frequency range between 10 and 200 kHz and an RVR (Received Voltage Response) of, approximately, −170 dB @ 1 V/µPa. Coupling the acoustic data together with the GPS coordinates of the vessel, a GIS map with spatiotemporal distribution of the basal sound pressure levels was made, identifying the sources of impulsive noise of interest and its temporal characteristics. This is a preliminary step for the development of future studies on underwater noise pollution and its potential impact on biodiversity in the environment of port facilities, with the maximum guarantees possible.

Bayesian Learning-Based Clustered-Sparse Channel Estimation for Time-Varying Underwater Acoustic OFDM Communication

“…For the matrix Y in (7), the remaining K d × M observations are typically not used as they contain the unknown data symbols. If the unknown data symbols are perfectly obtained, using the Bayes rule, the posterior mean of CIRs based on the prior probability in (17) and the channel measurement equation in (10) can be written by…”

“…The former type is presented in the background of the quiet deep sea, and exhibits a colored characteristic when approximated by Gaussian distribution, while for the site-specific noise, significant non-Gaussian components should be carefully considered [ 2 ]. Some experiments have confirmed that the noise is non-uniform across different locations, times and frequencies [ 17 ]. As a popular noise model in most UWA-OFDM systems, additive white Gaussian noise (AWGN) is straightforward for modeling and solving the noise distribution of the UWA channel, but it deviates from the actual underwater noise.…”