2019_programme: ROBUST DIRECTION FINDING IN THE FLUCTUATING OCEANS BY COMPLEX L1-NORM PRINCIPAL-COMPONENT ANALYSIS
- Session: 05. Underwater Communications and Networking
Organiser(s): Tsimenidis Charalampos, Mitchell Paul, Pelekanakis konstantinos
- Lecture: ROBUST DIRECTION FINDING IN THE FLUCTUATING OCEANS BY COMPLEX L1-NORM PRINCIPAL-COMPONENT ANALYSIS [invited]
Paper ID: 1006
Author(s): Sklivanitis George, Real Gaultier , Pados Dimitris
Presenter: Sklivanitis George
Presentation type: oral
Abstract: We consider the problem of robust direction-of-arrival (DoA) estimation in dynamic ocean environments. Robust direction finding of underwater acoustic signals transmitted from known locations may enable accurate localization of a receiver node underwater, as well as enhance link communication rate by instructing the receiver to listen for transmissions from a specific direction. We propose to estimate the DoA of underwater acoustic signals via subspace methods, executed at a receiver array, that involve performing what is known as principal-component analysis (PCA) for finding the L2-norm principal vector subspace of the recorded signal snapshots. However, in practice coherence loss, which typically arises from dynamic wavefront fluctuations due to internal waves, scattering from the sea surface and/or bottom and other unknown environmental parameters, may result in recorded signal snapshots that may be corrupted by faulty measurements, leading to an inaccurate estimation of the DoA and source position. We propose to model the loss of coherence as multiplicative random noise applied to the measured acoustic signal. In such cases, L2-norm PCA methods suffer from significant performance degradation. Motivated by the resistance of novel L1-norm-derived subspaces against the impact of irregular, highly deviating points in reduced-dimensionality data approximations, we propose to employ L1-norm (absolute error) maximum-projection PCA of the antenna array measurements and evaluate the performance of a novel, outlier-resistant DoA estimation algorithm. We evaluate the proposed DoA estimation algorithm via L1-norm derived subspaces for different coherence lengths, number of acoustic sources and antenna elements/transducers at the receiver. Experimental assessment of the proposed DoA algorithm is conducted over acoustic measurements acquired from an ultrasonic transmitter source (at 2.25MHz) operating in a controlled water tank environment that reproduces the effect of a fluctuating ocean. This experimental configuration allows to accurately reproduce the effects of spatial medium fluctuations on the propagated sound waves, in a fully reproducible and monitored fashion. The benchmark of the proposed DoA estimation algorithm on this experimental dataset represents a preliminary step before validating its performance on at-sea recorded data.
Download the full paper
- Corresponding author: Dr Sklivanitis Georgios
Affiliation: Florida Atlantic University
Country: United States
e-mail:
