Acoustic vector sensors measure acoustic pressure and directional components separately.
A claimed advantage of vector sensors over pressure-only arrays is the directional information
in a collocated device, making it an attractive option for size-restricted applications.
The employment of vector sensors as a receiver for underwater communications is relatively
new, where the inherent directionality, usually related to particle velocity, is used
for signal-to-noise gain and intersymbol interference mitigation. The fundamental question
is how to use vector sensor directional components to bene t communications, which
this work seeks to answer and to which it contributes by performing: analysis of acoustic
pressure and particle velocity components; comparison of vector sensor receiver structures
exploring beamforming and diversity; quanti cation of adapted receiver structures in distinct
acoustic scenarios and using di erent types of vector sensors. Analytic expressions
are shown for pressure and particle velocity channels, revealing extreme cases of correlation
between vector sensors' components. Based on the correlation hypothesis, receiver
structures are tested with simulated and experimental data. In a rst approach, called
vector sensor passive time-reversal, we take advantage of the channel diversity provided
by the inherent directivity of vector sensors' components. In a second approach named
vector sensor beam steering, pressure and particle velocity components are combined, resulting
in a steered beam for a speci c direction. At last, a joint beam steering and
passive time-reversal is proposed, adapted for vector sensors. Tested with two distinct
experimental datasets, where vector sensors are either positioned on the bottom or tied
to a vessel, a broad performance comparison shows the potential of each receiver structure.
Analysis of results suggests that the beam steering structure is preferable for shorter
source-receiver ranges, whereas the passive time-reversal is preferable for longer ranges.
Results show that the joint beam steering and passive time-reversal is the best option to
reduce communication error with robustness along the range.Sensores vetoriais acústicos (em inglês, acoustic vector sensors) são dispositivos que
medem, alem da pressão acústica, a velocidade de partícula. Esta ultima, é uma medida que
se refere a um eixo, portando, esta associada a uma direção. Ao combinar pressão acústica
com componentes de velocidade de partícula pode-se estimar a direção de uma fonte sonora
utilizando apenas um sensor vetorial. Na realidade, \um" sensor vetorial é composto de um
sensor de pressão (hidrofone) e um ou mais sensores que medem componentes da velocidade
de partícula. Como podemos notar, o aspecto inovador está na medição da velocidade de
partícula, dado que os hidrofones já são conhecidos.(...)This PhD thesis was supported by the Brazilian Navy Postgraduate Study Abroad
Program Port. 227/MB-14/08/2019
