RT Dissertation/Thesis
T1 Algorithms for propagation-aware underwater ranging and localization
A1 Dubrovinskaya, Elizaveta
A2 IMDEA Networks Institute, 
AB While oceans occupy most of our planet, their exploration and conservation are one ofthe crucial research problems of modern time. Underwater localization stands among thekey issues on the way to the proper inspection and monitoring of this significant part of ourworld. In this thesis, we investigate and tackle different challenges related to underwaterranging and localization. In particular, we focus on algorithms that consider underwateracoustic channel properties. This group of algorithms utilizes additional informationabout the environment and its impact on acoustic signal propagation, in order to improvethe accuracy of location estimates, or to achieve a reduced complexity, or a reducedamount of resources (e.g., anchor nodes) compared to traditional algorithms.First, we tackle the problem of passive range estimation using the differences in thetimes of arrival of multipath replicas of a transmitted acoustic signal. This is a costandenergy- effective algorithm that can be used for the localization of autonomousunderwater vehicles (AUVs), and utilizes information about signal propagation. We studythe accuracy of this method in the simplified case of constant sound speed profile (SSP)and compare it to a more realistic case with various non-constant SSP. We also proposean auxiliary quantity called effective sound speed. This quantity, when modeling acousticpropagation via ray models, takes into account the difference between rectilinear andnon-rectilinear sound ray paths. According to our evaluation, this offers improved rangeestimation results with respect to standard algorithms that consider the actual value ofthe speed of sound.We then propose an algorithm suitable for the non-invasive tracking of AUVs orvocalizing marine animals, using only a single receiver. This algorithm evaluates theunderwater acoustic channel impulse response differences induced by a diverse seabottom profile, and proposes a computationally- and energy-efficient solution for passivelocalization.Finally, we propose another algorithm to solve the issue of 3D acoustic localizationand tracking of marine fauna. To reach the expected degree of accuracy, more sensorsare often required than are available in typical commercial off-the-shelf (COTS) phasedarrays found, e.g., in ultra short baseline (USBL) systems. Direct combination of multipleCOTS arrays may be constrained by array body elements, and lead to breaking the optimal array element spacing, or the desired array layout. Thus, the application ofstate-of-the-art direction of arrival (DoA) estimation algorithms may not be possible. Wepropose a solution for passive 3D localization and tracking using a wideband acousticarray of arbitrary shape, and validate the algorithm in multiple experiments, involvingboth active and passive targets.
YR 2021
FD 2021-02
LK https://hdl.handle.net/10016/33184
UL https://hdl.handle.net/10016/33184
LA eng
NO Mención Internacional en el título de doctor
NO Part of the research in this thesis has been supported by the EU H2020 program underproject SYMBIOSIS (G.A. no. 773753).
NO This work has been supported by IMDEA Networks Institute
DS e-Archivo
RD 27 jul. 2024