The Widely scalable Mobile Underwater Sonar Technology (WiMUST) H2020 project: first year status

The Widely scalable Mobile Underwater Sonar Technology (WiMUST) project aims at developing a system of cooperative Autonomous Underwater Vehicles (AUVs) for geotechnical surveying and geophysical exploration. The paper reports about the first year activities and it gives an overview of the main objectives and methods. Results relative to distributed sensor array, cooperative control, mission planning, communications and preliminary experiments are summarized

Overview and first year progress of the Widely scalable Mobile Underwater Sonar Technology H2020 project

open20siPubblicazione su rivista di contributo a Convegno -10th IFAC Conference on Control Applications in Marine Systems (CAMS2016)The Widely scalable Mobile Underwater Sonar Technology (WiMUST) project is an H2020 Research and Innovation Action funded by the European Commission. The action's main goal is to develop robotic technologies exploiting Autonomous Underwater Vehicles (AUVs) for geotechnical surveying and geophysical exploration. The paper briefly describes the project and its state of the art after the first year of activities.openIndiveri, Giovanni; Antonelli, Gianluca; Arrichiello, Filippo; Caffaz, Andrea; Caiti, Andrea; Casalino, Giuseppe; Volpi, Nicola Catenacci; de Jong, Ivan Bielic; De Palma, Daniela; Duarte, Henrique; Gomes, Joao Pedro; Grimsdale, Jonathan; Jesus, Sergio; Kebkal, Konstantin; Kelholt, Elbert; Pascoal, Antonio; Polani, Daniel; Pollini, Lorenzo; Simetti, Enrico; Turetta, AlessioIndiveri, Giovanni; Antonelli, Gianluca; Arrichiello, Filippo; Caffaz, Andrea; Caiti, Andrea; Casalino, Giuseppe; Volpi, Nicola Catenacci; de Jong, Ivan Bielic; De Palma, Daniela; Duarte, Henrique; Gomes, Joao Pedro; Grimsdale, Jonathan; Jesus, Sergio; Kebkal, Konstantin; Kelholt, Elbert; Pascoal, Antonio; Polani, Daniel; Pollini, Lorenzo; Simetti, Enrico; Turetta, Alessi

Widely scalable mobile underwater sonar technology: an overview of the H2020 WiMUST project

The Widely scalable Mobile Underwater Sonar Technology (WIMUST) project is an H2020 Research and Innovation Action funded by European Commission. The project aims at developing a system of cooperative autonomous underwater vehicles (AUVs) for geotechnical surveying and geophysical exploration. The paper describes the main objectives of the project, given an overview of the methodologies adopted to achieve them, and summarizes the work done in the first year of R&D work

Underwater Localization via Wideband Direction-of-Arrival Estimation Using Acoustic Arrays of Arbitrary Shape

Underwater sensing and remote telemetry tasks necessitate the accurate geo-location of sensor data series, which often requires underwater acoustic arrays. These are ensembles of hydrophones that can be jointly operated in order to, e.g., direct acoustic energy towards a given direction, or to estimate the direction of arrival of a desired signal. When the available equipment does not provide the required level of accuracy, it may be convenient to merge multiple transceivers into a larger acoustic array, in order to achieve better processing performance. In this paper, we name such a structure an “array of opportunity” to signify the often inevitable sub-optimality of the resulting array design, e.g., a distance between nearest array elements larger than half the shortest acoustic wavelength that the array would receive. The most immediate consequence is that arrays of opportunity may be affected by spatial ambiguity, and may require additional processing to avoid large errors in wideband direction of arrival (DoA) estimation, especially as opposed to narrowband processing. We consider the design of practical algorithms to achieve accurate detections, DoA estimates, and position estimates using wideband arrays of opportunity. For this purpose, we rely jointly on DoA and rough multilateration estimates to eliminate spatial ambiguities arising from the array layout. By means of emulations that realistically reproduce underwater noise and acoustic clutter, we show that our algorithm yields accurate DoA and location estimates, and in some cases it allows arrays of opportunity to outperform properly designed arrays. For example, at a signal-to-noise ratio of –20 dB, a 15-element array of opportunity achieves lower average and median localization error (27 m and 12 m, respectively) than a 30-element array with proper λ / 2 element spacing (33 m and 15 m, respectively). We confirm the good accuracy of our approach via emulation results, and through a proof-of-concept lake experiment, where our algorithm applied to a 10-element array of opportunity achieves a 90th-percentile DoA estimation error of 4 ∘ and a 90th-percentile total location error of 5 m when applied to a real 10-element array of opportunity

Digital acoustic data exchange via a system of continuously varying frequencies

Unter kompliziertesten Randbedingungen sind Wale und insbesondere Delphine in der Lage, über vergleichsweise große Distanzen zu kommunizieren - und das offenbar mit hohen Informationsraten. Anhand von über 2000 aufgezeichneten Pfeifsignalen von freilebenden und dressierten Großen Tümmlern (Tursiops truncatus) wurden die Besonderheiten der zur Kommunikation verwendeten Signalstrukturen analysiert. Aus den bioakustischen Befunden ließen sich drei Grundprinzipien extrahieren, auf deren Basis ein neuartiges bionisches Verfahren für die digitale akustische Unterwasserkommunikation entwickelt wurde. Diese Prinzipien sind: 1. Nutzung eines Systems von kontinuierlich (fließend) veränderlichen Frequenzkanälen, wobei stets die signalinterne Proportionen beibehalten werden (definierte Abstände der Trägerfrequenzen). 2. Permanente Verbindung zwischen Sender und Empfänger über einen signaltechnisch separierbaren Grundton bzw. Kennton, relativ zu dem der Empfänger dann die übrigen Frequenzkomponenten des Signals auffinden kann und der gleichzeitig eine signalinterne Referenz für die Auswertung dieser Komponenten liefert. 3. Digitale Informationsübertragung mittels geeigneter Modulationen der übrigen Frequenzkanäle bzw. Obertöne (Senden von Bitmustern). Eine theoretische Betrachtung ergab, dass mit einem solchen, als "Variable Mehrkanalige Transmission" (VMT) bezeichneten Verfahren das Interferenzproblem weitestgehend gelöst, Doppler-Effekte ggf. vollständig kompensiert und die Rauscheinflüsse minimiert werden können. Somit lassen sich empfängerseitig die gesendeten Signalparameter in hoher Güte rekonstruieren. Das ermöglicht die Anwendung feiner abgestufter und komplexere Modulationsformen und dementsprechend höhere Bitraten. Computersimulationen in einer numerisch modellierten hydroakustischen Übertragungsstrecke gestatteten eine erste Überprüfung der Hypothesen sowie die Optimierung der Signalstrukturen und der Signalverarbeitung. Nachdem sicher gestellt war, dass alle essentiellen Bausteine von der Signalerzeugung bis zur Decodierung der Signalparameter zusammen spielen, folgte die praktische Überprüfung in einer natürlichen akustischen Messstrecke (Baggersee). In den physischen Validierungsexperimenten konnte die Funktionstüchtigkeit und die besondere Leistungsfähigkeit des bionischen VMT-Verfahrens nachgewiesen werden. In diesem Zusammenhang ergab sich auch ein Spektrum neuer Möglichkeiten zur optimalen Ausnutzung der physikalischen (hydroakustischen) Gegebenheiten. Von herausragender Bedeutung dürfte hierbei die erstmalige Chance zur Nutzung der natürlichen Redundanz für eine verbesserte Parameterbestimmung sein. Abschließend werden die jetzt schon erreichbaren Leistungsparameter und die weiteren Perspektiven abgeschätzt. Das technische Entwicklungspotential schließt auch neue Ansätze für tiefergehende bioakustische Untersuchungen ein, womit sich der Kreis zu den Naturvorbildern schließt

Full reconfiguration of underwater acoustic networks through low-level physical layer access

Underwater acoustic communications experiments often involve custom implementations of schemes and protocols for the physical and data link layers. However, most commercial modems focus on providing reliable or optimized communication links, rather than on allowing low-level reconfiguration or reprogramming of modulation and coding schemes. As a result, the physical layer is typically provided as a closed, non-reprogrammable black box, accessible by the user only through a specific interface. While software-defined modems would be the ultimate solution to overcome this issue, having access to the symbols transmitted by the modems using a proprietary modulation format already opens up a number of research opportunities, e.g., aimed at the cross-layer design and optimization of channel coding schemes and communication protocols. In this paper, we take the latter approach. We consider the commercial EvoLogics modem, driven by a custom firmware version that bypasses the channel coding methods applied by the modem, and allows the user to set the transmit bit rate to any desired value within a given set. This makes it possible to evaluate different coding schemes in the presence of different bit rates. Our results show that the custom firmware offers sufficient flexibility to test different configurations of the coding schemes and bit rates, by providing direct access both to correctly decoded and to corrupted symbols, which can be separated at the receiver for further processing. In addition, we show that the DESERT Underwater framework can also leverage the same flexibility by employing low-level physical layer access in more complex networking experiments

Environmental risk assessment of an underwater acoustic mobile network

International audienc

Environmental risk assessment of an underwater acoustic mobile network

International audienc

MarTERA UNDINA project: a multi-modal communication and network-aided positioning system for marine robotics and benthic stations

International audienc