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Wyszukujesz frazę "underwater vehicle" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Challenges associated with the design of a small unmanned autonomous maritime vehicle
Autorzy:
Gerigk, M.
Powiązania:
https://bibliotekanauki.pl/articles/135384.pdf
Data publikacji:
2016
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
unmanned autonomous underwater vehicle
precise position stabilization
simulation model
Opis:
The present paper begins with a presentation of an interdisciplinary research project, the method is then introduced, followed by a brief description of the unmanned autonomous maritime vehicle. The following chapter concerns a combined model describing the motion of the vehicle, including the hydrodynamic and aerodynamic forces. The model takes into account gravity, displacement, resistance, thrust, lift, and other hydrodynamic forces. The primary task of an advanced maritime vehicle is to precisely predict its position. To do so, an integrated model for the acquisition, analysis, and processing of the signals is necessary. The processed signals should then be used for the precise steering of the vehicle. The vehicle should be equipped with a stabilization system. Information on the integrated steering, positioning, and stabilization system of the vehicle is briefly presented in the paper. Such system enables to obtain a fully autonomous vehicle. Some information on the propulsion and underwater energy supply systems is also briefly presented. In the final part of the paper, some of the issues connected with vehicle safety are introduced.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2016, 46 (118); 22-28
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spoofing detection for underwater acoustic GNSS-like positioning systems
Autorzy:
Ochin, Evgeny
Powiązania:
https://bibliotekanauki.pl/articles/135055.pdf
Data publikacji:
2019
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
antiterrorism
GNSS
spoofer
antispoofing
spoofing detection algorithm
underwater vehicle
underwater transport safety
acoustic communication
Opis:
The need for accuracy, precision, and data registration in underwater positioning and navigation should be viewed as no less stringent than that which exists on the sea surface. In the same way in which GNSS (Global Navigation Satellite System) receivers rely on the signals from multiple satellites to calculate a precise position, undersea vehicles discern their location by ranging to the acoustic signals originating from several fixed underwater acoustic sources using the Time-of-Arrival algorithm (ToA) through the Ordinary Least Squares method (OLS). In this article, the scope has been limited to only considering underwater positioning systems in which the navigation receiver is acoustically passive. The receiver “listens” to the buoys, receives their messages and solves the problem of finding its own position based on the geographical coordinates of the buoys. Often, such systems are called GNSS-like Underwater Positioning Systems (GNSS-like UPS). It is important to note the distinction between general purpose GNSS-like UPS (mainly civil systems) and special purpose GNSS-like UPS (mainly military systems). In this article, only general purpose GNSS-like UPS systems have been considered. Depending on the scale of system’s service areas, GNSS-like UPS are divided into global, regional, zonal and local systems. Only local GNSS-like UPS systems have been considered in this article. The spoofing of acoustic GNSS-like UPS works as follows: the acoustic GNSS signal generator transmits a simulated signal of several satellites. If the level of the simulated signal exceeds the signal strength of the real satellites, the acoustic receiver of an underwater object will “capture” the fake signal and calculate a false position based on it. All receivers that fall into the spoofing zone will calculate the same coordinates, while the receivers located in different places will have a mismatch in the XYZ coordinates.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2019, 57 (129); 38-46
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A quick algorithm for planning a path for a biomimetic autonomous underwater vehicle
Autorzy:
Praczyk, T.
Powiązania:
https://bibliotekanauki.pl/articles/135094.pdf
Data publikacji:
2016
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
path planning
underwater vehicle
autonomy
collision avoidance
automatic control
effective planning algorithm
Opis:
Autonomous underwater vehicles are vehicles that are entirely or partly independent of human decisions. In order to obtain operational independence, the vehicles have to be equipped with specialized software. The task of the software is to move the vehicle along a trajectory while avoiding collisions. In its role of avoiding obstacles, the vehicle may sometimes encounter situations in which it is very difficult to determine what the next movement should be from an ad hoc perspective. When such a situation occurs, a planning component of the vehicle software should be run with the task of charting a safe trajectory between nearby obstacles. This paper presents a new path planning algorithm for a Biomimetic Autonomous Underwater Vehicle. The main distinguishing feature of the algorithm is its high speed compared with such classic planning algorithms as A*. In addition to presenting the algorithm, this paper also summarizes preliminary experiments intended to assess the effectiveness of the proposed algorithm.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2016, 45 (117); 23-28
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical determination of the hydrodynamic coefficients of an autonomous underwater vehicle
Autorzy:
Sakaki, Abdollah
Kerdabadi, Mohsen Sadeghian
Powiązania:
https://bibliotekanauki.pl/articles/135543.pdf
Data publikacji:
2020
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
Reynolds averaged Navier–Stokes
computational fluid dynamics
linear coefficients
non-linear coefficients
underwater vehicle
Opis:
Computational fluid dynamics (CFD) has progressed rapidly in the past fifty years and is now used in many industrial fields, such as air, space, and marine engineering. CFD has an irreplaceable role in marine design and scientific research, and its applications within this field continue to grow with the development of computers. CFD is used to quickly and inexpensively simulate fluid behaviour using the Reynolds Averaged Navier–Stokes (RANS) equations to calculate hydrodynamic coefficients, which are needed in manoeuvrability studies of underwater vehicles (UWV). Here, these computations are performed for six geometrical shapes that represent typical autonomous underwater vehicles (AUVs) currently in use. Resistance test simulations at up to 20o drift angles were conducted for AUVs with different length-to-diameter ratios. The results were compared with the experimental data and current quasi-experimental relationships, which suggested that the CFD predictions were adequately precise and accurate. These predictions indicated that there was a non-linear relationship between forces and moments and the lateral speed. Moreover, both linear and non-linear hydrodynamic coefficients were calculated.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2020, 62 (134); 124-135
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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