Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "underwater communications" wg kryterium: Temat

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-13 z 13
    Tytuł:
    Stationary underwater channel experiment: Acoustic measurements and characteristics in the Bornholm area for model validations
    Autorzy:
    Nissen, I.
    Kochańska, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/332083.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    underwater communications
    stationary time
    WSSUS indication
    Opis:
    The underwater acoustical channel is time-variant, and even on small time scales there is often existing no ‘acoustical frozen ocean’. Popular is the use of WSSUS-channel transmission modeling (Wide-Sense Stationary Uncorrelated Scattering) for the stochastic description of bandpass signals in GSM mobile phones with moving participants; since this results in a halved number of model parameters. For underwater sound applications such as detection, navigation and communication this approach provides limited a-priori-knowledge for adaptive algorithms with moving cooperative participants. The FWG of the WTD71 is collecting phase-accurate channel measurements from different sea areas in different time and application scenarios, with moving and stationary communication nodes since 2001. This paper presents a SIMO experiment from 2010, with a high precision continuous observation period of eleven hours using two stationary bottom nodes, mostly uncoupled from the influence of surface waves and from the sea floor. Transmitter and receiver node with a distance of two nautical miles between them were stationary installed on the bottom in shallow watersin the Bornholm Basin of the Baltic Sea. The sound speed has been measured continuously in the water column with a moving measurement chain. The question for this experiment was: Is the WSSUS-property fulfilled in water, when participants communicate motionless with negligible current, bottom influence and movements of the surface? The answer is: No, not in this experiment.
    Źródło:
    Hydroacoustics; 2016, 19; 285-296
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Limitations of WSSUS modeling of stationary underwater acoustic communication channel
    Autorzy:
    Kochańska, I.
    Nissen, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/331730.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    underwater communications
    impulse response
    stationary time
    stationary bandwidth
    adaptive communications
    WSSUS modeling
    Opis:
    Performances of underwater acoustic communication (UAC) systems are strongly related to specific propagation conditions of the underwater channel. Due to their large variability, there is a need for adaptive matching of the UAC systems signaling to the transmission properties of the channel. This requires a knowledge of instantaneous channel characteristics, in terms of the specific parameters of stochastic models. The wide-sense stationary uncorrelated scattering (WSSUS) assumption simplifies the estimation of terrestrial wireless channel transmission properties. Although UAC channels are hardly ever WSSUS, the rationale of such a stochastic modeling is that over a short period of time, and for a limited frequency range, this assumption is reasonably satisfied. The limits of application of the local-sense stationary uncorrelated scattering (LSSUS) model are determined by the stationary time and frequency. This paper presents the results of LSSUS model analysis for UAC channel measurements gathered by the former Research Department for Underwater Acoustics and Marine Geophysics (FWG), now part of the WTD71, during the SIMO experiment in the Bornholm Basin of the Baltic Sea.
    Źródło:
    Hydroacoustics; 2016, 19; 229-238
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Robot Local Network Using TQS Protocol for Land-to-Underwater Communications
    Autorzy:
    Irawan, Addie
    Abas, Mohammad Fadhil
    Hasan, Nurulfadzilah
    Powiązania:
    https://bibliotekanauki.pl/articles/307970.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    class of service
    land-to-underwater communications
    robot local network
    tag switching
    Opis:
    This paper presents a model and an analysis of the Tag QoS switching (TQS) protocol proposed for heterogeneous robots operating in different environments. Collaborative control is topic that is widely discussed in multirobot task allocation (MRTA) – an area which includes establishing network communication between each of the connected robots. Therefore, this research focuses on classifying, prioritizing and analyzing performance of the robot local network (RLN) model which comprises a point-to-point topology network between robot peers (nodes) in the air, on land, and under water. The proposed TQS protocol was inspired by multiprotocol label switching (MPLS), achieving a quality of service (QoS) where swapping and labeling operations involving the data packet header were applied. The OMNET++ discrete event simulator was used to analyze the percentage of losses, average access delay, and throughput of the transmitted data in different classes of service (CoS), in a line of transmission between underwater and land environments. The results show that inferior data transmission performance has the lowest priority with low bitrates and extremely high data packet loss rates when the network traffic was busy. On the other hand, simulation results for the highest CoS data forwarding show that its performance was not affected by different data transmission rates characterizing different mediums and environments.
    Źródło:
    Journal of Telecommunications and Information Technology; 2019, 1; 23-30
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Measurement of impulse response of shallow water communication channel by correlation method
    Autorzy:
    Schmidt, J.
    Kochańska, I.
    Schmidt, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/331786.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    underwater communications
    impulse response
    delay spread
    Doppler spread
    coherence time
    coherence bandwidth
    PRBS
    HFM
    Opis:
    Performances of underwater acoustic communication (UAC) systems are strongly related to specific propagation conditions of the underwater channel; conditions that can additionally change in time due to the movement of the acoustic system transmitter and receiver or to reflection by underwater objects of the transmitted signal. The time-varying impulse response is a comprehensive description of dynamically changing transmission properties of the UAC channel. It is a basis for estimation of stochastic parameters used for designing the signaling scheme of the communication system. The paper presents the results of a measurement experiment conducted in a shallow water environment. The channel impulse response was measured by the correlation method with the use of two kinds of broadband signals: pseudo-random binary sequence (PRBS) and hyperbolic frequency modulation chirp (HFM). For each measurement result statistical transmission parameters, namely delay spread, Doppler spread, coherence time, and coherence bandwidth were estimated.
    Źródło:
    Hydroacoustics; 2017, 20; 149-158
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transmitter Inclination Angle Characteristics for Underwater Optical Wireless Communication in a Variety of APD Detectors
    Autorzy:
    Mazin, Ali A. Ali
    Powiązania:
    https://bibliotekanauki.pl/articles/1192197.pdf
    Data publikacji:
    2016
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Communications
    Underwater Optical Communications
    Avalanche Photodiode
    Bit Error Rate
    Channel Capacity
    Opis:
    In this paper, the performance of an underwater optical wireless communications system is theoretically analyzed, using 4-PPM modulation technique and an avalanche photodiodes APD receiver over underwater environment channels. Based on the line of sight (LOS) geometrical model for optical beam propagation horizontally on an underwater medium and combined with signal to noise ratio model for Si, Ge and InGaAs APD and BER; then the impacts of the distance of transmission, power of the transmitter under Jerlov water types (I, IA, IB) are analyzed. The characteristics of bit error rate BER and channel capacity for 4-PPM optical modulation technique are studied under different APD detector and Jerlov water types. Simulation results indicate that the performance of PPM and Jerlov type (I) are more suited for an underwater optical wireless communication. On the other hand, we discuss the suitability of avalanche photodiodes under this modulation technique, where the photodiode Si APD has more advantage compared with the other detectors when used as a receiver in an underwater optical communication.
    Źródło:
    World Scientific News; 2016, 45, 2; 355-372
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Shallow Water Experiment of OFDM Underwater Acoustic Communications
    Autorzy:
    Kochańska, Iwona
    Schmidt, Jan H.
    Marszal, Jacek
    Powiązania:
    https://bibliotekanauki.pl/articles/177592.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    underwater acoustic communications
    UAC
    orthogonal frequency-division multiplexing
    OFDM
    Opis:
    The large variability of communication properties of underwater acoustic channels, and especially the strongly varying instantaneous conditions in shallow waters, is a challenge for the designers of underwater acoustic communication (UAC) systems. The use of phase modulated signals does not allow reliable data transmission through such a tough communication channel. However, orthogonal frequency-division multiplexing (OFDM), being a multi-carrier amplitude and phase modulation technique applied successfully in the latest standards of wireless communications, gives the chance of reliable communication with an acceptable error rate. This paper describes communication tests conducted with the use of a laboratory model of an OFDM data transmission system in a shallow water environment in Wdzydze Lake.
    Źródło:
    Archives of Acoustics; 2020, 45, 1; 11-18
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Asynchronous Demodulation Method for Four SSB arranged on Frequency Axis in Mobile Radio Path using Hilbert Transform
    Autorzy:
    Daikoku, Kazuhiro
    Powiązania:
    https://bibliotekanauki.pl/articles/1844503.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    asynchronous demodulation
    4-SSB
    ISB
    mobile radio path
    Hilbert transform
    HF/VHF band telecommunications
    tactical communications
    underwater communications
    Opis:
    In this paper, an asynchronous demodulation method for a four-single sideband (SSB) signal arranged on the frequency axis is developed to support burst mode transmission in a mobile radio path and to achieve greater data throughputs. When a reduced pilot carrier is placed at the center of the 4-SSB signal, it is guarded by lower and upper sidebands, that is, this scheme is classified into a tone-in-band (TIB) system. Digital signal processing (DSP) processors are useful for implementing a Hilbert transform. However, we have for a long time neglected introducing it into the demodulation process of SSB signals.
    Źródło:
    International Journal of Electronics and Telecommunications; 2021, 67, 3; 445-450
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance of coherent modulation scheme used in acoustic underwater communication system
    Autorzy:
    Schmidt, Jan H.
    Schmidt, Aleksander M.
    Kochańska, Iwona
    Powiązania:
    https://bibliotekanauki.pl/articles/127757.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    underwater acoustic communications
    shallow underwater channel
    coherent modulation
    akustyczna komunikacja podwodna
    płytki kanał podwodny
    modulacja koherentna
    Opis:
    The development of an acoustic underwater communication system for shallow waters is still a big scientific and construction challenge. Currently, non-coherent modulations in combination with strong channel coding are used to achieve reliable communication with low rate in such a channel. To obtain transmission with a higher transmission rate, it is required to use coherent modulation. This paper presents the assumptions of such a transmission system and the results of data transmission carried out by this system in the channel with the Rician fading, which reflects the short range shallow water channel. A digital version of the carrier phase modulation known as Phase-Shift Keying was selected for simulation.
    Źródło:
    Vibrations in Physical Systems; 2019, 30, 1; 1-8
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synchronization system for underwater acoustic communications using in shallow waters
    Autorzy:
    Schmidt, Jan H.
    Schmidt, Aleksander M.
    Powiązania:
    https://bibliotekanauki.pl/articles/24201990.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    synchronization system
    underwater acoustic communications
    shallow water
    układy synchronizacji
    akustyczna komunikacja podwodna
    wody płytkie
    Opis:
    A reliable synchronization system of the transmitted data frame has a significant impact on the efficiency of the underwater communication system. This applies in particular to communication systems dedicated to work in shallow waters, where the phenomenon of multipath permanently occurs. To overcome these difficulties, the concept of a synchronization system consisting of two broadband signals of opposite monotonicity was presented. The method of receiving these signals has been described in detail. The stochastic channel model with Rician fading and the Watermark simulator was used to test the efficiency of the synchronization system in the underwater multipath channel.
    Źródło:
    Vibrations in Physical Systems; 2023, 34, 1; art. no. 2023102
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A new direct-sequence spread spectrum signal detection method for underwater acoustic communications in shallow-water channel
    Autorzy:
    Kochańska, Iwona
    Powiązania:
    https://bibliotekanauki.pl/articles/2146643.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    underwater acoustic communications
    UAC
    direct sequence spread spectrum
    DSSS
    akustyczna komunikacja podwodna
    bezpośrednie modulowanie nośnej sekwencją kodową
    Opis:
    Direct-Sequence Spread Spectrum (DSSS) is one of the modulation and coding techniques used in Underwater Acoustic Communication (UAC) systems for reliable data transmision even at low signal levels. However, in a shallow water channel, there is a strong multipath propagation which causes a phase fluctuation of the received signal, affecting the performance of the spread-spectrum system. The article presents a differential method for DSSS signal detection. It is based on the calculation of the correlation coefficient of adjacent segments of signal at the output of filter matched to the spreading sequence used in the transmitter. A positive value of the correlation coefficient means that a given modulation symbol carries the same information bit as the previous one; a negative value means that the opposite bit has been transmitted. The reliability of the proposed method has been compared to classical method of DSSS signal detection, which consists in detecting the information directly from the signal at the output of the matched filter. Simulation and measurement tests of underwater acoustic communications in strong multipath propagation conditions have shown that the proposed method allows obtaining lower values of the DSSS transmission Bit Error Rate (BER) than the classical detection technique while maintaining the same data transmission rate.
    Źródło:
    Vibrations in Physical Systems; 2021, 32, 1; art. no. 2021106
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance of the Direct Sequence Spread Spectrum Underwater Acoustic Communication System with Differential Detection in Strong Multipath Propagation Conditions
    Autorzy:
    Schmidt, Jan H.
    Kochańska, Iwona
    Schmidt, Aleksander M.
    Powiązania:
    https://bibliotekanauki.pl/articles/31339747.pdf
    Data publikacji:
    2024
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    direct sequence spread spectrum
    DSSS
    m-sequences
    Kasami codes
    shallow-water channel
    multipath propagation
    underwater acoustic communications
    UAC
    Opis:
    The underwater acoustic communication (UAC) operating in very shallow-water should ensure reliable transmission in conditions of strong multipath propagation, significantly disturbing the received signal. One of the techniques to achieve this goal is the direct sequence spread spectrum (DSSS) technique, which consists in binary phase shift keying (BPSK) according to a pseudo-random spreading sequence. This paper describes the DSSS data transmission tests in the simulation and experimental environment, using different types of pseudo-noise sequences: m-sequences and Kasami codes of the order 6 and 8. The transmitted signals are of different bandwidth and the detection at the receiver side was performed using two detection methods: non-differential and differential. The performed experiments allowed to draw important conclusions for the designing of a physical layer of the shallow-water UAC system. Both, m-sequences and Kasami codes allow to achieve a similar bit error rate, which at best was less than 10−3. At the same time, the 6th order sequences are not long enough to achieve an acceptable BER under strong multipath conditions. In the case of transmission of wideband signals the differential detection algorithm allows to achieve a significantly better BER (less than 10−2) than nondifferential one (BER not less than 10−1). In the case of narrowband signals the simulation tests have shown that the non-differential algorithm gives a better BER, but experimental tests under conditions of strong multipath propagation did not confirm it. The differential algorithm allowed to achieve a BER less than 10−2 in experimental tests, while the second algorithm allowed to obtain, at best, a BER less than 10−1. In addition, two indicators have been proposed for a rough assessment which of the detection algorithms under current propagation conditions in the channel will allow to obtain a better BER.
    Źródło:
    Archives of Acoustics; 2024, 49, 1; 129-140
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Simulation of direct-sequence spread spectrum data transmission system for reliable underwater acoustic communications
    Autorzy:
    Kochańska, Iwona
    Schmidt, Jan H.
    Powiązania:
    https://bibliotekanauki.pl/articles/128008.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    underwater acoustic communications
    UAC
    direct sequence spread spectrum
    DSSS
    PRBS
    akustyczna komunikacja podwodna
    bezpośrednie modulowanie nośnej sekwencją kodową
    pseudolosowa sekwencja bitów
    Opis:
    Underwater acoustic communication (UAC) system designers tend to transmit as much information as possible, per unit of time, at as low as possible error rate. It is a particularly difficult task in a shallow underwater channel in which the signal suffers from strong time dispersion due to multipath propagation and refraction phenomena. The direct-sequence spread spectrum technique (DSSS) applied successfully in the latest standards of wireless communications, gives the chance of reliable data transmission with an acceptable error rate in a shallow underwater channel. It utilizes pseudo-random sequences to modulate data signals, and thus increases the transmitted signal resilience against the inter symbol interference (ISI) caused by multipath propagation. This paper presents the results of simulation tests of DSSS data transmission with the use of different UAC channel models using binary spreading sequences.
    Źródło:
    Vibrations in Physical Systems; 2019, 30, 1; 1-8
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Działalność Sprint S.A. w ramach projektu rozwojowego pod nazwą zintegrowany system planowania perymetrycznej ochrony i monitoringu morskich portów i obiektów krytycznych oparty o autonomiczne jednostki pływające
    The activity Sprint S.A. within the development project: integrated planning system for the perimetric protection and monitoring of sea-ports and critical objects with the use of on unmanned surface vehicles
    Autorzy:
    Baranowski, A.
    Czepczyński, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/366487.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Medycyny i Techniki Hiperbarycznej
    Tematy:
    pojazdy bezzałogowe nawodne
    pojazdy bezzałogowe podwodne
    systemy teleinformatyczne
    unmanned surface vehicles
    unmanned underwater vehicles
    data communications systems
    Opis:
    Sprint S.A., wiodący integrator systemow teleinformatycznych w kraju, działający na rynku od 1988 roku, bierze udział w projekcie rozwojowym pt.: "Zintegrowany system planowania perymetrycznej ochrony i monitoringu morskich portow i obiektow krytycznych, oparty o autonomiczne bezzałogowe jednostki pływające" (Nr O R00 0106 12). Projekt jest realizowany przez konsorcjum naukowo-przemysłowe, w skład ktorego wchodzą Sprint S.A., Polsko-Japońska Wyższa Szkoła Technik Komputerowych w Warszawie oraz Akademia Marynarki Wojennej w Gdyni. Celem projektu jest stworzenie demonstratora technologii obejmującego bezzałogową platformę pływającą USV (ang. unmanned surface vehicle), stanowisko planowania misji wraz z symulatorem planowanych rozwiązań, stanowisko realizacji planowanej misji umieszczone na bezzałogowym pojeździe nawodnym oraz system łączności integrujący systemy nawigacyjne, monitorujące i komunikacyjne. W niniejszym materiale przedstawiono zakres zadań realizowanych w ramach niniejszego projektu przez Sprint S.A.
    The company Sprint S.A., a leading ITC system integrator in Poland operating in the market since 1988, is a participant of the development project entitled: "Integrated planning system for the perimetric protection and monitoring of sea-ports and critical objects with the use of unmanned surface vehicles" (No. O R00 0106 12). The project is realised by a consortium consisting of the Polish-Japanese Institute of Information Technology and the Polish Naval Academy in Gdynia. The objective of the project is to create a technology demonstrator encompassing an unmanned surface vehicle - USV, a mission planning station together with a planned solutions simulator, a mission implementation station located on an unmanned surface vehicle and a communication system integrating navigational, monitoring and communication systems. The material presents the scope of tasks realized within the said project by the company Sprint S.A.
    Źródło:
    Polish Hyperbaric Research; 2012, 3(40); 81-98
    1734-7009
    2084-0535
    Pojawia się w:
    Polish Hyperbaric Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-13 z 13

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies