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1
Content available Investigation of the underwater noise associated with remotely-operated vehicles
Buszman K., Mironiuk W.
Zeszyty Naukowe Akademii Morskiej w Szczecinie
|
2018
|
nr 54 (126)
129--132
EN
There is increasing demand for various types of submersible and floating remotely-operated vehicles which have herein been studied with respect to the threats posed by these kinds of objects. Local physical field disorder analyses have demonstrated the possibility of detecting and classifying objects based on hydroacoustics. Hydroaocoustic analysis results are presented as narrowband and One-Third-Octave spectra of different types of remotely-operated vehicles. Investigations were performed using an underwater measuring system located in very shallow water in a coastal zone characterized by conditions considered as poor for sound propagation.
2
Content available Acoustic analysis of remote-controlled surface and underwater vehicles
Buszman K., Szymczak W., Mironiuk W.
Hydroacoustics
|
2017
|
Vol. 20
29--34
EN
Technological progress has made the use of remotely controlled objects moving on the surface and underwater, for a variety of purposes, become extraordinarily popular. The widespread use of such vehicles enables unauthorized use. Therefore, knowledge of the hydroacoustic field characteristics makes it possible to identify by passive underwater observation systems. The paper presents the results of narrowband and one-third-octave frequency analyzes of remote-controlled surface and underwater vehicles. The change in sound pressure was recorded for vehicles moving a short distance away from the hydrophone. The research was carried out in difficult conditions, propagation, at a small depth in the coastal zone.
3
Wyznaczanie odpowiedzi impulsowej kanału hydroakustycznego
Studański R., Żak A.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2016
|
nr 8-9
990--994, CD
PL
W artykule przedstawiono metodę wyznaczania odpowiedzi impulsowej kanału hydroakustycznego za pomocą sygnału zmodulowanego ciągiem pseudoprzypadkowym. Przedstawiono przykładowe odpowiedzi impulsowe wyznaczone w wodach płytkich, jakie stanowiło jezioro. Badania przeprowadzono w warunkach statycznych.
EN
The paper describes a method of determination of a radio communication channel response by means of a signal modulated by a pseudorandom sequence. The cross-correlation between received and sent signals was applied to calculate the impulse response. Conducted experiments were realized in static conditions. Results of trials in shallow water (a lake) are showed.
4
Content available Signals parametrization method of sailing vessels
Buszman K., Gloza I.
Hydroacoustics
|
2016
|
Vol. 19
27--36
EN
The expansion of maritime transport is directly connected with increased risk of the appearance of unidentified vessels in the approaches to ports, wind farms, and other sensitive places in the water-body. Creating a parameters database of sailing objects, based on recorded dynamic variations of different physical fields with the specified aims of increasing security within the strategic offshore areas.
5
Content available Magneto-acoustic seaports security systems: state of the art
Gucma L., Gucma M., Dobryakova L., Ochin E.
Zeszyty Naukowe / Akademia Morska w Szczecinie
|
2012
|
nr 29 (101)
37-44
EN
The popularity of wireless technologies during the last decade has created a considerable expansion of wireless networks. Many researchers work now on the area of wireless resource planning and optimization. Optimization is considered as the main approach to designing and improving the performance of Wireless Local Area Networks Infrastructure of Seaports Security Systems. The presented models and algorithms enable flexible coverage planning and optimization of Wireless Network Infrastructure.
PL
Popularność technologii bezprzewodowych w ciągu ostatniego dziesięciolecia świadczy o znacznym rozwoju sieci bezprzewodowych. Dzięki rozwojowi technologicznemu wielu pracowników naukowych może zajmować się projektowaniem i optymalizacją sieci komputerowych i telekomunikacyjnych. Jednym z ważnych zastosowań technologii bezprzewodowych lokalnych sieci komputerowych może być budowa kompleksowych systemów zabezpieczania portów morskich, co przedstawiono w artykule.
6
Content available SHL-101/T SONAR - results of the harbour and sea trials
Kotłowski A., Męciński W., Okuniewski M, Prosińska E., Zając R.
Hydroacoustics
|
2008
|
Vol. 11
139-148
EN
The safeguard of seaways, naval basis, harbours and sea frontiers from minefields, attackers, gun-running is essential in hazardous nowadays. Particularly modern sea mines sometimes buried and make in stealth technology are very difficult to detect. Therefore the echo-ranging detection systems require state-of-the-art hardware and efficient processing algorithms to protect sea areas. Such up-to-date hydroacoustic equipment was developed by R&D Marine Technology Centre. The SHL-101/T system is the triple frequency, wideband and very high resolution hull-mounted minehunting sonar. It was put into service to Polish Navy minesweeper on April 2007. Sonar underwent factory, harbour and sea acceptance trials. Presently Polish Navy carries out further exploitation and military tests. The results are remarkable and they enable to explore mysteries of the sunken objects in the Gdansk Gulf. The paper presents the results of SHL-101/T sonar harbour and sea trials. Its performances for different detection and classification modes are also depicted. Additionally displays of the found various underwater objects are included and detailed discussed.
7
Content available Selected results of the parametric soundings of the Gdańsk Bay
Grelowska G., Kozaczka E.
Hydroacoustics
|
2008
|
Vol. 11
105-112
EN
The aim of the paper is to present results of experimental investigation using parametric echosounder in natural conditions for profiling the sub-bottom sediments in the Gdansk Bay. The special experimental setup has been arranged allowing penetration of bottom sediments as well as precise positioning and following a given route. Measurements were conducted exactly along given routes, for those geological profiles have bean taken by means of another method. It allow as to compare detailed date obtained by means of parametric echosounding to ones given at geological map. In all investigations the primary frequency of the array was of 100 kHz, whereas the secondary frequency changed in range 5 kHz - 15 kHz.
8
Content available Propagation of pulsed sound signals on a shelf of free tidal sea: effects from coastal eddies and internal waves
Mikryukov A., Popov O., Serebryany A.
Hydroacoustics
|
2008
|
Vol. 11
279-288
EN
A long term experiment on studying fluctuations of the parameters of pulsed sound signals in a shallow sea was carried out in the region of the northeastern coast of the Black sea in autumn, 2004. the data were collected on a 1.2-km fixed propagation pathat a 2-km distance from the coastline. During the entire experimentation, observations of temperature fluctuations near the receiving point were performed by the using the line temperature sensor. Fluctuations of the shape, energy and propagation time of the pulsed signals were studied. an attempt of their relation to the hydrodynamic processes on the shelf was taken. The change in the shape and the energy levelof the signal was analyzed for the moment of passing the anticyclonic topographic eddy over the coastal zone. It was shown that the fluctuations of the propagation time were sometimes as high as 17.6 ms. An enhanceof the short-period acoustic fluctuations accompanying the internsification of the internal waves was observed.
9
Content available Ocean average current measurement using acoustic phase monitoring
Zieliński A., Zhou L., Butowski M.
Hydroacoustics
|
2008
|
Vol. 11
459-467
EN
Knowledge of water currents is important in several ocean-related activities. Typically, current speed and direction are measured at a certain fixed location and depth (or depth profile) by a suitable current meter. In this paper, we propose a novel method for average current speed measurement along a path, based on acoustic phase monitoring. In this method, a transmitter and a receiver are installed at the ends of a designated path. A transmitted sinusoidal signal propagates along the path to the receiver. Intervening currents will introduce Doppler frequency shifts that can be measured as a rate of phase change in the received signal. The phase is recovered by means of a phase detector and unwrapping techniques. The desirable feature of the proposed method is that average current speed is monitored along the entire path. Moreover, the estimated frequency shift via the phase measurement achieves a higher accuracy in current measurement than does a measure of frequency directly by an FM demodulator.
10
Content available Modelling multistatic of target detection
Klusek Z., Elminowicz A., Tęgowski J., Szczucka J., Dragan A.
Hydroacoustics
|
2008
|
Vol. 11
131-138
EN
The paper presents a numerical approach to modelling the detection of underwater targets with a bi- or multistatic active sonar systems in the shallow water areas using different waveform signals. The results of the numerical modelling of surface, bubble clouds and bottom reverberation for CW and using up and down time-varying instantaneous frequency of chirp signals are presented. Some suggestions are made on the basis of the development and practicality for the shallow sea modeling techniques and approaches to existing sonar models. The paper reports the literature of the model components required for active sonar modelling for different propagation conditions. Some examples of scattering of CW and chirp source signals at bubble clouds and corrugated surfaces, and coherence are given. Active propagation and the system performance are surveyed and modelled adaptable to the specific environmental condition of the shallow sea area of the Gdansk Gulf.
11
Content available Laboratory model of high frequency sonar
Buszman K., Szymczak W.
Hydroacoustics
|
2008
|
Vol. 11
39-46
EN
This article contains the construction and laboratory application of high frequency sonar model. In view of working in laboratory conditions, they must be fulfilled succeeding parametric cases: very narrow beam, low level of side lobes and low acoustic power of transmitted impulse sounding. When all of these conditions are fulfilled, it makes possible the explanation to students some terms like depth, angular resolution and making clear, that water is the best environment to acoustic waves transmission. Furthermore, there is used automatic component, namely rotary antenna, which make possibility to precision area scanning.
12
Content available Experimental evidence for enhanced target detection by sonar in bubbly water
Leighton T., Finfer D., White P.
Hydroacoustics
|
2008
|
Vol. 11
181-203
EN
A sonar system has been developed which allows one to discriminate targets from scattered energy from bubbles. The underlying theory and experimental testing of this system are presented. The effectiveness of this sonar system is demonstrated through experimentation within a large fresh water tank in which bubble clouds are generated. Some of the practical requirements associated with such an experiment are detailed.
13
Content available Design and implementation FIR filters using FPGA
Jastrzębski S.
Hydroacoustics
|
2008
|
Vol. 11
121-130
EN
Underwater acoustic channels are characterized by multipath phenomenon whose characteristics are time varying. Multipath propagation contributes to signal fading, and causes intersymbol interference (ISI) in a digital communication system. Raised cosine filters are widely used in wireless communication systems and the effects of these filters are crucial to wireless communication systems, for example underwater communication systems. Pulse shaping filters are commonly used in digital data communication systems to limit intersymbol interference. Thus, digital filters have been recognized as primary digital signal processing operation. In order to apply DSP algorithms to wireless communication systems high density Field Programmable Gate Arrays have recently emerged as ideal implementation platforms for digital filters due to its potential speed and flexibility. This paper presents the design and implementation of FIR filters using FPGA technology. The following architectures of filters are studied: multiply and accumulate (MAC) standard FIR filter, parallel transposed FIR filter, and direct-form filter using Distributed Arithmetic (DA). The proposed filters have been designed and synthesized with ISE software, and implemented with a Virtex-II FPGA device.
14
Content available Data processing of broad-band signals received by multi-element cylindrical transducer
Janowski T., Elminowicz A., Szworski K.
Hydroacoustics
|
2008
|
Vol. 11
113-120
EN
The sonar based on cylindrical transducer compared with linear transducer has few advantages. Particularly its omni-directional central symmetry enables simplification of the echo signal Direction of Arrival (DOA) estimation. When the number of transducer staves is the power of two the efficient Fast Fourier Transformation can be used to calculate spatial convolution. The article presents theoretical and technological principles of the real time digital data processing of the wideband echo signals received by cylindrical hydroacoustic transducer. Described procedures enable high resolution underwater target location and precise data display. The implementation of effective broadband pulse compression technique with high range resolution will be presented. The results of signal processing modeling and examples of application will be also discussed.
15
Content available Artificial neural networks for interpolation and identification of underwater object features
Balicki J., Gloza I.
Hydroacoustics
|
2008
|
Vol. 11
1-10
EN
Artificial neural networks can be applied for interpolation of function with multiple variables. Because of concurrent processing of data by neurons, that approach can be seen as hopeful alternative for numerical algorithms. From these reasons, the analysis of capabilities for some models of neural networks has been carried out in the purpose for identification of the underwater object properties. Features of the underwater objects can be recognized by characteristics of a amplitude according to the frequency of measured signals. The feed-forward multi-layer networks with different transfer functions have been applied. Those network models have been trained by some versions of back-propagation algorithm as well as the Levenberg-Marquardt gradient optimization technique. Finally, for determination of the amplitude for the frequency of signal by the two-layer network with the hidden layer of the radial neurons has been proposed.
16
Content available Acoustic method of valuation of ships' drive mechanism operation
Domagalski J., Dobrzeniecki J.
Hydroacoustics
|
2008
|
Vol. 11
79-86
EN
The paper is presented the method of valuation of ships drive mechanism operation by comparison of noise level in ship's rooms, vibrations in selected places of drive fastening and acoustic disturbances generated by a ship to water environment. Selected researches results are presented in form of graphs.
17
Wielokanałowy odbiór sygnałów boi hydroakustycznych
Karwowski A.
Prace Przemysłowego Instytutu Telekomunikacji
|
2005
|
Vol. 55, z. 136
25-31
PL
W artykule przedstawiono koncepcję i rozwiązanie opracowanego w PIT wielokanałowego odbiornika sygnałów boi hydroakustycznych przeznaczonych do zastosowania w podsystemie hydroakustycznym wykrywania okrętów podwodnych. Parametry techniczne odbiornika muszą umożliwiać jego eksploatację w gęstym środowisku elektromagnetycznym, tzn. muszą umożliwiać odbiór często słabych sygnałów użytecznych w obecności licznych zakłóceń. Prezentowane rozwiązanie charakteryzują wysoka czułość, selektywność i dynamika. Przedstawiono także podstawowe zagadnienia związane z lokalizacją boi hydroakustycznych.
EN
In the article the idea and solution of a multichannel receiver of the sonobuoy signals is presented. Developed in PIT receiver is dedicated to systems of detection, classification and localization submarines. Its primary function is to receive transmissions from deployed sonobuoys, amplify and demodulate those on particular tuned channels, and provide the baseband modulation information to acoustic signal processing equipment. This signal processing equipment will then execute spectral analysis to extract target related data from baseband information. The basic assumption for the receiver was the possibility of working is standard NATO frequency channels. Presented solution characterize high selectivity and dynamic range, making possible its exploitation in the dense electromagnetic environment i.e. make possible the reception of the often weak useful signals in the presence of interference. In the article also basic problems related to the location of sonobuoys are introduced.
18
Content available remote Sonar simulator as a tool of the hydrographic works` evaluation
Felski A., Wąż M., Szulc D.
Reports on Geodesy
|
2002
|
z. 1/61
235-241
EN
An important phase of hydrographic works planning is the assessment of the components that should be taken into consideration during planning and during qualitative evaluation of results. There are many procedures based on statistical calculations and historical experience. Besides, it is possible to verify certain ideas or the correctness of collected research material by its comparison to the simulation data. This paper proposes certain methods and software for such simulation of different hydroacoustic equipment results. The examples of results and discussion regarding the usefulness of this method have been presented.
19
Content available remote The hydrografic methods and system of sea bed classification with specjal emphasis of navies needs
Szulc D., Urbański J.
Zeszyty Naukowe Akademii Marynarki Wojennej
|
1998
|
R. 39 nr 2 (137)
15--30
EN
The methods of identification and cassification of sea-bottom sediments and sub-bottom layers are presented. However, specjal emphasis is done to real-time methods which can be employed separately or together with other surveying methods, and during realization of the other navy ships tasks. The employment of the presented methods is referred to the proper types of echo sounding systems or sonar systems. To simplify and specify the considerations, the main notions concerning the discussed problems have been defined and shortly characterized.
PL
W artykule zostały przedstawione metody identyfikacji i klasyfikacji osadów dennych oraz warstw poddennych. Szczególny nacisk położono na metody czasu rzeczywistego, które mogą być zastosowane samodzielnie lub wspólnie z innymi metodami pomiarowymi podczas realizacji różnych zadań okrętów. Wykorzystanie zaprezentowanych metod jest powiązane z odpowiednimi typami echosond i sonarów. Główna uwaga została skupiona na krótkiej definicji i charakterystyce tych metod.
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