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Wyszukujesz frazę "Marszal, J." wg kryterium: Autor


Tytuł:
Implementation of contemporary technologies in naval sonars modernization
Autorzy:
Marszal, J.
Powiązania:
https://bibliotekanauki.pl/articles/331808.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
Today’s fast technological advancement in electronics and signal processing methods makes electronic systems, including sonars, obsolete very quickly. The Polish Navy seems to be particularly affected as its ships were built in the 1970s and 1980s. Researchers at the Gdansk University of Technology have developed a methodology for modernising Navy sonars which involves the use of new electronic sub-systems and modern, bespoke methods of digital signal processing. Thanks to that, the existing large and expensive ultrasonic transducers and their systems for deployment and stabilisation remain unchanged. Between 2001 and 2013 this methodology was used by the Gdansk University of Technology to modernise 26 sonars of different types for the Polish Navy. The projects have significantly improved the technical and utility parameters of the sonars, while keeping the expenditure at about 20% of the value of new equipment.
Źródło:
Hydroacoustics; 2013, 16; 167-180
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Signal conditioning for examination of shallow-water acoustic noise correlation properties
Autorzy:
Rudnicki, M.
Marszal, J.
Powiązania:
https://bibliotekanauki.pl/articles/331724.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
underwater acoustics
ambient noise
noise envelope
tetrahedral antenna
Opis:
The article describes the process of signal conditioning for examination of acoustic noise correlation properties in shallow water. Knowledge of these properties is very important for the design processes of passive and active hydroacoustic systems. This paper focuses on the above issue from the point of view of passive sonar. In sonar systems, signal processing algorithms operate on both useful acoustic signals, and accompanying noise. Quantitative estimation of the correlation properties of acoustic noise enables an accurate determination of detection conditions. This will verify the validity of certain commonly used simplified models in simulations of hydroacoustic systems. The article presents how the measurement system was constructed, and the structure of files for storing measurement data. It describes the processing algorithm developed for the measured signal conditioning. Research results are presented and discussed.
Źródło:
Hydroacoustics; 2016, 19; 335-340
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Doppler estimation method for moving target location
Autorzy:
Salamon, R.
Marszal, J.
Powiązania:
https://bibliotekanauki.pl/articles/331983.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
The article presents an algorithm for target location based solely on Doppler shift of echo acoustic signals of a moving underwater object. The algorithm is designed for use in multi-static systems for protecting bodies of water from terrorist attacks by divers or submerged vehicles. The original source of signals is a transmitter emitting continuous acoustic waves. The echo signals from moving object are received by hydrophones located at fixed and known points in the water. Doppler shifts are determined from discrete Fourier transforms of hydrophone signals. The proposed iterative algorithm for target location calculates the approximate values of target speed vector and target coordinates which correspond to speed vectors as calculated previously.
Źródło:
Hydroacoustics; 2010, 13; 225-234
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical analysis of a new approach to order determination for a modified Prony method in swath mapping application
Autorzy:
Grall, P.
Marszal, J.
Powiązania:
https://bibliotekanauki.pl/articles/332107.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
swath bathymetry
interferometry
principal components
DOA
MBES
Opis:
This article presents a new approach to determine the model order (number of principal components) in the modified Prony method applied to swath acoustic mapping. Determination of the number of principal components is a crucial step in the modified Prony method. In the proposed approach the model order is chosen based on the underlying physical model of the underwater acoustic environment, and utilised signal processing operations. This data-driven approach, attempts to make use of all available information to assess the number of signals arriving at the receiver using pipeline processing in lieu of iterative processing.
Źródło:
Hydroacoustics; 2017, 20; 63-74
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation into interferometric sonar system accuracy
Autorzy:
Grall, G.
Marszal, J.
Powiązania:
https://bibliotekanauki.pl/articles/332610.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
bathymetry
phase differencing sonar
hydrographic standards
Opis:
The results of the accuracy measurements of phase differencing bathymetric sonar (PDBS) system in shallow waters are presented in the article. The measurement results were compared with the theoretical calculations for sonar system accuracy and international standards for hydrographic surveys. The proposed formulas enable to assess a priori sonar system performance using system quality factor (SQF), which takes into account influence of variable environmental conditions and auxiliary sensors on depth accuracy in a real-life scenario. The proposed SQF can be used in survey planning process to predict the swath width.
Źródło:
Hydroacoustics; 2015, 18; 69-76
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of distance measurement errors in CW FM sonar with MLS code modulation
Autorzy:
Jedel, A.
Marszal, J.
Salamon, R.
Powiązania:
https://bibliotekanauki.pl/articles/331626.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
CW FM sonar
pseudorandom sequence
Doppler effect
sonar parameters
Opis:
Although used in the classic silent sonar, the CW FM sounding signal has a major flaw which is its inaccuracy in determining the distance to a target. The authors of the article have developed a concept of silent sonar using frequency modulation signals switched by pseudorandom codes, already discussed in their previous work. This article presents a detailed analysis of errors in CW FM sonar with pseudo-random sequence code modulation confronted with errors which occur in similar sonar without code modulation.
Źródło:
Hydroacoustics; 2017, 20; 75-84
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Continuous wave sonar with hyperbolic frequency modulation keyed by pseudo-random sequence
Autorzy:
Jedel, A.
Marszal, J.
Salamon, R.
Powiązania:
https://bibliotekanauki.pl/articles/331999.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
CW FM
pseudorandom sequence
Doppler effect
matched filtering
Opis:
A CW FM type sounding signal is used in the classical solution of silent sonar. While the signal provides a relatively simple implementation of digital signal processing, and ensures good detection conditions, unfortunately, in the presence of the Doppler effect, distance measurement results tend to be wrong. This is due to the fact that the received signal’s instantaneous frequency value is dependent both on the distance to the object, and its speed. Sounding signal, as patented by the authors, is a combination of Pseudo-Random Sequences (PRS), and elementary signals of Hyperbolic Frequency Modulation (HFM) type. The structure of this signal is aimed at minimizing measurement error. The article presents the idea of a sounding signal of HFM+PRS type, and the results of computer simulations.
Źródło:
Hydroacoustics; 2016, 19; 185-196
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Small antenna for a dipping sonar
Autorzy:
Marszal, J.
Jedel, A.
Ostrowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/332487.pdf
Data publikacji:
2001
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
The dome enclosing the antenna of dipping sonar should be of the smallest possible size. Presented in the paper is a concept of hydroacoustic antennas of active and passive sonar. The active antenna performs mechanical scanning while the passive antenna uses the orthogonal array of gradient hydrophones. In addition to that the antenna array includes ultrasonic transducers of a sound velocity profiler, a pressure sensor for measuring the depth of antenna submergence. With that many sources of signal in the sonar's ease, a multiple fibre cable is required or signal modulation to transmit the signals over a limited number of wires. The sonar in question uses distribution over time and an original modulation method for simultaneous transmission of several signals using a cable channel. Block diagram and formulas describing the entire signal from the sonar's antenna are included.
Źródło:
Hydroacoustics; 2001, 4; 169-172
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of maximum length sequence in silent sonar
Autorzy:
Marszal, J.
Salamon, R.
Kilian, L.
Powiązania:
https://bibliotekanauki.pl/articles/331898.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
Silent sonars are designed to reduce the distance over which their sounding pulses can be detected by intercept sonars. In order to meet this objective, we can use periodical sounding signals that have low power, a very long duration and wide spectrum. If used in the silent sonar’s receiver, matched filtration ensures very good detection of motionless or slow moving targets. However, it is more difficult to detect echo signals of fast moving targets with Doppler effect causing significant error in target distance measurements. In an effort to find signals that can better resist Doppler effect, maximum length sequence was tested for its application in silent sonar. It has an elementary signal which includes linear frequency modulation. It was demonstrated that the signal produces much better results than those obtained with simple frequency modulation signals.
Źródło:
Hydroacoustics; 2012, 15; 143-152
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Silent sonar with matched filtration
Autorzy:
Salamon, R.
Marszal, J.
Schmidt, J.
Rudnicki, M.
Powiązania:
https://bibliotekanauki.pl/articles/331754.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
Radars with continuous wave frequency (CW FM sonars) are used in radiolocation as ‘silent radars’. They determine the distance to target by measuring the difference between the frequency of the sounding signal and echo signal. The article presents the principle of operation and parameters of silent CW FM sonars. Target distance determined by these sonars is based on the signal at the output of the matched filter. The Doppler effect is studied in detail to identify its effect on the sonar’s parameters. The results of theoretical calculations are presented together with the results of the sonar’s computer simulation.
Źródło:
Hydroacoustics; 2011, 14; 199-208
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic stabilization of beams in sonar with cylindrical array
Autorzy:
Marszal, J.
Leśniak, W.
Salamon, R.
Schmidt, J.
Powiązania:
https://bibliotekanauki.pl/articles/332362.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
The article presents the principle of operation of the beamformer of sonar with a cylin-drical array. It demonstrates that a modified beamformer can be used for beam electronic stabilization. The paper presents the algorithm of a digital beamformer used to ensure that the beam’s axis is maintained in a horizontal plane when the ship’s pitch and roll are known. Finally, the article gives an overview of the technical problems of electronic beam deflection.
Źródło:
Hydroacoustics; 2006, 9; 119-124
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Doppler effect in the cw fm sonar
Autorzy:
Marszal, J.
Salamon, R.
Zachariasz, K.
Schmidt, A.
Powiązania:
https://bibliotekanauki.pl/articles/331758.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
When sonars are used for military purposes they have to ensure unobtrusive operation, afeature that can be potentially secured by ‘silent sonars’ or continuous wave frequency modulation sonars (CW FM sonars). The article presents how these sonars operate and identifies the relations between their parameters. The Doppler effect and its impact on the CW FM sonar are studied to identify how it affects the sonar’s parameters. The results of simplified theoretical calculations are supported with results of computer simulations of a more realistic model.
Źródło:
Hydroacoustics; 2011, 14; 157-164
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Autonomous hydroacoustic sound velocity profiler
Autorzy:
Jedel, A.
Marszal, J.
Ostrowski, Z.
Kilian, L.
Powiązania:
https://bibliotekanauki.pl/articles/332093.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
sound velocity profiler
Opis:
The paper presents the autonomous hydroacoustic sound velocity profiler collaborating with ordinary PC by small box included interface & battery charger. The measurement and calibration methods and block diagram of the meter are presented as well as principles of operation, data collection, selection and transmission. There are described three versions of this meter - dropped from "normal" ships, installed in the light hull of submarines and casings in the hulls of variable depth sonar antennas.
Źródło:
Hydroacoustics; 2003, 6; 261-266
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Signal processing in the hydroacoustic ships berthing aid system
Autorzy:
Marszal, J.
Salamon, R.
Kilian, L.
Raganowicz, A.
Szurowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/332707.pdf
Data publikacji:
1997
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
The berthing of ships is an extremely complicated task that requires decisions on the movement of ships based on a large number of variabies: tide wind, visibility, speed, distance from jetty. Particular difficulties are related to the less maneuverable ships such as very large crude carriers. The presented hydroacoustic ships berthing aid system measures four distances of a ship to the jetty using the sonar echo method. The system computer calculates the bow and stern speed and distances to dolphins from the measured data. The results obtained are simultaneously presented on a large, high luminance display as well as printed out and recorded on computer discs. Additionally the dolphins displacements are measured and the data obtained together with its statistical parameters are recorded.
Źródło:
Hydroacoustics; 1997, 1; 237-242
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic control of the receiving beam horizontal cross-section in the side scan sonar
Autorzy:
Jedel, A.
Kilian, L.
Marszal, J.
Ostrowski, Z.
Salamon, R.
Powiązania:
https://bibliotekanauki.pl/articles/332725.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
A decade old side scan sonars are now being modernised by way of dynamically controlling the width of the receiving beam in the horizontal cross-section. The result is a quasi-constant linear resolution of the sonar (replacing constant angular resolution), when it picks up echo signals as it moves further away from the targets. The advantage of the treatment is that the ship using the side scan sonar can increase its speed without risking the loss of near targets’ echo. The articles describes how the system of dynamic control was implemented. Special TVG systems were introduced to control dynamic signal gain from several separate sections of the sonar’s acoustic array, which was divided symmetrically into unequal sections. The location of these systems in the sonar’s receiver is presented. Examples are given of curves that control TVG and of the effects of dynamic horizontal stabilisation of the sonar’s linear resolution as it receives signals.
Źródło:
Hydroacoustics; 2005, 8; 69-76
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł

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