Wyniki wyszukiwania - BazTech

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SHL-101/T SONAR - results of the harbour and sea trials

Kotłowski A., Męciński W., Okuniewski M, Prosińska E., Zając R.

Hydroacoustics

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2008

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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.

2

Coś z karafki

Kotłowski A.

Geodeta : magazyn geoinformacyjny

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2006

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nr 6

10-13

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Theoretical problems of the wideband sonar time-spatial filtration

Janowski T., Kotłowski A., Porosińska E.

Hydroacoustics

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2003

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Vol. 6

221--228

EN

The paper presents the synthesis of the time-spatial matched filtration algorithm. First part specifies base for the algorithm-input data. Successively, the matched filtration for continuous junction is depicted. This leads to the canonical form of the time-spatial filter. Consecutively, the decomposition into series connection of the matched and spatial filtration is realized. The next step is the signals approximation by Fourier series due to equivalence between approximation and interpolation on uniformly distributed discrete sampIes. The equation of the spatial filtration - in frequency domain - results from this mathematical operations. Application of the Bluestein's method to solve this equation provides to the final algorithm version. Advantages of the developed algorithm are presented in conclusions.

4

Simulation of the time - spatial filtration algorithm by 2d FFT expanded method and its properties

Janowski T, Kotłowski A., Męciński W., Okuniewski M.

Hydroacoustics

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2003

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Vol. 6

229--234

EN

The article presents the simulation results of the time-spatial matched filtration algorithm in detail described in [1]. The features of the algorithm are presented on figures of the realized simulations. Firstly, the simulation results in case of jar field are described. Successively the realizability of different filtrations types within algorithms is presented. Next the possibility of the algorithm adaptation to nearfield is shown. The last of the presented properties are possibilities of the directions of arrival choice.

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Stationary sonar for shallow water

Elminowicz A., Porosińska E., Kotłowski A.

Hydroacoustics

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2001

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Vol. 4

61--64

EN

The aim of the paper is checking possibility of building active stationary sonar designed for work in very shallow water, depth 8 - 10 m. Sonar is designed for monitoring very weak and moving targets by TS about -20 dB at the range up to few hundred metres. This paper presents construction of wide-sector sonar consists of two linear transducers. Beampatterns of the transducers are adjusted to conditions existing in very shallow water, particularly to minimize bottom and surface reverberation and effect of multipath propagation. Below are presented results of tests and measurements made for different types of targets and different environmental conditions - including: state of the sea, strong aeration of the near surface water, and influence of different sound propagation conditions for detection of the targets. The paper contains results of influence few types of signal processing for improvement SNR, thus increasing probability of the targets detection.