Search for dissertations about: "Underwater acoustics"

Showing result 1 - 5 of 11 swedish dissertations containing the words Underwater acoustics.

2. 1. Physical modelling of acoustic shallow-water communication channels

   Author : Elin Svensson; Ilkka Karasalo; Finn Jensen; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; underwater acoustics; hydroacoustics; time variability; ray tracing; Gaussian beam summation; sound propagation models; shallow water; waveguides; caustics; underwater communication; undervattensakustik; hydroakustik; tidsvariabilitet; strålgång; gaussisk strålsummation; ljudutbredningsmodeller; grunt vatten; vågledare; kaustikor; undervattenskommunikation; Acoustics; Akustik;

   Abstract : Akustiska kanaler för undervattenskommunikation är flervägskanaler där ljudet reflekteras från havets yta och botten och bryts vid ljudhastighetsförändringar. I grunt vatten är impulssvaret långt jämfört med symbolernas tidslängd i ett utskickat meddelande. READ MORE

4. 2. Underwater Positioning

   Author : Patric Jansson; Lars Sjöberg; KTH; []
   Keywords : ;

   Abstract : The project underwater positioning was initiated by the Swedish National Road Administration (SNRA) in 1990. The aim of the project is to study positioning techniques and methods which can be used to position and locate man-made structures and features, especially engineering structures, piles for the foundation*laying of bridge pillars, in shallow water. READ MORE

5. 3. A Novel Signal Model and Estimation Method for Acoustic Doppler Current Meters

   Author : Thomas L Lagö; Teknisk akustik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Doppler Profiler; Acoustic Doppler; Gaussian Backscattering Model; ADCM; ADCP; The Symmiktos Method; Estimation; Doppler; Current; MPCA.; Technological sciences; Teknik; Electromagnetism; optics; acoustics; Elektromagnetism; optik; akustik;

   Abstract : This thesis deals with the process of estimating underwater current from the backscattering signal transmitted from an ultrasonic transducer. The narrowband sinusoidal burst signal is Doppler-shifted due to the current, and this information is converted into current. READ MORE

6. 4. Homogeneous models of anechoic rubber coatings

   Author : Alex Cederholm; KTH; []
   Keywords : underwater acoustics anechoic reflection transmission ambient pressure genetic algorithm; inversion; underwater acoustics; anechoic; reflection; transmission; ambient pressure; genetic algorithm;

   Abstract : .... READ MORE

7. 5. Design and implementation of a programmable, wideband sonar for sediment mapping

   Author : Peter Jonsson; Teknisk geologi; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; centroid; programmable sonar; sediment mapping; underwater acoustics; hydroacoustics; echosounder;

   Abstract : To be able to explore different signal types and processing techniques, apt for sediment mapping, programmable, fully digital profiling systems has been built and tested. The systema are designed to be deployed also at small water depths from small boats, without special handling equipment. READ MORE