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Institution

Swedish Defence Research Agency

GovernmentStockholm, Sweden
About: Swedish Defence Research Agency is a government organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Radar & Synthetic aperture radar. The organization has 1413 authors who have published 2731 publications receiving 56083 citations. The organization is also known as: Totalförsvarets forskningsinstitut.


Papers
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Proceedings ArticleDOI
05 Oct 2006
TL;DR: The field trials show that images can be acquired at significantly longer distances with the gated camera, compared to a conventional video camera, and examples of image processing of the range-gated images, which increases the image quality significantly.
Abstract: In this work we evaluate the imaging performance of a range-gated underwater system in natural waters. Trials have been performed in both turbid and clear water. The field trials show that images can be acquired at significantly longer distances with the gated camera, compared to a conventional video camera. The distance where a target can be detected is increased by a factor of 2. For images suitable for object identification, the range improvement factor is typically 1.5. We also show examples of image processing of the range-gated images, which increases the image quality significantly.

18 citations

Proceedings ArticleDOI
13 Oct 2005
TL;DR: In this paper, phase screens are used to model laser beam propagation over land and sea, and a generic example describing laser countermeasure against an infrared homing missile in a naval scenario is presented.
Abstract: Understanding and predicting laser beam propagation effects in the atmosphere is of importance for laser countermeasures and related applications. Turbulence effects cause beam wander, beam broadening and intensity scintillations reducing e.g. the power in bucket and the tracking accuracy. Modelling laser beam propagation in turbulence using successive phase screens provides an efficient tool for performance predictions. In this work phase screens are used to model laser beam propagation over land and sea. Different phase screens generators utilising the Kolmogorov or von Karman spectra were considered. Critical parameters using phase screens include the number of screen applied along the propagation path, inner- and outer scale size, variations in the structure parameter and spatial frequencies. Effects such as beam wander, angle-of-arrival fluctuations and intensity scintillations are discussed. The simulated results are compared with experimental data recorded at different ranges, various turbulence strengths and for single- and double paths. A generic example describing laser countermeasure against an infrared homing missile in a naval scenario is presented.

18 citations

Journal ArticleDOI
TL;DR: In this article, the solar wind impacting on the magnetopause, i.e., the boundary between solar wind and the Earth's magnetosphere, can penetrate the magnetosphere.
Abstract: Plasma structures, here typified by the term 'plasmoids', in the solar wind impacting on the magnetopause, i. e. the boundary between the solar wind and the Earth's magnetosphere, can penetrate thi ...

18 citations

Book ChapterDOI
02 Jun 2008
TL;DR: In this paper, a bistatic ultra-wideband VHF-band SAR experiment was conducted in Switzerland with the ground-based receiver located on Mount Niesen in Berner Oberland.
Abstract: We describe a bistatic ultra-wideband VHF-band SAR experiment and present measurement results. The bistatic SAR system, operating in the band 28-73 MHz, is based on CARABAS-II as airborne transmitter and LORA as ground-based receiver. Monostatic SAR data can also be acquired simultaneously. In September 2007, a measurement campaign was conducted in Switzerland with the ground-based receiver located on Mount Niesen in Berner Oberland. The objective was to investigate the hypothesis that the bistatic signal-to-clutter ratio for a vehicle in a background of forested terrain or urban environment increases as the bistatic elevation angle increases. Both mono- and bistatic SAR images have been formed using backprojection techniques. Images with bistatic elevation angle of 4deg (quasi-monostatic case) show similar characteristics as the monostatic images. The images with bistatic elevation angle of 10deg and 20deg, however, indicate that the clutter level decreases over both forested and urban areas. Measurements show that the signal-to-clutter ratio for a truck vehicle in a forest background increases by up to 10 dB compared with the quasi-monostatic case. The corresponding increase in signal-to-clutter ratio for an urban background is 2-8 dB, with the higher value obtained for multi-level buildings. These observations indicate that target detection can be significantly improved by using bistatic VHF-band SAR geometries.

18 citations

Journal ArticleDOI
TL;DR: In this paper, a novel approach to computational almost inextensible transversely isotropic and nearly incompressible finite hyperelastic fiber mechanics is introduced which relies on using an equivalent generalised right Cauchy-Green stretch tensor which is volume preserving and simply-stretch free in the limit of incompressibility and inextensibility.

18 citations


Authors

Showing all 1417 results

NameH-indexPapersCitations
Anders Larsson80130733995
Anders Johansson7553821709
Anders Eriksson6867919487
Dan S. Henningson6636919038
Bengt Johansson6663519206
Anders Sjöstedt6319611422
Björn Johansson6263716030
Mats Gustafsson6152018574
D. G. Joakim Larsson5815113687
Anders Larsson5419855761
Mats Tysklind5325017534
Jerker Fick511438787
Erik Johansson501149437
Göran Finnveden4919312663
Ian A. Nicholls451947522
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20232
20228
202163
202074
2019102
201894