Temat: LFM - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Methods of Achieving Good GPR Image Resolution Using Focused SAR Processing
Autorzy:: Zych, M.
Powiązania:: https://bibliotekanauki.pl/articles/226575.pdf
Data publikacji:: 2011
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: GRP
LFM
multilook
mismatch shift
Opis:: The paper describes the simulation and measurement results for a ground penetrating SAR radar. The main purpose of this paper is to present the complexity of the issues relating to GPR. Permittivity of the ground determination error causes the resolution deterioration of the resulting image therefore an important task of the digital signal processing is the correct estimation of the permittivity. The article presents several methods devoted to this subject. As a simulation model of SAR system the pulse radar with LFM (Linear Frequency Modulation) signal has been applied. The aim of the experiment is to test ability of the SAR system to obtain fully focused image of the underground targets. The real data measurements took place on the 6th floor at the Faculty of Electronics and Information – Warsaw University of Technology. During measurement campaign the GPR SAR demonstrator mounted on the rails wagon has been used to generate radar motion.
Źródło:: International Journal of Electronics and Telecommunications; 2011, 57, 1; 49-54
2300-1933
Pojawia się w:: International Journal of Electronics and Telecommunications
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Mutual Clutter Suppression Techniques for FM Sonars
Autorzy:: Marszal, J.
Rudnicki, M.
Jedel, A.
Salamon, R.
Kochańska, I.
Powiązania:: https://bibliotekanauki.pl/articles/176495.pdf
Data publikacji:: 2016
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: sonar
signal processing
FM
LFM
HFM
clutter
crosstalk
Opis:: The article presents methods that help in the elimination of mutual clutter as well as the consequences of two FM sounding signal sonars operating in the same body of water and frequency band. An in-depth analysis of mutual clutter was carried out. The effects of sounding signal differentiation were determined, as was the Doppler effect on mutual clutter suppression. One of the methods analysed is of particular interest in a situation in which collaborating sonars are operating in opposite frequency modulation directions. This method is effective for both linear and hyperbolic frequency modulations. A formula was derived, identifying exactly how much quantities of clutter may be lessened. The work included comprehensive computer simulations and measurements as well as tests in real-life conditions.
Źródło:: Archives of Acoustics; 2016, 41, 4; 721-729
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Countering a Self-protection Frequency-shifting Jamming against LFM Pulse Compression Radars
Autorzy:: Baher Safa Hanbali, S.
Kastantin, R.
Powiązania:: https://bibliotekanauki.pl/articles/226354.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: anti-jamming
LFM
range-Doppler coupling
frequency-shifting jammer
repeater jammer
Opis:: The well-known range-Doppler coupling property of the LFM (Linear Frequency Modulation) pulse compression radar makes it more vulnerable to repeater jammer that shifts radar signal in the frequency domain before retransmitting it back to the radar. The repeater jammer, in this case, benefits from the pulse compression processing gain of the radar receiver, and generates many false targets that appear before and after the true target. Therefore, the radar cannot distinguish between the true target and the false ones. In this paper, we present a new technique to counter frequency shifting repeater jammers. The proposed technique is based on introducing a small change in the sweep bandwidth of LFM waveform. The effectiveness of the proposed technique is justified by mathematical analysis and demonstrated by simulation.
Źródło:: International Journal of Electronics and Telecommunications; 2017, 63, 2; 145-150
2300-1933
Pojawia się w:: International Journal of Electronics and Telecommunications
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Wpływ dyskretyzacji na parametry sygnału radarowego po kompresji
Discretization process impact on compressed radar signal parameters
Autorzy:: Leśnik, C.
Kawalec, A.
Pietrasiński, J.
Powiązania:: https://bibliotekanauki.pl/articles/210687.pdf
Data publikacji:: 2006
Wydawca:: Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:: radar
kompresja impulsu
LMCz
zjawisko Dopplera
cyfrowy filtr kompresji
pulse compression
LFM
Doppler effect
digital compression filter
Opis:: W artykule przedstawiono istotę zjawiska wywołanego dyskretyzacją radarowego sygnału złożonego. Dokonano próby jakościowej oraz ilościowej oceny wpływu tego zjawiska na parametry sygnału radarowego po kompresji. Do rozważań przyjęto sygnał z liniową modulacją częstotliwości (LMCz). Badanymi parametrami sygnału były: względny poziom maksymalnego listka bocznego (PSL) oraz straty sygnału użytecznego wywołane niedopasowaniem (LPG). Rozważania zilustrowano przykładowymi wynikami badań symulacyjnych. Na podstawie uzyskanych wyników dokonano próby sformułowania wniosków praktycznych.
Modem techniques of digital signal processing are the basis of modem radar receiver systems. It causes that radar characteristics are created among others by digitization procedure including its additional products. That is why awareness concerning these products presence and their qualitative and quantitative estimation is difficult to overestimate. An example of such a product is an effect of an echo — pulse leading edge random position with relation to a nearest discrete time value determined by an AD converter sampling clock. This effect influence on signal characteristics at the output of the digital compression filter is very important. The essence of the phenomenon caused by radar chirp signal digitization is presented in the paper. To be more precise - efforts leading to qualitative and quantitative estimation of this phenomenon influence on radar signal after compression were undertaken. The LFM signal was chosen into consideration. Tested signal parameters were as follows: relative level of a peak side lobe (PSL) and echo signal loses caused by a mismatch. Considerations are illustrated by simulation test results. Practical conclusions were taken on the basis of the achieved results.
Źródło:: Biuletyn Wojskowej Akademii Technicznej; 2006, 55, 1; 77-88
1234-5865
Pojawia się w:: Biuletyn Wojskowej Akademii Technicznej
Dostawca treści:: Biblioteka Nauki

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