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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

A comprehensive investigation of retrodirective cross-eye jamming

Du Plessis, W.P. (Warren Paul) 12 June 2010 (has links)
Cross-eye jamming is an Electronic Attack (EA) technique that induces an angular error in the radar being jammed. The main benefit of cross-eye jamming is that it is effective against monopulse tracking radars, which are largely immune to other forms of jamming. The objective of this research is to gain a complete understanding of cross-eye jamming so that systems that might be developed in future can be properly specied. The main contribution of this work is a comprehensive mathematical and experimental study of retrodirective cross-eye jamming. The mathematical analysis considers all aspects of an isolated, single-loop, retrodirective cross-eye jamming engagement, thereby avoiding the approximations inherent in other cross-eye jamming analyses. Laboratory experiments that accurately represent reality by using the radar for both transmission and reception, and simulating a true retrodirective cross-eye jammer were performed to validate the theoretical analysis. Lastly, the relationship between the angular error induced in the radar being jammed and the matching required from a cross-eye jammer system is explored. The most important conclusion of this work is that the traditional analyses of cross- eye jamming are inaccurate for the conditions under which cross-eye jammers operate. These inaccuracies mean that the traditional analyses are overly conservative, particularly at short ranges and for high cross-eye gains, suggesting that practical cross-eye jammers can be realised more easily than is generally believed. / Thesis (PhD)--University of Pretoria, 2010. / Electrical, Electronic and Computer Engineering / unrestricted
12

VHDL modeling and simulation of a digital image synthesizer for countering ISAR

Kantemir, Ozkan 06 1900 (has links)
Approved for public release, distribution is unlimited / This thesis discusses VHDL modeling and simulation of a full custom Application Specific Integrated Circuit (ASIC) for a Digital Image Synthesizer (DIS). The DIS synthesizes the characteristic echo signature of a pre-selected target. It is mainly used against Inverse Synthetic Aperture Radars as an electronic counter measure. The VHDL description of the DIS architecture was exported from Tanner S-Edit, modified, and simulated in Aldec Active HDLTM. Simulation results were compared with C++ and Matlab simulation results for verification. Main subcomponents, a single Range Bin Processor (RBP), a cascade of 4 RBP s and a cascade of 16 RBP s were tested and verified. The overhead control circuitry, including Self Test Circuitry and Phase Extractor, was tested separately. Finally overall DIS was tested and verified using the control circuitry and a cascade of 4 RBP s together, representing the actual 512 RBP s. As a result of this research, the majority of the DIS was functionally tested and verified. / First Lieutenant, Turkish Army

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