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Studies on carrier-free (or ultra-wideband) radar performance under clutter and stealth-target environments
Title
Studies on carrier-free (or ultra-wideband) radar performance under clutter and stealth-target environments.
Creator
Mendivil, Edwin David., Florida Atlantic University, De Groff, Dolores F., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
This thesis is concerned with the use of ultra-wideband radar detection specific to the following target and background considerations. (1) Statistical attributes of the RCS models of stealth-targets illuminated by ultra-wideband radars. (2) Analysis of radar echo signatures of low flying stealth-targets with a background of sea-clutter and illuminated by an ultra-wideband radar. (3) Analysis of impulse echoes from simple (planar) surface(s) coated with a radar absorbing material (RAM). The...
Show moreThis thesis is concerned with the use of ultra-wideband radar detection specific to the following target and background considerations. (1) Statistical attributes of the RCS models of stealth-targets illuminated by ultra-wideband radars. (2) Analysis of radar echo signatures of low flying stealth-targets with a background of sea-clutter and illuminated by an ultra-wideband radar. (3) Analysis of impulse echoes from simple (planar) surface(s) coated with a radar absorbing material (RAM). The first problem refers to the elucidation of Swerling-Marcum type classifications of RCS fluctuation(s) to characterize the stochastical aspects of the echoes from stealth-targets illuminated by an impulse from an ultra-wideband radar. In the second analysis, performance of a radar receiver configuration, using the log-likelihood function of the signal received from a stealth target flying at low altitude over the sea-surface is predicted. The third effort addressed provides analytical representations in time-domain of echoes from planar surface(s) coated with RAM's for normal incidence of ultra-wideband short pulse illumination.
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Date Issued
1996
PURL
http://purl.flvc.org/fcla/dt/15278
Subject Headings
Radar, Signal processing, Radar cross sections, Stealth aircraft
Format
Document (PDF)
Radar cross section of an open-ended rectangular waveguide cavity: A massively parallel implementation applied to high-resolution radar cross section imaging
Title
Radar cross section of an open-ended rectangular waveguide cavity: A massively parallel implementation applied to high-resolution radar cross section imaging.
Creator
Vann, Laura Dominick., Florida Atlantic University, Helmken, Henry, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
This thesis is concerned with adapting a sequential code that calculates the Radar Cross Section (RCS) of an open-ended rectangular waveguide cavity to a massively parallel computational platform. The primary motivation for doing this is to obtain wideband data over a large range of incident angles in order to generate a two-dimensional radar cross section image. Images generated from measured and computed data will be compared to evaluate program performance. The computer used in this...
Show moreThis thesis is concerned with adapting a sequential code that calculates the Radar Cross Section (RCS) of an open-ended rectangular waveguide cavity to a massively parallel computational platform. The primary motivation for doing this is to obtain wideband data over a large range of incident angles in order to generate a two-dimensional radar cross section image. Images generated from measured and computed data will be compared to evaluate program performance. The computer used in this implementation is a MasPar MP-1 single instruction, multiple data massively parallel computer consisting of 4,096 processors arranged in a two-dimensional mesh. The algorithm uses the mode matching method of analysis to match fields over the cavity aperture to obtain an expression for the scattered far field.
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Date Issued
1993
PURL
http://purl.flvc.org/fcla/dt/14984
Subject Headings
Radar cross sections, Algorithms--Data processing, Imaging systems
Format
Document (PDF)
maximum entropy bandwidth extrapolation technique using wavelet subspaces
Title
A maximum entropy bandwidth extrapolation technique using wavelet subspaces.
Creator
Vann, Laura Dominick., Florida Atlantic University, Helmken, Henry, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
This dissertation is concerned with the development of a bandwidth extrapolation technique that performs maximum entropy estimations over wavelet subspaces. Bandwidth extrapolation techniques have been used in radar applications to improve range and cross range resolution of radar cross section (RCS) images. Comparisons are made of the performance of conventional maximum entropy estimation to maximum entropy estimation over wavelet subspaces. A least squares prediction error measure is used...
Show moreThis dissertation is concerned with the development of a bandwidth extrapolation technique that performs maximum entropy estimations over wavelet subspaces. Bandwidth extrapolation techniques have been used in radar applications to improve range and cross range resolution of radar cross section (RCS) images. Comparisons are made of the performance of conventional maximum entropy estimation to maximum entropy estimation over wavelet subspaces. A least squares prediction error measure is used to compare original measured RCS data to extrapolated data. Then a relative error is defined as the ratio of prediction error using conventional maximum entropy to prediction error using maximum entropy over wavelet subspaces. Application of the bandwidth extrapolation technique is to measured RCS data of two objects. The first object consists of two 3/8" diameter conducting spheres placed 4" apart. Measurements used are for vertical polarization and 0 degree aspect angle covering a frequency range of 8.0 to 12.3827 GHz. The second object is a 1.6 meter aluminum cone. Measurements used are for vertical polarization and 0 degree aspect angle (nose on) covering a frequency range of 4.64 to 18.00 GHz. Results are shown for extrapolate measured data plus the original data with Gaussian white noise added to noise ratios of 25 dB, 20 dB, 15 dB, and 10 dB.
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Date Issued
1997
PURL
http://purl.flvc.org/fcla/dt/12531
Subject Headings
Maximum entropy method, Wavelets (Mathematics), Radar cross sections
Format
Document (PDF)
electromagnetic code evaluation in the 100 MHz to 1000 MHz region
Title
An electromagnetic code evaluation in the 100 MHz to 1000 MHz region.
Creator
Casciato, Mark D., Florida Atlantic University, Helmken, Henry
Abstract/Description
For certain wavelength size objects, the frequency range between 100 MHz and 1000 MHz spans a transition region when using low frequency electromagnetic scattering codes based on Method of Moments (MoM) to high frequency codes based on Physical Theory of Diffraction (PTD) and ray tracing techniques. As the wavelength size of the object increased, MoM codes can require prohibitively long computational times and hence the more approximate high frequency codes become more attractive. The Ohio...
Show moreFor certain wavelength size objects, the frequency range between 100 MHz and 1000 MHz spans a transition region when using low frequency electromagnetic scattering codes based on Method of Moments (MoM) to high frequency codes based on Physical Theory of Diffraction (PTD) and ray tracing techniques. As the wavelength size of the object increased, MoM codes can require prohibitively long computational times and hence the more approximate high frequency codes become more attractive. The Ohio State Material Wire code (MATWRS) was selected as a representative MoM code for characterizing the transition region. XPATCH was selected as a representative high frequency code with ACAD used as the general modeling program. To evaluate these codes, a comparison of Radar Cross Section (RCS) predictions for simple PEC canonical shapes was made. Comparisons were made to both measured data where available and predictions generated by the McDonnell Douglas Body of Revolution (BOR) code.
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Date Issued
1995
PURL
http://purl.flvc.org/fcla/dt/15191
Subject Headings
Computer-aided design, Radar cross sections, Electromagnetic waves, Moments method (Statistics)
Format
Document (PDF)