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Detection of direct-sequence spread-spectrum signals in a multipath fading environment
Title
Detection of direct-sequence spread-spectrum signals in a multipath fading environment.
Creator
Jodoin, Claude., Florida Atlantic University, Aalo, Valentine A.
Abstract/Description
In this thesis, we study the effect of Rice fading on the performance of Global Positioning System (GPS) receivers. The field-theoretic foundation of pseudo-random-noise (PRN) codes, their implementation, and their use in generating unique navigation messages in the GPS receiver is reviewed. The processing of the spread-spectrum signals within the digital delay locked loop (DDLL) in the receiver is also considered. In particular, we derive numerical expressions that can be easily evaluated...
Show moreIn this thesis, we study the effect of Rice fading on the performance of Global Positioning System (GPS) receivers. The field-theoretic foundation of pseudo-random-noise (PRN) codes, their implementation, and their use in generating unique navigation messages in the GPS receiver is reviewed. The processing of the spread-spectrum signals within the digital delay locked loop (DDLL) in the receiver is also considered. In particular, we derive numerical expressions that can be easily evaluated for the probability error and the mean-time to lose-lock, for a DDL operating in an additive white gaussian noise (AWGN) channel in the presence of Rice fading. The results obtained generalize results in the literature for the Rayleigh fading environment.
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Date Issued
1999
PURL
http://purl.flvc.org/fcla/dt/15712
Subject Headings
Global Positioning System, Radio--Transmitters and transmission--Fading, Spread spectrum communications
Format
Document (PDF)
Imaging through ground-level turbulence by fourier telescopy: simulations and preliminary experiments
Title
Imaging through ground-level turbulence by fourier telescopy: simulations and preliminary experiments.
Creator
Randunu-Pathirannehelage, Nishantha, Rhodes, William T., Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
Fourier telescopy imaging is a recently-developed imaging method that relies on active structured-light illumination of the object. Reflected/scattered light is measured by a large “light bucket” detector; processing of the detected signal yields the magnitude and phase of spatial frequency components of the object reflectance or transmittance function. An inverse Fourier transform results in the image. In 2012 a novel method, known as time-average Fourier telescopy (TAFT), was introduced by...
Show moreFourier telescopy imaging is a recently-developed imaging method that relies on active structured-light illumination of the object. Reflected/scattered light is measured by a large “light bucket” detector; processing of the detected signal yields the magnitude and phase of spatial frequency components of the object reflectance or transmittance function. An inverse Fourier transform results in the image. In 2012 a novel method, known as time-average Fourier telescopy (TAFT), was introduced by William T. Rhodes as a means for diffraction-limited imaging through ground-level atmospheric turbulence. This method, which can be applied to long horizontal-path terrestrial imaging, addresses a need that is not solved by the adaptive optics methods being used in astronomical imaging. Field-experiment verification of the TAFT concept requires instrumentation that is not available at Florida Atlantic University. The objective of this doctoral research program is thus to demonstrate, in the absence of full-scale experimentation, the feasibility of time-average Fourier telescopy through (a) the design, construction, and testing of smallscale laboratory instrumentation capable of exploring basic Fourier telescopy datagathering operations, and (b) the development of MATLAB-based software capable of demonstrating the effect of kilometer-scale passage of laser beams through ground-level turbulence in a numerical simulation of TAFT.
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Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FA00004401, http://purl.flvc.org/fau/fd/FA00004401
Subject Headings
Fourier analysis, Fourier integral operators, Interconnects (Integrated circuit technology), Remote sensing, Spread spectrum communications, Wireless sensor networks
Format
Document (PDF)
Transmitter-receiver system for time average fourier telescopy
Title
Transmitter-receiver system for time average fourier telescopy.
Creator
Pava, Diego F., Rhodes, William T., Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
Time Average Fourier Telescopy (TAFT) has been proposed as a means for obtaining high-resolution, diffraction-limited images over large distances through ground-level horizontal-path atmospheric turbulence. Image data is collected in the spatial-frequency, or Fourier, domain by means of Fourier Telescopy; an inverse two dimensional Fourier transform yields the actual image. TAFT requires active illumination of the distant object by moving interference fringe patterns. Light reflected from the...
Show moreTime Average Fourier Telescopy (TAFT) has been proposed as a means for obtaining high-resolution, diffraction-limited images over large distances through ground-level horizontal-path atmospheric turbulence. Image data is collected in the spatial-frequency, or Fourier, domain by means of Fourier Telescopy; an inverse two dimensional Fourier transform yields the actual image. TAFT requires active illumination of the distant object by moving interference fringe patterns. Light reflected from the object is collected by a “light-bucket” detector, and the resulting electrical signal is digitized and subjected to a series of signal processing operations, including an all-critical averaging of the amplitude and phase of a number of narrow-band signals.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00004314
Subject Headings
Digital communications, Fourier analysis, Fourier integral operators, Interconnects (Integrated circuit technology), Radio -- Transmitter receivers -- Design and construction, Spread spectrum communications, Wireless sensor networks
Format
Document (PDF)