Date of Award

6-1994

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Electrical and Computer Engineering

First Advisor

Byron M. Welsh, PhD

Abstract

This dissertation presents a new model for computing the angle dependent performance measures of an adaptive-optics system. By incorporating diffraction caused by the index-of-refraction variations of the atmosphere, the phase and amplitude fluctuations of the propagating wave are computed. New theory is presented, that uses the diffraction-based propagation model to yield optical transfer function (OTF) expressions that are more accurate as compared to current theory that neglects diffraction. An evaluation method for calculating the OTF is presented that utilizes a layered atmospheric model and normalized OTF expressions. The diffraction model is also used to present the first OTF signal-to-noise ratio (SNR) expressions that are a function of separation angle between the beacon and the object in an adaptive-optics system. An evaluation method for the SNR is presented that utilizes normalized correlation functions which are valid over a wide range of atmospheric conditions and correction geometries. An analysis of the angle dependency of the point spread function (PSF) is presented using the derived OTF expression. The diffraction model is then used to develop a new adaptive-optics wavefront correction algorithm that results in an extended correctable field-of-view (FOV) as compared to current correction algorithms.

AFIT Designator

AFIT-DS-ENG-94J-05

DTIC Accession Number

ADA280491

Comments

The author's Vita page is omitted.

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