Publication Date
2012
Document Type
Thesis
Committee Members
Mike Bryant (Committee Member), Fred Garber (Committee Member), Brian Rigling (Advisor)
Degree Name
Master of Science in Engineering (MSEgr)
Abstract
The Polar Format Algorithm (PFA) is an often used algorithm to image synthetic aperture radar (SAR) phase history data. The algorithm relies on a far-field approximation wherein the curved wavefront of the transmitted pulses is approximated as a planar wavefront, introducing spatially variant phase errors in the phase history. While allowing for faster image formation compared to more exact imaging algorithms such as convolution backprojection, these phase errors lead to the distortion and defocus of point targets, degrading the quality of the resulting imaged scene.
Historically, a Taylor expansion has been used to approximate the phase errors leading to distortion and defocus based on the dominant second-order approximation to a differential range expression. This thesis extends the previous study of these errors for broadside imaging scenarios to squinted imaging scenarios. The complications of the squinted geometry requires an additional Taylor expansion process to approximate linear and quadratic terms of the approximated phase error, yielding the distortion and defocus approximations respectively. These approximations are calculated based on both the conventional dominant polynomial error (DPE) described above and the true differential range error (DRE). The accuracy of these approximations is demonstrated, after which a bounding process is used to yield the scene size limits.
Page Count
142
Department or Program
Department of Electrical Engineering
Year Degree Awarded
2012
Copyright
Copyright 2012, all rights reserved. This open access ETD is published by Wright State University and OhioLINK.
