Publication Date
2023
Document Type
Thesis
Committee Members
Brian D. Rigling, Ph.D. (Advisor); Michael A. Saville, Ph.D., P.E. (Committee Member); Fred Garber, Ph.D. (Committee Member); Josh Ash, Ph.D. (Committee Member)
Degree Name
Master of Science in Electrical Engineering (MSEE)
Abstract
Calibration plays a critical role in the optimal performance of algorithms in digital beamforming arrays. Phase incoherency between elements results in poor beamforming with decreased gain and higher sidelobes, leading to a decrease in accuracy and sensitivity of measurements. A similar problem exists in performing multi-pass interferometric SAR (IFSAR) processing of SAR data stacks to generate topological maps of the scene, where phase errors translate to height errors. By treating each SAR image in the data stack like an element of a uniform linear array, this thesis explores several phase calibration techniques that can be used to calibrate digital beamforming arrays and introduces them to IFSAR processing to calibrate the SAR images. Three data-driven techniques are selected, where calibration coefficients are obtain using sources of opportunity, via a contrast-based method, and via a clutter-based method. These calibration algorithms are then demonstrated on synthetic data of a simulated scene, consisting of scatterers at different heights, and with added phase incoherency to the SAR images. Processing of the simulated data shows an improvement in height estimation of the scatterers, including an evident increase in the gain and focusing of the scatterers in the scene after calibration. Phase calibration is then introduced to the processing of measured Gotcha data, where results also show gain and focusing improvement of the scatterers. Additional research, however, will be needed to associate the height estimation of the scatterers in these results with ground truth data to ascertain an absolute height map of the scene.
Page Count
80
Department or Program
Department of Electrical Engineering
Year Degree Awarded
2023
Copyright
Copyright 2023, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.
