Methods for Ultra-Wideband Radar Imaging of Low Contrast, Low Radar Cross Section Targets

• Author / Creator

  Winter, Robert

• Ultra-wideband (UWB) radar systems have been used as sensing and imaging tools for many industrial needs, and many more applications of the technology are currently under investigation. This research attempts to solve some of the issues UWB time domain synthetic aperture radar (SAR) faces in imaging applications regarding low contrast target imaging.

  First, this work investigates the near-field UWB antennas for time-domain radiation and pulse shaping in the near-field. It proposes a new technique and calibration methods to quantify the near-field effects, such as superluminal propagation of the signal on imaging. Then it uses this information to improve the image quality in SAR processing. The near-field imaging technique is validated experimentally.

  Second, a new miniaturized antenna is proposed for pulse radiation. This antenna is used to investigate the performance of time-domain and frequency-domain imaging techniques. Different metrics, such as phase center control for time-domain antenna design, are presented. The radiated pulse shape and pulse-peak velocity in different directions are characterized.

  Third, a method is presented which can augment the data from arbitrary aperture locations to improve the image quality in case of an obscure target location. This method is validated and demonstrates the ability to enhance the quality of images and readability of target features under challenging measuring scenarios.

  Fourth, a new processing technique is presented to consider the variable group velocity of the signal, in the case of a multi-layered medium, to the Global Back-Projection (GBP) algorithm. This technique is shown to produce higher-quality images. This technique is validated using experimental data. Succeeding this point, a time domain alternative to harmonic radar is presented. The technique is shown theoretically and using basic experiments. This technique shows promise to be used to find and track non-linear objects.

• Subjects / Keywords

  • Radar
  • Synthetic Aperture Radar

• Graduation date

  Spring 2024

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-8q6f-p655

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.