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Waveform Design for Interference Mitigation in SAR Imaging and Sparse Image Recovery

Keyhani, Erfan | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55542 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Karbasi, Mohammad
  7. Abstract:
  8. In this research, we design a compatible waveform for the purpose of high-quality synthetic aperture radar (SAR) imaging in conjunction with sparse recovery methods for image formation. The goal is to make the imaging system tolerable against the wide-band and narrowband electromagnetic interferences. Actually, we consider minimizing the mutual interference between our radar and coexisting licensed emitters and minimizing the jamming signal (unlicensed emitters) power while enforcing some constraints over the waveform features like peak-to-average-power ratio (PAPR). For the constrained optimization problem to design a proper waveform, we introduce a new constraint to the optimization problem and show its effectiveness in some aspects. This constraint implicitly controls the integrated side lobes level (ISL) of the waveform and has some necessity requirement for the formulation of the CS problem. In addition, the optimization problem with this constraint results in a better waveform solution in terms of the objective function value and the constraints of the problem compared to other waveform design problem in this category. On the other hand, by nulling some frequency bands in the optimized waveform due to the interference sources (licensed or unlicensed), our sampled data in the frequency domain, which makes the phase history data for SAR imagery, becomes random in some sense. These randomly sampled data of the phase history encourages us to use the compressive sensing (CS) based methods for image formation. The high quality of the formed image via CS-based method comes at the cost of high computational effort. To reduce the inherent complexity of the CS-based method, we try to make the interpolation part in each iteration of the algorithm faster by using the Farrow filter concept. The simulation results show the effectiveness of the waveform design method on the final image quality in the presence of interference
  9. Keywords:
  10. Waveform Design ; Compressive Sensing ; Interference ; Optimization Problems ; Alternating Direction Method of Multipliers (ADMM)Algorithm ; Synthetic Aperture Radar (SAR) ; Synthetic Aperture Imaging

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