Enhanced SAR Compression through Multi-Look Doppler Compensation and Auto-Focusing Technique

Area of Science:

• Remote Sensing
• Signal Processing
• Radar Imaging

Background:

• Synthetic Aperture Radar (SAR) image quality is degraded by inaccurate Doppler estimation due to factors like orbital errors.
• Doppler estimation errors cause mismatches between the azimuth-matched filter and the received signal, impacting image resolution.

Purpose of the Study:

• To develop a simple and effective compensation technique for improving SAR image quality.
• To address the challenges of Doppler estimation errors in spaceborne SAR systems.

Main Methods:

• A novel Doppler estimation method utilizing the Fractional Fourier Transform (FrFT) and cross-correlation.
• Comparing received signals with the azimuth-matched filter in the FrFT domain to adjust the Doppler centroid for optimal alignment.

Main Results:

• The proposed method significantly improves SAR image quality and resolution.
• Experimental validation using real spaceborne SAR data confirms the technique's effectiveness.
• Achieved higher correlation values and enhanced image resolution compared to conventional algorithms.

Conclusions:

• The developed Doppler estimation technique offers a robust solution for enhancing SAR image quality.
• This approach is advantageous for various remote sensing applications requiring high-resolution SAR imagery.
• The FrFT-based method provides a streamlined compensation technique for SAR image processing.