An Improved Extended Wavenumber Domain Imaging Algorithm for Ultra-High-Resolution Spotlight SAR

Area of Science:

• Remote Sensing
• Signal Processing
• Radar Technology

Background:

• Ultra-high-resolution synthetic aperture radar (SAR) is crucial for military and civilian applications.
• Traditional SAR imaging faces challenges like slant range model limitations, spatial velocity variations, spectral aliasing, and stop-and-go inaccuracies.
• These issues degrade the quality of high-resolution SAR imagery.

Purpose of the Study:

• To propose an improved extended wavenumber domain imaging algorithm for ultra-high-resolution SAR.
• To systematically address and mitigate imaging quality degradation caused by existing processing challenges.
• To achieve high-precision focusing in ultra-high-resolution SAR imagery.

Main Methods:

• Employs a one-step motion compensation method to correct orbital curvature errors via range-dependent envelope shift interpolation and phase correction.
• Utilizes interpolation based on modified Stolt mapping for effective range and azimuth focusing separation.
• Applies residual range cell migration correction and azimuth compression for precise focusing.

Main Results:

• The proposed algorithm effectively compensates for errors in ultra-high-resolution SAR imaging.
• Demonstrates significant improvement in imaging quality compared to traditional methods.
• Validated through both simulation and spaceborne data experiments.

Conclusions:

• The improved extended wavenumber domain imaging algorithm successfully addresses key challenges in ultra-high-resolution SAR processing.
• The method achieves high-precision focusing, enhancing the utility of SAR imagery.
• Experimental results confirm the algorithm's effectiveness and potential for practical application.