Moving Target Indication for Dual-Channel Circular SAR/GMTI Systems.

Area of Science:

• Radar Systems Engineering
• Signal Processing
• Remote Sensing

Background:

• Dual-channel circular synthetic aperture radar (CSAR) systems face challenges with yaw angles causing signal decorrelation.
• This decorrelation degrades the performance of ground moving target indication (GMTI) by affecting image pair correlation.

Purpose of the Study:

• To develop a method for removing varying group-phase shifts in dual-channel CSAR systems.
• To improve channel registration and equalization for enhanced GMTI performance.
• To effectively detect moving targets in both uniform and non-uniform clutter environments.

Main Methods:

• Deduced and analyzed the interferometric phase term based on dual-channel CSAR geometry.
• Compensated for Doppler frequency-dependent phase terms and range-dependent group-phase shifts during channel registration.
• Applied blind channel equalization, including 2D calibration and amplitude equalization.
• Combined displaced phase center antenna (DPCA) amplitude images with along-track interferometry (ATI) phase images for target detection.

Main Results:

• Successfully compensated for varying group-phase shifts caused by yaw angles.
• Achieved effective channel equalization, eliminating amplitude and residual phase differences.
• Demonstrated the capability to detect moving targets by multiplying DPCA and ATI images.
• Verified the method's effectiveness in suppressing both uniform and non-uniform clutter.

Conclusions:

• The proposed method effectively resolves group-phase shift issues in dual-channel CSAR systems.
• The technique enhances the correlation of image pairs, crucial for accurate GMTI.
• The approach enables robust moving target detection and clutter suppression in diverse conditions.