A Synthetic Bandwidth Method for High-Resolution SAR Based on PGA in the Range Dimension

Area of Science:

• Remote Sensing
• Signal Processing
• Radar Systems

Background:

• Synthetic Aperture Radar (SAR) systems utilize synthetic bandwidth techniques for ultra-high range resolution.
• Implementing these techniques faces challenges in estimating and compensating for system errors like timing deviations and amplitude-phase errors.
• Combining sub-band signals into a wider bandwidth is also a significant hurdle.

Purpose of the Study:

• To present a novel synthetic bandwidth approach for SAR systems.
• To address the challenges of system error compensation and sub-band signal combination.
• To improve the accuracy and efficiency of achieving ultra-high range resolution in SAR imaging.

Main Methods:

• A two-order Phase Gradient Auto-Focus (PGA)-based method, termed TRPGA, is proposed to compensate for two main errors in multi-sub-band SAR systems.
• An improved frequency-domain cut-paste method is introduced for combining sub-band signals.
• The approach leverages error redundancy and requires limited azimuth data for estimation, avoiding up-sampling.

Main Results:

• The proposed TRPGA method effectively compensates for system errors in multi-sub-band SAR.
• The improved cut-paste method successfully combines sub-band signals without up-sampling.
• Validation through imaging results from both simulated and real SAR data confirms the approach's efficacy.

Conclusions:

• The novel synthetic bandwidth approach offers an effective solution for ultra-high range resolution SAR imaging.
• The TRPGA method and improved cut-paste technique overcome key implementation challenges.
• The presented method demonstrates robust performance with simulated and real-world SAR data.