Raw Data-Based Motion Compensation for High-Resolution Sliding Spotlight Synthetic Aperture Radar

Area of Science:

• Remote Sensing
• Geophysics
• Signal Processing

Background:

• Accurate motion compensation is crucial for airborne synthetic aperture radar (SAR) imaging.
• High-precision inertial navigation systems (INS) are often required but may be unavailable or insufficient.
• Existing methods may not meet the demands of high-resolution sliding spotlight SAR modes.

Purpose of the Study:

• To propose a new raw data-based motion compensation approach for high-resolution sliding spotlight SAR.
• To effectively extract line-of-sight (LOS) displacements without a high-precision INS.
• To validate the proposed method using real-world airborne SAR datasets.

Main Methods:

• A range-invariant motion compensation technique utilizing raw SAR data.
• Estimation of sub-aperture radial accelerations using a weighted total least square (WTLS) method.
• Consideration of time-varying beam direction in acceleration estimation.

Main Results:

• The proposed approach effectively extracts LOS displacements.
• Successful validation using two airborne sliding spotlight C-band SAR datasets.
• Achieved high spatial resolution of approximately 0.15 m in azimuth.

Conclusions:

• The developed motion compensation method is effective for high-resolution sliding spotlight SAR.
• The approach offers a viable alternative when high-precision INS is not available.
• The method demonstrates robustness across different terrain types.