Geometry-Driven Phase Error Estimation for Azimuth Multi-Channel SAR via Global Radar Landmark Control Point Library.

Area of Science:

• Geophysics
• Remote Sensing Technology
• Signal Processing

Background:

• Azimuth multi-channel synthetic aperture radar (SAR) is crucial for high-resolution wide-swath (HRWS) imaging.
• Inter-channel phase inconsistency in SAR systems leads to significant image distortions, impacting data usability.
• Current phase error estimation methods suffer from scene dependency, manual intervention, and performance degradation in complex environments.

Purpose of the Study:

• To develop a robust and automated framework for estimating inter-channel phase errors in multi-channel SAR systems.
• To overcome the limitations of existing methods, particularly in complex terrain scenarios.
• To enhance the accuracy and stability of SAR imaging for advanced applications.

Main Methods:

• A geometry-driven framework utilizing a Global Radar Landmark Control Point Library (GRL-CP) for phase error estimation.
• Automatic control point activation based on predicted echo positions using a range-Doppler geometric model, eliminating scene-dependent target selection.
• Frequency-domain correlation scheme applied to activated radar landmarks for phase error estimation.

Main Results:

• The proposed Global Radar Landmark Control Point (GRL-CP) framework enables fully automatic and reliable control point activation.
• Demonstrated improved stability and accuracy in inter-channel phase error estimation, even in complex terrain.
• Experimental validation on multi-channel spaceborne SAR datasets confirmed the method's effectiveness.

Conclusions:

• The geometry-driven approach offers a significant advancement over traditional methods for SAR phase error estimation.
• The GRL-CP framework provides a reliable and autonomous solution for enhancing SAR image quality.
• This method is vital for improving the reliability of HRWS SAR imaging in diverse geographical conditions.