Ionospheric Phase Compensation for InSAR Measurements Based on the Faraday Rotation Inversion Method

Area of Science:

• Geophysics
• Atmospheric Science
• Remote Sensing

Background:

• Ionospheric errors significantly impact Synthetic Aperture Radar (SAR) signals, especially at L-band and lower frequencies.
• These distortions degrade the precision of interferometric measurements by mixing with terrain and deformation signals.
• Detecting small-scale ionospheric structures is challenging due to rapid changes, complicating phase compensation in Interferometric SAR (InSAR).

Purpose of the Study:

• To present a Faraday rotation (FR) inversion method for compensating ionospheric errors in SAR interferograms.
• To develop a procedure for detecting variations in small-scale ionospheric disturbances.
• To improve the accuracy of InSAR measurements affected by ionospheric phase distortions.

Main Methods:

• Retrieving absolute total electron content (TEC) using FR estimation.
• Correcting ionospheric errors in InSAR by converting differential TEC into ionospheric phase.
• Testing the method with Phased Array L-band Synthetic Aperture Radar (PALSAR) full-polarimetric SAR images in high latitude and equatorial regions.

Main Results:

• The proposed FR inversion method effectively compensates for ionospheric phase distortions in SAR interferograms.
• The method demonstrates robustness in high latitude and equatorial regions prone to ionospheric disturbances.
• Comparison with the split-spectrum method and Global Ionosphere Maps (GIM) validates the accuracy of TEC retrieval and disturbance detection.

Conclusions:

• The developed procedure offers a robust solution for correcting ionospheric errors in SAR interferometry.
• This method serves as a powerful tool for measuring and analyzing small-scale ionospheric structures.
• The findings enhance the reliability and precision of InSAR applications in geophysics and atmospheric studies.