Estimation of Ionospheric Tec From Alos-2 Palsar-2 Split-Band Data

Ionospheric total electron content (TEC) can significantly affect the range geometric accuracy of spaceborne L-band synthetic aperture radar (SAR) data. This study aims to estimate the ionospheric TEC from single spaceborne L-band SAR data based on the concept of the split-spectrum method. We estimated the SAR-based TEC from the range misregistration between lower- and higher-range spectral split-band amplitude images acquired using the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) onboard the Advanced Land Observing Satellite-2 (ALOS-2). A comparison of the SAR-based TEC with the TEC observed by the Global Navigation Satellite System showed a linear relationship with a slope of 0.76 after correcting for offsets in the estimated value. This slope seemingly represents the ionospheric TEC ratio below the ALOS-2 orbit. Correcting the ionospheric range delay in PALSAR-2 data with the SAR-based TEC estimates improved the slant range accuracy from 2.67 m to 0.77 m.