SAR Doppler Calibration and Application for Sea Ice Drift Estimation

Abstract

We propose a Doppler calibration scheme that effectively removes errors come from attitude anomaly and antenna mispointing which are generic for all SAR sensors. The resulting calibrated Doppler signal of the entire ENVISAT ASAR ScanSAR data for one repeat cycle (35 days) showed well-balanced inter-swath measurements and largely reduced uncertainty without relying on bias correction using land reference. Sea ice drift in the Fram Strait was derived using both the offset-tracking and the Doppler estimation. An intercomparison of the time-averaged velocities showed overall high consistency with RMSE of 0.15 m/s.