An analysis of error in surface current mapping by an along-track interferometric FMCW SAR

Differences between surface velocity estimates from dual-beam along-track interferometric (ATI) synthetic aperture radar (SAR) and drift rate measurements by surface current drifters are presented for a tidally-driven river mouth. Using hydrodynamic and scattering models, we analyze the contributions from various sources in order to explain the observed differences. We find that the differences are largely explained by bias in the mean Doppler shift due to gravity waves. This work has relevance to improving the accuracy of implementing dual-beam ATI SAR for surface current measurements.