Digital Doppler Centroid Anomaly (DDCA): A Novel Ocean Surface Velocity Retrieval Estimator for Harmony

Abstract:
Harmony is the 10th Earth Explorer Mission focused on the observation of land deformations and ocean dynamics. The design of the instrument allows measuring ocean currents either with Along-Track Interferometry (ATI) or Digital Centroid Anomaly (DCA) techniques. Thanks to the parallel acquisition of three phase centres digital beam-forming (DBF) techniques can be considered on-ground. They not only use range-dependent azimuth DBF but also Doppler-dependent combinations that allow for tailored beam-forming techniques enabling shaping the received SAR data spectrum. By proper phase centre weighting spectrum narrowing can be accomplished, which in turn improves the DCA retrievals for some of the Sentinel-1 subswaths.