Ocean Wind Speed Estimation From the GNSS Scattered Power Function Volume

A model-based procedure for ocean wind speed estimation using global navigation satellite system reflectometry is presented. The method is based on the least-squares matching between the measured scattered power function volume and the volume of the Zavorotny–Voronovich wind-dependent scattered power model. Geometric terms depending on the orbit path as well as the antenna pattern and known propagation losses are considered in the model. Error sources are investigated, and their impact on wind speed estimates is evaluated and minimized. The performance of the proposed algorithm is assessed by simulating delay–Doppler maps in a realistic ocean scattering scenario with Cyclone Global Navigation Satellite System (CYGNSS) observatories, whereas the validation of the algorithm is carried out by comparisons of retrievals from real delay–Doppler maps collected by the space CYGNSS observatories and ground truth data processed within the collaborative NASA CYGNSS Science Team.