On deriving near-surface wind vector information from GPS ocean reflections: simulation and measurements

The power received by a GPS receiver located on an airplane flying over the ocean and collecting the GPS signal reflected off the surface is estimated for varying wind speed and wind direction, platform altitude, satellite elevation angle, and receiver integration time. By accounting for the wind-induced anisotropy on the surface, it is shown that the trailing edges of computed waveforms change with both wind speed and direction. Different wind directions cause substantial differences in the waveforms, particularly for reflections from low-elevation satellites. While this feature allows the retrieval of both modulus and direction it also creates an ambiguity if one tries to solve for modulus only, while neglecting direction.