Sensitivity analysis of wind vector measurements from ocean reflected GPS signals

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. When the receiver integration time is properly chosen, substantial differences in the waveforms at different wind directions are exhibited even at the beginning of the trailing edge, particularly for reflections from high-elevation satellites. These differences are associated with the extent and directional properties of the scattered fields as a function of reflection angle. An analysis of the interdependence of the observational (geometric) parameters, the coherence time, and the receiver integration time is presented to suggest a suitable arrangement for enhanced measurement sensitivity to the wind direction. (C) 2003 Elsevier Inc. All rights reserved.