Doppler analysis of GPS reflections from the ocean surface

The basic physics that governs the scattering of GPS signals from a wind-roughened sea surface (both delay and Doppler characteristics) is reviewed. We then describe the results of recent experimental campaigns in which reflected GPS signals have been recorded in the vicinity of coastal buoys or research vessels where independent in situ measurements were available. Comparisons between the measured and predicted Doppler spectra at both left- and right-hand circular polarization are presented and discussed. These polarization differences in the Doppler characteristics could lead to a more robust estimation of various geophysical parameters related to sea-surface roughness.