Sea Wind Measurement from Power Waveforms of GNSS-R Delay Signals of Beidou GEO Satellite

T205 remote sensing of global navigation satellite system is an important technical tool to retrieve information from earth's surface. By this time, this technique has achieved more advancement for sea state monitoring, especially for sea wind measurement, sea wave height measurement, sea roughness measurement and so on. In this paper, this technique is proposed to retrieve information from water surface. In order to estimate sea wind speed from GNSS delay signals, it is mainly generated the power waveforms of direct and reflected signals of Beidou GEO satellite. It's observed that the pattern (amplitude & shape) & characteristics of these power waveforms are clearly different for different sea weather conditions, which indicates that there is a direct relationship between amplitude of the waveforms and sea wind conditions. It is utilized the Z-V scattering model and Tanos Elfouhaily wave spectrum model to generate the waveforms of reflected signals. It is also collected the real wind speed of the experiment site for same time of GNSS-R data collection. Then linear regression method is used to fit the amplitude of power waveforms with real wind speed and the sea wind is estimated. The estimated wind speeds are matched closely with real wind speed and model waveforms and real data waveforms have performed a good matching each other.