High precision inversion of sea surface wind speed based on the data of BF-1 satellite

Global Navigation Satellite System reflectometry (GNSS-R) technology uses the signal receiver to receive the reflected signal of navigation satellite for ground feature inversion. It has the advantages of wide dynamic range, all day, all weather, light weight and low cost. It has a broad application prospect in the field of remote sensing. On June 5, 2019, China's first group of test satellites carrying GNSS-R payload, BF-1 A/B satellites, was successfully launched on the sea by using CZ-11 carrier rocket. GNSS-R data with high spatial and temporal resolution were obtained during the operation of the satellite in orbit. In order to solve the problem of low accuracy and few methods of GNSS-R inversion of sea surface wind speed, this paper proposes a sea surface wind speed inversion method based on the delay doppler map average (DDMA) of BF-1 satellite. Firstly, the GNSS-R sea surface scattering model is established by using Z-V model and Elfouhaily wave spectrum to verify the relationship between the observation of BF-1 satellite and the change of wind speed, Then, the principle of GNSS-R sea surface wind speed inversion is studied. Through the correction and normalization of observations, the inversion observation DDMA is obtained. Finally, the geophysical model function (GMF) is established by using L1 level satellite data to realize the high-precision inversion of sea surface wind speed. The root mean square (RMS) accuracy of wind speed inversion is 1.81m/s, which is slightly higher than that of CYGNSS when compared with that of CYGNSS at the same time. The experimental results show that the inversion trend of the same region and time is the same, which proves the accuracy and effectiveness of the data processing results, it will also provide support for the follow-up GNSS-R satellite development and the development and optimization of surface wind speed inversion algorithm.