Sea Surface Height Estimation by BDS GEO Satellite Reflectometry

GEO (Geostationary Earth Orbit) satellites are important components of BDS (BeiDou navigation satellite system), whose static characteristic ensures the long-term visibility and has special advantages in GNSS-R (global navigation satellite system reflectometry) sea surface height (SSH) measurement. In order to evaluate the ability of GEO satellite reflection in SSH estimation, we used DDMs (Delay Doppler Maps) and phase differences to perform the coastal experiment. On July 9, 2019 we conducted GNSS-R real-time ground-based sea level estimation experiment in Weihai, Shandong Province, China. By using DDMs and phase measurement of BDS B1I direct and reflected signal from GEO satellite we have got the offshore sea level height. Meanwhile we made the in-situ range measurements to verify the precision of the two kinds of SSH results. Finally, we found that the RMSE (Root Mean Square Error) of DDMs and phase altimetry is 0.82m and 0.039m respectively, which showed great potential of GEO satellite reflectometry in marine applications, especially in moving platforms.