“…Although this technique was first developed for the measurement of sea surface parameters such as height [ 6 ] and roughness [ 7 ], other more recent studies have focused on the monitoring of land surface characteristics such as soil moisture [ 8 , 9 ], fraction of vegetation cover [ 10 , 11 ], forest biomass [ 12 , 13 ], the mapping of flooded areas [ 14 ], and the detection of snow or ice [ 15 , 16 ]. Experimental campaigns from both fixed [ 17 , 18 , 19 ], airborne [ 13 , 20 , 21 , 22 ], balloon [ 23 ] and more recently from Low Earth Orbit [ 24 ] platforms have confirmed the sensitivity of GNSS receivers to soil and biomass characteristics. In parallel to these experimental developments, progress has been made with electromagnetic bistatic models [ 25 , 26 , 27 , 28 , 29 ], improving scientific understanding of the scattering effects taking place in GNSS reflectometry.…”