Wetland mapping and measurement of flood inundated area using ground-reflected GNSS signals in a bistatic radar system

Global Navigation Satellite System (GNSS) signals can be used as a kind of bistatic radar, with receivers opportunistically recording ground-reflected signals transmitted by the GNSS satellites themselves. The ground-reflected signals are sensitive to changes in surface permittivity, which for L-band is primarily a function of the moisture content of the surface. Here, we investigate the ability of GNSS signals, as recorded by a GPS receiver flown on a satellite, to measure changes in wetland extent and flood inundated area. We find that the ground-reflected signals give similar results as flood-inundation maps derived from other sources. Reflected power increases of over 10 dB in the vicinity of wetlands indicates that these signals could successfully map changes in wetlands around the globe.