GNSS reflectometry

Using GNSS -R ( for eng. Global navigation satellite system and Reflectometry) can be the nature of reflective surfaces (eg water, soil, snow), determined by applying the multipath reception of the signal of a satellite navigation is evaluated.

If a GPS satellite at the horizon, the receiver sees both the direct signal and the delayed signal that is mirrored on a water surface at grazing incidence. Since the position of the satellite is known with high accuracy is obtained by the propagation delay of a phase shift of the satellite coherent signal in response to the relative water level. The speckles of the signal allow conclusions about the roughness and the movements of the water surface.

Aircraft or satellite- borne receivers widen the angle of reception of GNSS satellites.