Characterization of dry-snow sub-structure using GNSS reflected signals

Signals of Global Navigation Satellite Systems (GNSS) bi-statically reflected off pristine dry snow in Dome-Concordia, Antarctica, were collected during an experimental campaign with the aim of investigating the potential capabilities of these signals to remotely sense dry snow areas. The data have been used to sense the sub-surface structure of the snow by means of a new holographic observable. The obtained reflected signals present interferometric patterns consistent with the coherent superposition of signals reflected in different layers of the snow sub-structure, down to a few hundred meters depth. A forward model has been developed to compare the amplitude and phase behavior of the interferences with the data. A new radio-holographic observable is also defined, to help identify the layer at which the internal reflections occur. This work represents the first step towards the potential use of a space-based GNSS-R mission for densely monitoring the depths of Antarcticaʹs thick dry snow; and/or complementing L-band radiometric observations.