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 Antarctica's thick dry snow; and/or complementing L-band radiometric observations.

► Global Navigation Satellite Systems (GNSS) signals are used to sense Polar dry-snow. ► Data are compound by direct GNSS radio-links and radio-links reflected off the snow. ► Interferences between direct and reflected signals produce spectral features. ► A scattering model off snow internal layers is developed to understand the features. ► A new holographic approach identifies the different reflecting snow internal layers.