An Inversion of Planetary Rough Surface Permittivity From Radar Sounder Observations

Radar sounder technologies have been implemented to investigate the surface/subsurface features, i.e. Mars layering media. One aim of these missions is to retrieve the physical properties of the surface/subsurface media, such as the dielectric permittivity, layer thickness, etc. In this letter, based on our numerical simulations of the radar sounder echoes from the cratered rough surface/subsurface media , the dielectric permittivity of the planetary surface is derived from the radar sounder echoes. It is found that the received echo at nadir direction preserves the functional dependence of the surface reflectivity. It leads to the inversion of the surface dielectric permittivity derived from the ratios of the received echo powers and the medium reflectivity. Employing a numerical calculation of the cratered rough surface based on the tangent plane approximation, the dataset of Mars digital elevation mapping (DEM) is applied to validate the derivations. Also, an inversion of the surface dielectric permittivity of the Mars surface is presented.