Mars surface models and subsurface detection performance in MARSIS

The MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument is a multi-spectral, low. frequency, nadir looking pulse limited radar sounder and altimeter with ground penetration capability. Moreover the detection of a subsurface interface will be possible only if the following conditions are met:-the level of the subsurface reflection is higher than the noise floor-the surface/subsurface dynamic is included in the system dynamic range-the subsurface reflection is higher than the corresponding surface clutter reflection For MARSIS the noise floor has been evaluated to be about 60 dB below the fully coherent surface echo, so that an overall 60 dB dynamic range will be allowed if sidelobes and nonlinearities are controlled and reduced down to the noise level with a proper design. In this case we can assess that the penetration depth can be defined as that depth where the subsurface power is equal to the surface clutter power. In this paper the subsurface to surface clutter ratio will be evaluated, taking also into account the results related to the new fractal models of the structure of the planet's surface and in particular the new MARS surface models obtained from the MGS/MOLA data.