GPR missions on mars

Recently in order to investigate the distribution of water, liquid and solid, in the upper portions of the crust of Mars planet two different instruments are actives, the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) and SHAallow RADar (SHARAD). Both the instruments are a low frequency (1.8-5MHz for MARSIS and 20 MHz for SHARAD) Ground Penetrating Radar (GPR) in altimeter configuration which uses the synthetic aperture technique. The manly differences between the two instruments are the spatial resolution (150 m vertical resolution, 5-10 Km along track resolution for MARSIS and 15 m vertical resolution, 300-500 m along track resolution for SHARAD) and the penetrating capability ( about 5 Km for MARSIS and 1 Km for SHARAD). After the instrument data acquisition from the Martian surface an appropriate processing shall be performed in azimuth (unfocused for MARSIS and focused for SHARAD) and range dimension to produce the scientific final data. In this work will be presented an efficient procedure to detect the possible subsurface presence using the available surface topography data. After the performance evaluation of this technique an example of application will be presented on real SHARAD data