Global topography of the Moon by means of a nadir looking interferometric synthetic aperture radar altimeter

A nadir looking radar altimeter, capable to operate coherently in both along track and cross track directions by means of Doppler beam sharpening (DBS) and small baseline nadir interferometry techniques, has being studied as a candidate instrument for a small satellite lunar topographic mission, aimed to cover the whole lunar surface in less than one year from a circular polar orbit of 100-200 km. Performance calculations indicate that the resulting instrument should be able to extract the three-dimensional profile of the observed surface with medium horizontal resolution (few hundreds meters) and high vertical resolution (few meters)