Best I used were older Vectronix PLRF series, but pretty hard to find and extremely expensive.
Better units will have a gating feature where you can set them up to ignore the closest or furthest reflections. Ignore furthest setting is good for close up targets with further background that may give bad reading. Second setting (ignore close) is great when you are ranging through brush and want to ignore branches, etc. Also works a little better in fog or rain, but still limited.