I gotcha. After finding the links to the lectures I found more info.
I was reading earlier in the thread and some comments about looking at rain out to a km or so were made.
Also this isn't doppler per se but a SAR unit, from what I can glean. You have to move it linearly and let the algorithm (not well discussed) do the work.
Cool idea, though.
I do have an old aircraft radar that was working when the guy replaced it in his plane from years ago However the wiring harness was sacrificed and to put the effort into getting it up and running now seems beyond my abilities, although when I bought it I thought it would be a snap, just wire up a bunch of those round Army connectors and bolt the waveguide on and voila! I'm sure I'd have a hard time getting a license for that baby, too.