[vonmoltke]

Anna, I'm replying to myself since your posts are coming up [dead] and I can't vouch for your reply to me like I did for your top-level comment.

Yes, that is basically how it works. The system takes measurements at a series of slant ranges (called range bins) for each beam position. The returns from those range bins can be mapped to a physical location as long as the location of the receiver is known. Record enough beam positions in a line and you can map a 2D image.