To protect your base it is essential that you have Security Bots (SB).  They have a large range of functionality, which their primary objective is to record what happened while you were away from base.

SB can inspect a field of view from 360 Degrees in the horizontal plane an from 0 - 90 Degrees in the vertical plane.  This corresponds to a full Hemisphere!

You could set your SB to sentinel mode and let it sweep through you base, or set it to view one area and record in various record modes.