I was watching a show about the variety of ways that folks are trying to protect from drones, from (the somewhat silly) shooting of nets thru attempting to jam the drone's controls, such as to force a Return-to-Home or even worse, to cause the drone to fall from the sky.
Forcing Return-to-Home has advantages since the intended target could then follow the drone to find the source, for example, a government wanting to find the source of the drone to then retaliate. Causing the drone to fall from the sky is a dangerous alternative, since the drone could be carrying explosives, and this then could easily result in danger of the explosives going off unintentionally upon the drone's impact.
Those companies that are attempting the variety of ways to stop a drone attack were absolutely frustrated by drones running autonomously, since they could not jam the signals from the source (since it is running autonomously), and, if a clever autonomous flight has been programmed, simply moving swiftly and in an irregular pattern would rather easily circumvent flying nets. This is of particular importance considering an adversary could launch a fleet of drones against a target, which would be a major threat.
It occurred to me that a way to prevent a drone attack would be to instead take advantage of the newer drones' obstacle-avoidance programming - that is, if you could make the drones believe they were headed towards an obstacle, they would then attempt to go around the obstacle, in effect, keeping the drone(s) from approaching a given target.
I have not heard of a company as yet attempting to do this. This would be effectively a 'force field', blocking drones from entering a given space - not by actually keeping them from flying into the space, but rather making them believe that there is an obstacle blocking them. So, this solution is to create an artificial obstacle - and "electronic ghost" wall. If such a "ghost" wall could be create (of sufficient size and power), targets could be completely protected from autonomous drones; remote controlled drones could be handled using current 'conventional' means.
I've not heard of such a security option currently being available. I wonder if it might be worth applying for a government or private industry grant might be worth the effort to create this "ghost wall" security function to protect from autonomous drone attacks.