The radar signature of a small projectile coming in at, say &gt;30m&#x2F;s is indeed a lot different from a running, tiny human.  What about something like a soccer ball, though? It&#x27;s a small-ish projectile, coming in quite slowly.  What about a hand grenade?<p>Hopefully they test for this stuff and have a firm idea of where they want their thresholds but, then again, sometimes bugs happen. <a href="https:&#x2F;&#x2F;www.wired.com&#x2F;2007&#x2F;10&#x2F;robot-cannon-ki&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.wired.com&#x2F;2007&#x2F;10&#x2F;robot-cannon-ki&#x2F;</a>