If you're familiar with Greek myths and legends, you'll know that 'Aegis' means 'shield.' AWS is the ultimate water-based defense system. It's not a singular device; it's a control methodology used to guide weapons, and also remotely issue instructions to them.
The latest computer and radar technology combines within AWS to pick up on threats at the earliest possible moment, and mobilize a means to neutralize the threat - and then target and destroy whatever the threat came from.