from Wiktionary, Creative Commons Attribution/Share-Alike License.
- initialism military anti-tank guided missile
Sorry, no etymologies found.
And SOF can also employ heavy weapons (Mortars, HMG and perhaps ATGW, Stingers won't last without batteries and coolant).
It seems like an eminently sensible idea, unlike most SACLOS weapons where you have to be located at the launch point with a big cloud of dust and smoke like a neon sign saying "ATGW launch here!