[thworp]

What would that even be? Sonar would be most likely, but there is very little reason for secrecy there, since all the innovation is in the signal analysis not the signal itself.

Could be communication but why would you use a medium as terrible and lossy as sound in water?

[Traubenfuchs]

Applying the troll's razor: Maybe it's just large scale trolling, nothing less, nothing more.

[hoseja]

Why couldn't there be innovation in the signal?