Stealth and Detection

Some units are covert: an army made only of covert units is invisible to enemies unless a detector reveals it. Fighting or firing reveals a covert army temporarily. Covert units are tied to a domain and can only be revealed by a detector of that domain.

Covert units

Land — Ghost Infantry, Griffon
Sea — Submarine
Air — Stealth Helicopter, B2 Bomber

Detectors

Detectors scan for covert units within a detection radius, with a chance to reveal them on each scan.

Land: Scout Vehicle
Sea: Destroyer
Air: Recon Drone
All domains: AWACS (best reveal chance of any detector) and the Strategic Radar fortification