How will the US detect China's attack in the Pacific? [ANALYSIS]

There are respective ways to build an early informing strategy against the attack of low-flying missiles and aircraft. The simplest involves the usage of radiolocation and electronic surveillance aircraft (AWACS class), thereby “moving” the radiolocation horizon further (resulting from the curvature of the Earth). However, this mode of operation is besides very expensive, as it forces the full fleet of aircraft to be constantly patrolled. And this for a long time and on a large watershed is simply not possible.