The target is usually acquired and tracked on radar first. Getting visual ID before firing the missile is a different story. In Iraq '91 they required IFF trans

The target is usually acquired and tracked on radar first. Getting visual ID before firing the missile is a different story. In Iraq '91 they required IFF transponder status to confirm a target as hostile which isn't always reliable. By 2003, the USAF made extensive use of E-3 AWACS and fighters required clearance from Joint Air Operations Center before engaging a target. The E-3 would vector the fighters for an intercept so it wouldn't start visually.