Systems that rely on GPS are defective in their design. US military systems have never trusted GPS, since inception, because the Soviets had the ability to destroy the satellites and tinker with the RF.

US military systems are inertially guided only accepting GPS corrections within the error bounds of their extraordinarily tight inertial measurements. If the GPS is outside the error bounds, it is presumed to be compromised. There is no such thing as an intrinsically GPS-guided weapon; they are always inertially guided with GPS corrections. Modern US inertial systems are similar to GPS in terms of precision so GPS is increasingly superfluous.

As a consequence, the US military has never been significantly vulnerable to loss of GPS. Their systems were designed, from Soviet days, to assume that GPS could be compromised or lost since the Soviets had that ability. Knock out GPS and you still have to deal with ultra-precise solid-state optical gyros.

Many commercial systems take a cheap shortcut and rely on GPS but, contrary to popular mythology, US military systems never have.