From Popular Mechanics:
As the administration dismantles its only backup system, the Air Force looks at replacements to guard against the Pentagon's over-reliance on GPS satellites.
Last week, the Air Force's Chief of Staff, Gen. Norton Schwartz, gave voice to a chink in the U.S. military's armor, one that many know about but few like to discuss in public: Without satellites, modern militaries lose most of their edge. "It seemed critical to me that the joint force reduce its dependence on GPS (Global Positioning System)," he told attendees at a national security conference in Washington.
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My Comment: I am surprised that the military is focusing on this weakness only now. One would think that with so much of our military dependent on such technologies, backups and alternative systems would have been developed and installed (a long time ago).