The military wants to develop alternatives to Global Positioning Systems (GPS) for positioning, navigation and timing (PNT). As useful as GPS is, it is not always reliable, or even available, in many places where the military has to operate, according to a report in C4ISR & Networks.
GPS turns up in many different settings, from navigation systems built into smart phones to guidance systems for missiles. It's very ubiquity, however, is another thing that limits is usefulness. Adversaries can easily block GPS access by jamming, spoofing and other GPS-denial threats.
Atomic clocks, platform distribution PNT and inertial navigation systems are among the alternative technologies the military is considering.
The Defense Department is one of the leading government components involved in GPS and navigation, but the civilian side of government has a major role as well. The Transportation Department co-chairs the National Executive Committee for Space-Based Positioning, Navigation, and Timing, and operates the Wide Area Augmentation System to support aviation safety. NASA operates the Global Differential GPS System and leads technology development for space-related uses of PNT. The Agriculture, State, Interior and Commerce departments all also have a significant stake in the technology.
The civilian side of government is also concerned about GPS vulnerabilities. The Transportation Department, for example, recently opened a public comment period on the use of an enhanced Long Range Navigation (eLoran) system as a complement to GPS, partly "to reduce or prevent operational and/or economic consequences from a GPS disruption."