Time Warfare: Threats to GPS Aren’t Just About Navigation and Positioning

When people talk about the U.S. military’s dependence on positioning, navigation, and timing, or PNT, information, they’re usually thinking about GPS — more formally, the NAVSTAR Global Positioning System. And these days, they’re often concerned about the ways adversaries can disrupt GPS signals and thereby deny U.S. forces the positioning and navigation information that enables the “American Way of War.” But there’s another aspect of PNT that is getting short shrift: the T, for timing.

But did you realize that GPS actually only provides timing information? The positioning and navigation information that we associate with GPS is simply derived from these timing signals by receiver devices, and far more users depend on this Air Force maintained constellation for timing information alone.

According to the Department of Homeland Security, 11 of the 16 critical industries identified in Presidential Policy Directive 21 rely on precision timing. In the civilian world, these uses include communications, cellular phones, power distribution, finance, and information technology. Military capabilities that depend on precision timing include sensing, sensor fusion, datalinks, secure communications, electronic warfare, network operations, and command and control. 

Yet the U.S. military organization responsible for PNT superiority is the Joint Navigation Warfare Center. The focus of much of the military’s training for contested, degraded, and operationally limited environments has been on identifying and mitigating the effects of GPS denial on positioning and navigation.

If timing is so essential, what can the U.S. military do to increase its time resilience? First, realize that a serious approach to assuring access to precision timing will require more than the current defensive efforts. Indeed, the U.S. military should embrace the concept of time warfare in the way it has adopted navigation warfare.

This means finding new and comprehensive ways to identify threats to U.S. timing systems, not just via electronic attack, but though the other warfighting domains as well. It means crafting defense time infrastructure and network operations to design, create, maintain, and improve friendly timing sources and timing distribution, with a focus on the broad uses of precision timing. And it means planning for offensive time operations that can enable U.S. military superiority across services and military functions.

Second, the Defense Department should elevate timing, long regarded as “the little t” in PNT, by disaggregating it from positioning and navigation, allowing precise-time-and-time-interval efforts to emerge from the shadows in policy, planning, and doctrine. The three elements of PN are not inextricably linked; there are many ways of measuring and distributing timing that do not rely on GPS or navigation systems at all. Examples include DARPA’s Chip-Scale Atomic Clock and palm-sized Atomic Clock with Enhanced Stability.

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Third, the U.S. military needs to choose an organization to be responsible for the operational aspects of time warfare. If this is to be the Joint Navigation Warfare Center, it should be renamed the Joint Time Warfare Center to reflect a more holistic PNT mission. It should also be moved out of U.S. Strategic Command’s Joint Functional Component Command for Space to deemphasize the focus on space-based systems like GPS for PNT, and handed to STRATCOM/J3 to emphasize the operational warfighting aspects of time warfare.

Few technologies have as broad an impact on both national security and Americans’ daily lives as precision timing, and so threats to this technology must be given appropriate priority. Yet even as the Defense Department works on new systems to spread the risk, it must also think more broadly about timing’s place in warfare. Without deliberate, comprehensive, coherent, and comprehensive guidance and policy now, the Defense Department risks replacing one well-functioning but vulnerable timing component — GPS — with dozens of disparate, non-interoperable, and possibly still vulnerable timing systems.

The views expressed in this article are those of the authors and do not reflect the official policy or position of the U.S. Air Force, Defense Department, or the U.S. government.