The recent $11 billion US arms sale to Taiwan, including HIMARS, drones, and artillery, has heightened tensions with China, but a critical vulnerability is often overlooked: US reliance on GPS for military operations. GPS signals are easily jammed or spoofed, which could undermine US deterrence and operational effectiveness in a Taiwan contingency. China, by contrast, operates a more resilient positioning, navigation, and timing (PNT) system combining satellites, terrestrial networks, and fiber timing grids, giving it a potential operational advantage.

Experts argue the US must develop a system-of-systems approach, integrating multi-constellation GNSS, terrestrial alternatives like eLoran, inertial navigation, sensor fusion, and allied coordination, to ensure forces can operate effectively even under GPS disruption, according to Sean Gorman of Breaking Defense. Investing in PNT resilience now is critical to prevent adversaries from exploiting this vulnerability. Gorman writes:

The recent US approval of an unprecedented $11 billion weapons package for Taiwan, including HIMARS, rockets, drones, and artillery systems, has sharply elevated tensions across the Taiwan Strait. Beijing has warned that the move risks driving the region toward “military confrontation and war,” while Washington views it as a necessary step to accelerate Taiwan’s defensive readiness. But amid the political signaling and hardware debates, a deeper and more dangerous vulnerability is receiving far too little attention.

The US remains overwhelmingly dependent on GPS for positioning, navigation, and timing (PNT). In a Taiwan contingency, that dependence could undermine US deterrence, complicate intervention decisions, and degrade operational effectiveness at precisely the moment clarity and speed matter most.

If Beijing chose to escalate toward armed conflict or sustained gray zone coercion, one of its most powerful asymmetric tools would not be naval or aerial alone. It would be the electromagnetic domain. […]

While the US has remained largely GPS-centric, China has pursued a more layered approach. It operates a mature BeiDou global navigation satellite system and has reportedly backed it with terrestrial timing and broadcast systems, fiber-based timing networks, and high-power long-wave terrestrial transmissions. Together, these elements form a PNT architecture that does not rely on space alone.

This layered approach matters most close to home. In the littoral regions surrounding Taiwan, Chinese forces can likely maintain more reliable positioning and timing even under heavy electronic warfare conditions. Public reporting suggests these terrestrial and fiber-based assets extend well offshore, allowing China to operate with greater PNT confidence while actively contesting GPS in the same battlespace. […]

Forces operating in the Indo-Pacific must train routinely for PNT-degraded and PNT-denied environments. Doctrine, tactics, logistics, and command-and-control must be stress-tested under these conditions well before a crisis begins.

This is not about abandoning GPS. It is about ensuring no single point of failure — in space, on land, or undersea — can determine the outcome of a crisis. The time to invest in PNT resilience is now, not after the first missile flies.

Sean Gorman, Ph.D., Co-Founder and CEO of Zephr.xyz, has a more than 20-year background as a researcher, academic, and subject matter expert in the field of geospatial data science and its national security implications. Gorman served as a subject matter expert for the DHS Critical Infrastructure Task Force and Homeland Security Advisory Council, and holds eight patents.

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