DARPA To Replace GPS With Atomic Clocks

This post is also available in: עברית (Hebrew)

US Defence Advanced Research Projects Agency (DARPA) plans to replace the Global Positioning System (GPS) with Atomic Clocks with Enhanced Stability (ACES) for military applications.

“All of our modern communications, navigation and electronic warfare systems, as well as our intelligence, surveillance and reconnaissance systems, depend on accurate time-keeping,” said DARPA project manager Robert Lutwak, who will oversee the new program. “If ACES is successful, virtually every Defense Department system will benefit.”

Since its first launch in 1978, GPS has become ubiquitous. Both the military and the civilian sphere have come to rely, and have become dependent, on GPS. This dependence is worrying. While positioning with the system requires triangulation using at least three satellites, and there are enough of them circling the globe to provide redundancy, it’s easy to imagine a scenario in which GPS goes out of order. Be it the growing danger of space debris, or deliberate action by a rogue state, if GPS stops working the consequences could prove catastrophic.

The way the system operates now, if GPS were to shut down, within 30 seconds a receiver could only specify that it’s somewhere in an area the size of a large city. After an hour, the area grows to the size of Germany.

ACES is set to serve as backup mechanism for navigation to prevent this outcome. The clock, once developed, will allow navigation systems to quantify position coordinates with accuracy up to 1,000 times better than current systems.

The system is to run on a quarter-watt of power and to fit in a package no larger than 30 cm3. DARPA is budgeting $50 million for a three-phase development plan that will “take a collaboration of teams with skillsets from diverse fields, including atomic physics, optics, photonics, micro-fabrication and vacuum technology to achieve the unprecedented clock stability that we seek,” Lutwak said.