Army Looks at Chip Scale Atomic Clock for GPS Blocked Combat

GPSThe Army is trying to figure out how to function in a combat environment where GPS signals could be blocked from soldiers.

One potential solution is through a small device called a Chip Scale Atomic Clock, or CSAC. It is a technology which results from the miniaturization of atomic clock components to a chip-sized scale, Army documents explain. The CSAC can provide units with precision timing for up to three days in a GPS-denied environment, said Mary Miller, deputy assistant secretary of the Army, Research and Technology.

“You are measuring vibrations at an atomic level,” Miller said.

The CSAC is being developed through a partnership between the Defense Advanced Project Research Agency, or DARPA, and the Army’s Communications-Electronics Center Research Development and Engineering Command, or CERDEC.

DARPA originally developed the technology and CERDEC is now working on maturing manufacturing technology in order to make CSAC more affordable, said Miller.

“If you lose track of your GPS then you can very quickly start drifting off of your path. This matters because we talk about these very precise munitions which can precisely hit the wrong target. We’re working on alternative ways to get that same level of confidence where we know we are going to hit that target precisely. The Chip Scale Atomic Clock provides us that precision timing,” Miller said.

CSAC can also be integrated with GPS receivers to improve and stabilize timing as well as proving “jamming” protections, Army officials indicated.

As part of the Pentagon’s “re-balance” to the Pacific, the Army is hoping to prepare for certain challenges and anticipate potential future conflicts across its vast areas. A substantial portion of this effort hinges upon the realization that potential conflicts in the area are not likely to be fought against lower-tech adversaries as was the case in Iraq and Afghanistan.

“In Afghanistan it was pretty much a low-tech adversary. The Army is very concerned as it makes this shift to the Pacific rim. We are going into a much more conjested and contested environment. We have potential peer adversaries or people that have purchased peer-adversary-like capabilities. We know that our stuff will not work as seamlessly was it was designed to do,” Miller said.

About the Author

Kris Osborn
Kris Osborn is the managing editor of Scout Warrior and a former associate editor at

17 Comments on "Army Looks at Chip Scale Atomic Clock for GPS Blocked Combat"

  1. It's about time we took our focus off the tiny 3rd world crap holes and started thinking about what we'd do if we got into a real war.


    Of interest would be magnetometers and gyroscopes as well.

  3. The GPS constellation is >24 satellites with atomic clocks. All transmit time information and their positions, and by calculating time-to-pick-up-transmission from a number of satellites the user calculates their position in space, with accurate time information transmitted, and used to compensate for drift.

    In an environment without the satellite constellation (under jamming, or destruction of the constellation), I'm not sure how the atomic clock is going to help. Wouldn't more accurate INS be appropriate for a GPS-less environment? Unless the plan is to have multiple chip-scale atomic clocks in the field, each with a transmitter to create an ad-hoc GPS that is pre-initialized from GPS reference data? [Edit 2: Under less-than-perfect jamming, the atomic clock and position data from an individual's CSAC, or more than one CSAC at a distance, could presumably augment in position-fixes).

    Wired makes the claim "military patrols can travel on foot and still carry backpack-sized jammers that prevent radio-controlled improvised explosive devices from detonating. The CSAC’s small size and low power consumption are vital to this mobile application, and the atomic clock’s precision prevents the units from self-jamming, or sending out a signal that overwhelms friendly radio signals."

    Not quite sure how that one works. I will look up the subject, or wait for an SME to post.


    On the military side, Fossi noted some examples. “You have soldiers in the field with GPS units ducking in and out of buildings and from under cover; they lose [GPS solution], and [this kind of chip] can greatly speed up the time to subsequent fix, no need for coarse acquisition.” There are many other military applications; having this precise timing source, independent of GPS time, means we can compare various signals to help detect and mitigate some forms of jamming, spoofing, and interference. Such solutions could be key in further developing indoor positioning solutions. I had asked Fossi about something that a few of the GNSS developers had hinted at: the notion of using the CSAC as the “extra satellite” in some GNSS solutions. In high-precision GNSS, such as in ambiguity fixing for RTK/RTN, the clock of a fifth satellite is used along with the observations from a minimum of four others—this could be quite useful in poor-sky-view situations. He said, “Of course, and [even for] low-precision GPS where you use three satellites,” the CSAC could act “as the fourth, or if you didn’t care about the elevation, there could even be only two satellites with the CSAC [acting as] the third.” The size, weight, and low power requirements of the CSACs have sparked a lot of interest in other positioning and timing applications as an alternative or supplement to satellite-based timing. It’s possible, “certainly in mining, with limited or no sky view, and in underwater applications,” said Fossi. “We have one client that is working on replacing [legacy] timing [chips] with CSAC in the design of deep sea sensors. The long life, low degradation in time, and very low power of the [CSACs] means this is a very practical and affordable solution—the whole unit uses a max of 120 milliwatts.” – See more at:


    Wrist watch inertial guidance system.

    The US capability to implement aerial seeding of the battle field with disposable (less expensive) inertial reference 6" mini-pods would make GPS jamming a waste of time. 100 yard device transmission range would insure that a suitable coverage (5 per sq. mile) could occur for other than vertical faces.

    Anti -GPS can't exist long while "transmitting" during the anti-anti-GPS hunt/ kill efforts.

  5. im sorry but the army needs to get back to basics: learn to read a damn map!

  6. Paper maps?

    Not high speed enough? Load them on a tablet…

  7. Guess a chart, compass and watch are out of the question today!

  8. What the hell is wrong with a map and a compass??? Resection and intersection worked great add a small laser range finder for known points used to do that all the time.

  9. Where the hell are we private? I have no idea sir but I can tell you the correct time to the femto second.

  10. To all the geniuses who want to jump back to maps–

    How do you find your bearings in featureless terrain like a flat desert or the ocean?

  11. Timing is everything. If communication is encrypted and the key sequence is time critical the time has to be very accurate. Just saying

  12. Looks like they are making a better map holder. The FBCB2 was a great at taping paper maps to.

  13. As Pleuris notes, for the ground troop, it's more about the timing for secure communications. The frequency hopping and the encryption/decryption depend on extremely precise timing. Today that's provided by GPS. But absent that, a CSAC would do nicely.

  14. protractor-$1, paper map-$19.99, compass-$50, wrist watch-$75, ability to read a map and call in arty…priceless.

  15. Ive been thinking this for 20 years now, but why are we talking about it. the lack of informational security in todays military is costing the US trillions of dollars in lost advantages that it isnt getting back in additional spending.

  16. I learned with a compass and a map– and that was extra.

  17. we could send space-drones to highjack the chinese gps that they are now building. use there system and or drag them back to earth to their demise. i heard somewhere the chinaman would use drones for a back-up gps system.

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