Home » Ground » Army Looks at Chip Scale Atomic Clock for GPS Blocked Combat

Army Looks at Chip Scale Atomic Clock for GPS Blocked Combat

by Kris Osborn on November 8, 2013

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.

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{ 69 comments… read them below or add one }

Dfens November 8, 2013 at 8:16 am

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.


Jason Ghent November 9, 2013 at 10:05 am

Because of US conventional dominance only an idiotic megalomaniac who doesn't understand self-preservation like Saddam Hussein, is going to fight them conventionally. Enemy's of the US will fight using unconventional tactics and guerrilla warfare and fight or deter with WMD.


Riceball November 11, 2013 at 1:17 pm

The most realistic scenario will be a mixed force of conventional and unconventional forces which will really test our ability to switch from a regular peer vs. peer/near peer with conventional forces to unconventional/guerilla warfare which, judging by our performance in Iraq, is not something we adapt very well to.


Dfens November 12, 2013 at 9:08 am

Hell, the most realistic scenario is that the Chicoms buy us lock stock and barrel and we have to fight a combination of our own armed forces backed by the Chinese to keep our own country. Given that by then our armed forces will consist entirely of women and men who prefer the company of other men, they shouldn't be much of a problem, but the Chicom regulars will be.


blight_ November 12, 2013 at 10:17 am

I don't know, the Chicom regulars will probably be single-children narcissists.

Maybe the Republic of Korea will save us? /sarc

Rest Pal November 11, 2013 at 1:43 pm

Brainwashed to the last cell. Saddam didn't want to fight the US at all. It was a war planned by Zionists and neo-cons years before the fact. Learn to sharply question what you know and what you are told.

Was the Korean War a nuclear war or guerrilla war?


blight_ November 8, 2013 at 10:25 am


Of interest would be magnetometers and gyroscopes as well.


Musson November 12, 2013 at 9:54 am

Does the microscopic atomic clock come with a tiny sextant?


blight_ November 8, 2013 at 10:40 am

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.

Edit: http://www.profsurv.com/magazine/article.aspx?i=7...

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: http://www.profsurv.com/magazine/article.aspx?i=7


tmb2 November 8, 2013 at 4:48 pm

"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."

Look up the Thor III IED jammer.


majr0d November 8, 2013 at 5:26 pm

I always avoid talking specifics when it comes to anti IED TTP.

There are other systems out there. The enemy doesn't need to know much more than that…


tmb2 November 8, 2013 at 5:46 pm

Fair enough, though it's hard to keep a lid on systems when the PM dedicates an entire webpage to the tech.


majr0d November 8, 2013 at 6:25 pm


An OER bullet :(

Bernard November 11, 2013 at 5:56 pm
Curt November 11, 2013 at 10:16 am

If you have every soldier with a very accurate clock, a radio, and a simple Navigation system, then every soldier, vehicle, and aircraft is a potential node for a robust system that functions just like GPS. Especially if every soldier is connected with some type of data system, you just send out a signal with a position and time and everyone who receives the signal has a line of position just like for GPS.


Dfens November 11, 2013 at 11:27 am

Time has always been the key to finding location on a spinning planet.


Musson November 12, 2013 at 9:56 am

True. But, you also need a sextant to shoot the stars.


RunningBear November 8, 2013 at 10:48 am


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.


Muttling November 8, 2013 at 1:27 pm

I understand what you're saying, but a GPS jammer is the size of a ruck sack and pretty damned cheap to build. It wouldn't be hard or expensive for an enemy to saturate an area with jammers and have them turn on at just the right time to support a major operation.


EW3 November 8, 2013 at 11:32 pm

Jamming a GPS is not as easy as it would seem.
Without revealing too much, I'd suggest people consider the types of antennas that are used in GPS receivers (very directional) and also consider the purpose of almanac data.


Hunter76 November 9, 2013 at 11:05 am

You can put a gps receiver on a chip. Where are these highly directional antennas?


EW3 November 9, 2013 at 2:46 pm

The antenna is usually bigger then the GPS module. A module contains the receiver chip TCXO, voltage regulators and interface chips. The last one I designed was 10 x 9 mm. Could have been smaller had I elected to add more layers to the PCB.
Have used this antenna in cheap commercial applications http://www.unictron.com/mana_php/Download/File/Pr
It's a bit bulky but provides excellent reception. I'm sure the DOD has some more expensive and more directional. Also, in many applications like on an aircraft, I suspect they have a much larger ground plane to work with, which makes the antenna even more directional.

Bruce November 10, 2013 at 7:08 pm

Just think of the GPS-enabled devices we take for granted today; smart phones and the even smaller bike computers are two common examples of tiny devices with GPS functionality. My bike computer is not much bigger than a wristwatch and it contains just about everything short of a moving map display.
As for the antennas don't restrict your thinking to something like a car radio aerial, they are often small enough to be contained within the case of the device itself (again, smart phones and bike computers).

john November 8, 2013 at 10:55 am

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


blight_ November 8, 2013 at 11:03 am

Which is fine and dandy until you get to countries where mapping data is incomplete.


FormerDirtDart November 8, 2013 at 11:13 am

And map reading is so easy while packed in the back of a Chinook or Blackhawk, in the middle of the night, flying at 150 knots, while scraping tree tops


blight_ November 8, 2013 at 11:15 am

The basics include eschewing modern technology including helicopters, I guess…


majr0d November 8, 2013 at 12:34 pm

It's not that hard. We even teach 2LTs how to do it. I've even done it, and BTW, you aren't doing nap of the earth at 150 knots.

Part of the Air Mission Brief that occurs between the ground commander and the air commander is listing the Air Control Points. Individual helicopter chalk leader typically have a headset plugged into the pilot's chatter so you can listen as they call them off. It only takes a little training.


FormerDirtDart November 8, 2013 at 12:57 pm

Actually, I have taught plenty of LTs to do it.

Arthur Savard November 8, 2013 at 1:22 pm

I used to fly sandblowers at 75 feet through the mountains with a chart in my lap, gooseneck to see it at a 180 knots and never ran into any ridge and dropped on target and on time doing nuke training.

I guess you have to rely on your pilots to tell you where you are.


majr0d November 8, 2013 at 2:14 pm

Art, understand but there's a difference between fixed wing and rotary wing NOE but you know this.

majr0d November 8, 2013 at 12:37 pm

Incomplete mapping data? In these days of satellites, ground penetrating radar etc, there aren't many places that are unmapped except the bottom of the ocean.


Arthur Savard November 8, 2013 at 1:19 pm

Guess I'm in the geezer crowd but in the 60s a good guy on the ground with a chart, compass and watch could get me on target and as far as I know the only thing I may have placed off target was my empty brass that could be a pain in the ass to friendlies.


Muttling November 8, 2013 at 1:34 pm

Actually, we have the bottom of the ocean pretty accurately mapped as well. While I love the OP's comment, the responses of others are a big issue. One of the most difficult things to do in land nav is figure out where the heck you are after you've been dropped in. Just read up on all of the confusion that followed the paratroopers during the D-Day invasion if you want a prime example (and keep in mind that they had 2 years of training which included studying their drop zones.)


blight_ November 8, 2013 at 2:20 pm

Tell it to the USS Guardian, or that SSN that hit a seamount (USS San Francisco)

That said, anybody know how complete the mapping is of say, Kampala? Or North Korea? I imagine someone could automate the process of collecting satellite footage and translating it into topo maps, but it's unlikely to be cheap or timely.

Riceball November 11, 2013 at 1:24 pm

To be fair that was largely because the airborne troops weren't landing where they were supposed to be. I don't recall if it was because the planes flew off course or they simply drifted off course after jumping but the fact remains that they weren't landing where they had expected and planned on landing which caused almost, maybe more, confusion for the Germans as it did the American troops.

CDS November 8, 2013 at 9:30 pm

Originally, I was thinking the same thing. I had to pass a land nav course using a compass and pace count before they let us use GPS. But I think this article is more about things like GPS guided munitions, not ground navigation.


majr0d November 8, 2013 at 12:35 pm

Paper maps?

Not high speed enough? Load them on a tablet…


tmb2 November 8, 2013 at 4:50 pm

Pretty sure they're putting CPOF data onto tablets now.


majr0d November 8, 2013 at 5:21 pm

I thought the subject was GPS and knowing where you're at?

That said, agree. The networking of tablets isn't a technically insurmountable obstacle and then there's old school put it in yourself. Grease pencil/Alcohol pen is old school but they do make styli.

Everything is hard when you aren't used to doing it. Look at the Army relearning to operate away from fixed facilities.


tmb2 November 8, 2013 at 5:42 pm

I can get onto a tangent with the best of them :)

I went through a fair amount of map reading as a cadet (15 years ago), but as a 2LT the schoolhouse only gave me a 2 hour class on the PLGR before sending me on my way.

I don't know about GD, but Harris' new radios have GPS devices built in to them now instead of needing a DAGR connected to them to get timing and location data.

As far as the generic "learning it again" motif, we had a serious discussion about field sanitation the other day because nobody remembered anything about it. We also struggled through a week of a decisive action MDMP with pre-CGSC Majors who hadn't touched the subject since they were junior captains.


majr0d November 8, 2013 at 6:32 pm

" a 2 hour class on the PLGR"

I could tell you a story about the "training" we got on the LD before crossing into Iraq for our just newly issued PLGR (one per CO) but I'm not sure you'd believe me…

jsallison November 8, 2013 at 8:11 pm
Arthur Savard November 8, 2013 at 1:17 pm

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


LeeRetArmy November 8, 2013 at 11:12 pm

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.


Curt November 11, 2013 at 10:32 am

Well, what if it is dark, raining, foggy, smokey, under fire' etc? Do you really want to be calling in precision weapons based on grease pencil or be forced to pull out a map as opposed to just knowing. Sure, you are in the ballpark with a map but is that good enough? Wouldn't it be better to know how to navigate with a map and compass if required but still have instant positioning data? Wouldn't it also be good to know where everyone else was to avoid fratricide? GPS enables all kind of capability beyond just position data because it is constant, no effort required, so having a reliable backup is a great capability to have. Just don't become wholly dependent on it?


hibeam November 8, 2013 at 11:26 pm

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


Hunter76 November 9, 2013 at 10:47 am

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?


blight_ November 9, 2013 at 11:36 am

Star-finders, though I've not heard of them much anymore, only on the SR-71, for ballistic missiles…and then there's the sextant and chronometer.


Hunter76 November 10, 2013 at 3:27 am

Now you're talking celestial navigation. The sky is not always visible. What about other satellites? Is Pent considering all space systems shut down? Can the Sun be accurately seen through overcast?


blight_ November 10, 2013 at 9:59 am

I'm just assuming the worst case scenario: the demise of the entire GPS constellation, in which case the other alternative is using fixed positions and something like LORAN. I suppose CSAC could work in such an environment as well…


Curt November 11, 2013 at 10:44 am

As long as you have accurate pre surveyed points with transmitters, you can accurately fix your position. From there you can fix position of highflying aircraft and then you have a pretty good GPS substitute. Once you have the timing part down, it becomes pretty easy. It would Also make GPS spoofing incredibly difficult as you would have literally hundreds of signals to compare to as well as the potential to.immediately triangulate the spoofing signal.

Riceball November 11, 2013 at 2:00 pm

Radio triangulation?


Drew January 14, 2014 at 4:11 pm

I could be wrong, but I think we've sailed across the ocean a couple of times in previous decades.


pleuris November 10, 2013 at 3:36 pm

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


blight_ November 10, 2013 at 3:43 pm

Fair enough. I've not looked into the black box that is over-the-air communications, let alone encrypted over-the-air communications.


RentAscout November 10, 2013 at 10:19 pm

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


xbradtc November 12, 2013 at 2:35 pm

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.


blight_ November 12, 2013 at 2:49 pm

Which would provide a second plus to pushing CSAC's into the field…and not just for GPS position-fixes (though they are helpful there as well).


CPT Eggshen November 12, 2013 at 4:39 pm

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


Keith Turk Jr. November 29, 2013 at 10:52 pm

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.


gt350 December 28, 2013 at 3:20 am

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


steve January 8, 2014 at 6:58 pm

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.


majr0d November 8, 2013 at 2:16 pm

FDD – great! Then why you making it sound hard?

"And map reading is so easy while packed in the back of a Chinook or Blackhawk, in the middle of the night, flying at 150 knots, while scraping tree tops"


Arthur Savard November 8, 2013 at 2:28 pm

Just get rid of the stuff in front of the eyes and return to the Mark 1 Mod 0 eyeball and it gets pretty easy.


Talmach November 8, 2013 at 3:51 pm

Pretty sure it's been done. Don't know that for a fact, just thinking about it from a class I took on Remote Sensing. But the technique is pretty straightforward, and computers do a lot of the heavy lifting I should think. The only issue should be new roads or water features changed from massive weather events. At any rate the whole planet has been parsed out into MGRS so that's standardized even if the map features aren't 100% accurate.

I think they must be thinking of other uses for GPS than individual navigation, because that's not really a big hurdle. Just revert to low-tech. Perhaps like some posters here have suggested it has to do with some higher technology issues, or issues with tracking large units of friendlies. But the article sure isn't clear!


RWB123 November 9, 2013 at 9:35 am

As far back as Vietnam we were using maps that were created by overlaying grids onto actual aerial photos. I don't imagine that all of that technology has gotten lost over the years. In fact, you can get a similar effect using google maps.


blight_ November 9, 2013 at 11:33 am
EW3 November 11, 2013 at 7:18 pm

Smart phones can use smaller antenna (usually chip type) because they actually are an AGPS. The augmentation comes via the phone network, which provides rough location and ephemeris data which reduces the signal strength requirements of the GPS reciever.


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