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Science

A Revolutionary Quantum Compass Could Soon Make GPS-Free Navigation a Reality (scitechdaily.com) 73

Posted by EditorDavid from the all-encompassing-research dept.
America's Department of Energy has three R&D labs, according to Wikipedia, one of which is Sandia National Labs. And that New Mexico-based lab has just announced that "A milestone in quantum sensing is drawing closer, promising exquisitely accurate, GPS-free navigation." with research into "a motion sensor so precise it could minimize the nation's reliance on global positioning satellites." Until recently, such a sensor — a thousand times more sensitive than today's navigation-grade devices — would have filled a moving truck. But advancements are dramatically shrinking the size and cost of this technology. For the first time, researchers from Sandia National Laboratories have used silicon photonic microchip components to perform a quantum sensing technique called atom interferometry, an ultra-precise way of measuring acceleration. It is the latest milestone toward developing a kind of quantum compass for navigation when GPS signals are unavailable. The team published its findings and introduced a new high-performance silicon photonic modulator — a device that controls light on a microchip — as the cover story in the journal Science Advances... The new modulator is the centerpiece of a laser system on a microchip. Rugged enough to handle heavy vibrations, it would replace a conventional laser system typically the size of a refrigerator...

Besides size, cost has been a major obstacle to deploying quantum navigation devices. Every atom interferometer needs a laser system, and laser systems need modulators. "Just one full-size single-sideband modulator, a commercially available one, is more than $10,000," said Sandia scientist Jongmin Lee. Miniaturizing bulky, expensive components into silicon photonic chips helps drive down these costs. "We can make hundreds of modulators on a single 8-inch wafer and even more on a 12-inch wafer," Kodigala said. And since they can be manufactured using the same process as virtually all computer chips, "This sophisticated four-channel component, including additional custom features, can be mass-produced at a much lower cost compared to today's commercial alternatives, enabling the production of quantum inertial measurement units at a reduced cost," Lee said.

As the technology gets closer to field deployment, the team is exploring other uses beyond navigation. Researchers are investigating whether it could help locate underground cavities and resources by detecting the tiny changes these make to Earth's gravitational force. They also see potential for the optical components they invented, including the modulator, in LIDAR, quantum computing, and optical communications.
Thanks to Slashdot reader schwit1 for sharing the news.
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A Revolutionary Quantum Compass Could Soon Make GPS-Free Navigation a Reality More

A Revolutionary Quantum Compass Could Soon Make GPS-Free Navigation a Reality

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  • silicon photonic modulator (Score:3)

    by jddj ( 1085169 ) on Sunday August 25, 2024 @09:40PM (#64734974) Journal

    Is this related to the Illudium Q-36 Explosive Space Modulator?

  • More concerning... (Score:3)

    by HotNeedleOfInquiry ( 598897 ) on Sunday August 25, 2024 @09:55PM (#64735002)
    Is the use of this technology in ICBM's and cruise missiles.

    • Re:More concerning... (Score:4, Interesting)

      by crow ( 16139 ) on Sunday August 25, 2024 @10:01PM (#64735012) Homepage Journal

      Yup, no more jamming of the navigation systems. That won't really matter for ICBMs so much, but certainly will be a big advance for other guided weapons. And if the technology costs $10K/unit at first, the military can fund it until it gets down to consumer price levels.

      How I feel about it depends on whose weapons we're talking about. Though really, it's pretty much inevitable that as we see how effective electronic warfare systems are at stopping HIMARS and the like from hitting their targets, clearly they're going to be working on getting much more precise inertial guidance systems.

      • Re:More concerning... (Score:4, Informative)

        by Anonymous Coward on Sunday August 25, 2024 @11:33PM (#64735072)

        as we see how effective electronic warfare systems are at stopping HIMARS

        Except we haven't seen that. There are Russian claims to that effect, but Ukraine kills Russian's every day with high precision HIMARS attacks. The truth is the rounds HIMARS uses (mostly M30/31) have both GPS primary guidance with inertial guidance fallback. When the rockets lose GPS they fall back to ring laser gyro inertial guidance and then reacquire GPS when possible. The net result is that, because GPS is rarely jammed through the entire trajectory, most rounds are highly accurate.

        • Re: (Score:2, Interesting)

          by Smogord ( 5480236 )
          The problem is with CEP down from 5m to say 30m $100k GLMRS becomes a glorified Tornado ($5k) rocket. And its payload is not enough to engage a target w/o massive rocket spend. All the while I don't hear the same reports about successful EW against Russian UMPK 500kg bombs with KOMET Glonass modules. If there's any game changer at current stage of the war, it's the Russians that have it.

        • It is not just GPS jamming. GPS can be spoofed thereby inserting incremental error that builds up and causes munitions to miss. Iran literally stole a US drone using this technique.

          HIMARS in Ukraine have been missing their targets but this issue might have been resolved. Software updates to better filter out bad GPS data are a real thing. You never know how good your algorithms are until they are actually deployed in a conflict.

          It reminds me of the high success rate of western air launched weapons

    • Re: (Score:2)

      by e3m4n ( 947977 )

      Most likely. During Desert Storm the gps navigation equipment we had was very large. Between GE and Texas Instruments they practically owned everything onboard. Our tomahawks still had map overlay navigation for the first part of it. GPS was still in its infancy. Now a gps chip in your cell phone is tiny as shit. I have no doubt tomahawks and short range missiles will get this. As to ICBM I cannot say. Their math is a bit more complicated. We had to do a whole nasa moon landing to learn the true ins and out

    • Re: More concerning... (Score:4, Interesting)

      by vbdasc ( 146051 ) on Monday August 26, 2024 @01:37AM (#64735172)

      From my cynical POV, improving the accuracy of ICBMs may be a good thing, if it means fewer collateral damage and casualties.

      • If they can hit a strategic target with pinpoint accuracy why do they need to be nuclear ? Presumably the point of being nuclear is that they can generate such huge energy releases that they don't need to be so closely targetted or are intended to be more "scattergun" and affect a wide radius.

    • All technology can be used for good or for evil. But few of us would want to throw it all away and go back to the stone age. In other words, the net effect of technology is positive.

      • Except there are technologies that people in general would gladly throw of knowledge of away. A number that increases when taking into account technologies that society in general feels it isn't mature enough to handle responsibly. Yes, in living memory the net effect of technology may be positive, but it won't always be that way.

        • All technology is also originally immature and irresponsible. Think about it, just a few decades ago, SMTP required no authentication whatsoever. How dumb is that! It was a time bomb waiting to go off! And yet, we adapted, and SMPT got its authentication.

          Technology has been positive not just in living memory, but throughout all of history. Humans have continued to try to improve their lot through technology, since the stone age and beyond. There is no historical precedent for what you are claiming, that "th

    • there's a reason this tech was developed at a weapons lab

    • They already have inertial guidance in missiles, plus terrain mapping and image recognition.

  • Cumulative error (Score:4, Insightful)

    by rcb1974 ( 654474 ) on Sunday August 25, 2024 @09:58PM (#64735006) Homepage
    So these devices navigate essentially using very precise dead reckoning? If so then the error will accumulate such that over time the mismatch between calculated and actual position will get progressively worse, until the device is update with true coordinates, either via GPS or user input.

    • I suppose it would matter what that error is and how often they measure. If it is small enough (they seem to working at the atomic level, so more than likely very small?) then the accumulation over a "reasonable" period of time might not make much of a difference.

      An atom is 0.1 nanometers, so assume an error of an entire atom ... I'm no math whiz but that would is 1e-10, so like 10 billion measurements which is like 30 years if you measure every second. I would guess they measure more often than that though

      • Smaller the level, the greater the electrical noise. If their claims are true then they have found a way around this noise issue by using "quantum sensing". Could be very cool, but don't expect it to replace GPS anytime soon.

      • Re:Cumulative error (Score:5, Interesting)

        by CaptQuark ( 2706165 ) on Sunday August 25, 2024 @11:40PM (#64735078)

        It's not the size of the sensor, it's the size of the angle error. If you are only traveling 10 feet, an error of 0.1% isn't significant. When you travel 1000 miles, the error grows to one mile. With most weapons, that means you missed.

        If you want to see this yourself. go into your kitchen, line yourself up with the fridge, close your eyes and try to walk to the fridge without peeking. Easy.
        Now try the same thing in a typical basketball court. Now try it across a football field.

        Small errors in any Inertial Navigation System will accumulate and compound the error. The next question is are there multiple sensors on each chip and do they need to be calibrated to each other? (Azimuth, Elevation, Acceleration) If GPS is down, how accurate do your starting coordinates have to be to get accurate results?

        https://www.advancednavigation... [advancednavigation.com]

        • I haven't read the paper, so admittedly I can't say what the "quantum" refers to in this case, but it is wrong to claim that the accumulation of error must necessarily be the reason this cannot work. The quantum world doesn't operate classically. For some things there is no gradual accumulation of error. That's because some properties are quantized, meaning they only ever can be measured in a handful of discrete forms. In those cases, our intuition from the macroscopic world misleads us.

          • Re: (Score:2)

            by Entrope ( 68843 )

            Accumulation of errors is the big challenge for dead-reckoning navigation in general. "Quantum" is not magic; a system based on quantum effects still has various sources of noise, bias and other error (such as quantization at the point it gets digitized).

          • That's because some properties are quantized, meaning they only ever can be measured in a handful of discrete forms. In those cases, our intuition from the macroscopic world misleads us.

            Which properties? It's nothing from what we're discussing here (anything related to space, or if you want spacetime). It's a common misconception that quantum something something means that spacetime is discrete instead of continuous; not only both relativity and quantum field theory operate assuming continuous spacetime, bu

            • That is indeed a misconception. The discreteness of quantization generally refers to a property of the spectrum of an operator. For example, the angular momentum of certain particles is quantized, but spacetime remains, as far as I know, incompatible with quantum theory.

              Now angular momentum is also a conserved quantity (think gyroscope) and at the quantum level it cannot be changed without the right amount of energy. If such a system could be kept isolated, it could point out of the plane of the ecliptic

        • Not only the sensor - the processor its attached to will have a floating point precision limit too. Even if they used some bignums library there'd still inevitably be rounding errors occasionally which will accumulate.

        • It's not the size of the sensor, it's the size of the angle error.

          It's neither - it is the accuracy with which it can measure linear and angular acceleration. In our universe only acceleration is defined on an absolute scale so you cannot measure displacement or velocity - whether linear or angular - without an external reference that you are measuring relative to.

          From the few details it seems that they have implemented a tiny laser interferometer and are using this to measure the acceleration. This is definitely an extremely accurate technique - the LIGO array uses t

        • When you travel 1000 miles, the error grows to one mile. With most weapons, that means you missed.

          Yes, you missed, but because it's quantum navigation, it also means that you hit your target.

        • It's not the size of the sensor, it's the size of the angle error. If you are only traveling 10 feet, an error of 0.1% isn't significant. When you travel 1000 miles, the error grows to one mile. With most weapons, that means you missed.

          Exactly this. I'm not an expert in this space in the least, but I think the paper [science.org] indicates that their gravitational acceleration measurements are +/- 0.01 m/s^2. I'll leave the math to someone more well-versed in the applicable formulas, but it seems evident that this wouldn't be something you'd want to rely on over the course of thousands of miles. Just as the SR-71 Blackbird and Trident missile used the stars to fix their location [wikipedia.org] as they were traveling, I'd expect any weapon systems built on this to sti

          • Re: (Score:2)

            by jabuzz ( 182671 )

            It's all irrelevant as any giro that would give you the accuracy of GPS over 1000km would be subject to ITAR embargo for anything but military usage. We can already do navigation with laser ring giros good enough that an airplane could fly over the Atlantic and be near enough to the airport (if you are even 1km out it matters not when you are picked up on the tower radar), but they not allowed to be used in commercial aircraft.

      • You have to measure continuously it is basically a inertia navigation system.
        Instead of using glass fibers and lasers - or old school - Gyrocompass, they use atomic interreference with a laser diode.
        A system like this might be long term impracticable for a mobile phone. But it is certainly good enough to let a missile fly a few times around the planet. And the precision of the missile in the end is determined by the accuracy of its flaps and engine and not by the navigation system.

    • Re: (Score:2)

      by SirSlud ( 67381 )

      The entire claim is that any accumulation error is so negligible as to not be meaningful. Like, is this something you think the people who're working on this don't understand?

      • Like, is this something you think the people who're working on this don't understand?

        I think this is something that the people poised to profit from it won't discuss honestly. And I doubt any such claims until they are proven. People make claims all the time. Many of them turn out to be false.

    • You'd not use this thing alone. There would still be sensor fusion. But maybe your Kalman filter gets a lower process noise.

    • So these devices navigate essentially using very precise dead reckoning?

      Essentially yes. They measure the linear and angular acceleration of the device extremely accurately and then use that to calculate the displacement and rotation from a known point of origin. They do not measure the Earth's magnetic field like a compass at all, instead they are an accelerometer since the universe only defines an absolute scale for acceleration, while velocity and displacement are reletive..

      Errors will accumulate which is why you cannot use existing accelerometers because they are suffic

      • Thank you. This was my understanding too. Without occasional calibrated position updates from an external source like GPS then the calculated position from clock and accelerometer readings will get more and more off.

    • Yes, and 'dead reckoning with occasional adjustments from a positional fix' has been around for centuries.

      This isn't going to replace GPS, it's going to augment GPS.

  • First in the air [bbc.co.uk]
    Then in the Underground [theguardian.com]

    Is this a component of that or something different entirely?

  • Complex physics (Score:5, Funny)

    by greytree ( 7124971 ) on Sunday August 25, 2024 @10:02PM (#64735014)
    "We can make hundreds of modulators on a single 8-inch wafer *and even more on a 12-inch wafer*,"

    Glad he made that clear.

    • Just think how many they could make with an 18-inch wafer!

    • Re: (Score:1)

      by Anonymous Coward

      Reading between the lines, this indicates that the precision needed for manufacture is not especially demanding. Precision limits wafer size: thermal and mechanical effects means that if you need greater precision, you must use smaller wafers.

      It's not surprising for this case: they're measuring phase shift. That's the essential function of the device. Their not making large number of tiny vias or other high precision fabrication. The inevitable variance between devices can be calibrated out, so lower

    • It's consistent with the headline which clearly implies navigation is impossible without GPS. I'm sure that would be a huge surprise to assorted Polynesians, Vikings, Henry the Navigator, Magellan, Cook, Bligh, Shackleton, etc, etc.

      • But using the stars is also a global positioning system. It even uses radio waves.

        Of course there are problems with it, like sunlight or clouds denying use of the service.

  • The title quotes "quantum compass", but compass infers a magnetic field sensor. The text later explains it is a sensor for inertial navigation, so presumably angular momentum sensor, so more reasonable application of lasers. And alas, that is all a variance of 'dead reckoning' rather than an absolute position device such as GPS. For a missile or guided bomb to navigate from known location, that is great, less so for discovering where I am.

    • Just travelling over the earth means you'll be subjected to a variable gravity field. This has been proven using highly sensitive laser interferometry equipment in jets flying over varying terrain. That's gotta influence the reading given by any device as sensitive as they claim. GPS (operating over considerably greater distances) does not contend with this but must contend with the overall lower gravity field in which the satellites operate (resulting in clocks that seem to run fast from our terrestrial

      • Agreed!

        Einstein taught us that gravity fields are indistinguishable from acceleration. Suppose you have an ideal acceleration sensor. If Earth's local gravity field is unknown at the 0.1% level, you'll have an error in your acceleration signal of about 1 cm /s /s. Let that accumulate for an hour and you are 1/2 (a) (t^2) = 65 km away from where you thought you were.

        Much of that will be in the vertical direction, but not all of it!

    • Re: (Score:2)

      by jaa101 ( 627731 )

      compass infers a magnetic field sensor.

      It does not. Compasses in large ships are gyrocompasses which rely on sensing the rotation of the earth. They do not use magnetism to operate and they point to true north, not magnetic north. Ships do also have magnetic compasses but only as a backup, in case the complex mechanism of the gyrocompass fails.

      • From Oxford Dictionary

        noun
        1.
        an instrument containing a magnetized pointer which shows the direction of magnetic north and bearings from it.
        "walkers should be equipped with a map and compass"
        2.
        an instrument for drawing circles and arcs and measuring distances between points, consisting of two arms linked by a movable joint, one arm ending in a point and the other usually carrying a pencil or pen.
        "a regular heptagon cannot be constructed accurately with only ruler and compass"

        • Re: (Score:2)

          by jaa101 ( 627731 )

          From the Encyclopaedia Britannia [britannica.com]

          compass, in navigation or surveying, the primary device for direction-finding on the surface of the Earth. Compasses may operate on magnetic or gyroscopic principles or by determining the direction of the Sun or a star.

          From the Merriam-Webster Dictionary [merriam-webster.com]

          3
          a
          : a device for determining directions by means of a magnetic needle or group of needles turning freely on a pivot and pointing to the magnetic north
          b
          : any of various nonmagnetic devices that indicate direction

  • Could be a good augmentation to GPS. It could be used for indoor mapping .. like for shopping or firemen could use it inside buildings.

  • or it was really close to producing something useful, we wouldn't read about it on Slashdot, I guess.

  • We go everywhere just with optical navigation.
    • Yes, that's used too, when possible. Check out this 1987 article on cruise missiles at nyt. It's kind of fun, e.g. "Cruise missiles, none of which have yet been fired in anger, are the most lethal of a new and potentially revolutionary category of arms called standoff weapons."

      https://www.nytimes.com/1987/1... [nytimes.com]

      2. At landfall, missile begins matching the landmarks seen by its optical sensors against a detailed map in its computer. If it wanders off course, it corrects itself.

      3. Computer, checking map, c

  • Until recently, such a sensor â" a thousand times more sensitive than today's navigation-grade devices â" would have filled a moving truck.

    "military grade" inertial navigation instruments have been in military jets now for decades. There's an old documentary on them that went into detail on their calibration. They're taken down underground a few miles in an old mine and BOLTED down on a large platform thats anchored to solid bedrock, and they calibrate themselves on detecting the rotation of the

  • Wasn't this already invented in the tenth season of The Big Bang Theory.? (just joking)
  • This kind of technology has already been delivering results that improve existing non-quantum sensor technology dramatically. And more is coming. Unlike quantum computing.
  • The test is simple: Define a precise starting point, drive the sensor around a city for 8 hours and and then set the sensor down exactly on the starting point. Then see where it says it is versus where it really is, and compute an actual error. They are still talking about hypotheticals when they supposedly have a prototype -- this is a red flag.

  • Finally, unjammable cruise missiles and guided bombs. We need to keep our boot on the world's neck.

  • Excellent demonstration of failure of basic reading comprehension, editors. As the linked Wikipedia article states, DOE **NNSA** operates 3 labs, which are basically the weapons labs. DOE operates 17 national labs. The vast majority of them have been discussed here before. https://www.energy.gov/nationa... [energy.gov]

  • Filling a moving truck? (Score:3)

    by Tony Isaac ( 1301187 ) on Monday August 26, 2024 @04:48PM (#64737146) Homepage

    Until recently, such a sensor — a thousand times more sensitive than today's navigation-grade devices — would have filled a moving truck.

    Maybe that's the problem, they were trying to fill a moving truck. If they just stopped the truck, it would have been easier to get it loaded!

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