• Rob T Firefly@lemmy.world
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    3 hours ago

    The trouble with Quantum Navigation is you might end up where you were trying to go, but at a random point in the past where you have to change history to put right something that once went wrong.

  • Charles@lemmy.charles.wiki
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    2 hours ago

    The only significant word here is “quantum”. This stuff is too expensive to be useful for anyone other than the military right now. Gravity maps are controlled information as well. Used for ballistic submarine missiles. The maps created by the military will never be made public. (It would look like a highway of where every vessel is or will be)The accuracy of satellite measurements is 3km, with physical topographic (sea/land) resolution at 1.2km. The long-term plan is to have these sensors traverse areas, record data, and then share it with a database. Even those maps are realistically only 300m~ in resolution. Compare that to GPS, which has a nominal resolution of 3m with 15 satellites, or about a foot, with a correction from ground relays. (I remember using a handheld device that would tell you how many you were connected to, and it stopped working once you were near a tree.) Gravimeters have been used by submarines since the 1980s.

    https://en.wikipedia.org/wiki/Gravimetry

  • diaphragmwp@discuss.tchncs.de
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    3 hours ago

    Wow, more AI. For some reason. This doesn’t sound like it needs AI but the investors would pay less, of course!

    • boonhet@sopuli.xyz
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      2 hours ago

      Chances are AI is easier than hand-rolling an algorithm for this. And that AI is almost certainly not an LLM.

      • xthexder@l.sw0.com
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        13 minutes ago

        We really should still be calling this machine learning… Calling stuff AI has so many connotations that aren’t really applicable to this type of software. We’ve had image recognition and other matching algorithms for years before LLMs came along.

  • melsaskca@lemmy.ca
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    7 hours ago

    The gravitational pull is stronger on the left side so you have to account for that or else you’ll just sail around in circles. /s

  • hamsamrich@lemmy.world
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    16 hours ago

    “Quantum sensors can sense the tiniest of changes in the gravity or magnetic field and use a previously prepared map of these properties to determine their location. Since a quantum sensor does not need to receive or send a signal to an external device, it cannot be hacked or be spoofed by a fake incoming signal either. “ Very cool!

      • frongt@lemmy.zip
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        4 hours ago

        Why do you think they expect it to be permanent? We survey all kinds of stuff like this all the time.

        • Knock_Knock_Lemmy_In@lemmy.world
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          3 hours ago

          Geography and celestial maps are permanent (mostly).

          The next question is, how long until a quantum measured map becomes unrecognised? Is the half life years or hours?

    • MangoCats@feddit.it
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      6 hours ago

      Two issues I have with the presentation:

      A magnetic field is an external signal - the Earth’s magnetic field is actually incredibly weak…

      10x better performance than GNSS … positioning accuracy of 1 nautical mile. Cheap old school handheld GPS out in the woods was accurate better than 10 feet most of the time, so what in this performance is 10x better? 10x more resistant to jamming? Seems like it should be completely impervious to jamming. 1 nm accuracy is useful, but hardly better performance.

      • lefaucet@slrpnk.net
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        2 hours ago

        GPS is vulnerable to various attacks.

        It’s unclear what the capabilities are, but there IS a Russian satellite that HAS jammed GPS for almost a whole hemisphere. It’s operated several times for a couple seconds over these past few years.

        Veritassium did a great presentation on how we know this.

        https://youtu.be/tz23G_UXCGA

      • ButtDrugs@lemmy.zip
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        5 hours ago

        Its better performance than existing non-gps systems - not better than GPS. For ships , being within 1nm after thousands of miles of travel is really well performing. Obvious the real play here is weaponry though, since GPS isnt reliable in warfare and on-board sensors can do the detail work of target identification once in an area, the hard part is a way for them to self navigate accurately over long distances without GPS.

        • frongt@lemmy.zip
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          4 hours ago

          The realer play is submarines. You don’t get any satellite signal at all underwater. Before this it was only INS or dead reckoning.

          • postmateDumbass@lemmy.world
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            2 hours ago

            Im pretty sure there were underwater beacons they used for aiding their navigation. Active or passive, man made or natural phenomena…

          • CookieOfFortune@lemmy.world
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            3 hours ago

            I suspect submarines can also use bottom facing radar to track features on the sea floor. But tracking the gravity should be even better.

            • frongt@lemmy.zip
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              2 hours ago

              Radar is radio, just like most satellites. It doesn’t do well through water. And that would require emissions, which submarines like to avoid.

        • zaphod@sopuli.xyz
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          8 hours ago

          So you constantly need updated maps. Reminds me of celestial navigation where you always need an up-to-date almanac.

            • zaphod@sopuli.xyz
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              6 hours ago

              What? You just download a new map for the area you want to go to every year or so, no need for GPS

              • ReluctantMuskrat@lemmy.world
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                3 hours ago

                I’m not sure you got me. How do the map makers update the map? If the gravity variance changes so it can’t be used to determine your position then clearly you need some other way to determine your position to update the gravity map. And what might that be??

                • zaphod@sopuli.xyz
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                  2 hours ago

                  Using the same reference points on earth that GPS uses, that doesn’t mean using GPS.

      • FooBarrington@lemmy.world
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        8 minutes ago

        I don’t think it’s realistically possible to do that totally undetected. Since the earth’s magnetic field is so weak and field strength goes down rapidly as distance increases, malicious actors probably couldn’t spoof patterns well enough to make the data look real, at least not without coming very close and staying near their target.

          • Echo Dot@feddit.uk
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            7 hours ago

            It’s a bit obvious that isn’t it. Hey captain there appears to be a ship with a giant boulder on board and it’s following us around, do you think that might be relevant?

          • lauha@lemmy.world
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            13 hours ago

            Our mission is to sneak this Ayers rock under the boat without being detected. In and out. 45 minutes tops.

            • 𝙈𝙞𝙖@quokk.au
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              7 hours ago

              Most people probably don’t know but we call it Uluru these days as that’s what the local Aboriginal people named it. Ayers Rock is the old coloniser name, and pretty out of fashion.

              • lauha@lemmy.world
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                6 hours ago

                I know and I am sorry, but the joke would have gone over the head for most of the people if I had said Uluru.

            • MalReynolds@slrpnk.net
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              13 hours ago

              I was going to say something about the scale of gravity changes needed, but your take is way better. Cheers.

  • Zedstrian@sopuli.xyz
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    17 hours ago

    The team achieved 10 times better performance than GNSS systems, with a one nautical mile of positioning accuracy.

    Variation up to a full nautical mile doesn’t seem very accurate?

    • Hasnep@lemmy.ml
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      12 hours ago

      If I were in the middle of the ocean I couldn’t find my location within 100 nautical miles without GPS so I’m pretty impressed

      • kbobabob@lemmy.dbzer0.com
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        8 hours ago

        Then you wouldn’t be the ideal thing to compare this to. An experienced navigator with a couple basic tools could do similarly.

        • Hasnep@lemmy.ml
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          7 hours ago

          Okay, so it’s as good as an experienced navigator, that seems pretty good to me!

        • Echo Dot@feddit.uk
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          7 hours ago

          Experience navigators with some basic tools often ended up hundreds and hundreds of miles off course because they had no reference points. If you’re navigation system is landmarks plus a sextant then it’s not going to be very accurate.

          When you’re trying to transit the ocean one nautical miles worth of accuracy isn’t bad, especially if the alternative is to use a potentially compromised GPS or a 15th century navigation tool.

    • Gsus4@mander.xyzOP
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      17 hours ago

      this article is better written:

      https://science.report/discover/quantum-gravimeter-demonstrates-gps-free-navigation-in-coral-sea-trial-86654/

      it maintained bounded position accuracy within 1 nautical mile over an 83-kilometer trajectory. This performance, achieved without access to satellite navigation, represents a more than tenfold improvement over standard navigation-grade inertial backup systems under similar conditions.

      • stylusmobilus@aussie.zone
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        10 hours ago

        That’s better, thank you

        As a holder of a spatial degree I found it difficult to directly compare it favourably to GNSS. Even a simple binary code calculating a position with GNSS gives sub 10-20 metre accuracy, generally closer to 2 or 3.

        • Kushan@lemmy.world
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          10 hours ago

          I don’t think it’s meant to be better than GNSS in terms of accuracy, just better in terms of reliability because it works entirely standalone without a need for satellite

          • UnityDevice@lemmy.zip
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            9 hours ago

            There have been lots of cases of GPS jamming lately, where this could be used as a backup. And even more crucial for certain situations, it could detect GPS spoofing attacks.

          • stylusmobilus@aussie.zone
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            9 hours ago

            Yeah nah I understood that, the quote made in the initial comment implies somewhat that it does.

      • SatanClaws@lemmy.world
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        12 hours ago

        Inertial navigation (INSS) and GNSS (Sat nav)is two completely different concepts. Too bad the article misses this. Perhaps AI hallucinations?

    • cmnybo@discuss.tchncs.de
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      16 hours ago

      That’s comparable to what a skilled navigator can do with a sextant and chronometer. That’s more than enough accuracy to cross the ocean and get close enough to the port that you can see it.

    • Deebster@infosec.pub
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      16 hours ago

      The only thing I can think is that they’re comparing with a single system (e.g. GPS or BeiDou), even though GNSS receivers will combine all four systems to get very high accuracy (a few metres).

      • Dimand@aussie.zone
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        13 hours ago

        They are comparing purely inertial navigation (I assume using the advanced nav boreas D90) and inertial nav combined with gravity map matching.

        It is more of a demonstration than a comparison. Pure inertial nav has no way to re zero from an external reference so the error only grows.

        Both of these systems are worse than any form of sat nav. But both of them keep working if the sat nav is jammed.

        https://doi.org/10.48550/arXiv.2608.25563

      • elmicha@feddit.org
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        16 hours ago

        20 years ago we had only GPS, and it already was accurate to 10 or 20 meters.

        • zqps@sh.itjust.works
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          15 hours ago

          GPS is actually far more accurate than that. There is deterministic jitter introduced to make civilian use cases precise to only a few meters, but military equipment has the algorithm to subtract that jitter and achieve precision measured in centimeters.

          Anyway, that statement is highly misleading. They were comparing to previous inertial navigation systems, not GPS navigation.

        • Deebster@infosec.pub
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          16 hours ago

          Is that true globally? I seem to remember that some ocean areas wouldn’t have as many satellites visible as e.g. polar orbits don’t visit all of the globe.

    • Gsus4@mander.xyzOP
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      17 hours ago

      Yeah, I agree that I didnt understand that bit. I also didn’t understand why you need a quantum sensor to follow a map of gravitational and magnetic anomalies for orientation.

      • Dimand@aussie.zone
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        13 hours ago

        You don’t. Any appropriately sensitive/accurate accelerometer or magnetometer is sufficient to do this.

        The quantum part is 90% hype used to and attract funding. There are some advantages to the cold atom based sensors Q-CTRL makes, along with issues that need to be worked on, but they are other sensing technologies that could beat it in the long run.

        • SmoothOperator@lemmy.world
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          11 hours ago

          You don’t. Any appropriately sensitive/accurate accelerometer or magnetometer is sufficient to do this.

          There are limits to sensitivity and accuracy that can only be overcome by quantum sensing though. So yes, you’re right, but that’s actually the point of the quantum part.

          • Dimand@aussie.zone
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            11 hours ago

            This is a rather common misconception about sensitivity, it is only true under the constraint where you are unable to increase the amplitude of your measurement.

            You are always limited by shot noise (counting noise, quantisation noise, Poisson noise, whatever name you give it). And people love to say that you can only beat it by squeezing (increase noise in one quadrature to reduce it in another). But another option is to just increase N, turn up the laser power to have more photons or atoms in your sensor and watch your noise floor drop way faster than you will ever get using squeezing.

            Now the cold atom sensors are an interesting case. No one has managed to laser cool atoms faster than an overall rate of around 10^9 atoms per second. And we have been stuck there since the mid 2000s. As a result, the fundamental noise limit from shot noise hampers these cold atom accelerometers significantly in short term sensitivity, as they just don’t have enough N of atoms in free fall. In this case, you might look to squeeze to get a better signal, but that’s a lot of complexity for not much gain.

            There are only 2 examples I know of where squeezing has made a difference to a real world measurement. LIGO, can’t increase photons without thermally heating the mirrors too much, and confocal microscopes looking at biological samples, cant turn up the laser power without burning the tissue. In 99% of cases, just increase N to make a better sensor.

            • SmoothOperator@lemmy.world
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              6 minutes ago

              This is a rather common misconception about sensitivity, it is only true under the constraint where you are unable to increase the amplitude of your measurement.

              Aren’t there plenty of situations where you can’t increase the amplitude of your measurement? Isn’t that why we use SQUIDS for high sensitivity magnetic measurements for example?

              Quadrature squeezing is great, but I don’t think it’s the only way (or main way?) quantum sensors compete with classical sensors.

    • MalReynolds@slrpnk.net
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      14 hours ago

      Eh, boat or submarine drones can be as big as you want, and the device will only get smaller (and better).