Royal Navy Tests Quantum Navigation

GPS has changed the way we get around the globe. But if you command a warship, you must think about what you would do if an adversary destroyed or compromised your GPS system. The Royal Navy and Imperial College London think a quantum navigation system might be the answer.
Of course, Heisenberg says you can’t know your speed and position simultaneously. But at the real-world level, you can apparently get close enough. The quantum sensors in question are essentially accelerometers. Unlike conventional accelerometers, though, these devices use ultracold atoms to make very precise measurements using a laser optical ruler, which means they do not drift as rapidly as, say, the accelerometer in your phone. Navigating with accelerometers is well understood, but the issue is how often you have to correct your computed position with an actual reference due to drift and other error accumulation. You can see a Sky News report on the trial below.The tests were done in a rapid prototyping pod carried onboard XV Patrick Blackett, a fitting name for an experimental ship since Lord Blackett was a Nobel laureate and head of the physics department at Imperial College for a decade ending in 1963. The underlying tech came out of the university back in 2018, but making it work in a real-world environment onboard a ship is another matter. You probably won’t have the cryonics and lasers needed for such a quantum compass anytime soon in your smartphone, but the tech could have civilian applications for larger vehicles.

32 thoughts on “Royal Navy Tests Quantum Navigation

        1. About 5 years ago there was a whole thing about blockchain. Any projects that could even say they had it in the process were given funding and time to investigate their feasibility and a lot of them were funded (even though there were better methods to do what people wanted to do, as in my opinion blockchain has very few use cases outside of anything transactional).

          A few years before that it was cloud.
          A few years before that it was smartphone apps.

        2. Who were you referring to? The guy who uses puffery to increase the odds of getting his grant, the guy who approves a grant on the basis of puffery, or the forum poster who noted that this occasionally happens?

    1. Can’t believe how many versions of this news item I’ve now seen without people realising it’s just inertial navigation. The paper this is based on is four years old and also doesn’t mention it clearly.

  1. Navigation using inertial positioning techniques with fixed, recognized positions can even accommodate real shifts due to earthquakes and such without the need for quantum effects that only occur near absolute zero still seems the best approach.

    Somewhat low tech but can make use of AI and terrestrial data readily available. No need for constellations of GPS satellites either. Just a bunch of data creating, 3d image snapping remote vehicles/drones.
    The collected data, which include fixed reference points can create an accurate map of the terrain in question. No need for GPS satellites.

      1. Exactly.

        Once worked in submarine control systems where inertial navigation was the ONLY source of navigation information when running submerged. Don’t remember the exact performance numbers but it was something on the order of a hundred yards per hour drift. That’s fine if you’re running submerged in the middle of the atlantic for a few hours, less fine if you’re trying to sneak through narrow straits very slowly.

        1. Only if you:

          a) Have accurate ocean floor maps (not a guarantee, even today)

          b) Can image the ocean floor without being detected. Active SONAR is contraindicated when in sneaky-beakey mode, optical imaging has very limited range underwater )even if you assume nobody will see your LASER pulses, you can only map a small area of seafloor, so you need exquisitely high resolution seafloor maps to match to).

          At best, you might be able to achieve some sort of optical odometry in situations where you can travel not far above the sea floor (or not far below an ice cap), but this is not always possible.

    1. Yes… but it’s not inappropriate for a warship. They try to be prepared for things like a bunch of flimsy satellites being comploded. Remember it might be the RN that takes out the satellites, if you can navigate better than everyone else it gives you a tactical advantage.

  2. Heisenberg only puts a limit on how precisely you can know something’s position and momentum. That limit is so ridiculously low in comparison to the size of the ship that it is irrelevant, the flexing, stretching, etc. of the hulls and other measurements errors handily eclipse any uncertainty due to Heidegger’s principle.

  3. i wouldn’t necessarily assume “You probably won’t have the cryonics and lasers … anytime soon in your smartphone” :)

    the way these problems scale can be really astonishing from an end-user perspective. it will take some advancements but if you can reduce the size of your system to much less than a miligram of supercooled material then the heat output of your cooling system doesn’t need to be more than a few miliwatts. once the details are worked out, a lot of these things that are incredibly difficult at a large scale with giant exotic machines filling your laboratory become incredibly trivial at a tiny scale.

    not that cutting a few zeroes off the inertial nav drift in your phone is such a high priority…but having inertial navigation in your phone at all isn’t even a priority and it only happened because once people invented a small enough “gyroscope” it became dirt cheap to put one everywhere. that kind of step will keep happening.

    just a little wild eyed optimism for your morning :)

    1. ^This. I remember about 40 years ago when I was applying to the Air Force Academy, one of the lectures we received was on the accuracy of fighter jet navigation systems. Simply based on the inertial navigation system present at that time, we were told a jet fighter could fly from one end to the other and back and then land within just a few feet of where it started. May have just been folklore but that was 40 years ago.

  4. The idea of using a super-stable collection of atoms floating in a vacuum to precisely track position is reminiscent of the so-called “Drag-free satellite” idea first published around 1962, and finally used in 2004 for Gravity Probe B and later several other satellites requiring super-precise orbits.

    The idea is that a very precise proof mass is free-floating in a cavity inside the satellite, unperturbed by solar radiation, residual air drag, etc., an so follows a perfect orbit defined by the gravitational field it is in. The satellite surrounding the proof mass maneuvers itself with thrusters to keep that mass centered in its cavity, and so also follows that ‘perfect’ orbit.

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