UK scientists build world’s first quantum compass | Hacker News Reader

UK scientists build world’s first quantum compass

ft.com

53 pointsolivermarks34 comments

It's likely that they've been using it for a long while - probably explains the first of the Astute navigation accidents. The fact that it happened in the sound of Skye was always odd. I'd imagine that the announcement is because the Russians and Chinese have been messing about with signals round RN assets (for example Lizzy) which have then been serenely and obviously ignoring the fandangling. At some point the we know you know we know thing stops being worth the bother, and I guess that the EU's messing about over Galileo meant that the sovereign deterrent would have looked implausible.

I'm guessing that this was about priority 3 on the nuclear sub quantum tech wish list. Priority 1 must always be stealth and sensing (avoiding merchant vessels could be a good thing), priority 2 must be comms as in how do you distribute orders when you have decommissioned your ultra long wave network?

It's early morning for me. I'm reading this having compulsively typed in the address for HN after turning on the computer. I have to say your comment is probably very concise and full of insight, but it reads to me like a Alice-in-Wonderland type thing. Paraphrasing what my first reading picked up:

> It's likely that they've been using it for a long while ...

What a great start for a story.

> Astute navigation accidents ... sound of Skye ... odd ... messing about with signals ... Lizzy ... serenely and obviously ignoring the fandangling ... we know you know we know ... bother ... messing about over Galileo ... implausible ... priority 3 ... nuclear sub ... quantum ... Priority 1 ... stealth and sensing ... merchant ... comms as in how ... your ultra long wave network.

This is the kind of downpour of imagery and imagination people take drugs for, and it all has this pleasant quality of wonder, spy-science-fiction crossed with literary-nonsense-fantasy. Thank You.

Thank you for the feedback, it's made me smile.

Basically it uses dead reckoning then. Cool stuff! There are other velocimeters, accelerometers, etc. that do that as well, the important part is the amount of error that builds over time. I wonder what this "quantum compass" has for error?

> The quantum device measures the movement of supercooled atoms at extremely low temperatures — close to absolute zero

Well, quite an improvment over traditional 'dead reckoning'. This is basically a more accurate inertial navigation system.

Unless corrected by additional positional information (GPS, landmarks, etc.) inertial navigation is completely reliant on dead reckoning. Any system that uses this has cumulative error. I'm guessing (like you) that these "quantum compasses" provide a much lower error, just now sure how much.

The cumulative error always exists because any sensor introduces error (I'm ignorant of anything "quantum" though). This means if you have several inputs (velocimeter, accelerometer, gyroscope, magnetometer, etc.), you are introducing multiple forms of error, each with it's own error band. Interestingly, there is an algorithm called a Kalman filter that takes in all these inputs and can spit out a best estimate for navigation, it's pretty amazing.

“Pirates are now sophisticated enough to cause disruptions to ships, and lure them to rocks or take over and board them, by disrupting GPS,” said Graeme Malcolm, founder and CEO of M Squared.

Whaaat?!?!?!

Where do I read reports about these pirates pulling sci-fi techniques on shipping?

>sophisticated enough to cause disruptions to ships, and lure them to rocks

those 2 US destroyer accidents do look like a GPS interference pulled [probably as a test] by a pretty sophisticated power (not pirates obviously, yet one can expect that the tech is leaking and spreading around).

No, the accidents involving the USN Destroyers were due to poor bridge procedures [0].

[0] https://www.defensenews.com/breaking-news/2017/11/01/navy-cr...

http://archive.is/FUakE

Thanks for the link, the article references:

UK National Quantum Technologies Programme

http://uknqt.epsrc.ac.uk

Here's the press release from the university where the work was done:

https://www.imperial.ac.uk/news/188973/quantum-compass-could...

As other people have mentioned, this isn't so much a compass, as am accelerometer. With it you can use dead reckoning to infer your position.

One of the problems with current system (for example MEMS accelerometers), is that any small offset at zero acceleration will cause position errors which accumulate quadratically with time. In theory at least, these quantum accelerometers provide a accurate, stable measure of the absolute acceleration.

Here's a paper detailing some of the physics behind the device:

https://arxiv.org/pdf/1603.03246.pdf

is there a netflix for newspapers? With all the press going subscrition based how can one read these articles?

What I find interesting is that if potential subscribers cannot read the articles, how will they come feel the articles are worth subscribing too?

By reading the physical paper, which is often made available by employers? The FT serves a market segment that knows the paper and has the funds to pay for it.

I find there's usually another source:

https://phys.org/news/2018-11-quantum-compass-satellites.htm...

https://www.scribd.com/magazines

Blendle: https://launch.blendle.com, my do the trick if you want to pay something.

It is originally from the Netherlands. I don't know how comprehensive it is for English periodicals.

http://inkl.com is pretty much that

As an aside have mobile phone MEMS systems improved much over the years (MRI He flushing excepted)

It would be nifty to have an app to map tunnels on a phone, but my cursory research suggests it’s too dire, mind you I should try and write one all the same.

How is this not big news? It sounds like it’s going to unseat GPS as the de facto navigation system.

Because you didn't read. This is just a fancy accelerometer. You need to integrate it to infer position. Repeated integration always produces errors. Even this accelerometer being 1,000 times more precise than existing ones doesn't help with how math works. Integration will always produce errors.

So, sure. I’ve written velocity guessers based on spinning rust disk accelerometers. It’s easy to build a poor quality system. But an afternoon hack can get you to a few percent accuracy.

Analog integration will improve your accuracy a ton. Multiple systems, averaged will improve accuracy even more.

Sure, there are problems. But tomahawk missiles use inertial guidance. Autopilots do it to. More data will give better answers. But don’t sell ig short. You can get very good answers.

Real gyro != Mems gyro.

Real gyro is REALLY rigid in space. Mems gyro isn't. It causes errors after mere minutes of integration. INS systems in planes and gyros in missiles are REAL gyros. This isn't. This is more like a better mems system.

It seems like the jury is still out. Perhaps 10,000 of them work out better than a large system. It’ll take time for a lab experiment to turn into a production system.

You’re probably right in the short term, for an arbitrarily large value of short.

I remember reading an article a few months ago (I guess here) about a precursor to GPS based navigation for cars that used inertial guidance. You needed to set the location when you started driving, but after that it just used inertial guidance to figure out your position.

I really wish smartphone navigation apps would use this, as I've ended up taking the wrong directions in tunnels or at the exits of tunnels (as it takes a few seconds to get a GPS fix).

Nowadays high-end accelerometers/gyros use fiber optic interferometers much more precisely than previously possible.[0][1]

[0] https://www.nist.gov/news-events/news/2017/03/measuring-acce... [1] https://en.wikipedia.org/wiki/Inertial_navigation_system#Fib...

The article almost makes it sound like the implementation is such that it only makes sense for extremely large vehicles. It will likely be a long time before it becomes small and cheap enough to replace a significant fraction of GPS uses.

I’m dumb: how does a quantum accelerometer make for something that can replace GPS?

> Although precise accelerometers exist in devices such as mobile phones and laptops, they must be recalibrated frequently and can only be used to navigate for up to a few hours at a time.

This sounds like they're using dead reckoning, i.e. integrating the acceleration twice to get the displacement from a known starting position. Regular accelerometers are too noisy and have a large drift because of this. Noise get's amplified when integrated, so if you're integrating twice you'll need a really low noise source.

I think the term is Inertial Navigation.

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

Better than Galileo I suppose.

What’s wrong with Galileo? Mind elaborating?

Compass, not computer, for those that misread the title.

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