
UK scientists build world’s first quantum compass - olivermarks
https://www.ft.com/content/e90f902a-e441-11e8-a6e5-792428919cee
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sgt101
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?

~~~
dmos62
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.

~~~
sgt101
Thank you for the feedback, it's made me smile.

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Ninjaneered
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?

~~~
craftyguy
> 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.

~~~
Ninjaneered
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.

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drivingmenuts
“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?

~~~
trhway
>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).

~~~
KineticLensman
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...](https://www.defensenews.com/breaking-news/2017/11/01/navy-crews-at-
fault-in-fatal-collisions-investigations-find/)

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neonate
[http://archive.is/FUakE](http://archive.is/FUakE)

~~~
zeristor
Thanks for the link, the article references:

UK National Quantum Technologies Programme

[http://uknqt.epsrc.ac.uk](http://uknqt.epsrc.ac.uk)

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

[https://www.imperial.ac.uk/news/188973/quantum-compass-
could...](https://www.imperial.ac.uk/news/188973/quantum-compass-could-allow-
navigation-without/)

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](https://arxiv.org/pdf/1603.03246.pdf)

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

~~~
DEADBEEFC0FFEE
What I find interesting is that if potential subscribers cannot read the
articles, how will they come feel the articles are worth subscribing too?

~~~
timthorn
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.

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zeristor
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.

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

~~~
dmitrygr
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.

~~~
jfoutz
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.

~~~
dmitrygr
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.

~~~
jfoutz
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.

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

~~~
sorenjan
> 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.

~~~
Jemm
I think the term is Inertial Navigation.

[https://en.wikipedia.org/wiki/Inertial_navigation_system](https://en.wikipedia.org/wiki/Inertial_navigation_system)

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sfcguyus
Better than Galileo I suppose.

~~~
diplocorp
What’s wrong with Galileo? Mind elaborating?

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aeosynth
_Compass_ , not computer, for those that misread the title.

