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Royal Navy says quantum navigation test a success

thequantuminsider.com

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Re: Royal Navy says quantum navigation test a success

#121

Post by 1letterunixname »

andyjohnson0 wrote: post #83
gnfargbl wrote: post #36

The Imperial College researcher who builds these things describes his research here: https://www.imperial.ac.uk/centre-for-cold-matter/research/q... The page claims that this device attempts to measure acceleration accurately enough that position can be determined (by integrating over time, twice).

I'm not a physicist but this reads like a more sensitive type of inertial navigation, which currently uses gyroscopes. https://en.wikipedia.org/wiki/Inertial_navigation_system

Vacuum mechanical gyros were used until about the 1960's when lasers (RLGs) were introduced. In the 90's, some RLGs were replaced by HRGs where space is at a premium for Q around 1e7-8. Very large RLGs are still used to detect very slow rotation and can have Q factors on the order of 1e13.

Re: Royal Navy says quantum navigation test a success

#122

Post by mc32 »

beambot wrote: post #117
1nf_ wrote: post #79

Earlier quoted context omitted.

The majority of INS platform drift is from a thing called "tilt error" - where the IRS initially misjudges the exact direction of the gravitational vector during alignment. All this will do is improve the accuracy of the accelerometers but will still have the drift caused in the INS itself. How will this make such a large improvement over what we have already?

Let's use a magnetometer as an example. Inertial navigation system (INS) is just using the magnetometer as a compass, so errors in bearing accumulate over time. Instead, if you built a map of magnetic field strength, the slight spatial variation of field strength would let you precisely localize on the map. In robotics parlance, this is the difference between dead reckoning versus SLAM (simultaneous localization and…

Then it looks like underwater landslides, volcanoes and earthquakes could throw things off from time to time.

Re: Royal Navy says quantum navigation test a success

#123

Post by hackernewds »

jchallis wrote: post #13

This is the most obvious practical application of my PhD topic. A Bose Einstein Condensate is an extremely sensitive detector of gravity- a nuclear submarine could use it to make an ultra-accurate map of the world based on variations in the gravitational constant g. This would remove one of the primary reasons subs need to surface , in order to GPS lock. It’s a naval chart that would not require surfacing. A French p…

what a sad outcome it is that research such as this is funded for, and classified by military interests such that it is barred from public collaboration and societal progress

Re: Royal Navy says quantum navigation test a success

#124

Post by 1letterunixname »

snovv_crash wrote: post #39
jchallis wrote: post #13

This is the most obvious practical application of my PhD topic. A Bose Einstein Condensate is an extremely sensitive detector of gravity- a nuclear submarine could use it to make an ultra-accurate map of the world based on variations in the gravitational constant g. This would remove one of the primary reasons subs need to surface , in order to GPS lock. It’s a naval chart that would not require surfacing. A French p…

Isn't this the method used by the sub in Hunt for Red October? Or did they also use a gyroscopic and look for changes in the gravitational vector, not just its magnitude?

Passive sonar in the SOFAR channel.

Re: Royal Navy says quantum navigation test a success

#125

Post by phkahler »

RobotToaster wrote: post #118
jchallis wrote: post #13

This is the most obvious practical application of my PhD topic. A Bose Einstein Condensate is an extremely sensitive detector of gravity- a nuclear submarine could use it to make an ultra-accurate map of the world based on variations in the gravitational constant g. This would remove one of the primary reasons subs need to surface , in order to GPS lock. It’s a naval chart that would not require surfacing. A French p…

Couldn't it also be used to detect submarines as well then? Given they're quite big.

They have the same (average) density as water.

Re: Royal Navy says quantum navigation test a success

#127

Post by johndunne »

HyperSane wrote: post #26
themodelplumber wrote: post #19

Earlier quoted context omitted.

Fascinating. Q for you since you are so clued in. I am a ham radio operator and was thinking about novel forms of signal propagation. I landed on the idea of gravitons. Could gravitonic signal propagation be done somehow? While researching, I keep coming across familiar terms I know from radio land. Just curious if the fields here could be harnessed for communication. Thanks.

Gravity waves are way too hard to detect and generate to be used for communication. The waves we can just barely detect too 8 solar masses worth of energy to generate.

Remember that that 8 solar mass gravity wave source is potentially 100’s millions of light years away. A sci-fi author could conjure up a ‘portable box’ containing a couple of orbiting micro-scopic black holes in a box to generate gravity wave signals someone somewhere in the solar system could pick up with a portable LIGO device. Consider this comment a patent on the idea :-)

Re: Royal Navy says quantum navigation test a success

#128

Post by 1letterunixname »

kebman wrote: post #30
rocqua wrote: post #25

I'm surprised we don't see more military research for SAT-NAV alternatives. In any big conflict SAT-NAV is trivial to turn off. If you can still position yourself and your enemy can't, that is an enormous advantage in targeting, logistics, coordination, and situational awareness. Seems like a no-brainer.

You're probably surprised that you don't see it, because it's top secret. Here's an example of something you don't hear about: AI Assisted Battlefield Tactics. While I've never heard of it (certainly not in the press), I simply assume that they're doing research on it. I base this assumption on the AlphaStar AI from DeepMind that would completely pawn Grand Masters in the game of StarCraft 2. While AlphaStar is obvio…

There are plenty of niches but most people aren't aware of them: surveying and navigation. There's nothing particular secret about an RLG or an MRG at this time. There are enough examples of civilian industrial equipment using them. There are also MEMS-based accelerometers, such as those in your phone, and ones with several orders more precision and accuracy.

Applications include:

- Underground

- Under dense rainforest canopy where GNSS signals don't reach

- In narrow and deep valleys

- Salt water deeper than 200 mm

- In space, far away from GNSS systems (GNSSes work in space)

Source: I may have wandered through Trimble Nav Ltd. once or twice.

Re: Royal Navy says quantum navigation test a success

#129

Post by closewith »

wongarsu wrote: post #105
rogers18445 wrote: post #29

Earlier quoted context omitted.

What would you do with the g measurement to get your location? Can g deltas be matched to sea floor contour maps? Otherwise it seems like subs would have to be following g-mapped routes.

I'd assume features below the sea floor have a much bigger impact than surface features. Large iron deposits, volcanic activity, natural gas deposits, whatever the LLSVPs are, etc. But you could use ships to correlate gravity measurements with GPS locations and make an accurate map that way. You don't need to map the entire ocean, just enough locations to allow subs to occasionally recalibrate their position.

>LLSVP

Large low-shear-velocity provinces, for anyone else wondering: https://en.wikipedia.org/wiki/Large_low-shear-velocity_provi...

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