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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

#131

Post by westurner »

samus wrote: post #106
otikik wrote: post #54

Earlier quoted context omitted.

A submarine itself is quite massive, and has big moving parts (e.g. the rotor). The crew has less mass, but it would be very close, and also in constant movement. Wouldn’t this interfere with those measurements? Would they need to stop the engine and play “frozen TikTok” while the measurement device is active?

Surely the influence of some of these sources of noise can be modeled and filtered out. A University of Vienna currently conducts experiments to measure the gravitational force at very small sales, and they already have to do this with things like crowds moving about the city during rush hours.

Sources of Noise?!

Doesn't that mean that the gravitational field is an information storage and transmission medium; a signal channel?

Is it lossy?

Is there a routable signal path to block harassing calls?

Is it slower or cheaper than nonlocal entanglement; like quantum radar?

What is the minimum energy necessary to cause a propagating thresholdable-as-binary pertubation of a gravitational field?

Re: Royal Navy says quantum navigation test a success

#132

Post by LgWoodenBadger »

kebman wrote: post #24

A friend of mine got PTSD from piloting huge nuclear subs in subsea ravines with a clearing of only one inch on each side of the sub. One wrong move, and the entire crew is gone. He also had to do this in conditions similar to surface storms. Looks like autonomous or automatic systems may be developed for those kinds of manoeuvres now, if it is truly that precise. Seems like a huge leap in navigational systems.

Oh come on...

"On 8 January 2005 at 02:43 GMT, San Francisco collided with an undersea mountain about 364 nautical miles (675 km) southeast of Guam while operating at flank (maximum) speed at a depth of 525 feet (160 m)."

https://en.wikipedia.org/wiki/USS_San_Francisco_(SSN-711)

Re: Royal Navy says quantum navigation test a success

#133

Post by vesinisa »

avidphantasm wrote: post #126

This sounds like fancy next-gen inertial navigation. You’ll still need charts (and ENCs) and still need GPS (for periodic updates to the inertially derived position).

Inertial navigation is a form of dead reckoning. It needs periodic updates (GPS fixes) to stay accurate.

If this however works like some other commenters have theorized (by finding reliable matches to the known contour of the bottom of the ocean), it's not a form of dead reckoning and can instead be used as a fix for dead reckoning.

Re: Royal Navy says quantum navigation test a success

#134

Post by Retric »

mc32 wrote: post #122
beambot wrote: post #117

Earlier quoted context omitted.

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.

Traditional dead reckoning is reasonably accurate over moderate timescales in the mostly empty ocean as subs are big/stable and relatively slow. Thus the existing approach of only occasionally surfacing for GPS. This is therefore more a supplement as being able to regularly recenter even a few times a day is good enough.

Re: Royal Navy says quantum navigation test a success

#135

Post by adonovan »

westurner wrote: post #131
samus wrote: post #106

Earlier quoted context omitted.

Surely the influence of some of these sources of noise can be modeled and filtered out. A University of Vienna currently conducts experiments to measure the gravitational force at very small sales, and they already have to do this with things like crowds moving about the city during rush hours.

Sources of Noise ?! Doesn't that mean that the gravitational field is an information storage and transmission medium; a signal channel? Is it lossy? Is there a routable signal path to block harassing calls? Is it slower or cheaper than nonlocal entanglement; like quantum radar? What is the minimum energy necessary to cause a propagating thresholdable-as-binary pertubation of a gravitational field?

It sure is a medium! One Denver (IIRC) gravitational experiment could measure the field distortion caused by 100,000 people and cars at a local sports arena. [citation needed]

Re: Royal Navy says quantum navigation test a success

#136

Post by krisoft »

jofer wrote: post #100
krisoft wrote: post #95

Earlier quoted context omitted.

> The biggest issue is that you also need to know absolute elevation very precisely to use the measurement of g that you get. I don't think so. What you are saying is true if for some reason you want to work with absolute values, but nobody would do that. You measure many data points as your submarine flies over the landscape for a time, and then you match the measured curve with predicted curves from bathymetric map…

> What you are saying is true if for some reason you want to work with absolute values, but nobody would do that. You measure many data points as your submarine flies over the landscape for a time, and then you match the measured curve with predicted curves from bathymetric maps. The variations due to changes in elevation are orders of magnitude larger than the variations you're relying on using for navigation. Dista…

> However, nothing about this requires a new quantum sensor.

Sure. The news can be many thing. Maybe they got a marginally better gyroscope. Maybe it is not better in terms of better error characteristic, but cheaper, or smaller, or lower maintenance.

Or maybe they got a new software package which brings them benefits, but the way they could sell it to the leaders is by telling them that the sensor they are using is "quantum".

Or maybe none of the above and they are just trying to fake out an adversary to trigger a costly mistake.

Re: Royal Navy says quantum navigation test a success

#137

Post by samus »

westurner wrote: post #131
samus wrote: post #106

Earlier quoted context omitted.

Surely the influence of some of these sources of noise can be modeled and filtered out. A University of Vienna currently conducts experiments to measure the gravitational force at very small sales, and they already have to do this with things like crowds moving about the city during rush hours.

Sources of Noise ?! Doesn't that mean that the gravitational field is an information storage and transmission medium; a signal channel? Is it lossy? Is there a routable signal path to block harassing calls? Is it slower or cheaper than nonlocal entanglement; like quantum radar? What is the minimum energy necessary to cause a propagating thresholdable-as-binary pertubation of a gravitational field?

Not a formal definition, but noise is simply the undesirable parts of the output of any information processing device, be it a sensor, an amplifier, or a transmission medium. But on Earth it's simply not practical as such. Gravitational waves observatories are used to detect events such as neutron star or black hole mergers that are otherwise unobservable, but they require an insane level of precision to be detected.

Re: Royal Navy says quantum navigation test a success

#138

Post by bluGill »

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…

The earths magnetic field is not constant. I don't know how much it changes, but I know magnetic north drifts a bit every year. And every once in a while the field reverses (IIRC we are like 10k years overdue for a reversal if we read the history of them right - a lot of guesses go into that of cousre)

Re: Royal Navy says quantum navigation test a success

#139

Post by BiteCode_dev »

beloch wrote: post #9
Animats wrote: post #4

Is there any info on this from a reliable source? No idea what "quantum" means here. Remote entanglement? Some new kind of gyro? There's something called a "quantum gyroscope".[1] Those exist as lab devices. One good enough for a submarine seems not too big a jump. [1] https://physics.aps.org/articles/v8/11

The article lacks detail, but sounds like it's talking about something like an atomic gyroscope[1]. There are a few types of passive quantum navigation systems, but the principle is similar to a using a stopwatch and an old-school gyroscope to measure changes in momentum and then calculating your position via dead reckoning. It just sounds like quantum methods have let them get a lot more precise. This is actually pr…

This is pretty exciting from the perspective of any kind of navigation. If this gets into a phone, we will be able to navigate on a digital map with no signal at all.

Re: Royal Navy says quantum navigation test a success

#140

Post by igufogkgg »

unyttigfjelltol wrote: post #114
mytailorisrich wrote: post #97

Earlier quoted context omitted.

No, as the parent said it isn't. This is why you can create a map of the variations like this one: https://svs.gsfc.nasa.gov/11234

Undersea mountains have gravity signatures very similar to overland mountains, even though the latter are significantly closer to space?

"Closeness to space" doesn't affect the gravitational force due to a particular piece of matter. Now, if water was as dense as rock, then undersea mountains wouldn't make such a difference to the gravitational field.

I'm trying to understand why you think "closeness to space" would be a factor. Maybe you are thinking that the seabed is going to be further from a detector than the terrain would be?

It is true that the further from the Earth the detector is, the smaller the anomaly will be.

Note that even hills are large enough to deflect the gravitational vector at the surface: https://en.wikipedia.org/wiki/Vertical_deflection

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

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