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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

#141

Post by ClumsyPilot »

wongarsu wrote: post #107
thesz wrote: post #87

Earlier quoted context omitted.

https://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_condensa... "n condensed matter physics, a Bose–Einstein condensate (BEC) is a state of matter that is typically formed when a gas of bosons at very low densities is cooled to temperatures very close to absolute zero (−273.15 °C or −459.67 °F)..." I guess, a special device is needed. The size of such device will be in thousands of mobile phones just in volume needed…

There wasn't much money in miniaturizing them so far. Cooling down tiny amounts of matter is much easier than cooling down larger amounts, so maybe there's hope for a microchip sized BEC in 20 years.

whats the smalled device to contain a gradient of 300 degrees C?

this is a but solly, like saying you will eventually have a fridge the size if a m9bile phone - us it usefull?

Re: Royal Navy says quantum navigation test a success

#142

Post by fho »

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.

I would assume that you'd use that data in conjunction with others (sensor fusion / kalman filter).

Wenn you know you were at location X 10 minutes ago and now one sensor tells you you are at Y ... You can reasonably assume that that sensor is wrong.

Re: Royal Navy says quantum navigation test a success

#143

Post by fho »

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…

May I ask: how sensitive?

Sensitive enough to, say, detect the movement of something moving at a known frequency on the other side of the planet?

Are we on the edge of gravitation based communication channels?

Re: Royal Navy says quantum navigation test a success

#144

Post by elbigbad »

1nf_ wrote: post #79
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…

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?

Can you talk more about this source of error? When I google this, your post is the main thing that comes up for the term…

Re: Royal Navy says quantum navigation test a success

#145

Post by punnerud »

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…

Can you also use it to detect other submarines? If they affect the gravitation

Re: Royal Navy says quantum navigation test a success

#146

Post by white_dragon88 »

fho wrote: post #143
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…

May I ask: how sensitive? Sensitive enough to, say, detect the movement of something moving at a known frequency on the other side of the planet? Are we on the edge of gravitation based communication channels?

I would imagine that there is is an insane amount of gravitational noise from things like the planet’s asymmetry and events occurring all the way from the core to the crust, the ocean… to cut through that noise you need one big thumper.

Re: Royal Navy says quantum navigation test a success

#147

Post by dumbo-octopus »

punnerud wrote: post #145
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…

Can you also use it to detect other submarines? If they affect the gravitation

I wonder how close you'd need to be for any small-scale buoyancy differences to be detectable, given the entire object would clearly be neutrally-buoyant.

Re: Royal Navy says quantum navigation test a success

#148

Post by martopix »

white_dragon88 wrote: post #146
fho wrote: post #143

Earlier quoted context omitted.

May I ask: how sensitive? Sensitive enough to, say, detect the movement of something moving at a known frequency on the other side of the planet? Are we on the edge of gravitation based communication channels?

I would imagine that there is is an insane amount of gravitational noise from things like the planet’s asymmetry and events occurring all the way from the core to the crust, the ocean… to cut through that noise you need one big thumper.

The most obvious source of noise seems to me the fact that the submarine is moving and has therefore nonzero accelerations all the time

Re: Royal Navy says quantum navigation test a success

#149

Post by hwillis »

fho wrote: post #143
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…

May I ask: how sensitive? Sensitive enough to, say, detect the movement of something moving at a known frequency on the other side of the planet? Are we on the edge of gravitation based communication channels?

Local surface gravity varies by up to a ten-thousandth, about .001 m/s: https://en.wikipedia.org/wiki/Gal_(unit)

Sensitive detectors can measure differences in hundreds of millionths (10^-8 parts) or around .1 um/s^2.

A 1 million tonne mass on the other side of the earth will create a TOTAL acceleration of 4*10^-16. Changes in that will not be detectable.

Re: Royal Navy says quantum navigation test a success

#150

Post by underdeserver »

1nf_ wrote: post #79
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…

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?

The accuracy of the reading determines the error. If today's error is so large that you have to resurface for GPS several times a day to reset it, maybe this can lower that error so you only have to resurface several times a month.

Huge game changer if true.

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