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Vaccum-chamber quantum sensor device could allow GPS-free navigation

breakingdefense.com

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Re: Vaccum-chamber quantum sensor device could allow GPS-free navigation

#21

Post by snerbles »

errcorrectcode wrote: post #16

How is this an improvement over other INS like LRG? INS mechanisms suffer from the same problem: that they only detect linear or rotational acceleration. To reach position, double integration must be performed, which rapidly accumulates error (drift) because velocity and position both have to be maintained to calculate the next position. Disclaimer: Trimble Nav alum

While I heard that the effect of double integration is bad, attempting it as a student with consumer MEMS devices was quite dramatic. Really underscores the importance of Kalman filters and updates from sensors with fewer derivatives.

Re: Vaccum-chamber quantum sensor device could allow GPS-free navigation

#22

Post by [deleted] »

aaaaaaaaaaab wrote: post #2

TLDR; Sandia researches dead reckoning with a new kind of atomic accelerometer and gyroscope. It has nothing to do with avocados, aside from someone comparing the device’s size to that of an avocado, and that was probably the only thing the journalist understood so they went with it…

[deleted]

Re: Vaccum-chamber quantum sensor device could allow GPS-free navigation

#24

Post by dang »

Url changed from https://asiatimes.com/2021/11/atomic-avocado-could-change-th..., which seems to be copying from other sources and mentioning them, but not linking to them. That's a shoddy practice and from a quick look at other submissions like they do it a lot, so I've banned the site.

If anyone knows of a better article on this, we can change the URL again.

Re: Vaccum-chamber quantum sensor device could allow GPS-free navigation

#25

Post by avsteele »

The innovation here appear to be the chamber. (caveat: I still need to read the paper). A few thoughts follow.

They are going for a UHV***, probably Still a lot of other work to do though. I see a table full of optics to make the MOT*. Also see a pair of anti-Helmholtz coils for the magnetic field. They could maybe replace those coils (which probably drive a few amps) with permanent magnets (assuming they don't need to switch the fields on and off which I imagine they don't because it can't imagine a pulsed design that wouldn't risk missing data)

Passive getters work for a good long time with low leak rates. These you can just buy**. To be honest I'm not sure why you need such a fancy chamber. I'd guess a good NEG pump, a small chamber, and good seals would make you fine for a long time, but I'd need to do the math to be sure.

*https://en.wikipedia.org/wiki/Magneto-optical_trap

**https://www.saesgetters.com/products-functions/products/neg-...

***https://en.wikipedia.org/wiki/Ultra-high_vacuum

Re: Vaccum-chamber quantum sensor device could allow GPS-free navigation

#26

Post by pdonis »

yetanother-1 wrote: post #4

Yes, but how will it determine its position without a reference, I read the article and missed that concept.

> how will it determine its position without a reference

It won't. It needs a starting position from an external source, and without periodic updates from some external source, errors will build up in this system just as with any inertial navigation system. As I understand it, this system is just supposed to build up errors much more slowly than existing inertial navigation systems, so it can go longer between updates from an external source before its error becomes too large to be acceptable.

Re: Vaccum-chamber quantum sensor device could allow GPS-free navigation

#27

Post by chana_masala »

avsteele wrote: post #25

The innovation here appear to be the chamber. (caveat: I still need to read the paper). A few thoughts follow. They are going for a UHV***, probably Still a lot of other work to do though. I see a table full of optics to make the MOT*. Also see a pair of anti-Helmholtz coils for the magnetic field. They could maybe replace those coils (which probably drive a few amps) with permanent magnets (assuming they don't need…

HackerNews amazes me with how for nearly any topic there will be deep expertise in the thread. Thank you for sharing

Re: Vaccum-chamber quantum sensor device could allow GPS-free navigation

#28

Post by JohnJamesRambo »

chana_masala wrote: post #27
avsteele wrote: post #25

The innovation here appear to be the chamber. (caveat: I still need to read the paper). A few thoughts follow. They are going for a UHV***, probably Still a lot of other work to do though. I see a table full of optics to make the MOT*. Also see a pair of anti-Helmholtz coils for the magnetic field. They could maybe replace those coils (which probably drive a few amps) with permanent magnets (assuming they don't need…

HackerNews amazes me with how for nearly any topic there will be deep expertise in the thread. Thank you for sharing

But then it also usually impresses me with how people think companies haven’t thought of and tried the things they thought of in reading the article and thinking about it for a few minutes.

Re: Vaccum-chamber quantum sensor device could allow GPS-free navigation

#29

Post by kadoban »

jonplackett wrote: post #10
Snoozus wrote: post #9

Earlier quoted context omitted.

Just like dead reckoning works today, you start from a known point at known attitude and integrate up accelerations and rotations to keep an up to date position. Whenever you can get a GPS signal you use that to reduce the drift. Cheap systems can do this for seconds, 10k$ buys you 15minutes (MEMS), 100k an hour (laser gyro), everything above is under export restrictions and NDAs so noone will tell you what the state…

The whole premise that this might be something in everyday use one day seems completely flawed. Even at the 1cm cube of physics it’s huge compared to GPS and it uses incredibly expensive materials. If you’re a nuclear submarine or stealth bomber it makes loads of sense. For anything else I don’t really get the point.

If you're anything to do with military, I bet you _really_ badly want this over GPS. GPS can be spoofed or blocked over an area. So every drone, every group of soldiers, every truck, every boat really needs one.

Even just as a person, having a nav system that doesn't need to sync before it can be used would be nice, and no possible issues with buildings, trees, hills, etc.

Re: Vaccum-chamber quantum sensor device could allow GPS-free navigation

#30

Post by namibj »

errcorrectcode wrote: post #16

How is this an improvement over other INS like LRG? INS mechanisms suffer from the same problem: that they only detect linear or rotational acceleration. To reach position, double integration must be performed, which rapidly accumulates error (drift) because velocity and position both have to be maintained to calculate the next position. Disclaimer: Trimble Nav alum

No, you can measure absolute rotation speed. Yes, via a good ring laser gyro. You just can't measure absolute linear speed.
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