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Comment by sandworm101 | Hacker News Reader

>>> It will never replace GNSS.

It will have to. That is the point. This isn't about better in-car navigation. The big money behind quantum gyroscopes is the potential to guide submarines/aircraft/missiles in times of war when the GNSS systems are down or otherwise unreliable, just like the best of traditional gyroscopes. Dead reckoning is a legitimate means of navigation, but there are also some aspects where actual replacement of GNSS might happen. An extremely sensitive gyroscope could probably determine latitude based on the earth's rotation (Foucault Pendulum). Then layer on a detailed map of variations in the earth's gravity and/or magnetic fields and one might be able to pinpoint a location absent external signals.

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

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Fair point, this would fit quite snugly on a ship or a sub.

the real ones will probably smaller.

I wonder will having more than one improve accuracy.

Never go to sea with two chronometers, take one or three.

Man with one clock, always knows what time it is. Man with two clocks... never quite sure.

You could combine it with another IMU using a Kalman filter and improve accuracy that way.

That's an extremely niche application unlikely to be scaled down to anything smaller than a backpack like laser ring gyros. As such, this type of positioning gear isn't for consumer use and is targeted mostly for underground surveying.

(I worked for Trimble.)

...yeah? I don't think anyone has claimed they're developing this for consumer use.

... that could replace GPS

That's the implied application, which is wrong.

... and GPS was initially developed for - right, the military.

GPS can and was miniaturized. LRGs and QGs aren't for retail use because they're very expensive, bulky, and largely unnecessary.

F(T) != F(T+1)

I, for one, am glad to see people working to innovate along well-trodden paths.

Yes, for their relevant applications. If you were a commercial spelunker or were the Ukrainian army needing to lob missiles into Russia that were impervious to encrypted GPS jamming, then you would gladly welcome your quantum overlords. Neither LRG or QG are ever going to be made into MEMS devices shoved into an iPhone. Its application is dead reckoning. For the use-case of navigation underground useable by everyday people, Skyhook-like services that rely on 5G UWB microcells are the most likely evolution beyond relying on Wi-Fi SSIDs and conventional cell towers for tower-assisted GNSS.

Why does it matter if it's not for consumer applications? GNSS is used for many more applications (and arguably more critical) than consumer applications (agriculture, mapping & surveying, aeronautics, shipping, etc.)

Also just want to mention that, yes, integration errors accumulate when using intero-receptive sensors but if errors are small enough (white noise, various biases, sample rates, quantization, etc.) from the inertial sensors an odometry solution might be adequate until an extero-receptive sensor can localize the sensor within an external frame.

This can shift the discussion from solving a problem that has no solution (i.e. how do I integrate a signal with white noise without any error) to an engineering problem (i.e. what error parameters allow the odometry to be accurate within x% over some timeframe).

There was interesting work DARPA was sponsoring around the above idea that you can read more about here: https://www.darpa.mil/program/micro-technology-for-positioni...

>The end goals of the TIMU program are the demonstration of a single-chip IMU which maintains an accumulated position error of less than 1 nmi/hour with device volume of less than 10 mm3 and power consumption of less than 200 mW.

(My job is related to estimating location of things).

nmi - Nautical mile (1 nmi/hour mentioned above)

Today the international nautical mile is defined as 1,852 metres (about 6,076 ft; 1.151 mi).

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

When one of the potential customers in this "extremely niche" space has an $800 billion annual budget, you don't lose sleep over it.

Underground surveying or jam-proof guidance for long range ordinance?

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