this post was submitted on 29 Aug 2026
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[–] charles@lemmy.charles.wiki 3 points 54 minutes ago

The only significant word here is "quantum". This stuff is too expensive to be useful for anyone other than the military right now. Gravity maps are controlled information as well. Used for ballistic submarine missiles. The maps created by the military will never be made public. (It would look like a highway of where every vessel is or will be)The accuracy of satellite measurements is 3km, with physical topographic (sea/land) resolution at 1.2km. The long-term plan is to have these sensors traverse areas, record data, and then share it with a database. Even those maps are realistically only 300m~ in resolution. Compare that to GPS, which has a nominal resolution of 3m with 15 satellites, or about a foot, with a correction from ground relays. (I remember using a handheld device that would tell you how many you were connected to, and it stopped working once you were near a tree.) Gravimeters have been used by submarines since the 1980s.

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

[–] rob_t_firefly@lemmy.world 11 points 2 hours ago (2 children)

The trouble with Quantum Navigation is you might end up where you were trying to go, but at a random point in the past where you have to change history to put right something that once went wrong.

[–] floofloof@lemmy.ca 3 points 44 minutes ago

As long as you keep it below 88 miles per hour you'll be fine.

And you'll never be able to return home too.

[–] vane@lemmy.world 2 points 1 hour ago

Perfect for autonomous military robots.

[–] diaphragmwp@discuss.tchncs.de -1 points 1 hour ago (1 children)

Wow, more AI. For some reason. This doesn't sound like it needs AI but the investors would pay less, of course!

[–] boonhet@sopuli.xyz 4 points 1 hour ago* (last edited 1 hour ago)

Chances are AI is easier than hand-rolling an algorithm for this. And that AI is almost certainly not an LLM.

[–] WhatThaFudge@lemmy.world 6 points 5 hours ago

The Quantum Compass! Sick!

[–] melsaskca@lemmy.ca 5 points 5 hours ago (1 children)

The gravitational pull is stronger on the left side so you have to account for that or else you'll just sail around in circles. /s

[–] TrollTrollrolllol@lemmy.world 1 points 1 hour ago

Most sailors spend their whole lives sailing around in circles

[–] Dimand@aussie.zone 54 points 11 hours ago
[–] hamsamrich@lemmy.world 136 points 14 hours ago (17 children)

“Quantum sensors can sense the tiniest of changes in the gravity or magnetic field and use a previously prepared map of these properties to determine their location. Since a quantum sensor does not need to receive or send a signal to an external device, it cannot be hacked or be spoofed by a fake incoming signal either. “ Very cool!

[–] Knock_Knock_Lemmy_In@lemmy.world 5 points 4 hours ago (1 children)

Why do we expect this quantum map of gravity and magnetic fields to be permanent?

[–] frongt@lemmy.zip 8 points 3 hours ago (1 children)

Why do you think they expect it to be permanent? We survey all kinds of stuff like this all the time.

[–] Knock_Knock_Lemmy_In@lemmy.world 5 points 1 hour ago (1 children)

Geography and celestial maps are permanent (mostly).

The next question is, how long until a quantum measured map becomes unrecognised? Is the half life years or hours?

[–] silicon@lemmy.dbzer0.com 1 points 1 hour ago

I'm guessing remote sensing will be involved with keeping the maps accurate.

[–] MangoCats@feddit.it 7 points 4 hours ago (3 children)

Two issues I have with the presentation:

A magnetic field is an external signal - the Earth's magnetic field is actually incredibly weak...

10x better performance than GNSS ... positioning accuracy of 1 nautical mile. Cheap old school handheld GPS out in the woods was accurate better than 10 feet most of the time, so what in this performance is 10x better? 10x more resistant to jamming? Seems like it should be completely impervious to jamming. 1 nm accuracy is useful, but hardly better performance.

[–] postmateDumbass@lemmy.world 5 points 1 hour ago

For those confused:

nm means Nautical mile here, not nano meter

[–] lefaucet@slrpnk.net 3 points 1 hour ago (1 children)

GPS is vulnerable to various attacks.

It's unclear what the capabilities are, but there IS a Russian satellite that HAS jammed GPS for almost a whole hemisphere. It's operated several times for a couple seconds over these past few years.

Veritassium did a great presentation on how we know this.

https://youtu.be/tz23G_UXCGA

[–] Cethin@lemmy.zip 1 points 27 minutes ago

I don't recommend Veritassium anymore. It's not the same channel it used to be. It was sold to a private equity group, and now makes garbage.

Here's an article: https://arstechnica.com/space/2026/06/tests-suggest-russian-satellites-can-jam-gps-on-a-continental-scale/

[–] ButtDrugs@lemmy.zip 7 points 4 hours ago (1 children)

Its better performance than existing non-gps systems - not better than GPS. For ships , being within 1nm after thousands of miles of travel is really well performing. Obvious the real play here is weaponry though, since GPS isnt reliable in warfare and on-board sensors can do the detail work of target identification once in an area, the hard part is a way for them to self navigate accurately over long distances without GPS.

[–] frongt@lemmy.zip 7 points 3 hours ago (2 children)

The realer play is submarines. You don't get any satellite signal at all underwater. Before this it was only INS or dead reckoning.

[–] postmateDumbass@lemmy.world 2 points 1 hour ago

Im pretty sure there were underwater beacons they used for aiding their navigation. Active or passive, man made or natural phenomena....

[–] CookieOfFortune@lemmy.world 1 points 1 hour ago (2 children)

I suspect submarines can also use bottom facing radar to track features on the sea floor. But tracking the gravity should be even better.

Radar doesn't work underwater. Sonar does, though most subs want to be stealthier than constantly shouting downwards.

[–] frongt@lemmy.zip 2 points 1 hour ago

Radar is radio, just like most satellites. It doesn't do well through water. And that would require emissions, which submarines like to avoid.

[–] Aqarius@lemmy.world 9 points 6 hours ago

So, like terrain-matching, but gravity field. Cool!

[–] Simulation6@sopuli.xyz 27 points 8 hours ago (1 children)

Don't these fields fluctuate in some currently not understood way?

[–] edg@lemmy.world 31 points 8 hours ago (1 children)

Yes, constantly. The prepared map becomes less accurate over time.

[–] zaphod@sopuli.xyz 13 points 7 hours ago (2 children)

So you constantly need updated maps. Reminds me of celestial navigation where you always need an up-to-date almanac.

[–] Bluewing@lemmy.world 9 points 6 hours ago

Hhhmmmm, sounds perfect for the subscription model......

[–] ReluctantMuskrat@lemmy.world 3 points 5 hours ago (1 children)

But how do you get your position to update your map? Oh... GPS will work!

[–] zaphod@sopuli.xyz 2 points 5 hours ago (1 children)

What? You just download a new map for the area you want to go to every year or so, no need for GPS

[–] ReluctantMuskrat@lemmy.world 1 points 1 hour ago (1 children)

I'm not sure you got me. How do the map makers update the map? If the gravity variance changes so it can't be used to determine your position then clearly you need some other way to determine your position to update the gravity map. And what might that be??

[–] zaphod@sopuli.xyz 2 points 1 hour ago (1 children)

Using the same reference points on earth that GPS uses, that doesn't mean using GPS.

[–] ReluctantMuskrat@lemmy.world 1 points 41 minutes ago

That doesn't work too well out in the ocean and lots of other places too. If you can't use your gravity map, you're gonna use GPS for precise position data.

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