Imperial College working with Royal Navy on system to replace GPS on ships

[VorticesRcool]

It looks like the research comes from this group: https://www.imperial.ac.uk/centre-for-cold-matter/research/q...

[fmajid]

France started developing quantum gravimeters (GIRAFE) in 2006 or so, with airborne versions trialed and ship and submarine trials due in 2023, for operational deployment in 2026–27.

https://www.capital.fr/?authId=d61dc7363d8137e2e9555b9578185...

It's not just for dead-reckoning, they are also mapping the Earth's gravitational field for submarine navigation:

https://www.onera.fr/en/news/shom-onera-cold-atoms-gravimetr...

[joren-]

This is a bit low on actual information but it seems a dead reckoning device based on a new type of - drift free? - accelerometer?

[garblegarble]

I found a video UCL put out a few years ago on what the article seems to be discussing: https://www.youtube.com/watch?v=xcqkXkWZhbM

[citrin_ru]

Making an accelerometer precise enough to be useful for dead reckoning on a time frame more than a few hours looks like a big challenge. On a ship another way is available - speed of a ship relative ocean bottom can be measured using Doppler effect (which can be used for dead reckoning). And it likely is more accurate.

[ISL]

If drift/noise is low-enough, it can be used for a long-enough period to be viable.

Ring gyros and precision accelerometers have been used in inertial navigation systems for ages. This is likely another step along that path.

[NegativeK]

I was under the impression that you can't avoid drift due to fundamental properties of calculus, but it sounds rad if I'm wrong.

[CoastalCoder]

Tangent: I was about to pedantically comment that the correct spelling is "ded reckoning", but TIL that's not true (assuming Wikipedia can be trusted) : [0]

[0] https://en.wikipedia.org/wiki/Dead_reckoning

[scrlk]

Reminds me of the rewards that were offered in the 1700s to build a marine chronometer that would allow for the accurate computation of longitude at sea.

See:

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

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

[fotta]

Dava Sobel’s Longitude is a great book on this topic.

[fotta]

Seems like it’s an inertial navigation system [0] but they’re using some quantum device for precision.

[0] https://en.m.wikipedia.org/wiki/Inertial_navigation_system

[moffkalast]

It's some serious irony that after all technological advancements we are returning to the very first naval navigational principle, dead reckoning.

[TheOtherHobbes]

Interesting idea. Not sure how they're going to disentangle the usual rolling, pitching, and yawing on a ship with straightforward level motion.

I guess you could contrive some kind of gimbal suspension, but that's not going to be friction-free so there will be cumulative inaccuracies.

[dr_orpheus]

No need to disentangle it. You would be integrating the linear motion with the accelerometer they are developing and use it with a gyroscope that measures the rotational motion. Then the full 6 degrees of freedom are measured. We already have very good gyroscopes that measure rotational motion (such as Fiber-optic gyros [0]) with really high stability.

[0] https://en.wikipedia.org/wiki/Fibre-optic_gyroscope

[AndrewDucker]

Not sure you'd need to disentangle it. Any given millisecond you'd move forward+up, forward+down, forward+port, forward+starbaord. Add them all up and you'd known that you'd mostly gone forward.

[JoeAltmaier]

Maybe not replace? A backup system? Because GPS is so much more accurate, it'll be hard to wean ships' crews from it.

[gchadwick]

I'd assume/hope Navy crew would be trained in and regularly drill non GPS navigation techniques. Even in the civilian/recreational sailing world you do (or at least did when I took my exam 15 years ago) blind pilotage where you have to sit below deck and navigate the boat through a harbour, without use of GPS, as a standard part of yachtmaster exams. Celestial navigation and use of a sextant was required for ocean yachtmaster.

[paganel]

> Because GPS is so much more accurate, it'll be hard to wean ships' crews from it.

The Russians have been really good as of late at jamming the GPS signals on the front-lines of Ukraine (see for example this recent piece [1] of news of them jamming the GPS targeting system of HIMARS rockets), so I guess that's what the British and the Atlanticists more generally are trying to defend against.

Granted, I do not know if it would be possible for the Russians (or the Chinese) to jam the GPS signal used by a ship that is sailing in the high seas, but the danger is there.

[1] https://edition.cnn.com/2023/05/05/politics/russia-jamming-h...

[varjag]

Addressed in the fine article:

He stressed such trials were important so as to explore and find “back ups to GPS”.

[lxgr]

Obviously it won't be a replacement.

A combination of a GPS receiver and one (or several) INSs will be much more accurate and resilient than either component by itself.

All ocean-crossing commercial airplanes already operate that way.

[ianburrell]

Submarines can't use GPS when underwater and need navigation system that work underwater. Once you have that, might as well put it on all ships as backup.