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

https://www.telegraph.co.uk/news/2023/05/21/ships-gps-alternative-warfare-tracking-impossible/

by nradov • 3 years ago

38 39 3 years ago

telegraph.co.uk

joren-• 3 years ago

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• 3 years ago

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

CoastalCoder• 3 years ago

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

NegativeK• 3 years ago

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.

kibwen• 3 years ago

Pretty sure you can't avoid drift due to fundamental inaccuracies in our ability to take measurements. Even GPS satellites synchronize with ground stations to correct their own drift, making the ground stations the frame of reference. And then the ground stations are all drifting relative to each other because of continental drift.

So in the event that your synchronization signals are being jammed, dead reckoning (where you are your own frame of reference) seems like the best you can do.

ISL2• 3 years ago

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.

citrin_ru• 3 years ago

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.

JoeAltmaier• 3 years ago

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

varjag• 3 years ago

Addressed in the fine article:

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

paganel2• 3 years ago

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...

nradov2• 3 years ago

Longer term there is danger that adversaries will simply shoot down GPS satellites instead of jamming them. Current anti-satellite weapons can only hit targets in LEO but I'm sure that Russia and China are researching ways to target higher orbits.

cf100clunk2• 3 years ago

If GPS is jammed, a device should then automatically try to use GLONASS and/or BeiDou in the expectation that the Russians and Chinese (respectively) would not jam their own systems. Perhaps simultaneous polling of all three is workable to avoid jamming as much as possible.

gchadwick• 3 years ago

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.

toss1• 3 years ago

This is so critical, especially in warfare — retaining the ability to function when fragile systems are degraded. And we see examples every day where GPS is rendered locally/regionally unusable and/or spoofed, nevermind the likely warfare scenario where GPS satellites are directly attacked.

I have no clue why you are getting downvoted. Evidently some are just so enamored of stuff they have on their phones they cannot imagine it going away. In any attack or general failure, they'll be the most lost!

ianburrell2• 3 years ago

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.

lxgr3• 3 years ago

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.

VorticesRcool• 3 years ago

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

TheOtherHobbes• 3 years ago

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.

AndrewDucker• 3 years ago

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.

moffkalast2• 3 years ago

Yeah it's kind of like summing gyroscope values at a constant rate, it just cancels out and gives a good rotation with a little drift over time. If only regular accelerometers were as good as mems gyros.

dr_orpheus• 3 years ago

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

scrlk2• 3 years ago

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

fotta2• 3 years ago

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

throw0101b• 3 years ago

The mini-series is also a fun watch:

* https://en.wikipedia.org/wiki/Longitude_(TV_series)

fotta2• 3 years ago

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

moffkalast2• 3 years ago

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

lxgr3• 3 years ago

Is it that ironic?

Self-contained navigation has always been a priority in aviation, for fairly obvious reasons (safety, i.e. not having to depend on the complex external single point of failure that GNSSs are, and security, i.e. GNSS spoofing).

Planes were using INSs long before GPS to navigate across oceans, but even today, they're required to carry several instances of each (GPS and INS, in addition to ground-based systems) for redundancy.

fmajid3• 3 years ago

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...

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

Related Stories