Imperial College working with Royal Navy on system to replace GPS on ships | Hacker News Reader

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

telegraph.co.uk

38 pointsnradov40 comments

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

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...

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

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

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

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.

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.

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.

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.

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

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

The mini-series is also a fun watch:

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

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

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

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.

Solid-state, read-only, shielded inertial navigation systems have been around since the 1950s. Is there anything more than incremental improvement to that technology at this point?

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.

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.

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.

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

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

Addressed in the fine article:

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

> 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...

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.

Yeah, I was about to mention that, too. Hopefully today's navy guys still get trained to navigate the good, old classical way, without GPS. They could also do without necessarily having to rely on radio transmissions, as a back-up, of course [1]. That goes for the entire Armed forces.

> In a preemptive strike, Red launched a massive salvo of cruise missiles that overwhelmed the Blue forces' electronic sensors and destroyed sixteen warships (...)

> Van Riper used motorcycle messengers to transmit orders to front-line troops and World-War-II-style light signals to launch airplanes without radio communications.

[1] https://en.wikipedia.org/wiki/Millennium_Challenge_2002

Yes, the US Navy has resumed celestial navigation training.

https://www.npr.org/2016/02/22/467210492/u-s-navy-brings-bac...

A series of embarrassing navigational incidents may have something to do with it:

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

https://en.wikipedia.org/wiki/USS_John_S._McCain_and_Alnic_M...

https://www.theregister.com/2021/09/21/hms_severn_fleet_navi...

> The FNO course takes naval officers who have passed the navy's first-stage navigation qualification, Preliminary Navigating Officer, and qualifies those people to navigate larger ships of frigate/destroyer size. It also teaches them to do it in the absence of GPS, falling back on age-old skills that would have been familiar to sailors in the early 20th century.

If one country can put a satellite somewhere, another country can readily put a bomb there. It is especially easy if the satellite is continually broadcasting its position.

Related: Perun just released a video on Anti Satellite Weapons. https://www.youtube.com/watch?v=-xl0C6K2Nug

The US and EU are looking into backups for GPS. For short-range, can use GPS-like beacons. This will work well for airports and close to cities. It is probably worth doing for increased accuracy.

There is talk of reviving eLoran which is enhancement of Loran long-range navigation. But countries keep shutting down transmitters because of lack of use.

Finally, it might be possible to use other satellite constellations for navigation. In particular, it sounds like Iridium provides timing information. In the worst, could add something the big constellations like Starlink.

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.

Jamming can be pretty directinal/targeted, and it's not that hard to imagine a situation where one side of a conflict would see it as a huge tactical advantage, even if it means both sides losing GNSS capabilities in some area.

That's the point where we go dark and pull out old tools that can't be intercepted (as with parent article). They'll waste time and energy developing and moving around GPS jammers to defend against smart weaponry, when the real threat changes to someone sneaking up on them and throwing dumb rocks. Slav logic amounts to Ewok warfare :)

China I'm unsure of, but Russia would absolutely jam their own systems to poke an adversary in the eye. America never would because corporate interests rely on Navstar; Communist regimes do not share our values or rules.

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.

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!

GPS jammers are cheap and a real issue:

https://insidegnss.com/fcc-fines-operator-of-gps-jammer-that...

Civilian-grade jammers may not be sufficient to interfere with encrypted military GPS, but the Iranians were able to hijack US Predator drones via GPS spoofing:

https://www.securityweek.com/reports-say-us-drone-was-hijack...

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.

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.

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