Could New Clocks Keep Airplanes Safe From GPS Jamming? (bbc.com)
- Reference: 0176623907
- News link: https://science.slashdot.org/story/25/03/05/1822239/could-new-clocks-keep-airplanes-safe-from-gps-jamming
- Source link: https://www.bbc.com/news/articles/cq6yg204pvmo
> Over the last three months of 2024, more than 800 cases of GPS interference were recorded in Lithuanian airspace. Estonia and Finland have also raised concerns, accusing Russia of deploying technology to jam satellite navigation signals near Nato's eastern flank.
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> A group of British scientists -- dubbed the "Time Lords" -- are working on a solution: [2]to develop portable atomic clocks . By carrying a group of atoms cooled to -273C on the plane itself, rather than relying on an external signal, the technology can't be interfered with by jamming. But the problem is that the equipment is still too large to be used routinely on planes.
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> The UK Hub for Quantum Enabled Position Navigation and Timing (QEPNT) was set up last December by the government to shrink the devices on to a chip, making them robust enough for everyday life and affordable for everyone. Henry White, part of the team from BAE Systems that worked on the test flight, told BBC News that he thought the first application could be aboard ships, "where there's a bit more space".
[1] https://slashdot.org/~Geoffrey.landis
[2] https://www.bbc.com/news/articles/cq6yg204pvmo
Very confused article (Score:4, Informative)
I realized the linked post about a very complex technology in an article is intended for a general audience but even by that standard it is very confused.
Chip scale atomic clocks have been commercially available for 20 years
[1]https://www.nist.gov/noac/tech... [nist.gov]
and continue to improve in accuracy, durability, and reliability. Reading some of the commercial supplier listings to the point just before they stop and say "DOD customers call your sales rep" it appears that there are CSACs designed and qualified to be fired inside artillery shells so I think we can conclude they can be made pretty tough.
I think the article is trying to say that what is needed is an atomic clock that would fit in an aircraft electronics rack that also has the accuracy of a cold atom fountain clock, which is the current NIST/NPL/NRC standard. To which laboratories around the world say, please, bring it on. And all the national labs have been working on such for quite a while, not only NPL.
[1] https://www.nist.gov/noac/technology/time-and-frequency/chip-scale-clocks
Re: (Score:3)
I tried to skim through the article and it seemed to jump around a bit. The thing I didn't see is how a more-accurate small-scale atomic clock replaces the need for GNSS. While yes, GNSS is based on accurate time, it's the reception and comparison of the time signals that give you distance to each transmitter (satellite) and so your current position. Having the time on board doesn't help with positioning.
Accelerometers are mentioned, which would be for inertial guidance... but if you have good inertial guid
Re: Very confused article (Score:2)
My thoughts go along the lines of how we used to navigate before GPS, namely by using a sextant combined with star charts at night, and looking at the angle of the sun during the day. All of which only work well when you have at least a vague idea of the current time and your current heading.
Buuut...Suppose we had some kind of automatic guidance system that combined artificial horizon with the relative position of celestial objects? All you'd need then to get good enough navigation would be a clock and a co
Re: (Score:2)
While I think that's what they are trying to say it is also completely and utterly pointless. You don't need that level of accuracy to travel accurately. A standard rubidium oscillator will suffice.
Re: (Score:2)
I share the confusion. No matter how good the plane's clock, the satellite signals need to reach the plane and not be spoofed. Hostile actors can jam the signals or potentially broadcast fakes. better clocks don't help these issues. I'd have thought they'd be working on lower cost better "laser gyros" and such, so that the planes could reliably use internal navigation when the GPS is iffy. But Time Lords wouldn't be the right title for folks working on better / cheaper internal guidance.
Re: (Score:2)
> I share the confusion. No matter how good the plane's clock, the satellite signals need to reach the plane and not be spoofed. Hostile actors can jam the signals or potentially broadcast fakes. better clocks don't help these issues.
Yes, they do. If your altimeter is accurate, an on-board clock means you only need to acquire signal from two satellites, presumably the two with strongest signal. The fewer satellites you need to acquire, the harder it is to jam.
Just like longitude (Score:4, Insightful)
As the article mentions, the parallels (haha) to John Harrison from 300 years ago are strong. He was an Englishman who solved the problem of finding how far east or west ship was, even in the middle of the ocean, by putting accurate clocks on ships, just like the UK scientists.
Dava Sobel covered it beautifully in the book Longitude, and I can highly recommend the illustrated version.
Difference (Score:2)
What's the difference between what they are building and off the shelf chip-based atomic clocks that are already available, like the CSAC-SA65?
BuckyBalls (Score:2)
BuckyBalls/Fullerenes would be accurate enough to allow for several mm level system location accuracy that requires very little power to maintain.
It will just flash 12:00 (Score:3)
Because pilots won't know how to set it.
Time is just one variable (Score:3)
GPS requires 4 satellites because it has to get you latitude, longitude, altitude and time, so you need 4 satellites to provide you with a solution for 4 variables. More is better, as it gets you an over-solution which lets you get better accuracy if you get a better constellation of satellites.
But having an atomic clock on board only resolves the time variable, so you're still needing 3 satellites to provide you with the lat/tong/altitude. And it's not great, because even at airliner altitudes and speeds, that atomic clock will drift, thanks to Einstein.
The INS (inertial navigation system) is still reasonably accurate - given most airliners will have ring laser gyros to measure acceleration and is technology already present today. Sure it drifts, because you get the fun of a double integration, but the INS errors are remarkably small - generally speaking a couple of nautical miles drift over the course of a 8-12 hour flight.
If you slaved the INS to the GPS then GPS jamming remains a non-issue since the INS can supply the positional information while GPS loses lock. And with a little computation smarts, you can detect if GPS is being jammed in a more sophisticated manner (where false information leads it to being off-course). Remember, the INS is quite accurate, so there's no reason for GPS position to differ very much when you compare positions. If you're calculating how the INS is drifting, it should be reasonably small between updates, and the absolute drift should remain small. If it suddenly jumps perhaps the GPS is receiving a spoofed signal.
But spoofing is a far more sophisticated attack than just mere jamming.
Re: (Score:2)
Inertial navigation isn't accurate enough for long distance navigation, though the new quantum IMUs being developed could finally change that.
VOR and ADF both use radio signals which are just as easy to jam as GPS signals and neither one is suitable for precision approaches the way GPS can be used.
Re: (Score:1)
> Inertial navigation isn't accurate enough for long distance navigation
Of course it was. It was used by the jets to cross the atlantic and pacific. It was a perfectly cromelent system.
The Donald and The Melon say "Fake News" (Score:2)
> Over the last three months of 2024, more than 800 cases of GPS interference were recorded in Lithuanian airspace. Estonia and Finland have also raised concerns, accusing Russia of deploying technology to jam satellite navigation signals near Nato's eastern flank.
No, I'm sure Zelensky did it - my country's president tells me we don't need to worry about Russia doing bad things.
Ah, what? (Score:2)
The problem is not that planes and ships lose GPS-provided _time_. The problem is that they lose GPS provided _position_ and vectors. How on earth is carrying better clocks supposed to help with that?
Re: (Score:2)
They are claiming that their clocks will make dead-reckoning (inertial navigation) accurate enough that, so long as you know the starting position precisely, then you know the current position. They are ignoring all of the other errors induced by the inertial sensors and just solving the time problem -- which is pretty useless on its own.
Before GPS (Score:2)
Planes found their destinations for a great many years before GPS was available. Various other technologies were used successfully, including ground-based beacons that were a lot harder to jam because of their much greater Signal strength. The issue is more about people's unwillingness to pay for alternate systems, than any real problem.
Existing Comercial Inertial Navigation Systems (Score:2)
Existing Commercial Inertial Navigation Systems are very good with an expected error of 0.2 to 2.0 km per hour. Not good enough to put the plane at the end of a runway, but good enough to get a plane in sight of the runway. The problem isn't a lack of inertial navigation capability, the problem is trusting GPS too much. Even with a significantly better clock, inertial navigation error isn't going to change much unless the inertial sensors themselves are improved. Time-error is just one of many factors c
Re: (Score:2)
Because the automated systems that actually fly the aircraft do not know how. Pilots are really only there to back up the automated systems, if something goes wrong. Apparently based on recent events, they are not doing that good a job.
Solution? (Score:3)
> By carrying a group of atoms cooled to -273C on the plane itself, ...
> But the problem is that the equipment is still too large to be used routinely on planes.
Bigger planes? Or smaller atoms... :-)