Could New Clocks Keep Airplanes Safe From GPS Jamming? (bbc.com) 55
Geoffrey.landis writes: 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.
A group of British scientists -- dubbed the "Time Lords" -- are working on a solution: 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.
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".
A group of British scientists -- dubbed the "Time Lords" -- are working on a solution: 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.
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".
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... :-)
Still Need External Signals (Score:3)
So, while having your own local, synchronized clock, will mean that you will not need to receive timing information from the GPS satellites you will still need to receive external
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Re:Still Need External Signals (Score:4, Interesting)
No, GPS does not work by triangulating.
The GP was almost correct, but got the word wrong. To be fair, though, in common parlance, the term triangulation is frequently used.
But you're right that the correct term is trilateration. Trilateration uses the distance from three (or more) fixed points to compute the position of something. Triangulation uses a combination of angles and distances to compute the position using only two fixed points.
For a triangulation example, if you look at the skyline of NYC and you compute the exact angle to the Empire State Building and the Chrysler building and you know the exact angles to both of them, you can accurately compute your location to one of two possible points even without knowing the distance to either of them by using trig, because you know how far apart the two buildings are.
With satellites, of course, the fact that GPS satellites are moving makes this problematic, and making any knowledge of the distance between the satellites even more problematic. And of course, GPS receivers tend not to be stationary, which makes measuring the angles way harder.
I have this vague memory that in an early design for GPS or one of the competing systems, they were going to have a small number of geostationary satellites, which could place you at one of two spots in the world even if the LEO birds all failed (as long as you're below about 81 degrees of latitude, which is to say not on Antarctica or in the Arctic Ocean, give or take), but I can't find any information about it, so maybe I'm imagining things.
But if you hypothetically did that, you could use triangulation more plausibly because of the fixed location of the satellites. Any vehicle crossing the equator would, of course, have a very bad time without a secondary frame of reference, such as a compass heading.
As an added advantage, you could make the antennas for a geostationary GPS alternative be highly directional (based on your last known location, the current time, and your compass heading, which can be supplemented with gyros for additional accuracy). That should make them much harder to jam.
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With GPS satellites, of course, the fact that the satellites are moving makes computing their angles problematic, and makes any knowledge of the distance between the satellites even more problematic.
Sorry. I edited that paragraph too many times and screwed it up pretty badly. Fixed above.
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The geostationary satellites are actually used (the three EGNOS satellites for example), but just as an augmentation system for improving the accuracy.
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Just knowing the time by itself is not a solution though so there is something missing from the article
There is indeed. This is all about developing quantum inertial navigation systems for real-world use. Clocks are just one part of it.
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smaller atoms
Do you have any idea how much those cost??
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Do you have any idea how much those cost??
It's not just the cost but the shelf life.
Muonic hydrogen is 200-fold smaller than normal hydrogen but has a half-life of only a few microseconds.
Very confused article (Score:5, 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
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.
Re:Very confused article (Score:4, Insightful)
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 guidance, you don't care what time it is. And if you don't have good inertial guidance, the time still isn't going to help.
Re: Very confused article (Score:4, Interesting)
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 compass.
At a cursory glance, it seems like a very doable thing, possibly even fit it in an object about the size of a golf ball if not smaller, but I think such a system would be the bigger story than a clock.
Re: how we used to navigate before GPS (Score:2)
You went waaay to far back, we've had many electronic aids to navigation before GPS.
One such electronic aid to navigation that benefits from a very accurate clock is Inertial Navigation.
At aircraft speeds enhanced precision has proved an asset.
Re: how we used to navigate before GPS (Score:2)
That's called dead reckoning, and it didn't help Korean Air flight 007
Re: how we used to navigate before GPS (Score:2)
Oh and, apparently it's a thing:
https://www.bluewatersuperyach... [bluewatersuperyacht.com]
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Neither did the sextant, though - the 747-200 still had that.
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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.
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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.
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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.
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Or connect to a half dozen or more and make sure more than one pair (or triplet) all agree on location.
Or use a secondary method like VOR, etc. and compare results vs. GPS.
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>Chip scale atomic clocks have been commercially available for 20 years
Not quite. I remember looking around when NIST first announced that research, but it took several more years until they were commercially available. The first one you could actually buy was the SA.45s in 2011. source [si.edu]
Just like longitude (Score:5, 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.
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Difference (Score:2)
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)
Time is just one variable (Score:5, Informative)
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.
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And it's not great, because even at airliner altitudes and speeds, that atomic clock will drift, thanks to Einstein.
Aircraft know their speed and altitude pretty well, even without GPS, so this would seem to be easy to correct for. Wind would be the largest uncertainty, because it makes airspeed different from the ground speed, but I guess you could still reduce the atomic clock drift due to these effects by an order of magnitude.
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You only need three - facepalm.
On top of that the timing is in the signal anyway.
Because: oh, we use the timing to calculate our position and not the angels.
A fourth satellite is nice: so we can pick 3 with the strongest signal.
Jamming, is not changing the information the satellites sent you.
It is just a radio signal stronger than one/some of the satellites. Your receiver picks the 4 or 5 strongest signals, and they tell you: I am at X,y, z ... and so on. Can be a single sender just telling you bogus inform
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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.
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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.
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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.
Jets?
In early 1953, the government convened a meeting of researchers in Los Angeles to discuss the possibility of inertial navigation.
"Doc" Draper and his MIT team stuck their prototype INS unit in a B-29, but had no time to test it before flying non-stop from outside Boston.
After 2,500 miles of flying with no input from the pilots, it was only 10 miles off.
Draper went to the meeting and said that yeah, it was possible, since he'd just done it.
I feel sorry for whatever presentater followed him.
The Donald and The Melon say "Fake News" (Score:3)
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?
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For inertia navigation, you do not need better clocks.
And it has nothing to do with GPS anyway.
We have laser based inertia based tracking since 50 years.
Obviously: it can not recognize if a wind pushes you around.
Point is: that article has nothing to do with GPS. My local clock being worth or better: does not change at all that some super beam identifies itself as satellite A and is pumping 5 times the radio strength on me, as the real satellite would do.
Before GPS (Score:3)
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Existing Comercial Inertial Navigation Systems (Score:2)
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British scientists -- dubbed the "Time Lords" (Score:4, Funny)
"the equipment is still too large to be used routinely on planes."
Just make the plane bigger on the inside than it is on the outside.
TFA is not particularly great. (Score:2)
1. MEMS clocks with microsecond-per-day accuracy are commercially available and they're getting better.
2. 1 ns drift = 30 cm position accuracy.
3. You still need signals from known positions to triangulate your location.
So while jamming GPS is trivial, the alternative is using other sat networks or building terrestrial radio beacons. Variations on the same problem. Just having accurate, portable clocks does not help.
This article boils down to: UK is working on portable atomic clocks, just like everyone els
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Just having accurate, portable clocks does not help.
This.
GPS does NOT depend on an absolute time accurate clock at the receiver. Or my cheapo handheld GPS could not exist*. What it does need to do is to accurately measure the time difference between several received satellite signals. And that is a (relatively) easier thing to do. Assuming that no one is screwing with the received sat signals. Which is in fact what is going on.
The terrestrial beacon idea is a good one. Ground-based 'virtual satellites' can be set up near critical areas like airports to giv
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And if anyone tries to jam them, the signal strength will make them sitting ducks for an AGM-88.
Russia is already fucking with GPS signals. But apparently they're the good guys now and everyone should bend over backwards for them and give them free land because apparently that's the best thing to do now.
There are other solutions (Score:2)
I know this is going to get modded as flamebait ... but there are still pilots out there that remember how to fly without satellite data. This isn't lost knowledge that needs to be dug up by an archeologist.
There are perfectly serviceable land based navigation aids, and looking out windows....
We don't need new tech to do this.
Maybe solve with very different satellite tech? (Score:2)
Instead of a unidirectional signal, use something bidirectional like Starlink satellites. Use beamforming across multiple satellites to punch through any interference. Configure the satellites to aggressively crank up the transmission gain and the number of satellites participating in the beamforming if it loses the signal from an in-motion airplane until it is able to get confirmation that the aircraft is receiving the signal. Provide a switch to keep that feature enabled while on the ground if you're
Works until GPS jammers improve (Score:2)
The technology maintain a local precise time with two benefits:
- the distance from all true GPS satellites is now determinable, removing uncertainty; et least, one less GPS satellite is needed
- GPS jammers with grossly inaccurate time reference are weeded out
So my best guess is that countermeasure won't work against GPS jammers with an accurate time base, or smart enough to align their time base to other GPS satellites.
Why not work on spoofing resistance instead? (Score:2)
GPS spoofing and jamming originates from sources beneath the aircraft, Russia doesn't have jamming satellites in orbit AFAIK. At least not yet. All genuine GPS signals always come from high above the horizon. All sources of interference come from way below. There must be a way to exploit that fundamental difference to distinguish between genuine signals and all noise. Array receivers should be able to tell where in space a signal is coming from and with a little additional logic could determine where the ho