EU's GPS satellites have been down for four days in mysterious outage
zdnet.com
zdnet.com
GPS satellites broadcast "ephemerides" letting receivers work out where the satellite is - and some other details like clock error and predicted effects of the ionosphere.
You can make a rough prediction of these weeks in advance, but not precisely enough to meet GPS's precision requirements. Up-to-date short term predictions are needed to make things precise enough, so a ground-based 'ground segment' or 'control segment' broadcasts updates to these every 30 minutes or so.
The 'ground segment' is comprised of ~20 monitoring stations (at known locations, measuring the errors on signals from satellites), one 'master control station' that aggregates this data and decides what update to send next, 4 ground antennas that can send that update to the satellite no matter what side of the globe it happens to be on, and a backup MCS.
This is what is meant by "ground infrastructure".
The design of GPS is informed by its cold-war-era-military origins, so there's a backup master control station, and the satellites have an 'Autonav mode' letting them operate for 60 days in even if the entire ground segment has been destroyed.
Assuming the Galileo system has a broadly similar design, you can imagine the criteria for a four-day outage:
* Failure of both the master control station and the backup, in a way that takes more than 4 days to recover from. Maybe their backup control station wasn't fully commissioned yet, wasn't fully redundant, or some IT problem hit both sites at once?
* Discovery of some fault severe enough they felt they had to shut down until it was fixed, and the fix couldn't be rushed out.
* Either satellites have no autonav mode, or it somehow failed (such as due to bad data from the ground segment), or it's imprecise enough they decided pushing people onto GPS was a more responsible option.
I suppose it's possible the second GCC hadn't been fully commissioned? Or the switchover failed in some very hard to recover way?
[1] https://reports.nlr.nl/xmlui/bitstream/handle/10921/210/TP-2...
Presumably if one atomic clock seems suspect, they simply look to their other seven?
edit: no, the below link states clearly this is grounds-based trouble. > technical incident related to its ground infrastructure
Pretty sure universities and other institutions would be able to inquire though.
[0] https://www.gsa.europa.eu/newsroom/news/update-availability-...
> A technical incident in the Galileo ground infrastructure is affecting the functioning of the Galileo system, as a result of which there is a temporary interruption of some of the Galileo initial services.
> The cause of the technical incident is identified and recovery actions are implemented to ensure that the nominal service is resumed as soon as possible while safeguarding quality of the services.
Another way is selling online access to better-quality correction data.
Neither necessarily involves telling anyone where you are.
If you want to get more accurate you don't use the encrypted channel you put a GPS in a fixed location on earth and have it send corrections to you. (called RTK)
Edit: Note that I have no information on what the US military uses their classified channel for. It is unlikely they get any accuracy information from it anymore given what civilian GPS systems have figured out.
In practice the Americans learned that COTS dominates for electronics. You can buy 100 of the special military product with the secret key, delivery in 18 months or for the same price you can have 5000 of the generic civilian product, 10 days lead time.
So these secret extra channels are of dubious value. But they're cheap to implement so they remain something new GPS style systems have.
In theory keeping the key secret defends against a sophisticated adversary spoofing your signal. But there's an obvious trade, if you only make ten units you can probably ensure the adversary doesn't capture one, but it's not very useful. If you make a million units that's initially more useful but your adversary will definitely get the key.
You don't request a positioning signal, they are broadcast by the satellites and nothing is sent back by the receivers. Some devices (like smartphones) may send their GPS discovered position over the Internet, where encryption may be used, but this is not what is being referred to.
Encryption allows you to restrict access, or provided tiered access to signals of varying accuracy. You can also use cryptography in order to prevent spoofing.
I think that's probably the biggest selling point given how many important infrastructures rely heavily on GPS these days.
You get anti-spoofing naturally if you're just using secret symmetric encryption (if your adversary doesn't know the key, they can't generate a valid signal to trick you with). To prevent spoofing against the public, you'd need to make use of public-key cryptography.
That's the plan (or at least something explicitly reserved as an option), yes.
Encrypting what?
Except if you want people not to be able to use the GPS signal, which sure make sense in military context (and even then, it's pretty meaningless, except if you change the key pretty regularly and you have a safe way to propagate it that won't be possible for enemies to get their hands on).
You know right that GPS signal is a one way signal? The receiver doesn't transmit anything, he just receive and use the timing and its data with some fancy math to be able find your position.
As a result, while we have sub-5ft accuracy now, there's no guarantee that in war time, we won't lose that.
My guess is that the heater was being run by the machine that required the update and the update download process meant the machine was not available for usual operation. But I don't really know.
It doesn't involve Windows as far as I can tell - they don't say what the cause of the problem was.
https://www.bas.ac.uk/media-post/update-power-down-at-britis...
The only thing those satalites need to do is, accept signal, do math, and transmit signal.
I don't see why you would use Windows for this.
However, it's more than likely that there's a bunch of Windows machines on the ground segment side of the operation, since a lot of satellite fleet management software is Windows based.
No.
But for some reason the op implied windows was to blame without evidence.
I mentioned the implausibly of it.
Op is misleading people.
If someone is running even important tasks that must not be interrupted, much less critical infrastructure like this, on consumer versions of Windows they're absolute idiots and should never be trusted with those sorts of decisions again.
If one insists on using Windows for uninterruptible tasks they should be using a server edition.
That said I'd always recommend
> Recently heard about an Antarctic base that lost heating for 36 hears after a Windows Update triggered a several GB download over the base's modem downlink.
That seems implausible, or at least to have been miscommunicated. The download and install phases are separate, so nothing would have gone down until the download completed. If the heating system required constant communication and went down due to not enough bandwidth being left over that's obviously a very poor design in general, especially in Antarctica. Even if that were somehow the case, it wouldn't take 36 hours for their network team to block/throttle the update traffic to let it work again.
The server edition can also be configured to perform automatic updates.
I've been researching this. There was an outage. It wasn't caused by Windows. What is your source for this claim?
> Halley lost power on 30 July after the station’s generators overheated and shut down after a large coolant leak from the main arterial pipe in the station’s heating system.
https://www.chemistryworld.com/news/research-on-ice-at-briti...
I cannot find any other Antarctic outages.
When you are several billion euros in, have 24 satellites on orbit, and have been broadcasting with the 'Valid' bit set for 2 years you aren't really in 'beta' as we use it.
They have been in production mode in all but name. Given the life/safety implications, there are some rather rigid qualification checks that have to be done to be 'fully certified'. That's what's been going on.
I wonder what this could mean?
As deployed today the two needn't have any electronic connection although they do.
Eventually a MEOSAR is intended to use the accompanying navigation transmitter to send replies from ground SAR. Initially an acknowledgement ("We see your distress beacon" and by implication "somebody will try to help") and perhaps later more.
But that requires proof of concept and then newer beacons as today's beacons, even the ones with GPS (many rely on COSPAS SARSAT to triangulate their position itself) do not know such an acknowledgment might arrive or how to interpret it.
It's not DNS
There's no way it's DNS
It was DNS
Guenter Hein, Professor Emeritus of Excellence at the University FAF Munich told us, “As far as I know, it is a problem of the PTF [Precise Timing Facility] in Italy – time has an impact on the whole constellation!”
The Linux timekeeping system can normally deal with a clock that is steady but not the right rate by learning what correction to apply, but these were far enough off to be well beyond the maximum correction.
This only affected particular instance types, so changing to a non-affect type could fix it, but all the working types were more expensive than the types we were using which was annoying. Sometimes you could change to a working type then back to the buggy type and end up with one that did not have the problem.
There were a few people asking about this in the support forums, but apparently it was only hitting cheapskates like us who had not paid extra for support. Finally, someone paid for incident support and opened a ticket and Amazon quickly found and fixed the problem.
Wouldn't be too surprised if that ground station's job (which I guess is compensating for relativistic effects to the clocks' timing) was extended to compensate for rebooting clocks.
It seems like a little drift shouldn't make that much difference, but keep in mind that the speed of light in a vacuum (or air) is about 1 foot per nanosecond, so for every nanosecond one of those clocks has drifted, that's a foot of positional accuracy you no longer have...
(later generation satellites have an 'autonav' mode that presumably makes this less severe (by using SV-to-SV ranging and such so they're not completely blind to changes), but Galileo may not have that capability or there might not be enough SVs to use that capability yet)
Sat nav obviously, Amazon package tracking, Grindr? (I assume that falls back to cell tower triangulation???).
I guess theres some more serious things, any examples?
"Everyone go to Area 51 -- they can't stop all of us" essentially.
As to if it's just internet cranks, the US military shifting views, or aggressive, foreign AGI-PROP is debatable. My money says it's a distraction, but I don't know what it's a distraction from.
Can you imagine if these people decided to, say, storm immigrant detention centers, or abusive corporations... or anything that productive in a meaningful sense?
trucking companies rely on it to enforce rest periods. so more truck accidents?
turn by turn direction on phones would go out. wi fi is enough for nav, unless your phone and the wifi are on different ntp networks maybe I had a phone with broken gps and I didn't really notice.
I suppose the Qualcomm unit might eventually be off by a second or three. But I don't know if its clock is updated by GPS, phone or wifi. I'm guessing phone.
We're also required to carry paper log sheets in case of Qualcomm outage. So then it would be paper, watch and honesty. The honesty can be sanity checked by speed an distance.
Base stations should be using GPS (and others) to discipline a local oscilator that should be ok enough for a while in absence of signal. They can probably also get a timing signal from their backhaul.
It works better with precise timing, but I think it's workable with best efforts.
I certainly noticed in the UK on an iPhone 6 where the GPS chip was borked. You would drive for 10 minutes and then you would get an updated location. This was in outer London.
How could I test that?
Something similar is used to test German Toll Collect On-Board Units (OBUs) before refurbishment.
Galileo hasn't reached full operating capability yet, so that's probably why few people have noticed (as why would you depend on an incomplete system?)
There is actually an article from the New Yorker answering your question: much less traffic, all planes grounded, no train, etc. [1]
> The U.S. Department of Homeland Security classifies sixteen infrastructure sectors—including dams, agriculture, health care, emergency services, and information technology—as critical, and therefore particularly vulnerable to sabotage. All but three require G.P.S. for essential functions.
[1] https://www.newyorker.com/tech/annals-of-technology/what-wou...
Without GPS, these reference oscillators can free-run for a while but they will eventually drift out of tolerance.
Basically, without GPS, most/all cellular/digital radio networks will fail in some manner after a while. Precise failure modes will depend on a lot of things including exactly what is wrong with GPS and the type of emission, how the base station software is written, etc.
Or do they do something simpler, and just derive a frequency reference from the frequency of the carrier signals and sync the local to some fixed ratio of the carrier frequency?
The former would be more accurate, but would break if something went wrong with the data. The latter would probably not be as accurate, due to Doppler effect (I'm getting +/-0.00041% shift from Doppler effect), but would keep working as long as the carrier is being broadcast. You could probably correct for a good part of the Doppler effect just from the last known orbital parameters of the satellite--even if the data updates have been broken for a long time that should work.
It's the first - the GPS modules used for these purposes decode the time and then generate a digital pulse on an output pin at the top of each second (this is called a 1PPS output). A hardware counter counts the cycles from a local oscillator between pulses. The count between pulses is latched (this is all in hardware so far) and then the software reads the latched value. If your local reference oscillator is supposed to be 10MHz, your counter should report 10,000,000 ticks exactly. If it's high or low, the software can adjust the temperature of a little mini-oven that the oscillator resides in to speed it up or slow it down (some oscillators just use a voltage to speed up or slow down instead of an oven). Usually this is done in a PID loop or similar feedback loop. At this stage you can apply some filtering logic to help ride out certain errors (if you're suddenly off by 50% something else is probably wrong, etc.).
To ensure the GPS timing is as accurate as possible, you can have the GPS module survey its position for a lengthy period of time (since it is presumably mounted on an antenna mast somewhere and not moving) and average it out to establish a more accurate well-known location. The GPS can then use that known location to apply a correction to the GPS signals. Basically, if it's currently-computed position based on GPS signals is 50 meters away from the true well-known location of the receiver, it can figure out how far off the timing computation is and adjust. This is mostly handled by the GPS module itself, and is probably even more automated and accurate now than when I worked on it ~15 years ago.
There's also ways to increase GPS accuracy using supplementary broadcasts that contain localized offset correction information, referred to as Differential GPS (DGPS) run by many groups including the US Coast Guard and a similar technology called WAAS (wide area augmentation system) run by the US FAA. The GPS we were using didn't have the capability to use those sources but modern units probably do.
I'm not too sure about LTE, but some initial googling suggests that while it does need a precision frequency and time source, there are ways of deriving that from the network, which makes sense if you think about indoor base stations that often don't have a clear view of the sky.
Link: here are some survey markers for sale, linking it so you can see a picture of what they commonly look like: https://www.berntsen.com/Surveying/Survey-Markers/Aluminum-S...
At least regular receivers (e.g. in phones) utilize signals from multiple satellite constellations simultaneously, not sure if this is the case here as well.
Disclaimer: Trimble Ltd. alum
Italy has a pretty big space-related industrial sector, and excellent academic standards in some fields. It might not produce geniuses with the same frequency of the past (Galvani, Volta, Marconi, Fermi and so on) but it's not some random backwater.
And nobody really thinks that.
My god, what a time to be alive, when you can't make simple jokes anymore, because somebody somewhere always is offended and thinks there must be some racist agenda in place.
Even as a German with a total lack of humour (and an Italian motorcycle with strange quirks in the garage) I found this funny. Funnier than the Holocaust at least.
As an Italian expat, I can assure you this is unfortunately incorrect.
> you can't make simple jokes anymore
No, you can't make jokes based on lazy stereotypes that end up affecting the lives of millions. It's a different thing. It might have been fundamentally innocuous, back when populations didn't mix as much as we do today, but now it's a real problem. If I go to a job interview and the potential employer assumes Italian == lazy, I'm done for. That's the casual bigotry that these jokes end up entrenching.