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>The reliance of Ukraine’s substations on GPS for time synchronization, a standard in industrial control systems for its accuracy and affordability, becomes a v
by mellow-lake-day 3y ago
>The reliance of Ukraine’s substations on GPS for time synchronization, a standard in industrial control systems for its accuracy and affordability, becomes a vulnerability when faced with such jamming.
>Cisco’s response involved shipping a large order of modified equipment, specifically designed to maintain accurate time even under radio jamming conditions. This solution employs the Cisco Industrial Ethernet switch with an internal crystal oscillator, enabling new clock recovery algorithms for accurate timekeeping when GPS is unavailable.
That's really neat. Didn't know GPS was also used for time synchronization.
- whalesalad 3y agoIt’s really the only way to do accurate time.
- gambiting 3y agoWell no, it isn't - it's just that every other solution is several orders of magnitude more expensive.
- whalesalad 3y agoSo the pragmatic approach that everyone is utilizing (including AWS’ latest announcement for microsecond accuracy) relies on hardware GPS. Why am I being attacked here. This is how it’s done.
- pwagland 3y agoI'm not the one attacking you, but I think I can explain. Your original statement was quite absolutist "It’s really the only way to do accurate time." A statement which would have had more agreement would be "It’s really the only practical way to do accurate time."
- whalesalad 3y agoFair.
- skybrian 3y agoRadio clocks [1] often don’t use GPS. Many countries have a radio signal they can pick up. In the continental US, it comes from Fort Collins, Colorado. [2] [1] https://en.m.wikipedia.org/wiki/Radio_clock https://en.m.wikipedia.org/wiki/Radio_clock [2] https://en.m.wikipedia.org/wiki/WWVB https://en.m.wikipedia.org/wiki/WWVB
- callalex 3y agoThat suffers from the same vulnerabilities.
- sneak 3y agoI have trouble picking up WWVB indoors at home even without jamming.
- pwagland 3y agoTo be fair, this isn't really _that_ accurate, it's only good to about 10ms, GPS will get you to 0.001ms accuracy, at least with the right kit.
- romaindivuolo 3y agoTechnically you can broadcast a new time to your neighborhood and have most people late to work (the ones having that kind of clock alarm), it's far from secure and accurate.
- femto 3y agoPrecision Time Protocol [1] is an alternative. CERN has been using it as part of a project to achieve sub-nanosecond accuracy over a wired network [2]. [1] https://en.wikipedia.org/wiki/Precision_Time_Protocol https://en.wikipedia.org/wiki/Precision_Time_Protocol [2] https://en.wikipedia.org/wiki/White_Rabbit_Project https://en.wikipedia.org/wiki/White_Rabbit_Project
- Andaith 3y agoBit horrifying if you ask me, because I bet that happens everywhere. So if we lose GPS, we lose electricity? Awesome. Not at all fragile.
- deleted 3y ago[deleted]
- sneak 3y agoThe electric grid is already extremely fragile. Its uptime is dependent on constant maintenance and repairs and many people on 24/7 standby to make more repairs in outages. Its resilience is in the support network, not in the physical structures itself. That support network building custom hardware in a GPS outage is that system functioning as expected. A GPS outage without a bunch of concerned humans doing everything they can to fix it isn’t going to happen.
- sgift 3y agoAlso on making sure that it is balanced all the time. The effort it takes to make sure that there's always input exactly as much energy as is taken out of the system is just staggering. And if only a few of the things needed to adjust it fail .. here comes the brown/blackout.
- jnsaff2 3y agoMost of the effort has been done in design. Rotating mass of generators is a nice self-correcting system, also the frequency is a near-zero latency signaling mechanism across the entire grid. Each participant can measure it and make independent decisions whether the grid needs more power or more consumption. There is a lot of work that goes into predicting and commanding large participants and it's a complex system but some of the design is just beautiful in it's simplicity.
- Andaith 3y agoThat's really interesting! I assumed that everybody would aim for a resilient system to reduce support costs, but you're saying the electric grid is built cheap & fragile and the cost of support is just an accepted part of it? How come the support costs are cheaper for maintaining the electric grid than paying a bit more for hardware that requires less support? You can't even outsource your support costs to a cheaper COL country. Is it because the infra is subject to nature & thus always being degraded in all sorts of ways in all different environments?
- calamari4065 3y agoBasically, GPS satellites need ridiculous precision in their clocks to make navigation work. They all have atomic reference clocks to accomplish this. Since GPS satellites are already broadcasting a ridiculously precise signal to the entire planet for free, it makes a lot of sense to use that signal when you need very precise time. Though in cases like this where critical infrastructure is involved, I'm confused why they don't have an adequate clock source locally. You don't usually rely totally on GPS, you use it as a reference to check your local clock against.
- lmz 3y agoMore to the point, all GPS satellites broadcast the time - the receiver takes the multiple (different) times from multiple satellites and the satellite's known location to determine the receiver's location.
- instagib 3y agoIt’s related to power generation. Finding line faults, keeping equipment at 60hz or 50hz whatever they use there. They need precision location information for multiple power plants. They can do without it but you end up with dirty power which most equipment doesn’t like very much and some will shut off and not work at all or break. I remember UK had an issue where they produced low frequency power and everyone’s kettles started turning on early due to the clock mismatch. https://medium.com/drax/what-is-electrical-frequency-and-why-does-it-matter-fb60ae883246 https://medium.com/drax/what-is-electrical-frequency-and-why...
- calamari4065 3y agoYou can make a reference oscillator almost as precise as an atomic clock with a temperature compensated crystal oscillator. They cost tens of dollars. We've also been synchronizing grid generation since long before spaceflight. It seems that the core problems here have been solved a long time ago. Then again, I don't know much about the grid at this scale. I very much doubt that a few PPM phase difference would actually matter, but I don't really know. Either way, it still seems insane to rely on GPS for your sole source of truth, even with its remarkable reliability.