I do wonder how many of these are supported by common hardware like mobile phones, anybody have a pointer to a compatibility list? I know the Chinese government had been prodding its manufacturers to add BeiDou support pretty hard.
Most phones are compatible with GPS(US) +Galileo(Europe)+Glonass(Russia). Most of them also report which constellation the locks are from. GPS status and toolbox on android is a fun way to see what you're connected to.
What we need, and will probably get soon, is inertial guidance based on laser ring or fibre optic gyros in mobiles. You get a location fix every week or so and it starts out much more accurate than gps.
The US system was first by maybe a decade or more so support is nearly universal. The other systems are largely copycat, purposely compatible with existing GPS receivers.
That's why it seems like we're relying on the US for GPS, they invented it and had a full constellation in orbit before anyone else even thought of it.
Of course we're on the internet which was also invented by the US govt so I'm not so surprised why
"the backups for this backbone of the global economy have to be American" in reference to GPS at least
Corrections every week? This isn't possible given the drift rates of high end FOG or Lazer ring IMUs. A high-end marine-grade INS can cost over 1 million dollars. These systems will typically provide un-aided navigation solution drifts that are less than 1.8 km per day. This means that if the device were left stationary for one day, due to slight errors in the sensors and imperfect sensor calibrations, after integrating the position solution, the calculated position after one day would be 1800 meters away from the sensors actual position.
With ones that you can affordably put in a phone within minutes the drift will be huge. You need something to regularly correct for the drift and currently this is GPS.
From the abstract
> In 2006, we presented at DGON symposium in Stuttgart  the design and navigation results of MARINS, the first FOG-based navigation system within the class of 1 nautical mile per day. This navigation system in now in production...
> have we reached the limits of the technology or can we still improve the performance of our sensors?
> Of course, the present FOG design is not good enough for the required performance, even in a strictly controlled environment.
This is a discussion of how it could be improved not what is available in production and certainly not close to being available within a phone - which was the original point.
High end civilian IMU's typically use mechanical gyros which have been obsolete for decades. Also, a phone isn't typically moving constantly like the oceans so error rates would be lower.
Even if we could make that cheap and small enough it would still need regular corrections far more frequently than a week to be as good as a GPS is now.
Of course, that was the proposal. There's more datapoints if you're willing to get creative, wifi networks (already used for this), cooperative comparison with other mobile devices in a local meshnet, acoustic cues from the environment, machine analysis of captured images, etc. Obviously dead reckoning without gps is going to require a multi-pronged approach.
Please explain how this will work?
You don't think such a system is practical, or you don't think such a system is technologically feasible?
Or you just don't understand the system I'm describing?
If you really care you could sketch out what exactly it is and how it'd work for yourself for a couple of devices (or more) and see what issues you uncover.
If your acceleration sensor is off by 1 part per million, 9.8 m/s^2 (i.e. gravity) will turn into a positioning error of ~73km in one day.
And because of a long fly time or imprecise initial reference point (a submarine is floating) some do corrections. One of the coolest one for ICBMs is to use celestial navigation to correct errors. They'd have a window with a camera and would "look" for a few stars.
- GPS; widespread, low accuracy
- INS; always available, high short-term accuracy, terrible long-term accuracy
- terrain-matching: large-scale corrections.
The different characteristics allow one sensor to correct another to a degree to produce an overall stable position.
The system only went live in 2016. It's only been supported by Apple since the iPhone 6s, and Samsung has supported since the S8.
I would be hesitant to say that most phones are compatible. In 2016 most of the flagship phones had support but even having a compatible SoC doesn't mean it was implemented. The Google Pixel was released in 2016 with a Snapdragon 821 that is compatible yet the Pixel does not support Galileo.
Isn't this precisely how accelerometers/gyros in mobiles work?
For some reason I was convinced phone gyros use light interference in a spiral of optic fiber. Probably because I read about that design when I was looking how solid-state gyros in RC models work.
iPhone X specs list "GPS, GLONASS, Galileo, and QZSS" . I'm pretty sure they've supported multiple GNSS systems for a few generations.
I know I've seen several GNSS modules from u-blox that support multiple GNSS systems as well. One example, NEO-M8, supports "BeiDou, Galileo, GLONASS, GPS / QZSS." 
I know I've also seen several cheap GPS modules that are GPS-only, so multiple GNSS support isn't ubiquitous, but it's probably ahead of IPv6 adoption.
Also eLORAN when?
"In GPS technology, the term "COCOM Limits" also refers to a limit placed on GPS tracking devices that disables tracking when the device calculates that it is moving faster than 1,000 knots (1,900 km/h; 1,200 mph) at an altitude higher than 18,000 m (59,000 ft). This was intended to prevent the use of GPS in intercontinental ballistic missile-like applications.
Some manufacturers apply this limit only when both speed and altitude limits are reached, while other manufacturers disable tracking when either limit is reached. In the latter case, this causes some devices to refuse to operate in very high altitude balloons."
Every app on your phone cares about "Where am I now", but no app wants to know "Where was I 5 seconds ago, but with more accuracy than you knew when I last asked".
Neither android not iPhone have an API to allow GPS hardware to refine the accuracy of historic position locations.
Any sensitive Spectrum Analyser or SDR can see the bump in the spectrum caused by the GPS Signals. And quite a few amateurs have built homebrew GPS receivers.
Or they can buy a little GPS module and use the data stream for a huge range of projects.
Most modern digital Ham communication methods require a 10MHz feed from a GPS module to maintain sufficient time and frequency accuracy.
The limits are real, encoded in public law. I don't understand how you could possibly disagree with me on this point
The fact that you are enclosed in a faraday cage also isn't helping, but they make planes from plastic now, so this shouldn't always be the case.
The linked article that we're commenting on was about a software bug in GPS only
The root cause was a bug in the GPS network. When the U.S. Air Force, which operates the 31 satellites, decommissioned an older one and zeroed out its database values, it accidentally introduced tiny errors into the database, skewing the numbers
this is pretty old news.
I see GLONASS compatibility on "the specs" list of almost every smart phone on gsmarena. Even iPhone 4S has it. Just did a quick look-up, newer phones now support GALILEO and BDS too.
Two other issues - the biggest one is mentioned in the article - global coverage. GLONASS is the only one to claim global coverage.
The other issue is that there's still a huge number of devices that don't support those systems. Most of the time if something says it uses/depends upon GPS, it means literally just that one system, not the others.
Where does the article say that?
I must apologize again for going a little off-topic
Very few. The Kremlin and the presidential palace in Damascus come to mind, but Russia is actively antagonizing the rest of the developed world, including the areas just outside the walls of those two.
And historically, I believe they have been allied with the Soviet Union whilst the USA has historically allied with their arch-rival Pakistan.
I'd go out on a limb and assert that if China disappeared tomorrow, the consequences to the world economy would be far more devastating. So much of the global economy is tied—directly or indirectly—to Chinese manufacturing. It would take multiple decades for the world to replace the supply chains and highly skilled labour.
Is the world dependent on the US? No, you're right that dependent is a very strong word. However, the US, for better or worse, provides a very high amount of global stability. The US has a massive economy and a very strong military, and the world would be very different if any country like that were to fail.
It depends on what you value, I guess.
"The products we do require really advanced tooling, and the precision that you have to have, the tooling and working with the materials that we do are state of the art. And the tooling skill is very deep here. In the US you could have a meeting of tooling engineers and I'm not sure we could fill the room. In China you could fill multiple football fields."
-- Tim Cook, from this article: https://www.inc.com/glenn-leibowitz/apple-ceo-tim-cook-this-...
Take power plants for example: they are all interconnected in large regional grids and deal with such large quantities of power that bringing a power plant online is a dangerous process that has to be coordinated with the rest of the system. You have to spin up the power plant and make sure that you are in phase with the grid before connecting your power output - all while accounting for geographic distribution losses, predicted load changes, and so on. Theoretically, any discrepancies (like power flow being too high due to phase difference) would activate breakers and other safeties should an adversarial actor decide to bring a power plant online online willy-nilly. Unfortunately, the last few decades have shown that those safeties are barely able to handle common scenarios, let alone an attack. There is a serious risk that a single power plant could cause systemic damage to many devices in a region's grid but for the entire history of the US, we have just assumed that anyone with tens of millions of dollars to invest in a power plant is just too profit-driven to pull off anything like that.
If the last few years (decades it seems) have taught me anything, it's that we have to reevaluate many of the assumptions we have been holding about reality and our peers. From the Target/Home Depot/Equifax breaches to Facebook's Cambridge Analytica fiasco, we have just been way too lucky and way too trusting. GPS is just one of many such cases, although a surprising one. I never thought the world would put so much trust in a system created by and for the US armed forces.
The way I see it, this is a feature, not a bug. The energy costs of trying to build a civilization like ours on trustless systems would be prohibitive (and no one would be happy about the amount of bureaucracy it would involve).
Trust is not only vital to the continuous existence of our civilization, it's also a very powerful tool for advancing it. That's why the growing lack of trust of the general population worries me. The rule of law works only as long as most people trust in its implementation. Money works only as long as most people trust in its implementation. That's why, for instance, I'm very critical of mainsteam journalism and media platforms - all they seem to be doing these days is to sow discord, burning people's trust in institutions to get their eyeballs. That's why I've been so critical of Uber since the very day they entered the taxi market, as by breaking laws and getting away with it they were eroding trust in the rule of law (half of the blame goes to municipal governments that failed to immediately ban them).
In my view, trust is so important that working to destroy it is antisocial behaviour, and one that should be punished swiftly and severely. Much more than it is these days.
> If the last few years (decades it seems) have taught me anything, it's that we have to reevaluate many of the assumptions we have been holding about reality and our peers. From the Target/Home Depot/Equifax breaches to Facebook's Cambridge Analytica fiasco, we have just been way too lucky and way too trusting.
IMO the examples you give aren't very powerful. Nothing significant happened because of Target/Home Depot/Equifax breaches, nor the Cambridge Analytica fiasco led to anything of relevance - when compared with the previous scenario of power grid failures. I'd use the 2008 financial crisis as a better example.
> GPS is just one of many such cases, although a surprising one. I never thought the world would put so much trust in a system created by and for the US armed forces.
What about the Internet? ;).
That trust somehow builds consistently in small groups -- humans seem good at quickly deciding, based on a few personal experiences, whether to deal with / trust another person. The major challenge is that this approach does not scale -- one does not trust strangers in a large city. Using a few trusted agents (newspapers, TV, etc.) for things you cannot personally see and assess kind-of worked 50+ years ago, but that model has now failed.
IMO building a framework of trust in a larger, denser, more interconnected world, is one of the major existential issues for a modern civilization. Allowing folks to organize in smaller groups (and set their own rules) and not forcing mixing based on federal laws might be a start. It might work better that universal doctrines ("trust the state"), universal technology ("trust the app") or behavior changes ("trust a stranger"). My 2c.
Oh, absolutely. Don't get me wrong, I fully believe in a trust-based cooperative world. I mean more to emphasize that we aren't really doing any analysis on the risk debt we are accumulating through profit driven global development. Without putting some time and thought into it, we can't make decisions about which risks are acceptable to keep long term and which ones need to be revisited.
> Trust is not only vital to the continuous existence of our civilization, it's also a very powerful tool for advancing it. That's why the growing lack of trust of the general population worries me. The rule of law works only as long as most people trust in its implementation.
Again, I agree, although I don't how you'd go about justly identifying such behavior, let alone enforcing and punishing it fairly.
> What about the Internet? ;).
GPS is a special case because of how expensive geosynchronous access is and how few the points of failure are. The US could just turn off the spigot or Russia/China could shoot down the satellites - the GPS signal they send out is basically a giant homing beacon so it's not as difficult as shooting down spy satellites - and that's that. The tech for laying fiber and connecting to the rest of the world is far cheaper and more accessible making it much harder to disconnect an adversary completely. It's easier to trust a system built to be decentralized instead of dependent on a single constellation.
It's a difficult problem and I'm not sure what even approaches a good - and stable over time - solution; naïve approaches would quickly degenerate into totalitarianism...
> GPS is a special case because of how expensive geosynchronous access is and how few the points of failure are.
Fair enough :). I was just addressing the "created by and for the US armed forces" angle.
Satellites are fragile, but they're also very expensive to shoot down. So I think GNSS systems are pretty safe, as points of failure go. Random rogue actors won't be able to afford destroying them, and if anti-satellite missiles start flying, we'll have much bigger problems than lack of satellite navigation systems.
IMO the Kessler Syndrome is overblown as a risk. Most of our space infrastructure would go to hell in such a scenario, but it’s not an existential threat like it’s often made out to be.
It's not a threat to existence of life (or civilization) - though losing satellites would have severe economical and geopolitical consequences. GNSS systems are one thing, but then there are also weather satellites, climate observatories, satellite comms, emergency beacon tracking and spy satellites.
The main worry here is that a full-blown case of Kessler syndrome would simply lock us out of space access for couple decades or centuries, depending on the severity of it. You could forget about satellites. Space probes might work if launched straight into some transfer orbit. Manned missions would be most likely deemed too dangerous.
And yet here you are, sowing distrust in the media!
This isn't an indictment - I do agree with you on both fronts. I'm pointing out that it's decay-turtles all the way down.
The issue with trust is that it doesn't scale. Or really, as soon as people start trusting symbols (eg institutions), concentrated value is created, which then is profitable to arbitrage away. With the overall trend of increasing communications, we are better able to observe this behind-the-scenes selling out, and thus our trust is eroded.
If we wish to restore faith in our institutions (ie make them trustable again), we need to move their philosophy and governance from "trust" towards "trust but verify".
> Or really, as soon as people start trusting symbols (eg institutions), concentrated value is created, which then is profitable to arbitrage away.
That is the most succinct way of expressing this that I've ever seen. Thanks! It also explains the problem in terms of the same forces that also drive markets, which sounds very plausible (due to simplicity).
Amazon making bank by coasting on a shared hallucination that their prices are competitive isn't really a big deal, societally. The popping of that bubble won't be a big deal either.
Having people view peace officers akin to an occupying military force is a problem (but so was the routine criminality of police before the median person became aware). The troubling bit is that rather than these institutions attempting to self-reform (eg just start prosecuting uniformed criminals), they seem to be digging their heels in - aiming to preserve their power rather than aiming to preserve their justification.
Of course this is the same model-precessing modus operandi common to all established organizations, which is why they die so hard. I think the ethos of creative destruction is so baked into our society that we really don't know how to deal with these organizations that have been adopted as institutions and will not simply be left to fail in isolation.
The surprising part is that this phenomena has extended to geopolitics: having control over the GPS constellation is the kind of thing that would have single handedly decided both world wars, yet is now taken for granted by intelligence operatives of hostile nations using our GPS system. It's hard to believe it's worked for so long.
As for the Christian value of honesty stuff, I strongly disagree. Communities of chimpanzees and prairie dogs!! commonly exhibit social behaviors that would be indistinguishable from humans despite the fact that they have no formalized moral framework. Chimpanzees or prairie dogs who yell wolf too many times will be ignored. Those that are dishonest or manipulative are shunned. Those that are too aggressive are put down by the tribe.
Christianity has nothing to do with it. Honesty is a necessary trait for survival of any complex species dependent on communication for survival
That's not trust.
Of course, if it's fast/cheap enough, you can go with the much superior "verify and don't even waste time asking", but that's often impractical.
0: Well, the steel-man interpretation anyway; the historical version seems to just be a euphemism for "Don't trust, but claim you do so they look bad if they try to complain about it.".
What is "trust"?
In your scenario, I wouldn't classify it as trust at all, yet I know I've used that word to describe something similar when describing building software.
But if you wanted to pin me down, I'd waffle and say, yeah, I'm not really talking about trust. If I trusted function X, I wouldn't check anything about it, I'd assume it's right.
So in your scenario, I wouldn't classify what you were doing as platonic trust either. I wouldn't call it trust unless the verification came when the deliverable was due. But then by then, your trust has been violated.
For instance I ordered something online. I trust the information FedEx gives me is accurate. It says my package is delivered. I am going home and I expect to see the package at my door. I trust my neighborhood/apt complex enough that I don't expect it to be stolen. That is trust. I don't have anything to confirm what I currently believe, but I still believe it.
In contrast, I stopped trusting the USPS at my old apartment. Because a couple of times, they've claimed a failed delivery attempt even when I was home. So I stopped expecting things to get delivered when they said they would be when they would come through USPS.
And I never trusted packages to be delivered to the house I lived at before that place. I'd get things delivered to work.
When people tell me they "trust, but verify", I tell them it's either or. You can trust or you can verify. When they tell me they trust the results of my work but want to verify it, I explicitly tell them, "I don't want you to trust it, I want you to double-check me to make sure I got it right. I don't fully trust myself. Accuracy is important, I want a critical eye on this in case I missed something. I don't mind being wrong if it means we are right."
> What is "trust"?
Actually I was talking exclusively about the phrase "trust but verify". Absent context, "trust" is like "know"; it's a useful shorthand but shouldn't be used if you're trying to speak rigorously about what's actually happening.
1) Western liberal values are not co-extensive with Christianity. Christianity is geographically much larger. This has been true historically, and even more true today with the rise of Christian nations like South Korea and various nations in Southern Africa.
2) Western liberal values came to predominate in Europe centuries, even millennia, after Europe was Christianized.
3) Many Western liberal values are easily traced to pre-Christian movements, such as Greek Stoicism.
4) The Christianity of most Western Europeans today is not the Christianity of centuries ago, let alone millennia ago. The Protestant Revolution was like a giant flask where people took Christian doctrines and mixed them together with contemporary civil and philosophical values which emerged from the Enlightenment and then the dawn of the scientific and industrial ages. It's one thing to say that Christianity was conducive to the emergence of those other phenomena; it's quite another to say that they were Christian.
2) That's hardly a compelling case against the influence of religion on Western values. It could even be a contributor, or neutral.
3) These values were well-documented but, for whatever reason, did not spread to the Muslim or Hindu world first. Islam had its brief progressive renaissance but was not able to sustain liberal values over the long-term. There are some small exceptions - Ismaili Muslims are quite liberal - but they're a tiny fraction of the Islamic world.
4) America was essentially founded by religious zealots and/or adherents to marginalized religions. The very architecture of early America - the gothic styling of Boston, for example - is of that era and persists. You can't wipe out that kind of influence in 100 years.
I'm not saying religion is the ONLY factor, but I find it odd that people try to ignore the impact it's had on the shaping of the modern world. I'm an atheist so I view this more as a historical fact - I'm not a fan of organized religion and would be perfectly happy if it went away.
The Protestant Reformation was a religious movement, but ended up importing a lot of western beliefs into Christianity. Democracy for example is a western belief, Christianity is closely tied to Kings.
I would argue that Christianity has influenced western culture far less than western culture has influenced Christianity. And that the key benefit attributable to Christianity—insofar as it was the lucky religion which happened be closest to the people who built western civilisation—is arguably its adaptable and relatively non-invasive nature compared to many of its contemporaries.
For example, Christianity is tolerant of the concept that God primarily operates indirectly through physical laws, a concept which was normatively rejected early in Islam (circa 1100). Thus, Christianity was relatively more conducive to the emergence of science. But, Christianity is hardly the only religion so tolerant, so it's not like it deserves special credit in that regard. Indeed, this tolerance is sort of a fluke and really a vestige of Roman and Greek influence--influence that Muslim scholars were deliberately rejecting.
Christmas trees and holly are obvious, but compare old vs new testament and it's much deeper than that. On top of that you get the Protestant Revolution which really westernized Christianity.
Perhaps you're thinking of guilt and conscience, which means people might think that not being affirmatively honest could be considered wrong. Christianity is sometimes conflated with guilt culture (which emphasizes personal conscience), but Western guilt culture comes from Greek Stoicism and it took awhile to permeate through Europe--much longer than Christianity (like millennia longer). And there are plenty of modern Christian converts (entire countries, in fact) which are devoutly Christian but absolutely have not internalized a guilt culture. Very little, if anything, about Christianity requires a guilt culture--indeed, all of the Old and much of the New Testament is perfectly consonant with a shame/honor culture.
Note that not telling the truth is not the same as lying. For example, you could choose simply not to disclosure unless asked. Also, the Abrahamic commandment, "thou shall not lie", aka "thou shall not bear false witness against thy neighbor", was a legal rule. Most societies have this rule. Twisting it into a personal moral rule about how you go about your daily life is a result of our guilt-based culture which, again, is separate from Christianity, per se.
That's why I'm suspicious of technologies and systems that are meant to be trustless. They seem like a step in the wrong direction.
One, it's stated vaguely. What would qualify? Which religion, and which society? You would likely claim that there was some society somewhere which already had such a standard, and that therefore religion had nothing to do with it. It's too easy for you to dismiss any example because your requirements are not well defined.
Second, how far back are you willing to go? Go far enough back in human existence and we can't trace the provenance of a certain moral value.
Third, it depends on your existing beliefs about religion, creation, etc. If you believe that humans were created by a creator being who endowed them with certain abilities and tendencies, then who's to say whether a certain tendency was a matter of religion or society? If one believes that the tendency first came innate from our creation, and later was made explicit in revelation, was that tendency from religion or society?
On the other hand, if you believe that life happened spontaneously and that humans gradually evolved from single-cell organisms, then you have already eliminated religion as a possible source of anything, because no religion would be true, in which case everything would fall under the category of "society." (Alternatively, anyone can claim, "A god spoke to me and you should do what I say," and that would qualify as religion. In which case, I could claim that a god spoke to me, and that you should therefore believe everything I say. And then "religion" ceases to be a meaningful category, leaving us once again with only "society.")
So, as you can see, your request is not so simple, and is really just fodder for useless Internet arguments. If you want to discuss it seriously, you will have to address these matters first.
This is completely orthogonal to the belief question: that is, you could perfectly believe that Jesus is the son of God, and still you will observe that all moral values introduced by Christianity were already present in the existing society.
Note: actually, to be precise, discussion with believers will always reach a point where rational discussion completely breaks down, since, by definition, humans can not understand the ways of God. At some point I will struggle to understand a situation which says the "wall is black and the wall is white", and a believer will rightly point to me that understanding this is simply over my head, and that I just need to accept it as it is.
The world lives on the knife-edge of chaos. It's trivial to cause mass panic by driving a car into a group of people, or by a multitude of other means.
The only reason society manages to even exist is that we generally trust each other. It's the fundamental underpinning of society. Most people are generally law abiding citizens. The reason that people don't murder each other isn't because it's illegal, it's because they don't want to.
Society relies on the fact that we are generally nice people.
I would argue it's because there is no financial incentive to destroy the grid. Humans are willing to make entire species (overfishing, poaching, etc...) extinct for a quick buck.
Perhaps we all need to stop watching so much TV.
1. The attacker might be too powerful to deter, or might be able to make a coordinated attack that would prevent their punishment. A general great-power war would bring down many of these systems in the first few hours.
2. The attacker might be able to avoid detection or identification. This is the bucket most of those security fall under - if an attacker can take advantage of these systems anonymously, there's no deterrent effect.
Cambridge Analytica is a bit of a hybrid case; it was used by powerful probably-state actors for deniable attacks.
Pompous social engineer blog post: "Dunkin Donuts is laughably insecure. I was able to steal lots of donuts by lying and abusing the trust of employees. Hahaha, Dunkin Donuts security sucks, what a joke. They don't even question that my story was completely fake and that I was just a good actor, what a trash company"
Sure, you can knock out a power grid with seemingly trivial means. But once you do, you're just as shit out of luck as the other guys.
It's pretty much the "too big to fail" scenario. Too much of the infrastructure we've become dependent on is just not worth taking down in an attack. Sure, GPS may have a single point of failure... but GPS is kind of useful for you as well so you don't really want to knock it out. You can't afford to replace it.
It's like these systems are just sitting around saying "Fuck with me and I will burn this whole place to the fucking ground. The fucking ground"
I'm not convinced there wouldn't be a system degradation cliff after that point of 3+ SPOFs being attacked, e.g. a GPS issue, a massive BGP hack, Tier 3 Comm. or equivalent outage, and a DNS issue--all around the same time.
That "cliff" could cause a biblical amount of damage.
I'm sure those could all be mitigated, but the idea of them failing all at once, even coincidentally, is terrifying.
You could waste endless cycles not trusting.
Even startups that I thought were absurd ideas ... I maybe wouldn't have done it because of a lack of trust... but they worked out.
We've just had this alert from DHS on RUS hacking into our grid:
The preliminary R&D and tests seem to have been run in Ukraine
Clearly, it's being tracked, but ...
That's one way to look at it. The other way is that it depends on incentive.
> that bringing a power plant online is a dangerous process
Not really. Power plants are connected and disconnected from the grid several times each day.
> You have to spin up the power plant and make sure that you are in phase with the grid before connecting your power output
This is done by computer in all cases, and it's incredibly fast and easy to do so. Especially considering we're only dealing with 60Hz here. This only applies to certain types of power plants, solar plants have entirely different interconnection considerations.
> There is a serious risk that a single power plant could cause systemic damage to many devices in a region's grid but for the entire history of the US
There is serious risk that a single tree branch could cause a system wide blackout for a major portion of the US. 
> we have just assumed that anyone with tens of millions of dollars to invest in a power plant is just too profit-driven to pull off anything like that.
Breakers and automatic protection devices respond with incredible speed and are typically controlled by an external agency operating at a State or Regional level.
Relative to what? Fraud and theft will always be factors in a functioning society. Is the total value extracted by newer frauds increasing faster than our global GDP?
> I never thought the world would put so much trust in a system created by and for the US armed forces.
What are the alternatives? The world putting it's trust in a commercial system? We'd just be trading one set of known issues with another.
The entirety of modern economic and psychological theory can be reduced to "it depends on incentives." That's utterly unhelpful.
> Not really. Power plants are connected and disconnected from the grid several times each day.
I said "bringing a power plant online." You said "connected and disconnected from the grid." They're not even remotely the same thing: the latter is a tiny step in implementing the former.
> This is done by computer in all cases, and it's incredibly fast and easy to do so. Especially considering we're only dealing with 60Hz here. This only applies to certain types of power plants, solar plants have entirely different interconnection considerations.
Uhm... what? Power flow adjustments have been "done by computers" since at least the 1970s and the frequency is only relevant in so much as it sets physical limits on how fast geographically distributed hardware can respond to changes in the system. It doesn't really matter what the frequency is, as long as everyone agrees, the system will be fine.
> There is serious risk that a single tree branch could cause a system wide blackout for a major portion of the US. 
Are you arguing with me or agreeing?
> Breakers and automatic protection devices respond with incredible speed and are typically controlled by an external agency operating at a State or Regional level.
No, they don't and aren't: https://www.nvc.vt.edu/lmili/docs/Mili-Risk%20of%20Cascading... - privatization has opened us up to a lot of unforeseen weaknesses.
> Relative to what? Fraud and theft will always be factors in a functioning society. Is the total value extracted by newer frauds increasing faster than our global GDP?
Relative to where we were less than a decade ago, when Facebook was nothing more than some Ivy League hook up site.
> What are the alternatives? The world putting it's trust in a commercial system? We'd just be trading one set of known issues with another.
The alternative is fucking vigilance. Vigilance of tradeoffs. Vigilance of bad faith actors. Vigilance of the legislative branch. Vigilance of our public servants.
1. Cell sites have their own high precision clock, so they can go at least 10-20 minutes and probably longer without any difficulty.
2. The site really only needs to see a single satellite to get time synchronization if it has the almanac and ephemeris because it knows exactly where it is and how far away the satellite is. In fact, in the presence of noise, it can integrate over a long period to pull a jammed signal out from under the noise floor.
3. There are already a number of other terrestrial sources of time. TV stations have precise timing, and a defined offset to GPS time. They also have huge output power that is more difficult to jam.
4. The cell networks can synchronize with each other. If the network simply adjusts the time to be an average of neighboring cells and its own clock, they will stay in sync. It's not required for the mobile phone network to have correct absolute time, only correct time relative to other nearby network elements.
 Pg. 22 https://freeviewnz.tv/media/1216/freeview_dtt_transmission_r...
Also, if you already have a time, you can keep it using the 50/60 Hz of the electric grid (which is specifically regulated to keep cheap alarm clocks in sync) or the TV refresh rate (which was also kept in sync deliberately for clocks in the analog days, dunno about now)
It's all old stuff, but you said your interested was "I didn't even know that existed until now".
So yeah, it's possible to have a clock you never have to set that's always correct just by having an antenna.
GPS is such a weak signal that almost anyone transmitting ground based signals on the right frequency could easily drown out GPS - and do spoofing with a little extra research. So theoretically you could spoof near a data center and mess up a lot of data powering 1000s of applications.
On top of this civilian GPS is made to be jammed and innacurate - there's a better one the military has moved onto because of this (see the m-code section: https://en.m.wikipedia.org/wiki/GPS_Block_IIIA)
So yes, relying on an easily jammed atomic clock hurtling through space seems like a bad idea... But it's kind of the best we've got right now. At least until the cost of putting your own satellite into orbit goes down.
"Selective Availability" was the first incarnation of this pipe dream. Civilian GPS would be deliberately corrupted by up to 100 metres and the correct offset would be transmitted separately to authorised military devices. But, see above, in practice when the US military needed GPS it found civilian devices were available while accurate military ones were not, so it reduces the induced error to zero and bought civilian kit for the Gulf War.
The M-code won't be deployed until 2022 (probably later, these things always get delayed). That's when those Block IIIA birds "go live" even though some will be in orbit for years before that.
Jamming the M-code is not really harder than jamming other codes, this is a broadcast radio signal you can easily transmit a more powerful signal yourself. The Block IIIA birds have an extra transmitter so they can increase power... but they still can't drown out even a relatively disposable local jammer.
Spoof genuinely is harder with an extra code... and this is the supposed benefit with owning any of the GNSS systems, you can keep a secret shared key that makes your system spoof proof until bad guys learn the key. But again, in practice when war breaks out you turn out not to have thousands of expensive military-only devices with the shared secret, so you rely on the civilian stuff anyway.
The same principle is likely applicable to other standards as well, until the day they add encryption, which will probably need a lot of time and research to overcome the inevitable associated timing problems.
If doable at military level, the possible scenarios are catastrophic: country A launches say 5 test missiles, country B from nearby hidden submarine launches 5 much smaller and stealth jamming missiles. The jamming missiles approach the bigger ones then jam them into believing they're slightly off course forcing them to adjust, while in reality they're being slowly directed to country C.
Of course any loss of control by ground base should be interpreted as self destruct by the missile, so it'd be near impossible to do it actually, but if other signals could be spoofed as well as positioning, then that would be a problem.
They use a highly precise inertial measurement unit to track their location since launch.
All similar in function and implementation.
The coolest part about GPS is the fact that temporal relativity is employed to establish a 3D location from accurate flying clock radios, that’s rad.
But that's an extreme case. Localized and targeted GPS spoofing is not science fiction. What's worse - the GPS spoofing can be designed to warp world geometry in particularly nefarious ways to coerce the trajectory of objects for specific purposes. It's not even that expensive, it's just a different algorithmic problem.
Those algorithms will become trivial in the future - and they will have not been tested by most (if any) of the various autonomous service providers.
Beidou-2 is just like GPS, positioning service only, no SMS or shit.
No, they're not.
LEO is an orbital period of 128 minutes or less, which for circular orbits is ~1200 miles or less . GPS satellites are in 12 hour orbits ( see "Orbital Characteristics" in , putting them at a little more than 12,500 miles out .
And anyway, a satellite's altitude has little to do with how soft a target it might be. It's not simple.
That said, I'm glad training emphasizes non-GPS modalities. You never can tell when Carrington will come calling .
(according to Wikipedia, this discussion got me to read more about it)
Let say an opponent already have satellites in space with laser weapons, could they just destroy the GPS satellites using such a tech ? Or do you guys think that this technology does not exists ?
We saw some videos in recent years of NASA laser weapons taking down planes. That's why I'm thinking about this. Maybe the distance in space would make it impossible... I have no clue.
If aiming a laser accurately is too tough of a challenge (probably is) then as an alternative you would need 6 weapons and launch each one in one of the 6 orbital planes that the GPS constellation uses and just have a little bit lower orbit than the GPS satellites so it would come around and catch up to each satellite but not be travelling so fast as to make accurately aiming impossible.
Its design features are:
1. Long-duration flight (low-single-digit years).
2. In very small numbers (at most one in orbit at a time).
3. Recoverability of payload.
4. Very high delta-V (i.e. can shift orbits a lot, and has been observed doing so in big jumps during deployments).
The most likely guess is a testbed for military satellite subsystems; put a camera or a radar on there, and you can get a feel for its performance at different altitudes/angles, and also bring the prototypes back down to do a teardown after the fact.
As to technical details, here is a write up of the NAS26 astro-inertial guidance system from the '70s:
The navy and the air force get all the coolest toys, I tell you what.
On either side?
And anyways, what country has the budget to knock out twenty four satellites in quick succession?
And what if this doesn't work? I'm having a hard time thinking the US Gov. doesn't have a shadow GPS constellation up there, somewhere, but I will concede this is the most wahoo part of my meanderings...
I think knocking out GPS is a rather risky move to even try.
The only countries between whom a war would be a globally consequential event: the United States, China, and Russia.
And that is quite a few: Israel, UK, France, India with North Korea/Iran not that far behind.
It's not very easy to do.
And of course to get around that, is to put your own sat. nav. system together.
The US military uses very advanced and highly classified inertial navigation technology for both guidance and navigation systems pervasively. GPS was just a way to collect the data required to make inertial guidance effective. The US military has never relied on GPS for anything; the Soviets could destroy it the day it was designed, so it wasn't designed for war.
When they can get it, GPS reduces error, though I agree that systems are designed to be tolerant of jamming and shootdowns.
China and USA. Any war that they don't participate in is anyway irrelevant on the global scene.
Another option would be hacking the enemie's GPS-like system. I assume we're already hard at work on that.
They don't have to take them all out at once. Just the threat of the system going sown at any time is enough to make it unreliant.
as well as the system of the US allies (EU) and if you do that, you're in hot water with those allies.
I say, good luck with that, sir.
I think 24 missiles pointed at earth targets would have more impact than some pesky satellites.
You will already be in a lot of hot water if you're in a war with the US. The countries who have the capability of doing this have thousands of missiles. A hundred of them being used to knock out some sats is nothing.
And again, what if it doesn't work? You can only try this one time. After that, you lose your element of surprise. Your enemy now knows the enormity of your intent to do harm. Lesson to be learned from Pearl Harbor.
Risky. Risky. Risky.
LoRa is particularly susceptible to jamming. Given the frequencies used, accidental jamming by legally operating transmitters is a very real possibility.
It also turns out that LoRaWAN is vulnerable to selective jamming, but I'm not sure whether or not FOAM is looking to make use of the LoRaWAN layer.