I'm an Amazon driver and we heavily rely on GPS for delivering. We don't just use it for navigating, we also make each delivery inside of a geofence, and the delivery location is recorded and used for future routing. When the GPS says you're a block away from where you are, you're unable to make the delivery without contacting support. I've had days where GPS problems wasted a lot of my time, so I imagine it would be expensive if it happened across an entire region. On the other hand, these kinds of disruptions are already factored into the business model and planned for, so saying it cost an industry X amount of dollars is assuming that the industry was planning for ideal conditions in the first place.
This is exactly the sort of thing that leads to people getting reincarcerated after their electronic monitoring devices mistakenly report them leaving their homes.
I'm reading your article and it seems to be about police coming to check and realizing that the reporting of being miles away was in error, not people getting reincarcerted because of GPS incorrectly reporting they moved ~30 feet too far? One of these is much more insane than the other.
The story is about GPS errors which end up making life hell for people under monitoring since they end up generating a Police response. If 80% alerts were false, then an error like this can result in a surge of these alerts. It is an important story to tell.
The monitoring device story seems important to tell but the problem seems to be related to monitoring devices, which are supposed to be accurate to 30 meters 90% of the time, being miles off or even reporting the wrong state. That kind of systematic failure does not make a few meters of displacement any more relevant. Saying so really makes it sound like the problem is something significantly less egregious than the devices being incomprehensibly inaccurate - as if we have to solve space weather prediction to a new level of science to not have them report someone in Chicagoland as being in Delaware.
Not sure where your confusion is coming from. Have you never used GPS in a place with bad signal? Where it gets confused and you miss your turn? It's the same failure mode. Just the repercussions are getting arrested instead of getting off on the wrong exit.
I think the confusion is probably coming from the fact that the one reference to people being potentially re-incarcerated is buried right down the story.
> Harkins said that since last October, she has seen 30-40 people ordered back into custody based on these progress reports. When asked what can be done to improve CCSO’s EM program, Harkins said that the sheriff’s office needs to “properly and fully” investigate alleged violations before writing reports or taking actions.
You're claiming that erroneously reported movements by ~33 ft lead to incarceration, yet the article you're linking to reports that erroneously reported movements by ~1mi+ lead to police coming to double-check what's going on. Am I incorrect and do you therefore have examples of ~30ft errors actually leading to their incarceration, or are you struggling to see the disconnect between what you're claiming vs. what is actually happening?
If someone's home is 30' by 30' feet, yes, that person's device will report them having left their home and they'll get a visit if GPS suddenly shifts 30 feet to the left.
I'm talking about the class of problem. It happens in normal weather conditions and things like this exacerbate the problem.
As a neutral participant I think “the hostility” is probably because of your condescending tone when you said “hopefully it helps your confusion”. Your initial article really didn’t say anything about people being re-incarcerated for these sorts of errors. I really want to say “maybe you got CONFUSED and posted the wrong one!” but that would be snotty and condescending too.
You seem to care a lot about these issues, and probably have real face-to-face experience with the victims of that.
Problem is though that this feeling type of empathy makes you not the best advocate for them - as you can see here, where (on a platform with worse rules than HN) a flamewar would've broken out over not everyone being as emotionally involved.
We definitely need people like you, but we also need people like you to not be everywhere and scare/annoy people into not caring.
Though, I also agree that scaring/annoying _into_ caring is also often required.
GPS is not that accurate even on a good day. A small device attached to someone’s ankle with a small antenna and an obstructed view of the sky will frequently be registering locations outside of the footprint of someone’s house.
A single 33 foot anomaly is already within the geofence buffer zones used. In dense urban areas the geofence buffer allowance may be 10X that already.
It should be treated that way but we’re talking about elected prosecutors who are itching for an excuse to put people in prison rather than looking “soft on crime” by allowing people to live under house arrest.
No, I’m saying it’s literally treated like that with a buffer zone. That’s how these systems work.
If people were getting arrested every time their GPS tracker was recording a ping 33 feet from the center of their house, nobody would ever survive house arrest.
Do you have any examples of someone getting thrown behind bars due to a GPS error on the order of ~30ft like you're claiming? That's all I'm asking. Really don't understand why you keep avoiding it. You've essentially claimed police/judges are doing something rather stupid and terrible. I'm asking you to show example(s) of what you claimed (~30ft error → thrown behind bars), not something significantly different (~1+ mi error → only-police-visit-but-not-thrown-behind-bars).
"You've essentially claimed police/judges are doing something rather stupid and terrible."
Yes, yes I am. You really need to realize just how unbelievably fucking arbitrary the criminal courts are. At every level. They're not tech people.
To answer your question, I have examples of motions by prosecutors to suspend people from the EM program where they specifically cite specific data points just barely out of their homes, where video footage provably shows they were inside the whole time. They're not mine to share.
Btw, the courts are public and you should try some criminal courts watching. Pick a random day and just go.
> Btw, the courts are public and you should try some criminal courts watching. Pick a random day and just go.
So you could find an example easily but you don't want to? Or you're suggesting court watching in general and not to find an example?
"I have an example I won't share" is better than nothing, I guess. But you were being snarky before you even said that much, when you were just linking your article and not saying if examples existed at all.
I'm curious why they're not yours to share, though. Did someone give them to you under private circumstances, or can people get there from public information but you think you shouldn't spread the word?
It wasn't easy to find, heh. Lots of FOIA requests to even get to a point of where I could go through court records at the Clerk of Courts. Obstinate lawyers for months and months. But after all that, I can find the court documents at the Clerk of Courts. I printed them there and I don't have them anymore. I would need to redact even if I had them. But they were all the same form, but with the actual violations largely hand-written notes written by a prosecutor in a hurry. It was usually a list of like, ten instances that they seemingly picked from random of the GPS rlogs. The best glance I had into what was by FOIA'ing the GPS records of someone who died much later but had a lawyer who fought tooth and nail to show he didn't leave his home. GPS is truly all over the place in these logs. I validate a lot of that against call center records that themselves took months to get but show when alarms and calls are made to the devices, plus when dispatch is done.
A lot of this stuff is hard to talk about because it's about real people in real pending (at the time) cases.. and I'm also not a criminal defense attorney by any means. There's a reason the first article I posted had their identity completely removed. There's weird liability and believe me I want to say more.
Very honestly, I wish I could have done more reporting on how fucked up those devices were. I put a lot of time and effort into reporting that couldn't make it to print, largely because I was doing freelance work at the time. The first offer I got for that piece was $50. Wasn't sustainable.
Do you have any questions about these EM programs?
If you FOIA’d them, then why would you need to redact?
If you can’t show evidence, then it’s probably best not to cite that evidence. At that point it seems to me that you’re asking people to just trust your claim. You seem like a nice person, but what sort of rational reader trusts an internet stranger.
This is an important issue and you seem interested in the topic.
The documents I'm talking about didn't come from FOIA. They came from printing them at the clerk of courts' office. They aren't redacted.
But yes, these documents should be FOIA'able and I shouldn't have to redact them. It's one of the reasons why I'm involved in advocating for masking the judicial branch FOIA'able in Illinois.
You've kind of spoiled my day with this. Its like an angry chess game when you've got momentum, you POUNCE! But nobody else here appears to have chosen violence. really I get that he "maybe snarked you". But you should be reminded of the beautiful rules of hn discussions.
Thanks for the feedback, but I think you're missing something. This is not about us, it's about everything and everyone else implicated in the discussion. About the fact that we're essentially being demanded to assume - without clear evidence - that the vast majority of those with power over us are categorically incredibly incompetent or malicious. That is not only incredibly insulting toward the good subset of humans who have dedicated and even risked their lives for the public good, but it goes further and sows deep distrust and resentment, continuing to tear apart the very fabric of society. If you/we want to do that, be my guest. It is HN after all. But we damn better be able to justify it with rock-solid evidence, not just go "trust me bro, they're all stupid, they're not techies like us."
Throughout this entire chain of comments, there has not been one shred of evidence that this has actually even happened once, never mind that it is a repeating phenomenon as they claimed. All we have been given is repeated attempts to make us believe those claims were true, supported by claims of existence of (not actual) evidence that - even if existent - would not remotely imply the claim is true. If we want to believe things without evidence and damn other who disagree to hell based purely on beliefs, we certainly can - that's what freedom of religion is for. However, I hope the irony isn't lost on anyone that it's quite literally the diametric opposite of what we're expecting from the justice system.
Whether the claim is ultimately accurate or not, that is what what should be spoiling your day before anything I wrote. It certainly did mine. It should absolutely spoil your day to watch the integrity of huge swathes of people running your society get smeared without clear evidence, with more nails being hammered into the coffin that is the trust holding your society together. Either you're watching something unjustified, in which case that should make you upset on its own, or it's justified, in which case it's even sadder. Either way, I would think that seeing evidence should be at the bedrock of it all, not the last straw whose demand finally spoils your day.
Those of us who already knew this about the justice system generally can't afford to let that by itself spoil every day? But yes, I can sure see that learning about it would spoil your day.
I mean, I know some good people who work in the US justice system in order to make the world better. But I can list even more US prosecutors who have been caught lying to convict someone who was innocent. Cops who faked evidence, or destroyed it. The judges who convicted kids in order to get kickbacks from the private children's prison, that was pretty bad. It's pretty shocking to be reminded that there are people who believe that the US justice system is made up of well-meaning, well-informed people who do not attempt to ruin anyone's life. Or that it is not a collection of rules that are sometimes designed to ruin many people's lives, or best case simply happen to do that because they were written without any interest in their effect on people's lives or by people with actively incorrect understanding of what their actual impact would be. There is enough information to contradict this naive faith in the justice system, just in the national headlines over the past few decades; people who have gone to the effort of reading entire articles and follow up research, or ever gotten involved personally, can simply forget the level of mistaken trust that half the country grows up with. Like ...you're asking "what is water? How dare you mention water without lab evidence!"
Next time try to make yourself easier to talk to and maybe you'll get better answers. When responding to you it felt like all you were trying to do was "own the left" instead of approach it with actual curiosity and interest. The sort of thing where nothing I say will ever, ever, ever satisfy you. Have a good one.
Neither I nor you should appreciate spreading unsubstantiated rumors that directly attack the public servants neither of us personally know. If it bothers you that I'm defending them, then perhaps don't launch your attacks on them until you can share solid evidence that directly supports your claims. They're not going to be the ones defending themselves here and neither are you, and surely you don't expect us to accept whatever we read as true with zero evidence. Otherwise you're just spreading rumors. You owe it to the people you're talking to to justify any distrust that you're sowing.
And no, I'm not here to "own" anyone, whether left or right or up or down. I'm here to figure out what is true and what is false, and what is a rumor. Hence my question. If you had actually provided solid evidence for your claims in the beginning, I would have spread your words in support of your cause. I don't want innocent people being harmed any more than you do, whether they're wearing ankle monitors or robes.
Okay thanks, so here's what I don't understand. When there is video evidence that someone was in their house the whole time, and given that everyone who has used a GPS knows it can easily be inaccurate by 30ft, why in the world would the judge trust the ankle monitor accuracy over video footage they see with their own eyes that directly contradicts it?
Something about this just doesn't seem very plausible, especially if this kind of thing is happening more than once in a blue moon. Either the video evidence is not as convincing as we're being led to assume (thus leaving more doubt in the judge's mind than ours, even if the person is innocent), or there should be some other explanation.
I don't know what to tell you besides yes, it's really that bad. A lot of it is just people passing the buck down the road, a lot of it (at the time) was covid, a lot of it was the difficulty of people on EM to publicly talk about their situation. Defense attorneys just want to get their clients out of jail and a lot of the EM stuff is a distraction to that. It's very much a, "we'll put in a ticket" sort of situation across many moving parts.
Lawyers began telling their clients to film themselves in their homes at all times so that they could prove to judges that they were in their homes when the devices went off. That's advice they give because the risks of not doing that are going back into jail. And to prove all that, you still have to go through all that process, filming yourself, etc. It's truly bad.
Everyone knows video footage can be faked. Why would the judge ever trust video provided by the defendant over serious professional technology like GPS? Might as well just take their word for it!
What’s funny here is that you are displaying misplaced trust in the justice system that exactly parallels my hypothetical judge’s misplaced trust in technology.
No, most people don't know GPS can be spoofed, or at best think of it as a nation-state level action. I'd be surprised if you got less than 100% of non-tech people saying that if GPS contradicts a video then the video is faked.
Why did literally hundreds of judges in the UK accept bogus evidence from the Post Office and Fujitsu leading to nearly 900 innocent postmasters being convicted?
Because judges are nearly always the kind of people who instinctively trust authority. They wouldn't be judges otherwise.
The point is that the enforcement agencies make the assumption that GPS data is always correct. But there are any number of issues that can cause problems with it. People making decisions about how to enforce house arrest or design autonomous farm equipment need to take GPS flakiness into account. Differences in scale are not the point.
> so presumably a number of them are attached to people who did no crimes.
You and I have very divergent views of the type of person likely to be charged or prosecuted for a crime or indeed to participate in a diversion program that involves GPS trackers, my friend.
Your heuristic is flawed. The pool of defendants with pending charges who were granted pre-trial home detention are going to be disproportionately non-violent, first-time offenders compared to those denied bail or with prohibitively large amounts.
Meaning an error like this harms innocent people wrongly accused more than the stereotypically hardened repeat offenders you imagine to be undeserving of your sympathy and presumed guilty.
They absolutely can, depending on the jurisdiction. I saw plenty of cases out of Atlanta with drug possession cases with no prior history getting an ankle monitor, back when they were live streaming bond hearings from Rice street.
What on earth is this claim? Are you sure you’re on top of Fulton County’s 1500-person ankle monitoring program, and the push to reduce jail overcrowding? Have you really been tracking the national trend to introduce ankle monitors for pre-trial defendants who would have been simply released on recognizance?
Okay but the claim is people are being re-arrested because of this "sort of thing". But I read the linked article, and it doesn't mention anyone getting re-arrested. There is only one situation described where the person is arrested and then let go after the cops got proof the alert was faulty.
So yes, it absolutely sucks that this technology is so inconvenient and bad but at the same time, the author and GP claims are not proved or truthful in totality (even in the article they posted).
We can agree GPS tracking sucks but also question claims that are not true. Also telling people to "calm down" over text when they are not even talking to you is very passive aggresive for no reason.
Consider that, from the justice system's point of view, there's no distinction between between someone breaking house arrest for a drug fix versus due to GPS error. They don't have the resource to investigate every single violation, so they always just assume that the device is infallible and that the human is lying.
That's why there's no data for someone getting rearrested due to GPS, and why the few instances where someone do prove an error is concerning.
>Also telling people to "calm down" over text when they are not even talking to you is very passive aggresive for no reason.
Your "This" quote was the least genuine comment I've seen on HN in a very long time. You took a comment and removed all context to complain about how it's wrong, when it wasn't wrong at all. There should be no doubt that GPS glitches can cause people with ankle monitors a lot of needless trouble, and "the system" likely won't believe it, and simply won't care.
If you had an ankle monitor, and someone wanted to fuck with you, it would be trivially easy to block or spoof GPS signals to put you back in jail. All it takes is an SDR and some software you can find on github. Think about that before you quip "This" again.
This time the glitch was 33 feet, who's to say next time it couldn't be 3300 feet?
> This time the glitch was 33 feet, who's to say next time it couldn't be 3300 feet?
People who study this. This glitch was caused by unusual, structured, widespread distortions in the ionosphere. There's no known mechanism that would cause enough distortion to make the errors 100 times as large. There would also be other symptoms of any unknown cause.
https://claude.ai/share/5cc4163e-9cbf-47cd-9749-4bb55bca42fe if you don't mind discursions into safety of aviation navigation systems. Caution: Do not take the error bounds in the second half as relevant to errors for unaugmented single-frequency users; those users will see much bigger errors.
According to this firm selling them, this model has <15ft error, usually 3-4 ft. Given the permissible area is entirely up to what the judge orders, it seems eminently plausible that someone confined to their apartment could be placed outside with a 33ft jump causing a false alarm.
At the very least, it's not enough evidence provided to claim the scenario is inherently impossible based on undefined "allowances" without any actual numbers for something completely dependent on the jurisdiction, monitoring software implementation, and attitude of the police officer/judge.
I also found Reddit anecdotes of getting alert texts stepping outside onto the street from their yard, or false alarms while still inside but not enough details were provided to be sure they were actually GPS and not RF so not as helpful.
It happened with both RF and GPS! The Cook County Sheriff's Office moved between the two at one point so it was possible to see the effects over time as folk moved over. Some people got more false alarms when moving to GPS, some got fewer. IIRC it was about even.
That might be true for a place in the middle of nowhere with no features, the same device model managed by the same company and the same call center person and same sheriff and judges and prosecutor. But with GPS in an urban environment where many homes are over 100 years built from many different materials, 33 feet is a lot.
Urban environments have larger buffer areas due to multipath interference.
The story you linked has examples about false alerts triggering in a different state.
Do you have any actual examples of 33 feet getting someone arrested? I’ve worked enough with GPS that I could tell you that any system with thresholds that low would result in everyone getting false triggers
Yes, everyone on the devices received false alarms. It's why there was a call center that managed the false alarm flows. I highly suggest you read the articles I've shared.
I fought tooth and nail to get access to the data showing how often devices reported "invalid" status (where the device's specs said it was something like, within 150 feet of inaccuracy it reported "invalid"). They initially told me they couldn't get me that data because it'd crash their database running that query. Basically threatened to sue them and over the next 6mo or so I got two 100GB MSSQL dumps. Hundreds of millions of rows of devices reporting back that their GPS signal was invalid. It would take a lot of time to make it sharable because they included the actual GPS location infos.
Sounds like you could be a convict, have your gang interfere GPS on a local level but enough to have other people in the neighborhood notice, make a quick run for whatever you'd need to, and still claim plausible deniability.
TFA article claims: "Indeed, the solar storm of May 2024 is estimated to have cost the US agricultural industry $500 million due to disruptions in precision navigation."
This seems hard to believe. The link provided hand waves through how it maybe could happen, and ends with an Economist just SWAGing that it could have been maybe a dollar an acre or so.
"He estimates that affected farms lost about $1 per acre. Nationally, this equates to an estimated half-billion dollars in lost earning potential, Griffin says."
So yeah, hard to believe was the right call. Very few farms were affected, but if we assume half of the total 900 million acres of farm land were, add 10% to get a round number, and guess it at a dollar per acre, we get the quoted big number.
That’s how all “estimated damages” work. It’s all just made up by some random person who guesstimated a number then multiplied it by the maximum possible people effected, realistic or not.
Yes, it's actually based on an economic model seemingly developed with a detailed understanding of modern farming practices and historical effects of timeline disruptions on yields. It may be approximate but isn't just some random dude guesstimating based on vibes or something.
It's an order of magnitude estimate of the worst case per acre, multiplied by a very course estimate of the number of acres affected, with little or no accounting for the length of the outage, the timing of the outage relative to specific crop-planting times in specific regions, and similar factors. It relies on manufacturer's estimates of the benefit of using their technology to assess the impact of not being able to use the technology. In other words, it's a SWAG.
Consider: the outage may have meant that some equipment would be slower, less accurate, or missing some features, causing time delays and other losses that may or may not be equivalent to using the non-GPS equipment. Or it could have rendered the equipment entirely unusable during the outage. It could even have permanently damaged the equipment (e.g. causing it to drive over an embankment or something). There is no apparent attempt to differentiate these outcomes, which could have significant impact on the estimate.
It's not reasonable because the error bars of each estimate compound and they may not even be normally distributed in the first place.
You should rather convolve probability distributions - assuming factors are independent - and if the IQR covers a huge range, perhaps orders of magnitude even, you should state that.
Is this considered "outside-in" GPS? That is, relying on satellites orbiting the Earth? Is there such thing as "inside-out" where maybe you rely on the images of the sky above? I guess without IR or other secondary scanning technologies, that would be difficult.
There's also the classic of dead reckoning, which is usually infeasible but modern commercial aircraft have the capability of bounded accuracy in their dead reckoning navigation for several hours at a time if needed, and if you are the US government, you can build fantastical machines to measure your own motion and dead reckon yourself to a very very tight point on the other side of the world.
That thing still has orders of magnitude better stability than common laser ring gyros as used on those airplanes, and the same for the price tag.
GPS was dominant because it's cheapish and high performance and easy for a lot of contexts. However, it is critically easy to jam, for physics reasons. A jamming transmitter will always be thousands of miles closer to you than the GPS satellites are. Jamming GPS is cheap and easy, so all war will involve the denial of precision GPS guidance, so we are looking into alternative guidance again.
TERCOM as used in the Tomahawk missile existed to guide them semi-inertially back in the 80s and was functional.
In Ukraine, various providers have developed (supposedly) ways of using commodity cameras to watch the scenery pass by under a flying drone to ground medium quality inertial systems, to allow dirt cheap, unjammable navigation over long distances. It will be interesting how this plays out.
fun fact: the first mass-produced consumer in-car live navigation (1981) was all dead reckoning and gyroscopes. at this point, the GPS network was operational but not available for consumer use until 1988.
It seems worth mentioning that the last time GPS had issues like this afaik, it was due to the US utilizing 'selective availability' due to national security issues. We used it somewhat famously during the 9/11 attacks.
Also the page 404's via archive.org, but information formerly from gps.gov can still be found here:
https://archive.ph/trwOo
Indeed, the link in the parent even says it hasn't been used since May 2000. So, yeah, it certainly wasn't used "famously".
Perhaps the commenter is thinking of the fact it was used globally prior to May 1, 2000. From a civilian point of view, GPS appeared to be invented around this time but it had actually been available for a couple of decades already, just in a degraded form that wasn't very useful.
Differential GPS was already in widespread use in many counties by 2000, which made "selective ability" pointless at it provided automatic corrections to the 'degraded' GPS signal.
An interesting warning as Austin is blanketed by Cybercabs. I think a town full of golden driverless cars 33 feet from where they think they should be is terrifying.
Adjacent to that, I'm a bit surprised that there hasn't been a mass rollout of assisted GNSS in large cities. Maybe not full RTK, but something more than just delivering almanac being delivered.
Are the current GNSS solutions good enough (or too degraded?) in city jungles that there would not be any mass benefit? Too expensive to run a few base stations here and there?
It's strange that agriculture incurred so large losses, I would expect precision farming to rely on RTK (with relatively close reference base station at a fixed location).
The article doesn't mention, but how immune or affected were base station corrected RTK positioning systems?
It sounds a lot less dramatic if we can absorb such events with RTK base stations.
That does add the extra dependency of network links to get the RTK correction stream, unless some day it is standardized to be broadcast locally on FM or so.
I recall that event. It wasn’t the error that was the problem, it was that the units weren’t able to get fixes amid the solar storm, rendering the machines inoperable; save driving by hand, of course, but that isn’t practical with many modern planters.
Feet are actually great units for RF because a nanosecond is very close to a foot. Since feet has many prime factors and/or the foot-meter conversion is also easy, you can quickly get a wavelength of, say a 2GHz (6 inches), and get it in cm (15cm).
Of course, ideally we'd ditch the silly metric system and use natural units. Then these 30 feet are a more comfortable 50M/eV. But those SI guys are really conservative and attached to confusing unit system based on fractions of the diameter of an arbitrary planet.
Maybe not intentionally (at least by the U.S. Government, but the consequences are far greater now.
Now that GPS has subsumed a large part of air navigation as more VOR and ILS approaches at non-towered airports are being left to fall into disrepair, it forces more and more aircraft operating in instrument conditions to fall back to a navigation system that may not operate to the tolerances that you need to shoot an approach to LPV minimums (which puts you close to 200 feet or so above the ground) or LNAV minimums (higher, but still pretty low to the ground). If you lose signal integrity, you abort the approach. You don't want to break out at minimums only to find that the runway is 33 feet to the left or right of the centerline when it's not a circling only approach where you're expecting it. If that field only has RNAV (GPS) approaches, you have to divert. Hopefully the alternate airport you filed has a ground based approach plate available that is authorized .
When SA was around, we had more VORs, more VOR and ILS approaches, and while NDBs (decades old radionavigation beacon that operated on the AM band) were on their way out, they were still around.
One of the reasons SA was discontinued was that if you knew the coordinates of a base station, you could correct for the error. Are airports not doing this already?
Actually, several airports are. So you have normal WAAS and it has a ground segment. Most (new) IFR certified GPS receivers installed in airplanes today are WAAS capable.
To that, you can augment something called GBAS (we used to call it Local Area Augmentation System but switched over to the ICAO name for it). It’s basically a ground station that sits at an airport and corrects for GPS errors where you need it most (airports definitely qualify here and that’s where you need the best GPS performance).
Ultimately, the FAA is going to go 100% GPS and it’ll fall back to the minimum number of land-based sources for redundancy. It’s about cost. The issues with GPS may cause them to push the timeline back and develop plans to mitigate the issue, but they’re too far down this path to stop now.
To meet its integrity budget, a GBAS needs at least triple redundancy, not just a single station.
If one has a lot of patience, one can read the details of how it works at https://elibrary.icao.int/product/299828 (along with SBAS, the ICAO name for what WAAS does; the constellations they can augment; GRAS, a weird hybrid between GBAS and SBAS that apparently went nowhere; ILS; VOR; DME; and VHF marker beacons). Annex 10 Vol I probably doesn't say explicitly that triple redundancy is required, because if you had a single receiver with an MTBF of something like 10 billion hours then you could use just that one.
This particular 30-foot error should go away almost entirely for future receivers that implement DFMC SBAS or ARAIM.
The linked actual research article did look at multiple GNSS systems. GPS is presumably being reported out of familiarity https://doi.org/10.1029/2026GL124645
1. Not today. November 2025. They don't make it clear.
1.1. One would expect that to be put in the title, when the article is written almost a year after that.
1.2. No, the article doesn't state that in the first paragraph. Posting in it full seem to be the only way to fend off lazy comments:
In November 2025, Earth was buffeted by several massive eruptions of solar material that slammed into the magnetosphere.
That's it - the whole paragraph. Several paragraphs later - GPS first mentioned. No clear links between dates stated.
2. It is unclear what is the source of the claim.
UPD: Commenter below found the source, but TFA doesn't make a good job of presenting that as a source of the 33 feet glitch claim, but rather posts another citation from it.
They should've just quote this and be done with it:
During the storm main phase, an east–west elongated band of intense auroral brightness expanded equatorward, producing a horizontally extended strip of strong density gradients that favored the development of small-scale irregularities. These small-scale irregularities triggered pronounced amplitude scintillations (S4 > 0.5) and caused significant positioning errors exceeding 10 m—large enough to disrupt GNSS-dependent applications across CONUS for hours, particularly precision agriculture and autonomous transportation industries. [1]
3. Navigation issues happened before, they state it right there. They were more disruptive as well.
4. The author has articles all over the topics. Everything is sensationalized.
5. Every presented link seem to have this awful Cloudflare js challenge.
Bad article overall.
P.S. Response to the false claim below - no, there's nothing about GPS in "the first 3 words of the article".
not just space weather, I am pretty sure the atmosphere is being disturbed by toxic human activity both by accident and on purpose
I've run outside every morning for decades and used Garmin with GPS since 2015, I've never had so much trouble
Garmins finally supports dual-band (L1+L5) and BeiDou on newest models but it's still not enough to compensate, I have to use a Stryd footpod to guarantee accurate distances/speed
btw BeiDou GPS blows away US GPS for number of sats and precision but despite Russia's GPS being legal in US, technically BeiDou is not
For resiliency reasons alone, it's been proposed to allow (stop software-disabling) BeiDou in the US, but the last time this was brought up, the administration ran out of time. It's a shame, because when there is precise coverage, it enables things like lane-level city navigation.
but of course this administration is never going allow China-anything like low cost electric cars even if it means saving people a fortune in gas
so hopefully in 2029 it can be looked at again
or maybe Dems will also get the Senate too and can be petitioned if they run out of corruption investigations before 2029
it is critical to explain to everyone who isn't technical that GPS is "read only" and no data is being sent to China via BeiDou (just like it's not sent to Russia's Glonass) because that apparently is some kind of weird misunderstanding
on that same note if they somehow made Starlink into a lower resolution GPS backup I'd even trust that too despite personally being anti-Musk everything
Whoops I don't know how I missed that in your links!
The weird part to me is that Glonass was not approved either, yet it's as openly as allowed as Galileo that went through a tedious FCC approval process that was invented later. Grandfathered or not, we're clearly not in a worse place using Russian tech for the last 15 years.
Read only or not, relying on Chinese or Russian gps data for increased accuracy even in civilian increases dependency no?
That seems like a bad idea to me. I’ve thought for about 20 years that increasing our dependence on anti democratic regimes was a risk, no matter what the benefits for global development etc. It’s not isolationist to want to only rely on your friends and not enemies.
(Which is why Europe needs to disentangle itself from the US as fast as possible).
If you are relying on it without a graceful fall back then it would be a problem. If you take it as a boost on top of existing capabilities then it is a pure win. In practice it can be hard to parse the two scenarios. People get used to thinking that something is available and it turns out that it was always leverage against them.
It decreases dependency on GPS and thus it decreases risk because if there's an attack on a GPS system by an adversary, it's likely that they will not be attacking their own system at the same time. I'd rather have my enemy's open source, perfectly functional clock in my back pocket than be without the time. Enjoying that the competing clock has a sub second display is optional.
> BeiDou GPS blows away US GPS for number of sats and precision
Both BeiDou and GPS are supposed to be limited to 10m precision for civilians.
But, going down a rabbit hole, I found that BeiDou is way more accurate than 10m--3.6m and 2.6m outside and inside the Asia-Pacific region, respectively [1]. And that's with the most simple algorithm. It goes down to ~2.5m using dual-frequencies to account for atmospheric error.
Oh interesting, I think I conflated two things; Selective Availability and the military-only bands on GPS. While it's true that access to the military band could improve accuracy with dual-band receivers, consumer devices can use dual-band as well (as your link shows), since there are multiple unencrypted bands from navigation satellites nowadays.
I am not sure how to interpret your link, though. It doesn't measure accuracy on it's own, and doesn't include a number for precision between the two units.
The L1 signal had selective availability in the 90s, and it no longer does. SA had the real-world accuracy around 30m in practice; the "up to" 100m rarely happened. Without SA, plain L1 with good skyview (low DOP) gets you around 10m, or down under 5m if WAAS is having a good day.
Availability of multiple civilian bands, and cost-effective dual-band receivers, allows an ionosphere-free (no need for WAAS) solution in the 1-2m range, with a single receiver.
Ubiquity of internet connections makes it trivial to apply RTK correction data without having to set up your own base station, and/or, availability of affordable medium-range data radios makes it easy to set up your own base station. In either case, it's easier to run RTK than ever before, and dual-band RTK gets you down into the low centimeters, limited mostly by how accurately your base station was surveyed-in.
My understanding is that the encrypted military-level GPS is much more robust against jamming and spoofing. There's probably a lot of capabilities we don't know that's classified, too.
M-Code is a new encrypted signal that is not fully operational yet. OCX was supposed to enable it.
GPS has always had the P(Y) code, which is an encrypted signal, at a higher chip rate than the C/A code that has been broadcast on L1 forever. The P(Y) code has its own interesting history of (semi-)codeless processing. If the US military is lucky, the history books will close on that by 2030: https://www.gps.gov/codelesssemi-codeless-gps-access-commitm... . (Currently, 21 GPS satellites broadcast L5.)
It seems that all the device manufacturers (they mention Apple, Samsung, and Google) are using BeiDou anyway. I don't know if that includes Garmin watches, though.
This is only to make getting a fix faster - A-GPS downloads the almanac data via the internet (fast, but needs internet) instead of directly from the GPS satellites (slow but works everywhere). It doesn't make it any more accurate.
I'm an Amazon driver and we heavily rely on GPS for delivering. We don't just use it for navigating, we also make each delivery inside of a geofence, and the delivery location is recorded and used for future routing. When the GPS says you're a block away from where you are, you're unable to make the delivery without contacting support. I've had days where GPS problems wasted a lot of my time, so I imagine it would be expensive if it happened across an entire region. On the other hand, these kinds of disruptions are already factored into the business model and planned for, so saying it cost an industry X amount of dollars is assuming that the industry was planning for ideal conditions in the first place.
This is exactly the sort of thing that leads to people getting reincarcerated after their electronic monitoring devices mistakenly report them leaving their homes.
Some reporting I did on the topic a few years back: https://chicagoreader.com/news/many-on-house-arrest-in-cook-...
> This
As in, GPS being off by 33 feet?
> leads to people getting reincarcerated
I'm reading your article and it seems to be about police coming to check and realizing that the reporting of being miles away was in error, not people getting reincarcerted because of GPS incorrectly reporting they moved ~30 feet too far? One of these is much more insane than the other.
The story is about GPS errors which end up making life hell for people under monitoring since they end up generating a Police response. If 80% alerts were false, then an error like this can result in a surge of these alerts. It is an important story to tell.
The monitoring device story seems important to tell but the problem seems to be related to monitoring devices, which are supposed to be accurate to 30 meters 90% of the time, being miles off or even reporting the wrong state. That kind of systematic failure does not make a few meters of displacement any more relevant. Saying so really makes it sound like the problem is something significantly less egregious than the devices being incomprehensibly inaccurate - as if we have to solve space weather prediction to a new level of science to not have them report someone in Chicagoland as being in Delaware.
It’s the same category of error, is the point he was making. Relax a bit.
Not sure where your confusion is coming from. Have you never used GPS in a place with bad signal? Where it gets confused and you miss your turn? It's the same failure mode. Just the repercussions are getting arrested instead of getting off on the wrong exit.
Also wrote this one, hopefully it helps your confusion: https://chicagoreader.com/news/false-alarms/
I think the confusion is probably coming from the fact that the one reference to people being potentially re-incarcerated is buried right down the story.
> Harkins said that since last October, she has seen 30-40 people ordered back into custody based on these progress reports. When asked what can be done to improve CCSO’s EM program, Harkins said that the sheriff’s office needs to “properly and fully” investigate alleged violations before writing reports or taking actions.
Ah. That's probably just a result of the pasted article being part of a series.
To be explicit: yes, many, many, many people were reinarcerated because of faulty GPS.
FWIW I enjoyed your articles. You write very clearly.
You're claiming that erroneously reported movements by ~33 ft lead to incarceration, yet the article you're linking to reports that erroneously reported movements by ~1mi+ lead to police coming to double-check what's going on. Am I incorrect and do you therefore have examples of ~30ft errors actually leading to their incarceration, or are you struggling to see the disconnect between what you're claiming vs. what is actually happening?
If someone's home is 30' by 30' feet, yes, that person's device will report them having left their home and they'll get a visit if GPS suddenly shifts 30 feet to the left.
I'm talking about the class of problem. It happens in normal weather conditions and things like this exacerbate the problem.
Really not sure what the hostility's about.
As a neutral participant I think “the hostility” is probably because of your condescending tone when you said “hopefully it helps your confusion”. Your initial article really didn’t say anything about people being re-incarcerated for these sorts of errors. I really want to say “maybe you got CONFUSED and posted the wrong one!” but that would be snotty and condescending too.
But maybe you posted the wrong one to begin with.
Let’s all be friends and nice to each other.
That's totally fair, I shouldn't have said it like that!
You seem to care a lot about these issues, and probably have real face-to-face experience with the victims of that.
Problem is though that this feeling type of empathy makes you not the best advocate for them - as you can see here, where (on a platform with worse rules than HN) a flamewar would've broken out over not everyone being as emotionally involved.
We definitely need people like you, but we also need people like you to not be everywhere and scare/annoy people into not caring. Though, I also agree that scaring/annoying _into_ caring is also often required.
Idk. Activism is weird and hard and all.
GPS is not that accurate even on a good day. A small device attached to someone’s ankle with a small antenna and an obstructed view of the sky will frequently be registering locations outside of the footprint of someone’s house.
A single 33 foot anomaly is already within the geofence buffer zones used. In dense urban areas the geofence buffer allowance may be 10X that already.
It should be treated that way but we’re talking about elected prosecutors who are itching for an excuse to put people in prison rather than looking “soft on crime” by allowing people to live under house arrest.
No, I’m saying it’s literally treated like that with a buffer zone. That’s how these systems work.
If people were getting arrested every time their GPS tracker was recording a ping 33 feet from the center of their house, nobody would ever survive house arrest.
This is a basic reality of using GPS.
Friend, these things happen even with buffer zones.
Do you have any examples of someone getting thrown behind bars due to a GPS error on the order of ~30ft like you're claiming? That's all I'm asking. Really don't understand why you keep avoiding it. You've essentially claimed police/judges are doing something rather stupid and terrible. I'm asking you to show example(s) of what you claimed (~30ft error → thrown behind bars), not something significantly different (~1+ mi error → only-police-visit-but-not-thrown-behind-bars).
"You've essentially claimed police/judges are doing something rather stupid and terrible."
Yes, yes I am. You really need to realize just how unbelievably fucking arbitrary the criminal courts are. At every level. They're not tech people.
To answer your question, I have examples of motions by prosecutors to suspend people from the EM program where they specifically cite specific data points just barely out of their homes, where video footage provably shows they were inside the whole time. They're not mine to share.
Btw, the courts are public and you should try some criminal courts watching. Pick a random day and just go.
> Btw, the courts are public and you should try some criminal courts watching. Pick a random day and just go.
So you could find an example easily but you don't want to? Or you're suggesting court watching in general and not to find an example?
"I have an example I won't share" is better than nothing, I guess. But you were being snarky before you even said that much, when you were just linking your article and not saying if examples existed at all.
I'm curious why they're not yours to share, though. Did someone give them to you under private circumstances, or can people get there from public information but you think you shouldn't spread the word?
It wasn't easy to find, heh. Lots of FOIA requests to even get to a point of where I could go through court records at the Clerk of Courts. Obstinate lawyers for months and months. But after all that, I can find the court documents at the Clerk of Courts. I printed them there and I don't have them anymore. I would need to redact even if I had them. But they were all the same form, but with the actual violations largely hand-written notes written by a prosecutor in a hurry. It was usually a list of like, ten instances that they seemingly picked from random of the GPS rlogs. The best glance I had into what was by FOIA'ing the GPS records of someone who died much later but had a lawyer who fought tooth and nail to show he didn't leave his home. GPS is truly all over the place in these logs. I validate a lot of that against call center records that themselves took months to get but show when alarms and calls are made to the devices, plus when dispatch is done.
A lot of this stuff is hard to talk about because it's about real people in real pending (at the time) cases.. and I'm also not a criminal defense attorney by any means. There's a reason the first article I posted had their identity completely removed. There's weird liability and believe me I want to say more.
Very honestly, I wish I could have done more reporting on how fucked up those devices were. I put a lot of time and effort into reporting that couldn't make it to print, largely because I was doing freelance work at the time. The first offer I got for that piece was $50. Wasn't sustainable.
Do you have any questions about these EM programs?
If you FOIA’d them, then why would you need to redact?
If you can’t show evidence, then it’s probably best not to cite that evidence. At that point it seems to me that you’re asking people to just trust your claim. You seem like a nice person, but what sort of rational reader trusts an internet stranger.
This is an important issue and you seem interested in the topic.
The documents I'm talking about didn't come from FOIA. They came from printing them at the clerk of courts' office. They aren't redacted.
But yes, these documents should be FOIA'able and I shouldn't have to redact them. It's one of the reasons why I'm involved in advocating for masking the judicial branch FOIA'able in Illinois.
> To answer your question
Looking forward!
> motions by prosecutors
Motion ≠ incarceration. So, not an answer (yet?)...
Did defendants get incarcerated as a result of these motions, or no?
You've kind of spoiled my day with this. Its like an angry chess game when you've got momentum, you POUNCE! But nobody else here appears to have chosen violence. really I get that he "maybe snarked you". But you should be reminded of the beautiful rules of hn discussions.
Thanks for the feedback, but I think you're missing something. This is not about us, it's about everything and everyone else implicated in the discussion. About the fact that we're essentially being demanded to assume - without clear evidence - that the vast majority of those with power over us are categorically incredibly incompetent or malicious. That is not only incredibly insulting toward the good subset of humans who have dedicated and even risked their lives for the public good, but it goes further and sows deep distrust and resentment, continuing to tear apart the very fabric of society. If you/we want to do that, be my guest. It is HN after all. But we damn better be able to justify it with rock-solid evidence, not just go "trust me bro, they're all stupid, they're not techies like us."
Throughout this entire chain of comments, there has not been one shred of evidence that this has actually even happened once, never mind that it is a repeating phenomenon as they claimed. All we have been given is repeated attempts to make us believe those claims were true, supported by claims of existence of (not actual) evidence that - even if existent - would not remotely imply the claim is true. If we want to believe things without evidence and damn other who disagree to hell based purely on beliefs, we certainly can - that's what freedom of religion is for. However, I hope the irony isn't lost on anyone that it's quite literally the diametric opposite of what we're expecting from the justice system.
Whether the claim is ultimately accurate or not, that is what what should be spoiling your day before anything I wrote. It certainly did mine. It should absolutely spoil your day to watch the integrity of huge swathes of people running your society get smeared without clear evidence, with more nails being hammered into the coffin that is the trust holding your society together. Either you're watching something unjustified, in which case that should make you upset on its own, or it's justified, in which case it's even sadder. Either way, I would think that seeing evidence should be at the bedrock of it all, not the last straw whose demand finally spoils your day.
Those of us who already knew this about the justice system generally can't afford to let that by itself spoil every day? But yes, I can sure see that learning about it would spoil your day.
I mean, I know some good people who work in the US justice system in order to make the world better. But I can list even more US prosecutors who have been caught lying to convict someone who was innocent. Cops who faked evidence, or destroyed it. The judges who convicted kids in order to get kickbacks from the private children's prison, that was pretty bad. It's pretty shocking to be reminded that there are people who believe that the US justice system is made up of well-meaning, well-informed people who do not attempt to ruin anyone's life. Or that it is not a collection of rules that are sometimes designed to ruin many people's lives, or best case simply happen to do that because they were written without any interest in their effect on people's lives or by people with actively incorrect understanding of what their actual impact would be. There is enough information to contradict this naive faith in the justice system, just in the national headlines over the past few decades; people who have gone to the effort of reading entire articles and follow up research, or ever gotten involved personally, can simply forget the level of mistaken trust that half the country grows up with. Like ...you're asking "what is water? How dare you mention water without lab evidence!"
Next time try to make yourself easier to talk to and maybe you'll get better answers. When responding to you it felt like all you were trying to do was "own the left" instead of approach it with actual curiosity and interest. The sort of thing where nothing I say will ever, ever, ever satisfy you. Have a good one.
Neither I nor you should appreciate spreading unsubstantiated rumors that directly attack the public servants neither of us personally know. If it bothers you that I'm defending them, then perhaps don't launch your attacks on them until you can share solid evidence that directly supports your claims. They're not going to be the ones defending themselves here and neither are you, and surely you don't expect us to accept whatever we read as true with zero evidence. Otherwise you're just spreading rumors. You owe it to the people you're talking to to justify any distrust that you're sowing.
And no, I'm not here to "own" anyone, whether left or right or up or down. I'm here to figure out what is true and what is false, and what is a rumor. Hence my question. If you had actually provided solid evidence for your claims in the beginning, I would have spread your words in support of your cause. I don't want innocent people being harmed any more than you do, whether they're wearing ankle monitors or robes.
You have a substantially undeserved set of rosy glasses for the courts. For your own sake, please try some court watching. :)
They did, yes. I hope you have a better day.
Okay thanks, so here's what I don't understand. When there is video evidence that someone was in their house the whole time, and given that everyone who has used a GPS knows it can easily be inaccurate by 30ft, why in the world would the judge trust the ankle monitor accuracy over video footage they see with their own eyes that directly contradicts it?
Something about this just doesn't seem very plausible, especially if this kind of thing is happening more than once in a blue moon. Either the video evidence is not as convincing as we're being led to assume (thus leaving more doubt in the judge's mind than ours, even if the person is innocent), or there should be some other explanation.
I don't know what to tell you besides yes, it's really that bad. A lot of it is just people passing the buck down the road, a lot of it (at the time) was covid, a lot of it was the difficulty of people on EM to publicly talk about their situation. Defense attorneys just want to get their clients out of jail and a lot of the EM stuff is a distraction to that. It's very much a, "we'll put in a ticket" sort of situation across many moving parts.
Lawyers began telling their clients to film themselves in their homes at all times so that they could prove to judges that they were in their homes when the devices went off. That's advice they give because the risks of not doing that are going back into jail. And to prove all that, you still have to go through all that process, filming yourself, etc. It's truly bad.
Everyone knows video footage can be faked. Why would the judge ever trust video provided by the defendant over serious professional technology like GPS? Might as well just take their word for it!
What’s funny here is that you are displaying misplaced trust in the justice system that exactly parallels my hypothetical judge’s misplaced trust in technology.
> Everyone knows video footage can be faked.
Everyone also knows GPS can be spoofed.
Your point?
No, most people don't know GPS can be spoofed, or at best think of it as a nation-state level action. I'd be surprised if you got less than 100% of non-tech people saying that if GPS contradicts a video then the video is faked.
Why did literally hundreds of judges in the UK accept bogus evidence from the Post Office and Fujitsu leading to nearly 900 innocent postmasters being convicted?
Because judges are nearly always the kind of people who instinctively trust authority. They wouldn't be judges otherwise.
Hope that helps.
https://en.wikipedia.org/wiki/British_Post_Office_scandal
The point is that the enforcement agencies make the assumption that GPS data is always correct. But there are any number of issues that can cause problems with it. People making decisions about how to enforce house arrest or design autonomous farm equipment need to take GPS flakiness into account. Differences in scale are not the point.
Well, don’t commit crimes and you won’t get a gps tracker attached to you, I guess. So that’s easy.
Not really sure what it has to do with tech though. That’s a problem with how certain humans behave, not ancillary technology.
The trackers are part of CCSO’s pretrial house arrest program, so presumably a number of them are attached to people who did no crimes.
> so presumably a number of them are attached to people who did no crimes.
You and I have very divergent views of the type of person likely to be charged or prosecuted for a crime or indeed to participate in a diversion program that involves GPS trackers, my friend.
Your heuristic is flawed. The pool of defendants with pending charges who were granted pre-trial home detention are going to be disproportionately non-violent, first-time offenders compared to those denied bail or with prohibitively large amounts.
Meaning an error like this harms innocent people wrongly accused more than the stereotypically hardened repeat offenders you imagine to be undeserving of your sympathy and presumed guilty.
> non-violent, first-time offenders
Non-violent, first-time offenders don't get ankle monitors. But thank you for highlighting my point.
They absolutely can, depending on the jurisdiction. I saw plenty of cases out of Atlanta with drug possession cases with no prior history getting an ankle monitor, back when they were live streaming bond hearings from Rice street.
You do not get an ankle monitor for misdemeanour possession as a first time offender, in Atlanta or anywhere else.
Like, actual lol mate.
What on earth is this claim? Are you sure you’re on top of Fulton County’s 1500-person ankle monitoring program, and the push to reduce jail overcrowding? Have you really been tracking the national trend to introduce ankle monitors for pre-trial defendants who would have been simply released on recognizance?
Right, because only guilty people become involved with the justice system.
Not at all. They're remarkably similar. What differs is our cost:benefit analysis of closing off this errata.
Yours (inferred) is "Too Much : Zero".
Given that those are terminal values it would challenging for literally-any-other-view not to diverge from yours, on this.
They are innocent until they’re proven guilty.
Don't live in the US.
>This
You're cherry-picking a single word to start a pointless internet argument? Calm down. Nobody claimed this exact event lead to problems for anyone.
This is what OP actually said:
>>This is exactly the sort of thing
Yes, this absolutely is the sort of thing. No, 33 feet isn't "the thing" but GPS glitching is the sort of thing at a different increment.
Okay but the claim is people are being re-arrested because of this "sort of thing". But I read the linked article, and it doesn't mention anyone getting re-arrested. There is only one situation described where the person is arrested and then let go after the cops got proof the alert was faulty.
So yes, it absolutely sucks that this technology is so inconvenient and bad but at the same time, the author and GP claims are not proved or truthful in totality (even in the article they posted).
We can agree GPS tracking sucks but also question claims that are not true. Also telling people to "calm down" over text when they are not even talking to you is very passive aggresive for no reason.
Consider that, from the justice system's point of view, there's no distinction between between someone breaking house arrest for a drug fix versus due to GPS error. They don't have the resource to investigate every single violation, so they always just assume that the device is infallible and that the human is lying.
That's why there's no data for someone getting rearrested due to GPS, and why the few instances where someone do prove an error is concerning.
>Also telling people to "calm down" over text when they are not even talking to you is very passive aggresive for no reason.
Your "This" quote was the least genuine comment I've seen on HN in a very long time. You took a comment and removed all context to complain about how it's wrong, when it wasn't wrong at all. There should be no doubt that GPS glitches can cause people with ankle monitors a lot of needless trouble, and "the system" likely won't believe it, and simply won't care.
If you had an ankle monitor, and someone wanted to fuck with you, it would be trivially easy to block or spoof GPS signals to put you back in jail. All it takes is an SDR and some software you can find on github. Think about that before you quip "This" again.
This time the glitch was 33 feet, who's to say next time it couldn't be 3300 feet?
> This time the glitch was 33 feet, who's to say next time it couldn't be 3300 feet?
People who study this. This glitch was caused by unusual, structured, widespread distortions in the ionosphere. There's no known mechanism that would cause enough distortion to make the errors 100 times as large. There would also be other symptoms of any unknown cause.
https://claude.ai/share/5cc4163e-9cbf-47cd-9749-4bb55bca42fe if you don't mind discursions into safety of aviation navigation systems. Caution: Do not take the error bounds in the second half as relevant to errors for unaugmented single-frequency users; those users will see much bigger errors.
I misread that as "people getting reincarnated" and was momentarily very confused.
Probably more beneficial than "people getting reincinerated" which is how I almost read it but thought that couldn't possibly be it.
Geofence monitors have buffer zones because a small GPS on someone’s ankle inside a house, potentially a high rise, isn’t going to be that precise.
33 feet is well within the allowances IIRC. Varies by state.
According to this firm selling them, this model has <15ft error, usually 3-4 ft. Given the permissible area is entirely up to what the judge orders, it seems eminently plausible that someone confined to their apartment could be placed outside with a 33ft jump causing a false alarm.
At the very least, it's not enough evidence provided to claim the scenario is inherently impossible based on undefined "allowances" without any actual numbers for something completely dependent on the jurisdiction, monitoring software implementation, and attitude of the police officer/judge.
https://www.youtube.com/shorts/o0sPXL9C53g
I also found Reddit anecdotes of getting alert texts stepping outside onto the street from their yard, or false alarms while still inside but not enough details were provided to be sure they were actually GPS and not RF so not as helpful.
It happened with both RF and GPS! The Cook County Sheriff's Office moved between the two at one point so it was possible to see the effects over time as folk moved over. Some people got more false alarms when moving to GPS, some got fewer. IIRC it was about even.
That might be true for a place in the middle of nowhere with no features, the same device model managed by the same company and the same call center person and same sheriff and judges and prosecutor. But with GPS in an urban environment where many homes are over 100 years built from many different materials, 33 feet is a lot.
Urban environments have larger buffer areas due to multipath interference.
The story you linked has examples about false alerts triggering in a different state.
Do you have any actual examples of 33 feet getting someone arrested? I’ve worked enough with GPS that I could tell you that any system with thresholds that low would result in everyone getting false triggers
Yes, everyone on the devices received false alarms. It's why there was a call center that managed the false alarm flows. I highly suggest you read the articles I've shared.
I fought tooth and nail to get access to the data showing how often devices reported "invalid" status (where the device's specs said it was something like, within 150 feet of inaccuracy it reported "invalid"). They initially told me they couldn't get me that data because it'd crash their database running that query. Basically threatened to sue them and over the next 6mo or so I got two 100GB MSSQL dumps. Hundreds of millions of rows of devices reporting back that their GPS signal was invalid. It would take a lot of time to make it sharable because they included the actual GPS location infos.
Sounds like you could be a convict, have your gang interfere GPS on a local level but enough to have other people in the neighborhood notice, make a quick run for whatever you'd need to, and still claim plausible deniability.
Or you could cause such localized things more so to try to get a person sent back to prison or otherwise penalized intentionally
Also true.
I mean, you had the chance to leave the house, compensating for the GPS error. Why didn't you take that chance?
There's always someone who roots for the criminals
TFA article claims: "Indeed, the solar storm of May 2024 is estimated to have cost the US agricultural industry $500 million due to disruptions in precision navigation."
This seems hard to believe. The link provided hand waves through how it maybe could happen, and ends with an Economist just SWAGing that it could have been maybe a dollar an acre or so.
"He estimates that affected farms lost about $1 per acre. Nationally, this equates to an estimated half-billion dollars in lost earning potential, Griffin says."
So yeah, hard to believe was the right call. Very few farms were affected, but if we assume half of the total 900 million acres of farm land were, add 10% to get a round number, and guess it at a dollar per acre, we get the quoted big number.
That’s how all “estimated damages” work. It’s all just made up by some random person who guesstimated a number then multiplied it by the maximum possible people effected, realistic or not.
Tell me "it's different" with this one please https://sustainability.stanford.edu/news/study-links-past-em...
There’s probably a reasonable methodology but it has a lot of multiplications and some base parameters that make the whole thing wildly sensitive.
Yes, it's actually based on an economic model seemingly developed with a detailed understanding of modern farming practices and historical effects of timeline disruptions on yields. It may be approximate but isn't just some random dude guesstimating based on vibes or something.
https://farmdocdaily.illinois.edu/2024/05/how-will-the-gps-o...
https://shiny.agmanager.info/cottonBotsDev/
It's an order of magnitude estimate of the worst case per acre, multiplied by a very course estimate of the number of acres affected, with little or no accounting for the length of the outage, the timing of the outage relative to specific crop-planting times in specific regions, and similar factors. It relies on manufacturer's estimates of the benefit of using their technology to assess the impact of not being able to use the technology. In other words, it's a SWAG.
Consider: the outage may have meant that some equipment would be slower, less accurate, or missing some features, causing time delays and other losses that may or may not be equivalent to using the non-GPS equipment. Or it could have rendered the equipment entirely unusable during the outage. It could even have permanently damaged the equipment (e.g. causing it to drive over an embankment or something). There is no apparent attempt to differentiate these outcomes, which could have significant impact on the estimate.
It's not reasonable because the error bars of each estimate compound and they may not even be normally distributed in the first place. You should rather convolve probability distributions - assuming factors are independent - and if the IQR covers a huge range, perhaps orders of magnitude even, you should state that.
Is this considered "outside-in" GPS? That is, relying on satellites orbiting the Earth? Is there such thing as "inside-out" where maybe you rely on the images of the sky above? I guess without IR or other secondary scanning technologies, that would be difficult.
https://en.wikipedia.org/wiki/Star_tracker
It's old tech
There's also the classic of dead reckoning, which is usually infeasible but modern commercial aircraft have the capability of bounded accuracy in their dead reckoning navigation for several hours at a time if needed, and if you are the US government, you can build fantastical machines to measure your own motion and dead reckon yourself to a very very tight point on the other side of the world.
https://en.wikipedia.org/wiki/Advanced_Inertial_Reference_Sp...
That thing still has orders of magnitude better stability than common laser ring gyros as used on those airplanes, and the same for the price tag.
GPS was dominant because it's cheapish and high performance and easy for a lot of contexts. However, it is critically easy to jam, for physics reasons. A jamming transmitter will always be thousands of miles closer to you than the GPS satellites are. Jamming GPS is cheap and easy, so all war will involve the denial of precision GPS guidance, so we are looking into alternative guidance again.
TERCOM as used in the Tomahawk missile existed to guide them semi-inertially back in the 80s and was functional.
In Ukraine, various providers have developed (supposedly) ways of using commodity cameras to watch the scenery pass by under a flying drone to ground medium quality inertial systems, to allow dirt cheap, unjammable navigation over long distances. It will be interesting how this plays out.
fun fact: the first mass-produced consumer in-car live navigation (1981) was all dead reckoning and gyroscopes. at this point, the GPS network was operational but not available for consumer use until 1988.
https://en.wikipedia.org/wiki/Electro_Gyrocator
It seems worth mentioning that the last time GPS had issues like this afaik, it was due to the US utilizing 'selective availability' due to national security issues. We used it somewhat famously during the 9/11 attacks.
Also the page 404's via archive.org, but information formerly from gps.gov can still be found here: https://archive.ph/trwOo
Edit: The selective availability page moved to https://www.gps.gov/selective-availability
> We used it somewhat famously during the 9/11 attacks.
I have not been able to locate any source that backs up this claim.
Indeed, the link in the parent even says it hasn't been used since May 2000. So, yeah, it certainly wasn't used "famously".
Perhaps the commenter is thinking of the fact it was used globally prior to May 1, 2000. From a civilian point of view, GPS appeared to be invented around this time but it had actually been available for a couple of decades already, just in a degraded form that wasn't very useful.
> just in a degraded form that wasn't very useful
Differential GPS was already in widespread use in many counties by 2000, which made "selective ability" pointless at it provided automatic corrections to the 'degraded' GPS signal.
https://en.wikipedia.org/wiki/Differential_GNSS
An interesting warning as Austin is blanketed by Cybercabs. I think a town full of golden driverless cars 33 feet from where they think they should be is terrifying.
I would be shocked if Cybercabs solely rely on GPS for positioning. I imagine they look at their surrondings, etc.
I would be shocked if Tesla had properly considered and mitigated all of the single points of failure, given their track record. [1]
[1] https://www.bloomberg.com/features/2025-tesla-dangerous-door...
Wouldn't RTK help mitigate this, as the base stations would also be affected by the atmospheric disturbance?
Adjacent to that, I'm a bit surprised that there hasn't been a mass rollout of assisted GNSS in large cities. Maybe not full RTK, but something more than just delivering almanac being delivered.
Are the current GNSS solutions good enough (or too degraded?) in city jungles that there would not be any mass benefit? Too expensive to run a few base stations here and there?
I think so, yes. That's the main purpose of RTK
Yes. WAAS should also help a lot, or at least tell you that you can't get a good position.
It's strange that agriculture incurred so large losses, I would expect precision farming to rely on RTK (with relatively close reference base station at a fixed location).
The article doesn't mention, but how immune or affected were base station corrected RTK positioning systems?
It sounds a lot less dramatic if we can absorb such events with RTK base stations.
That does add the extra dependency of network links to get the RTK correction stream, unless some day it is standardized to be broadcast locally on FM or so.
I recall that event. It wasn’t the error that was the problem, it was that the units weren’t able to get fixes amid the solar storm, rendering the machines inoperable; save driving by hand, of course, but that isn’t practical with many modern planters.
Related:
https://news.ycombinator.com/item?id=49500504 Cheap GPS jammers are filling the world with navigation dead zones (wsj.com) 3 days ago
https://news.ycombinator.com/item?id=48606271 Satellite reveals immense scale of GPS signal tampering (space.com) 3 months ago
*10 metres
Feet are actually great units for RF because a nanosecond is very close to a foot. Since feet has many prime factors and/or the foot-meter conversion is also easy, you can quickly get a wavelength of, say a 2GHz (6 inches), and get it in cm (15cm).
Of course, ideally we'd ditch the silly metric system and use natural units. Then these 30 feet are a more comfortable 50M/eV. But those SI guys are really conservative and attached to confusing unit system based on fractions of the diameter of an arbitrary planet.
I would love a new measurement system based on planck units.
Obligatory: https://www.xkcd.com/3248/
Somehow, Selective Availability returned.
Maybe not intentionally (at least by the U.S. Government, but the consequences are far greater now.
Now that GPS has subsumed a large part of air navigation as more VOR and ILS approaches at non-towered airports are being left to fall into disrepair, it forces more and more aircraft operating in instrument conditions to fall back to a navigation system that may not operate to the tolerances that you need to shoot an approach to LPV minimums (which puts you close to 200 feet or so above the ground) or LNAV minimums (higher, but still pretty low to the ground). If you lose signal integrity, you abort the approach. You don't want to break out at minimums only to find that the runway is 33 feet to the left or right of the centerline when it's not a circling only approach where you're expecting it. If that field only has RNAV (GPS) approaches, you have to divert. Hopefully the alternate airport you filed has a ground based approach plate available that is authorized .
When SA was around, we had more VORs, more VOR and ILS approaches, and while NDBs (decades old radionavigation beacon that operated on the AM band) were on their way out, they were still around.
One of the reasons SA was discontinued was that if you knew the coordinates of a base station, you could correct for the error. Are airports not doing this already?
Actually, several airports are. So you have normal WAAS and it has a ground segment. Most (new) IFR certified GPS receivers installed in airplanes today are WAAS capable.
To that, you can augment something called GBAS (we used to call it Local Area Augmentation System but switched over to the ICAO name for it). It’s basically a ground station that sits at an airport and corrects for GPS errors where you need it most (airports definitely qualify here and that’s where you need the best GPS performance).
Ultimately, the FAA is going to go 100% GPS and it’ll fall back to the minimum number of land-based sources for redundancy. It’s about cost. The issues with GPS may cause them to push the timeline back and develop plans to mitigate the issue, but they’re too far down this path to stop now.
The GPS-independent fallback is MON: https://www.faa.gov/about/office_org/headquarters_offices/at...
To meet its integrity budget, a GBAS needs at least triple redundancy, not just a single station.
If one has a lot of patience, one can read the details of how it works at https://elibrary.icao.int/product/299828 (along with SBAS, the ICAO name for what WAAS does; the constellations they can augment; GRAS, a weird hybrid between GBAS and SBAS that apparently went nowhere; ILS; VOR; DME; and VHF marker beacons). Annex 10 Vol I probably doesn't say explicitly that triple redundancy is required, because if you had a single receiver with an MTBF of something like 10 billion hours then you could use just that one.
This particular 30-foot error should go away almost entirely for future receivers that implement DFMC SBAS or ARAIM.
iiuc, this is differential GPS (DGPS) and not only airports are doing that. At least in Europe there are quite a few such transmitters, see https://de.wikipedia.org/wiki/Liste_von_DGPS-Sendern
33ft/10m seems less than the multipath error in many cases (buildings, tall forests)
The gps on my phone drifts by a few city blocks all the time...
Ah yes, 33 feet, the suspiciously not round number which suspiciously translates to almost exactly 10 meters. Just use meters, lol.
were other satellite positioning systems affected as well? was it checked that it wasn't just a misconfig on US command side?
The linked actual research article did look at multiple GNSS systems. GPS is presumably being reported out of familiarity https://doi.org/10.1029/2026GL124645
TL;DR:
1. Not today. November 2025. They don't make it clear.
1.1. One would expect that to be put in the title, when the article is written almost a year after that.
1.2. No, the article doesn't state that in the first paragraph. Posting in it full seem to be the only way to fend off lazy comments:
That's it - the whole paragraph. Several paragraphs later - GPS first mentioned. No clear links between dates stated.2. It is unclear what is the source of the claim.
UPD: Commenter below found the source, but TFA doesn't make a good job of presenting that as a source of the 33 feet glitch claim, but rather posts another citation from it.
They should've just quote this and be done with it:
3. Navigation issues happened before, they state it right there. They were more disruptive as well.4. The author has articles all over the topics. Everything is sensationalized.
5. Every presented link seem to have this awful Cloudflare js challenge.
Bad article overall.
P.S. Response to the false claim below - no, there's nothing about GPS in "the first 3 words of the article".
[1] https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2026GL12...
>P.S. A separate comment would be too much to respond to the false claim below - no, there's nothing about GPS in "the first 3 words of the article".
He's talking about your first (incorrect) claim. The article begins "In November 2025"
> 2. It is unclear what is the source of the claim.
7th paragraph of the article states the source, and contains a link to research paper where they go into great detail.
> Not today. November 2025. They don't make it clear.
My brother in christ it's the first 3 words of the article.
Their first line is TL;DR!
not just space weather, I am pretty sure the atmosphere is being disturbed by toxic human activity both by accident and on purpose
I've run outside every morning for decades and used Garmin with GPS since 2015, I've never had so much trouble
Garmins finally supports dual-band (L1+L5) and BeiDou on newest models but it's still not enough to compensate, I have to use a Stryd footpod to guarantee accurate distances/speed
btw BeiDou GPS blows away US GPS for number of sats and precision but despite Russia's GPS being legal in US, technically BeiDou is not
* https://warontherocks.com/a-signal-point-of-failure-integrat...
* https://payloadspace.com/gps-faces-growing-competition-from-...
* https://en.wikipedia.org/wiki/BeiDou#GPS_vs._BeiDou_Capabili...
For resiliency reasons alone, it's been proposed to allow (stop software-disabling) BeiDou in the US, but the last time this was brought up, the administration ran out of time. It's a shame, because when there is precise coverage, it enables things like lane-level city navigation.
https://warontherocks.com/a-signal-point-of-failure-integrat...
yup that was my first link
but of course this administration is never going allow China-anything like low cost electric cars even if it means saving people a fortune in gas
so hopefully in 2029 it can be looked at again
or maybe Dems will also get the Senate too and can be petitioned if they run out of corruption investigations before 2029
it is critical to explain to everyone who isn't technical that GPS is "read only" and no data is being sent to China via BeiDou (just like it's not sent to Russia's Glonass) because that apparently is some kind of weird misunderstanding
on that same note if they somehow made Starlink into a lower resolution GPS backup I'd even trust that too despite personally being anti-Musk everything
Whoops I don't know how I missed that in your links!
The weird part to me is that Glonass was not approved either, yet it's as openly as allowed as Galileo that went through a tedious FCC approval process that was invented later. Grandfathered or not, we're clearly not in a worse place using Russian tech for the last 15 years.
Read only or not, relying on Chinese or Russian gps data for increased accuracy even in civilian increases dependency no? That seems like a bad idea to me. I’ve thought for about 20 years that increasing our dependence on anti democratic regimes was a risk, no matter what the benefits for global development etc. It’s not isolationist to want to only rely on your friends and not enemies. (Which is why Europe needs to disentangle itself from the US as fast as possible).
If you are relying on it without a graceful fall back then it would be a problem. If you take it as a boost on top of existing capabilities then it is a pure win. In practice it can be hard to parse the two scenarios. People get used to thinking that something is available and it turns out that it was always leverage against them.
It decreases dependency on GPS and thus it decreases risk because if there's an attack on a GPS system by an adversary, it's likely that they will not be attacking their own system at the same time. I'd rather have my enemy's open source, perfectly functional clock in my back pocket than be without the time. Enjoying that the competing clock has a sub second display is optional.
> BeiDou GPS blows away US GPS for number of sats and precision
Both BeiDou and GPS are supposed to be limited to 10m precision for civilians.
But, going down a rabbit hole, I found that BeiDou is way more accurate than 10m--3.6m and 2.6m outside and inside the Asia-Pacific region, respectively [1]. And that's with the most simple algorithm. It goes down to ~2.5m using dual-frequencies to account for atmospheric error.
[1] https://www.nature.com/articles/s41598-022-12012-y
> Both BeiDou and GPS are supposed to be limited to 10m precision for civilians.
Maybe in 1998, but Selective Availability was turned off in 2000, and here in the modern era: https://rtklibexplorer.wordpress.com/2024/04/28/dual-frequen...
Oh interesting, I think I conflated two things; Selective Availability and the military-only bands on GPS. While it's true that access to the military band could improve accuracy with dual-band receivers, consumer devices can use dual-band as well (as your link shows), since there are multiple unencrypted bands from navigation satellites nowadays.
I am not sure how to interpret your link, though. It doesn't measure accuracy on it's own, and doesn't include a number for precision between the two units.
There are a couple of points:
The L1 signal had selective availability in the 90s, and it no longer does. SA had the real-world accuracy around 30m in practice; the "up to" 100m rarely happened. Without SA, plain L1 with good skyview (low DOP) gets you around 10m, or down under 5m if WAAS is having a good day.
Availability of multiple civilian bands, and cost-effective dual-band receivers, allows an ionosphere-free (no need for WAAS) solution in the 1-2m range, with a single receiver.
Ubiquity of internet connections makes it trivial to apply RTK correction data without having to set up your own base station, and/or, availability of affordable medium-range data radios makes it easy to set up your own base station. In either case, it's easier to run RTK than ever before, and dual-band RTK gets you down into the low centimeters, limited mostly by how accurately your base station was surveyed-in.
And none of that touches the military signals.
My understanding is that the encrypted military-level GPS is much more robust against jamming and spoofing. There's probably a lot of capabilities we don't know that's classified, too.
Called M-Code.
Has a fascinating history.
https://odimpact.org/case-united-states-opening-gps-data-for...
M-Code is a new encrypted signal that is not fully operational yet. OCX was supposed to enable it.
GPS has always had the P(Y) code, which is an encrypted signal, at a higher chip rate than the C/A code that has been broadcast on L1 forever. The P(Y) code has its own interesting history of (semi-)codeless processing. If the US military is lucky, the history books will close on that by 2030: https://www.gps.gov/codelesssemi-codeless-gps-access-commitm... . (Currently, 21 GPS satellites broadcast L5.)
I think the new US GPS satellites have ability to do a spot beam of increased strength in a region of interest.
That is my understanding as well. But having another band allows for error correction as a side benefit.
With a base station in a known position you can get to cm resolution with somewhat pricey but decidedly hobbyist-accessible gear: https://www.sparkfun.com/sparkfun-gps-rtk-sma-breakout-zed-f...
It seems that all the device manufacturers (they mention Apple, Samsung, and Google) are using BeiDou anyway. I don't know if that includes Garmin watches, though.
https://www.reuters.com/technology/us-agency-probes-risks-fo...
AGPS also helps if you have cell towers nearby.
This is only to make getting a fix faster - A-GPS downloads the almanac data via the internet (fast, but needs internet) instead of directly from the GPS satellites (slow but works everywhere). It doesn't make it any more accurate.
The Russians at it again no doubt. The dastards.