GPS glitched across the US by as much as 33 feet(sciencealert.com) |
GPS glitched across the US by as much as 33 feet(sciencealert.com) |
Some reporting I did on the topic a few years back: https://chicagoreader.com/news/many-on-house-arrest-in-cook-...
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.
Also wrote this one, hopefully it helps your confusion: https://chicagoreader.com/news/false-alarms/
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.
33 feet is well within the allowances IIRC. Varies by state.
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.
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.
[1] https://www.bloomberg.com/features/2025-tesla-dangerous-door...
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
I have not been able to locate any source that backs up this claim.
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.
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 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.
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
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.
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.
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.
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.
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]
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...
He's talking about your first (incorrect) claim. The article begins "In November 2025"
7th paragraph of the article states the source, and contains a link to research paper where they go into great detail.
My brother in christ it's the first 3 words of the article.
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...
https://warontherocks.com/a-signal-point-of-failure-integrat...
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
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.
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...
https://www.reuters.com/technology/us-agency-probes-risks-fo...
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.
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
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.
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.
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.
https://farmdocdaily.illinois.edu/2024/05/how-will-the-gps-o...
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.
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.
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.
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.
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?
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 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.
And none of that touches the military signals.
Has a fascinating history.
https://odimpact.org/case-united-states-opening-gps-data-for...
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.)
> 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.
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.
But maybe you posted the wrong one to begin with.
Let’s all be friends and nice to each other.
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.
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.
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.
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.
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?
He does a ton of really great journalism, a lot of FOIA work, to try and keep governments honest. Here's one of his struggles:
https://mchap.io/losing-a-5yr-long-illinois-foia-lawsuit-for...
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?
Looking forward!
> motions by prosecutors
Motion ≠ incarceration. So, not an answer (yet?)...
Did defendants get incarcerated as a result of these motions, or no?
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.
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.
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.
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.
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 also knows GPS can be spoofed.
Your point?
Because judges are nearly always the kind of people who instinctively trust authority. They wouldn't be judges otherwise.
Hope that helps.
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.
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!"
Source please
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.