I've been working on mapping GPS jamming using ADS-B data for a couple years, and I'll try to address questions and points brought up here based on what I know.
Relevant previous posts on HN:
2022: https://news.ycombinator.com/item?id=32245346
2023: https://news.ycombinator.com/item?id=37868106
(From my comment on that 2023 post: "Why haven't FlightRadar24, FlightAware, or any of the other flight trackers done this?")
"A single observer can't really say for certain that jamming is happening; you need a distributed sample from multiple different sensors over a period of time to have reasonably high confidence."
There are heuristics you can use that allow you to make a pretty good guess about whether jamming is happening based on signals from just one or two aircraft, and have worked well on GPSJAM for the past couple years.
With regard to localization of GPS jammers, yes you can do direction finding of the emitted signal directly, but that's easy mode. For a fun challenge, do it based just on observations of the ADS-B data from affected (and unaffected aircraft). Here's one approach from researchers at the GPS laboratory at Stanford, "GNSS Interference Source Localization Using ADS-B data": https://web.stanford.edu/group/scpnt/gpslab/pubs/papers/Liu_...
I have some other ideas about how to do that localization.
https://twitter.com/lemonodor/status/1764054377982308484
"Do aircraft systems really only use GPS and not the full constellation of navigational satellite systems?"
ADS-B doesn't tell you what navigation system is, but my understanding is that most aircraft are still using GPS. Maybe someone who works on aircraft avionics will chime in. A few years ago I did see data that distinguished between different GNSS, and GPS was experiencing more jamming than the others. I assume as multi-network systems become more and more common jammers will just target all of them, if they're not already.
"There looks like a big hole of no data over Ukraine, where I'd most expect GPS jamming, but I suppose there are no civilian flights either. Maybe they could setup an GPS observation station on the ground at a surveyed point to get data there."
That's right, no (or few) flights over Ukraine with ADS-B transponders means no data. I actually first started mapping GPS jamming on Feb. 14, 2022 (https://gpsjam.org/?lat=45.00000&lon=35.00000&z=3.0&date=202...), because I thought it might give me an early warning of the expected Russian invasion of Ukraine. It didn't work out that way--there was no indication of interference right up until Feb 24., and then all civil aviation stopped and there was no more data for that region (https://gpsjam.org/?lat=49.18928&lon=33.51687&z=3.9&date=202...).
As some of you have noticed, GPS jamming is highly correlated with conflict zones. Some conflicts are higher intensity than others--for example, I think the airspace around Cyprus has been jammed for years (since 2018 maybe?), and I get the feeling it's more harrassment than anything else (maybe someone more geopolitically savvy than me knows more).
"I see 2 red cells on the US/Mexico border right about Texas/Coahuila region". Someone always says it's cartels, and the evidence is that it's much more likely to be U.S. military testing and training. First, the interference is always in the Laughlin and Randolph military operating areas (MOAs) (https://imgur.com/vieGhgN). Second, the interference usually runs during the week and takes weekends off--which I doubt cartels do, but that's the typical pattern seen for military exercises.
"am I missing any other GPS jamming mapping or data collection projects?"
From 2/24/2022 until 3/19/2024, gpsjam.org was the only site with regularly updated GPS jamming maps. On Twitter, @auonsson (https://twitter.com/auonsson) and @rundradion (https://twitter.com/rundradion) have been posting geospatial and other analysis of similar data for the past several months at least, and @x00live (https://twitter.com/x00live) has looked at ADS-B and GPS interference for a while too. (I'm not even going to try to catalog academic or government efforts, though I will mention HawkEye 360's satellite based GPS interference mapping: https://spacenews.com/hawkeye-360-gps-ukr/)
"If line of sight to the jamming antenna is required to be jammed, why do aircraft not have a downwards shield so that they only receive GPS signal from the sky (satellites) and not from jammers (coming from the bottom hemisphere)? Or is the jamming signal so many orders of magnitudes stronger than the satellites that there's always going to be some gain no matter how good the shield is?"
Yes, GPS signals are so weak (below the noise floor!) that it's just super easy to overpower them with terrestrial (or airborne) jammers. But there are special antennas and other techniques for building jam-resistant systems, e.g. "controlled reception pattern antennas" (CRPA): https://www.gpsworld.com/anti-jam-technology-demystifying-th... But I think the main reason most civilian aircraft systems aren't jam resistant is because they didn't need to be--For the past several decades GPS jamming has been a much smaller issue than it is now, and I don't think there was sufficient reason to spend time and money on what would have been an over-engineered, mostly unnecessary system. But the situation is changing, and I expect anti-jamming to become a more significant concern by equipment manufacturers and aviation authorities.
[Edited to add:]
"I'm in the middle of one of the red blobs on the map and just used my phone with google maps to drive around. It worked fine."
From the GPSJAM FAQ: ""I live in one of the red zones and my GPS was fine?"" (https://gpsjam.org/faq/#i-live-in-one-of-the-red-zones). Yeah, the answer is, as you mentioned, aircraft fly at higher altitudes, so they get much longer line of sight to the jammer.
On the general idea of using ADS-B to map GPS interference, when I thought of this idea I was pretty excited. I realized that if you had access to worldwide ADS-B data, which ADS-B Exchange graciously gave me as part of my Advisory Circular project (https://news.ycombinator.com/item?id=24188661), you could also make a worldwide map of GPS jamming, and I hadn't seen anyone do that before (later I found some researchers who realized you could get GPS jamming information from ADS-B, but they only looked at a couple aircraft).
I just think it's pretty neat that even though there were multiple companies devoted to processing, analyzing, and selling ADS-B data, and ADS-B data is not all that complicated, none of those companies had realized this new way of using it. Sometimes there's gold left even in data that you think must have been completely mined out.
Even specifically looking at ADS-B data as it relates to GPS interference, there's still lots to be done! FR24 is mapping jamming, but I don't think anyone else has made worldwide maps of spoofing (yet!): https://twitter.com/lemonodor/status/1770515361739493488
[Edited to add more:]
With respect to safety issues, yes, aircraft have redundant navigation systems. But GPS is one of the important layers that add safety to aviation, and it is not at all normal for entire countries or even larger regions to lsoe GPS while still maintaining passenger flights. This Eurocontrol presentation, "GNSS Interference and Civil Aviation", has lots of details: https://rntfnd.org/wp-content/uploads/Aviation-GNSS-interfer...
From the presentation:
Aviation Safety is built on two main principles:
• Trust your instruments
• Follow standard operating procedure
GNSS RFI causes pilots to have to question both principles!
I'm not a NATO strategist or anything, so I'm adding this as a child comment, but I think the big story in the GPS/aviation world these days is probably Russia's n̵e̵a̵r̵-̵c̵o̵n̵s̵t̵a̵n̵t̵ frequent jamming of GPS over Poland, Finland, Sweden, Estonia, and Lithuania. Degrading and even neutralizing strategic infrastructure in EU and NATO countries, significantly affecting commercial aviation at the least, is a big deal. There's some reluctance to say it's Russia doing the jamming, though that seems to be the consensus among experts. I assume governments know with 100% confidence who it is.
Why the reluctance? I do not think there is much love lost in regards to Russia.
Well, if you identify them then you might have to do something about it. But it's not clear there's much to be done. Sometimes it's easier to deny or just not mention that someone is acting in a hostile way. The example I often think of is Iran firing missiles at U.S. warships during Operation Praying Mantis, and then, as Wikipedia puts it: "The Pentagon and the Reagan Administration later denied that any Silkworm missile attacks took place, possibly in order to keep the situation from escalating further - as they had promised publicly that any such attacks would merit retaliation against targets on Iranian soil."
https://en.wikipedia.org/wiki/Operation_Praying_Mantis
The situation with Russia is well past escalation by accusation of civil aircraft jamming. After all, they've pretty much stolen all planes they had under lease from Western owners.
Appeasement of someone like Putin is always a mistake.
So far every time the West calls his bluff he cowardly pretends nothing happened, be it HIMARS, Storm Shadow and HARM missile shipments, tank shipments, AWACS support, you name it.
He only attacked Ukraine because he hoped to win in a week, and this wouldn't have happened if the West armed Ukraine earlier. The desire not to escalate with Putin cost Europe a war.
every few weeks they're threttening to nuke some country, i think there's nothing that can be called excalation at this point (except the obvious idea to retaliate with guns, but that's a very bad idea).
Can you provide sources where they actually threaten to nuke anyone out of the blue (excluding Medvedev, he’s especially nuts)? All I can find is them clarifying their nuclear policy when pressed about it (would only use in situation of existential threat). Which seems less bellicose than US policy (as the US changed ours not long ago, seemingly allowing for first strike which is pretty insane): https://www.armscontrol.org/act/2022-12/focus/bidens-disappo...
Then you remember they called Ukraine in NATO an existential threat, and wiped their butts with international treaties that were supposed to be much more set in stone than some half-official nuclear doctrine.
However, this is all playing chicken. Whenever they were facing actual opposition, they backed down.
Which threats and treaties, specifically? I don't have a great memory - so please share actual sources.
Also, are you aware of this?: https://www.armscontrol.org/act/2019-09/news/us-completes-in...
Here are a few.
https://www.ukrinform.net/rubric-polytics/3503924-president-...
That is not an unbiased primary source in the slightest.
Is BFMTV also biased when reporting words directly from the mouth of Piotr Tolstoi or are you just trolling ?
https://en.wikipedia.org/wiki/Budapest_Memorandum
As for INF, US withdrawal was a response to Russia testing infringing missiles first.
Maybe, but US pulled out first:
https://www.npr.org/2019/02/05/691521600/russia-pulls-out-of...
For some speculative context: this is because of the "pivot to Asia" as the US does not have a strategic arms reduction treaty with China and is not intended to escalate the arms race with Russia (although that might be a side-effect).
Medvedev is chairman of the Russian security council though, who else would be more qualified for dishing out the weekly nuclear threat?
Which weekly nuclear threat?
Sensational out of context drive by sound bytes from the likes of Guardian, Fox News, Twitter and video gammer subreddits are not sources - they’re click bait.
https://twitter.com/JuliaDavisNews
Months and months of this nonsense now.
Do you really think Solovyov and Simonyan are broadcasting it without official approval?
Also here: https://www.understandingwar.org/backgrounder/russian-offens...
This is not a source, it’s an option piece and not even on topic. Anything from ISW is not neutral, it’s ideological due to the Nuland-Kagan connection: https://pbs.twimg.com/media/F1kjvOsXwAA1tVk.jpg
I literally just wrote Twitter is not news. And you posted a random Twitter profile. I’m not even sure what you expect me to see there.
Show me any actual authoritative source not from social or drive-by media pointing out where the official Russian position is some kind of first strike.
You mean like Piotr Tolstoi talking about nuking Paris on BFMTV just today ? (https://fr.yahoo.com/news/calcule-proche-vladimir-poutine-%C...).
Sticking to the truth & what you really know, and not scape goating?
It should be a big story, as should be the fact that Russia invaded a peaceful neighboring country and keeps murdering, raping and torturing its residents.
But somehow much of the world pretends not to notice and only does whatever is convenient at the moment (buy Russian oil/gas, do business in Russia, stay "neutral", etc). I find it incredibly depressing, I thought that surely in the 2020s our civilization would have progressed further.
Russia will play the slowly boiled frog game to their advantage — GPS jamming is just the beginning. We will likely soon see further small incursions, each one ever so slightly larger than the previous one. And we'll hear Mr Scholz say something about doing something, but we won't see him actually do anything. Mr Macron will use grand words and do nothing as well. Austria will "declare neutrality" (easy to do when you have other countries as buffers from the aggressor).
As someone currently living in the EU close to Ukraine, I find all this very sad.
I always wonder why people expect of others what they refuse to do themselves. Luckily though, this does not depress me, but rather amuses me to no end, especially when people try to justify their naughtiness with "facts".
Indeed, what a shame it is.
As the song goes:
Something like that anyways, I'm just going by memory.
I haven't the slightest idea what point you're trying to make, except perhaps arguing that the GP should for some reason go to Ukraine and fight if they think the invasion was wrong?
Yes, if that's what they expect "the world" to do lest it "only does whatever is convenient".
The news is not able to keep maintaining the level of outrage at the war. They don't even try in a lot of cases because I think deep down people don't care.
That doesn't mean people don't care about the people though. Human suffering is always bad.
I find it rather sad too, especially the US politics at the moment where it seems one man basically can block the political system and let Putin win.
There are plenty of Russian apologists in the US as well, unfortunately
Does this affect everyone there? Google maps on people's phones etc?
No, not unless you're really close to the jammer. If you're on the ground the horizon is typically a lot closer than the jammer is (it's speculated that Kaliningrad is the location of at least some of the jammers affecting the Baltic), so you don't have line of sight to it and you're not affected. Aircraft are flying way up where they _do_ have line of sight to the jammer, so their receivers are impacted.
OSINT by Markus Jonsson (https://x.com/auonsson?s=21&t=L_vyKMe6Kz1tXjeWTeGk3g) has been tracking this for some time now.
"Do aircraft systems really only use GPS"
I know older long-range planes from the 70s and 80s had excellent inertial navigation systems.
Not quite as good as GPS, but good enough to know the location of the plane within a few nautical miles. The main problem is that inertial navigation systems drifted over time and required constant recalibration from the crew whenever they had a fix from real navigation beacons and errors could be catastrophic (especially when skirting the edge of Soviet airspace).
I've always wondered if modern avionics suites kept the older style inertial navigation systems as a backup to GPS, or if the systems were deleted when everyone switched to GPS.
I think it would be smart for larger planes to have a modern inertial navigation system that constantly recalibrated off GPS, ready to take over in the case of GPS jamming or spoofing.
They do that! Unfortunately, they don't always know when they're being spoofed, so oops, your inertial reference system has just been infected by the spoofed location and now both nav systems are hosed.
https://ops.group/blog/gps-spoof-attacks-irs/
https://aerospace.honeywell.com/us/en/about-us/blogs/spoofin...
Though shouldn't be that hard to know if you are being spoofed. You probably have a decent idea of how much the IRS drifts and any large deviations from that or unexpected jumps in GPS should be noted and possibly, maybe manually, rolled-back so that the IRS only considers data before that point.
I understand that current civilian aircraft wasn't designed with that in mind though.
Based on discussions of some accidents, pilots often ignore inertial navigation systems at which they rarely look today, and sometimes forget to set the known good location before flights (which does not depend on GPS, as airports don't move).
Who is jamming around Tallinn area? Also is GPSIII just as susceptible to jamming?
Hawkeye + SAR data would be pretty interesting for ship tracking. I think I've seen some papers here before, but nothing interactive like your site. I think open SAR data is not quite realtime yet, but hope soon is.
Search and Rescue data? How does that help here? And is there a repository of SAR rescues somewhere?
Think it's Synthetic Aperture RADAR.
Thank you, wasn’t aware of this. Learned something today!
It might be sampling bias. More military aviation with erratic movement and also planes turning off and on their transmitters.
To measure GPS jamming, you should measure from a fixed object. Trying to do that with planes is unnecessary hard.
You can see a real-time display of aircraft that have possible GNSS interference at https://globe.adsbexchange.com/?badgps
If you look at that for a few seconds, you'll see that it's almost entirely civilian passenger aircraft that are not making erratic movements, and that are near conflict zones.
Detecting GPS jamming with planes actually works a lot better than from a fixed terrestrial object, because 1. They have greater sensor range, 2. There are lots of them, 3. They move and cover lots of area, 4. they cover e.g. parts of the Black Sea where it would be more difficult to put a ground-based sensor.
GNSS, GPS plus other constellations depends on the receiver. Even drones or consumer ones support that these days, some bigger drones even support L5 bands.
John, I've been following your work for years (including back in the old lemonodor years). I just wanted to say thank you here, for sharing your expertise for all on this topic, and for all the other tremendous work you've done. What an inspiration.