Thanks for linking gpsjam -- flightradar24's map is total trash by comparison (colours, lack of borders).
Does anyone know if a similar service covers things like GLONASS, Galileo or BeiDou?
EDIT: nevermind, these services can't distinguish. From the FAQ:
> The ADS-B data used by this map includes information on the accuracy of the navigation system used by each aircraft, but doesn't specify the type of navigation system. It could be GPS, another global navigation satellite system (GNSS) like GLONASS, or it could be an inertial navigation system (INS). My understanding is that most aircraft are using GPS, so that's probably mostly what the map shows.
Flightradar24's visual representation definitely sucks, but comparing the two, gpsjam has a lot of unexpected missing areas across Africa, South America, and SE Asia that at least have some data on FR24.
I'm not sure if that means FR24 has a better dataset, or they're processing it differently or if they're just extrapolating from few data points when they maybe shouldn't be.
They are fairly large cells. I assume the “bad” cells are displaying some maxima-based aggregate rather than implying the whole area (or a large part of it) in them is noticeably jammed.
Also, the reports are coming from aircraft which have a much larger horizon at altitude. The jamming from Kaliningrad probably doesn't have any effect on the ground at long distances.
Any chance the area being referenced in relation to Germany is near the headquarters of a company named aaronia? They manufacture, high-end spectrum rf analyzers, and high-end drone tracking and jamming/drone disabling equipment.
(As a result, I would expect them to be testing, and or demonstrating their equipment near their headquarters.)
Just a guess/speculation as I’m familiar with aaronia’s products and services (indirectly)
If any civilian company jammed GPS enough to affect commercial aviation that would be a huge no-no - RF emissions in places like Germany are strictly controlled, even if you're just 'testing'
That is Eagle Pass, TX. The infamous, massive border crossing area where suspected criminal border crossers are corraled under the bridge, where Elon visited, etc.
The jamming is done to make crossing the border without going through the checkpoint more difficult
TL;DR: It's weak signal, not jamming. The weak signal reports come from military training aircraft carrying out maneuvers that cause temporary signal loss.
So I'm a little skeptical on that front because military aircraft are still not that often broadcasting ADSB even during routine flights, at least in my (also close to the border) region. In theory the Air Force was supposed to have completed ADSB installation on their fleet last year but they blew the deadline pretty bad on even installing transponders, and of course they still reserve the right to disable them during military operations.
Maybe with the data we can figure out what portion of military flights are included?
For the helicopter training flights that I notice most often, it's still rare to see one that broadcasts ADSB, probably <10%. C-130s usually don't either here but it's more often, maybe more like 25%. Perhaps for other categories of aircraft they've installed more transponders. But in the city where I live, even passive mode-C MLAT is probably around 50% success on tracking military flights for ADSB Exchange. FlightAware might have better coverage for mode-C. mode-C can't contribute to this GPS reliability data anyway but it illustrates that even C-130 pattern practice is sometimes "stealth" from a radio perspective due to the low installation rates for ADSB and difficulty of good mode-C coverage.
The paper linked elsewhere (https://web.stanford.edu/group/scpnt/gpslab/pubs/papers/Liu_...) mentioned issues with military training flights resulting in spurious low-NIC cases but unfortunately doesn't quantify it. With the way the AF rollout has gone it probably depends on the specific installation, command, and aircraft type.
In the border region specifically we would tend to expect the majority of non-military flights to be civilian CBP aircraft that aren't performing unusual maneuvers. CBP has a somewhat complicated and limited authority to disable ADS-B that I don't know the contours of, I'm not sure how often they do so on their larger (non-sUAS) aircraft. Involvement of the Air National Guard in the Texas area might complicate the analysis though.
ATC is used to working with military aircraft without ADSB since it's been the status quo (and keep in mind that ADSB is not required on aircraft in general, although the set of airspace situations in which it's required has been expanded over the years to become a de facto near universal mandate). But the FAA doesn't like it, which is why they set the deadline for the Air Force to install ADSB, which the Air Force missed.
Military aircraft on military maneuvers don't deal with FAA ATC, the military has its own controllers. It's mostly an issue when they're operating near civilian airports (or the many, many military facilities that share an airfield with an airport). There are still adverse safety impacts to the lack of ADSB on many military aircraft, in that it defeats things like TCAS.
Actually this topic is slightly complex and I think a lot of people have misconceptions, so let's lay it out. These rules have gotten stricter and stricter in recent years.
1. ADSB is not required. Meaning, there is no universal requirement that aircraft be equipped with ADSB, and plenty of aircraft still legally operate without.
2. ADSB is required in class A, B, C, in many cases in class E, and within the "Mode-C veil" surrounding major airports.
3. ADSB is required in any case where a transponder is required, for those edge cases that are not included in the above.
4. The result is that the areas in which you can legally operate without ADS-B are mostly limited to low altitudes in rural areas. Of course, this encompasses a large portion of hobby aviation especially, but not very much commercial flight.
I can say that in San Antonio where I live and also operate a ADSB receiver the dedicated air force flight trainers (T38 Talons and T6 Texans) routinely fly with ADSB on. The C5 cargo plans also fly with ADSB on when doing training but I've seen non-training flights fly overhead with ADSB off.
I can actually receive high flighting planes over Del Rio so it would be interesting to see if they are reporting bad NIC values.
I thought Mode C was just barometric pressure data measured by the aircraft. It's related to altitude, not position, so there's no such thing as Mode C "coverage".
e; oh wait you said passive MLAT off Mode C, that makes more sense then
Yep, this map doesn't show jamming. It shows weak signals, of which jamming is one potential cause. An airplane pointing their GPS receiver at the ground will also cause a weak signal.
How does an airplane "point their GPS receiver at the ground" (for an extended period of time since a combined GNSS/INS positioning solution, which is what all airliners use at this point as far as I know, will need an extended signal loss to report decreased accuracy)?
From the FAQ, it sounds like they simply presume that anywhere with multiple low NIC values is indicative of interference.
> The GPS interference data is derived from NIC (navigation integrity category) values that we receive as part of the ADS-B protocol. We mark regions as affected if a significant number of flights in that area report lowered NIC values.
Unfortunately some of the data that's most directly applicable to determining aircraft attitude, like roll, is optional and rarely sent by aircraft, but yes I'm sure you could do a decent job of inferring maneuvering from change in heading and vertical rate (especially if you're looking at ADS-B data with high temporal resolution vs., say, every 10-60 seconds.)
on a pure radar scan, what would return of formation flying like this look like to a radar operator? is it just one large dot, or can they distinguish the number of planes in the formation?
That's a good link (that I should have posted). I suspect that some of the yellow (maybe even red) hexes in the U.S., and maybe some in Europe too, are due to that effect.
For people doubting that aircraft maneuvering can affect navigation accuracy as reported by ADS-B, I found a fun example. Around 1300 UTC today (0800 Texas time), 4 T-38s took off from Laughlin AFB for what looks like training, with lots of maneuvering. This link shows what it looks like when mapped in 2D: https://globe.adsbexchange.com/?icao=adffc3,adfff9,adffd2,ae...
If you click on the track, you can inspect the ADS-B data at that point in time in the sidebar on the left. If you scroll to the bottom of that sidebar, there's an "ACCURACY" section, that shows the Estimated Position Uncertainty (EPU). You can see it change from better than < 30 meter uncertainty to > 18.5 km(!) uncertainty as it performs the maneuver.
I made a video that shows how to see those values, and also shows the maneuver in a 3D viewer so you can see how steep the dive is (it's steep!): https://www.youtube.com/watch?v=jfHlpnEdHxw
(The viewer uses a generic aircraft model, FYI, don't be distracted by that.)
Is the data actually interesting? I feel like any place that would have widespread jamming would also see routing away of non-military aircraft meaning you'd never see the jamming taking place except if you happen to get lucky and the jamming zone is larger than the "stay out" zone. This makes sense then why the map is entirely green with some red just at the periphery of Ukraine with the majority of Ukraine having no data since it's a no-fly zone for civilian traffic.
The jamming over Kaliningrad affecting civil aviation has made the news recently, and the map does provide some interesting insights both how far the effect reaches into Poland and Sweden, and how often it is turned on and off.
If you read the article, jamming is based on uncertainty of the aircraft, just because it's uncertain, doesn't mean that it's dangerous level of uncertainty
This is a case where nominally, with a solid understanding of geopolitical events, maybe it's not interesting on average. BUT, all of a sudden something might pop up one day. The accessible, "crowdsourced" data is helpful to have in those cases.
To the north is the Black Sea, and the Russia-Ukraine war. To the east is Armenia and Azerbaijan (as well as Iran). To the south is the middle east. Also Cyprus with the frozen conflict, there.
> > Turkey has had a significant internal conflict with the PKK (Kurds)
> PKK the terrorist organization, yes. Kurds the ethnic group, no.
The Turkish government has a decades long history of discrimination against Kurds, including banning their language, even denying their existence as a people. If Turkey had treated Kurds better, PKK may well have never existed, and almost certainly would not have had as many Kurds supporting it even if it still had.
Turkish Government has had many high-ranking Kurdish officials, including multiple presidents and prime ministers.
There have been more Kurds served in the Turkish Army than all the other armed organizations combined.
Majority of Kurds in Turkey openly support the Turkish Government, especially against the PKK terror.
Several Kurdish organizations in Iraq, Syria, and Iran support the Turkish Government, especially against the PKK terror.
PKK kills Kurds. PKK kills Turks. PKK will happily kill you if doing so benefits the crime and propaganda business they have been profiting for decades.
Let's not parrot some politically charged material as facts without having any actual understanding about such sensitive matter.
> The Kurdish language was banned in a large portion of Kurdistan for some time. After the 1980 Turkish coup d'état until 1991 the use of the Kurdish language was illegal in Turkey.[52]
> Before August 2002, the Turkish government placed severe restrictions on the use of Kurdish, prohibiting the language in education and broadcast media.[55][56] In March 2006, Turkey allowed private television channels to begin airing programming in Kurdish. However, the Turkish government said that they must avoid showing children's cartoons, or educational programs that teach Kurdish, and could broadcast only for 45 minutes a day or four hours a week
It is true that over the last 20 years or so, the Turkish government has relaxed many (but not all) of its anti-Kurdish laws and policies. But that doesn't erase the reality of the decades of oppression which proceeded it.
In the 1980s, Iraqi Kurds were fleeing to Turkey for freedom and safety. The Prime Minister was of Kurdish origin. You could hear people speak Kurdish freely anywhere between the west and east end of the country.
There were no "anti-Kurdish" laws and policies. The pro-American coup d'état in 1980 came with a law to control non-Turkish publications, but it was never put into action.
You can't just dump links to 10,000-word political essays, and expect them to support your original premise that the PKK terrorism is justified.
You must have a knowledge about the history and currency of the topic to hold such strong opinions. You should also use your own words to articulate your arguments, so I can keep myself engaged in this conversation.
Nevertheless, I've read the report. It misinterprets the government's certain actions to protect the public against several jihadist, separatist, and other destructive movements, which are not exclusive to a specific ethnic group.
It also fails to recognize the newly founded republic's goal to build an inclusive Turkish citizenship identity, and to provide a progressive and secular education program to everyone regardless of their race, religion, and gender while preserving the cultural value of each.
"Kurdish" isn't a single language anyway. There is a reason Kurds use French in France, English in USA/UK/Canada, and Turkish in every part of Turkey to communicate with each other, unless they're from the same tribe. It's not realistically possible to institute a system to provide public service to every individual without establishing a common ground.
> and expect them to support your original premise that the PKK terrorism is justified.
I'm not defending attacks on innocent civilians. Consider Northern Ireland: the IRA's attacks on civilians were shameful and wrong. But, if it were not for the oppression of Catholics by the Stormont government, and the failure of the UK government to stop it, those attacks may well have never started.
You're trying to connect the dots between two separate phenomenons. This oversimplification will only mislead you.
You'd think that your left-wing instincts will guide you through this, but you will accidentally end up taking ugly sides in proxy wars in this part of the world.
PKK started out according to CIA's Operation Gladio to justify the 1980 coup, and continued operating in line with the Carter Doctrine. Its first actions were assassinating Kurdish and Turkish left-wing leaders (Zeki Ön, Mehmet Ongan, Adil Turan, Hasan Erkiliç to name a few).
Today, PKK follows the radical Islamist narratives (Seyh Said, Seyit Riza, etc. are often celebrated by them). PKK is in agreement with an Islamist terrorist organization (FETÖ) behind the 2016 coup attempt, whose leader (Fethullah Gülen) resides in the US. PKK conducts international drug trafficking at "cartel" scale (between Asia and Europe; ask your neighborhood drug dealer about it). PKK is backed by several crime syndicates and tribes who are responsible for countless human rights violations from systematic child/woman abuse to forced labour and human trafficking. PKK is currently taking part in the ethnic cleansing of Arabic, Turkish, Assyrian population in Syria and Iraq to make a space for an American-backed puppet state under "YPG" alias.
How is your IRA-PKK correlation shaping up now?
Your "reputable sources" are compilations of quotes by "usual suspects" anyway. Western organizations are not known for being the gold standard of social justice advocacy here, as they have a history of endorsing any "project" that fits their financial and political agenda; from cyanide process in gold mining, to civil warfare for carving up sovereign states.
So how should I interpret this? The map lacks geopolitical boundaries, so it's hard to interpret.
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.
There's a big red blob over Turkey, is that maybe the southern edge of the reach of Russian jammers in the Black sea?
There's also a big red blob over the eastern Mediterranean. Is that Israel? I'm not so sure though, because it's not centered on Israel and parts of Israel proper are green on the map. I also assume they're heavy users of GPS, so wouldn't want to jam it.
There's a red blob in Southeast Asia, and that looks like Myanmar, where there's a civil war right now.
There's a little red blob over what looks like Kashmir.
I was curious too. Did some sleuthing, it looks more like Punjab. I think that’s to block drone infiltration from Pakistan [1]. It does change going back to 14th March there is no jamming in the region, US and Europe blobs also reduced, so I think this stuff is event driven, wonder what goes on, fascinating stuff.
Their data comes from commercial flights. If there are no flights, there's no data. There aren't many commercial flights over Ukraine or Belarus right now, so that whole area's empty.
It tracks private flights too. I'm only tangentially familiar (though I have an ADS-B receiver reporting to FR24), but my understanding is that it's not required for private flight now, but more and more aircraft are being retrofitted.
The hole over Ukraine is definitely the lack of civilian flights.
Another notable spot is Kaliningrad, the Russian exclave. It looks relatively normal on some days, like today, but on others like yesterday it's covered by solid red stretching far into Poland, Sweden and even Germany.
> Another notable spot is Kaliningrad, the Russian exclave. It looks relatively normal on some days, like today, but on others like yesterday it's solid red.
Oh yeah, I totally forgot that was a thing, and that explains that spur of red in the Baltic. I'd (probably incorrectly) assumed it was some kind of spillover from jamming in Ukraine.
I didn't realize you could look at it over multiple days. One interesting thing about that blob is the outline of red seems to always be there, in the same shape, but the middle is often green. Maybe that's some artifact of their agreement algorithm? More overflights around the edges than through?
It also looks like there's some jamming in Estonia? Or maybe that's just the edge of jamming around St Petersburg?
Russians do plenty of jamming that expands beyond their borders in the Baltic, either on purpose or just as a spillover as they don't care. Before Finland joined NATO they used to also violate our airspace on frequent basis, but since then that has stopped.
They violated NATO airspace a lot with their "Bear" nuclear-capable bombers until very recently. Not sure if it's still happening. It was so frequent that it didn't make the news every time.
The idea that russians are doing these things 'by accident' ain't even funny, just dangerously naive and nobody from intelligence community thinks so. They know damn well what they do and its well planned and even heroic in some childish fashion in their f*cked up mindset.
They are at war with west (more Europe than US though) for solid 2 decades straight, just that they started to use military only in last decade, but were subverting public opinions in usual command & conquer strategy for much longer (riling western and former soviet populations against EU and Nato, supporting ultra-right groups, spreading false rumors ie on covid in us vs them psi-ops).
Whatever politicians on their side say is meaningless or diversion and definitely just wasted time, just look at actions alone.
> Before Finland joined NATO they used to also violate our airspace on frequent basis, but since then that has stopped.
Probably temporarily. They violate the Estonian airspace on a regular basis with military planes, with their responders turned off. The NATO planes stationed in Estonia then take off and go see them off.
Yea, oddly, if you go back to like august, there's still a bunch of red over the Mediterranean, parts of Israel, Jordan, Lebanon, etc. so it's not totally clear what that is. I've heard anecdotally that gps has gotten unusable in Israel in recent weeks but it's not clear why that's changed based on the mapping information we're seeing here.
That’s because Beirut is 60 miles from northern Israel and Tinder’s max is 100 miles IIRC. These are small countries we’re talking about here.
Phones don’t use GPS these days if they can help it - WiFi triangulation is significantly faster and uses much less battery - so GPS jamming wouldn’t have anything to do with Tinder matches.
I see 2 red cells on the US/Mexico border right about Texas/Coahuila region. Navigating that dessert region without GPS or with GPS for that matter can be deadly.
Organized crime in Mexico would probably do it to prevent other people from using migration routes they control and reduce police efficacy. Of course, slightly rogue Mexican police or even US vigilantes also have an incentive.
The Eastern Mediterranean might be the (significant, underreported, under-remembered) Russian military presence in Syria. They have airbases, a naval base, they rotate and train their officers there, they constantly ship military equipment back and forth from the Black Sea ports via the Bosphorus to Syria, they train the Syrian army, they build human shield observation posts overlooking Israel.
What's unfathomable to me is how Israel (or Netanyahu?) keeps treating them as a frenemy.
I think there are probably many parties contributing to the interference in the Eastern Mediterrarnean. Russia and Israel are two of the big ones right now (and both have admitted doing it).
> As part of the ADS-B messages we receive from each aircraft, the Navigation integrity category (NIC) encodes the quality and consistency of navigational data received by the aircraft. The NIC value informs how certain the aircraft is of its position by providing a radius of uncertainty.
> Poor NIC values alone might indicate a problem with an aircraft’s equipment or unfavorable positioning. However, when observed in multiple aircraft in close proximity during the same time frame, it suggests the presence of a radio signal interfering with normal GNSS operation.
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.
> 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.
Could you use RTLSDR triangulation to hone in on granular lat long of jamming sources?
You can get rough areas with a GPS and a RTLSDR and a bunch of samples (either over time OR with lots of people with the same device)
But to get fine granular data, you need a timestamping SDR. (each parcel of signal data for a quantum of data needs an exact time down to 6-8 significant figures, basically GPS timebase).
Most your cheaper SDRs cant do that.
Stuff like the BladeRF and higher do provide timestamped data.
With synchronized receivers you could do some rudimentary direction finding. Note that synchronizing SDRs is much more achievable if they're physically nearby (e.g. can run a cable between them for a common clock) vs if they're physically distant observers (can't exactly use GPS time for synchronization if you're measuring GPS interference)
Very helpful (as well as sibling comment by pierat). Thank you both. I will need to do some research with regards to pairing SDRs with local disciplined clock that can tolerate temporary loss of remote (stratum-0,1) time precision.
> can't exactly use GPS time for synchronization if you're measuring GPS interference
Can other GNSSes (Galileo/BeiDou/GLONASS/etc) give usable timestamps? Seems like it'd be tricky for a jammer to target all of them simultaneously. (Of course, since they'd be on a different band, unless your SDR is wideband enough you'd need two RX heads which gives you potential issues with phase drift between the tuning VCOs even if your sampling is coherent).
Perhaps a sufficiently directional antenna/phased array (for getting an actual satellite signal) as well as an omnidirectional one (for picking up the jamming signal) could get you somewhere...
Or perhaps one could look at computing AoA at each receiver site (using MIMO-y techniques, e.g. Kraken/KerberosSDR) and triangulating based on angles instead, which wouldn't require synchronizing physically-distant sites at all...
The problem definitely seems soluble, though I don't have the technical background to know how realistic that is.
>> Can other GNSS give usable timestamps? Seems like it'd be tricky for a jammer to target all of them
Actually the opposite; GNSS systems are all purposely designed to operate at virtually the same frequency (check out this figure [1]) while cleverly not interfering with each other. There are sub-bands within each constellation too (L1,L2,L5 etc) but it's very easy to pump out wideband noise across all the GNSS bands.
KrakenSDR would do a good job of this, they combine five RTLSDR into a coherent array. The top end of their tuning range is 1766 MHz which would include the 1575 MHz of the GPS L1 signal.
The little five antenna array can even attach on the roof of a car for a handy ground plane. Prob not a good idea to drive with it out there tho.
You could also use a single receiver with a small antenna array (GPS wavelength is around 20 cm) to estimate the angle of arrival of the incoming signals.
Do aircraft systems really only use GPS and not the full constellation of navigational satellite systems?
Besides GPS, the GNSS currently includes other satellite navigation systems, such as the Russian GLONASS, and may soon include others such as the European Union’s Galileo and China’s Beidou.
The linked page already says that it reports on the constellation, not just GPS:
"The map uses are color coded overlay to indicate low (green) to high (red) levels of interference with global navigation satellite systems (GNSS). Often just referred to as GPS, there are actually multiple systems beside the US GPS constellation, such as Russia’s GLONASS, Europe’s Galileo, China’s BeiDou, and others."
Like the article states, many people use GPS as a shorthand for GNSS generally. In any case, they're all at similar frequencies, so typically they'll all go out together if there's significant interference.
It doesn't matter too much, aircraft don't rely solely on any GNSS for navigation, because they're all susceptible to similar availability issues. Magnetic, inertial, barometric, and land-based radio systems are also used. One or more of those other systems are used as a fallback when GNSS fails.
Modern phones use all the available navigation constellations, and have done so for years.
But aviation is much more conservative due to its safety-critical nature. Galileo was only just recently (2023) certified for use in aircraft systems by ICAO:
Just for the record, this must have been written ages ago. Today you would rather look up to NavIC joining them as a global system and QZSS operating independently from GPS soon.
This is really cool since ASDBExchange was bought out by a private equity firm and has since stopped giving out data to cool projects. I see they are being sued for IP theft and a couple other items. Link to Lawsuit in CA is below because I was reading it tonight.
There are things that will naturally interfere with GPS and they are fairly well known. The FAA provides an expected outage map [1] (a forecast, if you will) for pilots that may need that info. Jamming is an act by humans to intentionally disrupt the GPS signal.
Could be. I was directly answering "what's the difference?"
It's hard to know intentionality without also knowing where there is expected+natural interference. Of course, when a region is surrounded by persistent GNSS issues and is a known war-zone with large actors, intentionality is fairly reasonably assumed.
The GPS jamming map linked to in the article[1] discusses this somewhat, in the "About the data" box:
- ADS-B messages include position information from Global Navigation Satellite Systems (GNSS), like GPS, Galileo, GLONASS, BeiDou, etc.
- It is not possible to directly measure GNSS interference, but we do calculate the NIC (Navigation integrity category) for ADS-B messages.
- The NIC value encodes the quality and consistency of navigational data received by the aircraft.
- Poor NIC values alone might indicate a problem with an aircraft’s equipment or unfavorable positioning. However, when observed in multiple aircraft in close proximity during the same time frame, it suggests the presence of a radio signal interfering with normal GNSS operation.
Most of the time it is not that strong but few weeks ago my family living north have problems with mobile internet and phones (gps was almost fully dead) for like two days cause of interference from r*ssia.
> Erm mate, have you tried looking at different days ? Those cells you find so suspicious in Australia are not there on other days !
That kind of disproves the "no data" hypothesis though, no?
One explanation could be they have a simplistic algorithm like "if uncertainty > (something indicating more than 5 minutes of GNSS-to-INS fallback) on more than 50% of all flights of a day", and there's only one flight per day in that region.
> Seriously, given the largely community-based nature of FR24 data I would not expect too much in term of accuracy.
Flightradar24 data is accurate enough for some commercial entities to rely on it. Also, in case of a lack of ADS-B receiver data we'd also expect a grey square, not a red one, right?
If green or "no data" areas randomly turn red sometimes, I'd expect to see them elsewhere in the world sometimes on different days as well. But I've checked every day that's available and I never see them appear in e.g. that big empty space in eastern Russia.
I don't really see any other evidence that low data areas can turn into red areas when there's no actual interference.
Ok, but let's acknowledge the difference between no data (depicted as no colored cell in the map) and data which reports high interference (depicted as a red cell). In remote western Aus we see a few red cells to the west of a large area of empty cells. So they do have ADS-B receivers there, and at least some of them are reporting a troublesome NIC, and there are enough reports for FR24 to place a colored cell there rather than an empty cell. Why exactly do you think that a red cell comes from no data or very limited data, when the article does not indicate that no data / limited data results in a red cell?
I'm not expert on it, but I suspect that two of them might somehow be related to the Transmit and Receive stations for Australia's JORN (over the horizon radar) that are located in Western Australia near Laverton.
Though if that were the case, I'd probably guess there should be more areas at the other site locations around northern Australia - so that might invalidate my guess.
The choice of cells as a fundamental unit is interesting, I guess it’s better than a color coded gradient map. But this will still suffer from centroid issues.
The data is taken from aircraft [EDIT: not airlines; see traceroute66's comment], so it doesn't give full coverage of the world, but it does include other satellite navigation systems aside from just GPS. Looks like the jammed/interfered areas are:
* A large part of Eastern Europe around Ukraine is missing data, and there are many jammed/interfered areas around it, including the southern coast of the Black Sea and parts of Poland and the Baltic. Part of the Baltic Sea off the coast of Kaliningrad are also jammed/interfered.
* Part of Germany near Berlin, possibly part of the Ukraine-related jamming/interference?
* A large part of the eastern Mediterranean and some of the Middle East around Gaza.
* A small area on the India-Pakistan border near Punjab and Lahore.
* Two medium-sized areas in western Myanmar.
* Two small areas in New Guinea with a gap in the data between them, spanning the Indonesia-Papua New Guinea border.
* Two small areas in western Australia.
* A small area on the US-Mexico border.
* A dot in southern China with some gaps in the data around it near the border with Vietnam.
Ukraine, Gaza, and Myanmar all have major conflicts going on. Other comments have suggested that the US-Mexico interference might be related to drug cartels. The India-Pakistan border is a longstanding point of tension. Not sure what (if anything) is going on in New Guinea and Australia.
The jamming/interference in India-Pakistan, US-Mexico, and China all went away in the last 6 hours -- they're only visible in the 24-hour data.
The data is ADS-B data which is broadcast by aircraft.
FR24 (and other similar services) obtain the data via a community[1], you can take part too[2].
For certain parts of the world, they may have the option to augment the data via commercial services, but that is highly unlikely to be on a global basis.
Conclusion: Missing coverage means no community coverage in that area and no commercial augmentation.
FR24 is a bit of farce as their blocking and removal of 1000's of aircraft makes the data picture incomplete. Plus it's kinda of a money hungry commercial enterprise. Same reason that Raytheon bought FlightAware and Silversmith Capital Partners via JETNET bought ADSBexchange -DATA = CASH - the later buyout is going to court because they apparently stole IP from the company that built the infrastructure. https://www.documentcloud.org/documents/23963235-golden-hamm... - wild stuff in there!
> Part of Germany near Berlin, possibly part of the Ukraine-related jamming/interference?
Of the four tiles in that area (for March 19th at least), one is entirely in Poland, one is covering the Polish-German border, one is a bit of the German coast around Rügen but mostly the Baltic Sea, and the other is Bornholm (island in the Baltic Sea) and a bit of the Swedish coast.
My guess is, this is part of a larger system to limit Russian military use of the Baltic, and possibly also a single layer of defence against Russian aircraft and missiles targeting Berlin and Copenhagen. Likewise, I would guess that the strip of interference from St Petersburg in the direction of Moscow is a similar single-layer of defence by Russia.
At this resolution, it also looks like the west is interfering with access to St Petersburg and someone (could reasonably be either side) is worried about Kaliningrad, but that image is also also making me think "WTF?" about the Gulf of Riga.
The single tile near Kandalaksha (Russia) suggests something interesting is going on there, but I have no idea what that might be, and there's a non-zero possibility that it's a deliberate red-herring to make western analysts waste time — as an analogy, imagine a troll releasing three greased pigs with the numbers "1", "2", and "4" painted on the side.
This is suspiciously similar to `gpsjam.org`. It's useful, for sure, and it does use readily-available ADS-B data that FR24 (and ADSBExchange) uses anyway, but the data viz is just eerily similar.
Then again, I'm not very GIS/geodesy minded, so maybe hexagons are the best shape that'll tessellate over a sphere easily.
Was this work in any meaningful way inspired by GPSjam? If yes, it'd be nice to have an acknowledgement in there.
I can't say if it's inspired by the site you link, but basing your suspicion on the hexagonal shape is very weak, at best.
Also, the data seems to be in different resolutions, and the actual jamming data is quite different just looking at both sites.
I've seen hexagons used for maps and boardgames for years.
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?
I thought GPS signals from space were incredibly weak. Limited power budget + 100km in the sky. Seems trivial for a ground based system to crank up the watts to whatever arbitrary limit they desire.
True, signal per satellite is only around 150-160dBW on earth despite them radiating at 25W. Satellites are ~20000km away. If a jammer is 100 times closer (200km), they need to use only 1/10,000 (1/100^2) the power, so it's very easy to jam sadly.
- GPS positioning is more accurate if the satellites it sees come from a variety of angles (GDOP), so the satellites near the horizon are valuable.
- Aircraft pitch and roll, so a fixed antenna like this would lose precision as it turns to make an approach - just about the worst possible time.
It's difficult to make an antenna with a sharp cutoff to limit the ground vs. above-ground. So, most anti-jammers will use beamforming to cancel out interference in one or more specific directions. So, the null in the antenna moves to follow the interference.
Does anyone know if the how the ADS-B uncertainty measurements interact with GPS spoofing? Often when you look at these maps you see a donut around Kaliningrad - could it be that there's wide area jamming, and then localized spoofing more directly around Kaliningrad?
I'm a little surprised that Shenzhen doesn't seem to be churning out ITAR-busting anti-jamming systems. The tech is pretty old by now and the market is there.
I love this feature, especially how they were able to create it from data that they were already getting, but personally my excitement about it is overshadowed by how colorblind unfriendly it is. Considering how many people are colorblind, ~4% of the global population, or roughly 1 out of 25 people, it's remarkable how often designers get this detail wrong.
If anyone found the above interesting, I wrote a short article mapping plane activity on FlightRadar's 'blocked' list (i.e FlightRadar had agreed to remove the ADBS data from their dataset following probable legal pressure).
The article was interesting alone, simply for the Google Dork technique explanation. Have not heard the "unusual, yet specifically frequent" search technique described that way previously. Very similar to what's necessary for searching StackExchange and similar, such as "site:https://aviation.stackexchange.com/ tracking private planes"
Known Conversions: GlobalEye, Project Dolphin, Raytheon Sentinel, Saab Swordfish, PAL Aerospace P-6, E-11A, HALOE, PEGASUS, Hava SOJ, CAEW, HADES.
Actually has a tie-in with the article, since the Hava SOJ is an air stand-off jammer configuration for the Turkish region.
Otherwise, if I still worked for the government contracting, I'd probably offer you a job, although you're apparently British, so there might have been citizenship issues.
Apparently people now call using Google's advanced search operators Dorking, neat! I guess I've been dorking for a while.
Most of us know about "site:" since it's extremely handy, but there are a lot more. For some reason I had it in my head that many of the documented operators didn't work properly -- or at least I couldn't get them to work properly the last time I tried to experiment. I'll have to try again.
Thanks, had no idea there were that many specific operators and combinations of operators.
At least in the last year, looks like "inurl", "intitle", and "intext" have all been getting a lot of use.
Also, a lot of "index of". "db.py", "store", "secret", "ec2 -aws", "mysql inurl:./db/", ect... in combination. Must be a lot of low hanging fruit in the orchard.
(Your comment downplaying someone else's work, while simultaneously showing your lack of historical knowledge on the topic about which you're commenting, based on my specific googling to find the date of coinage, might make you eligible to be "a foolish or inept person as revealed by Google".)
That's LADD (Limited Aircraft Data Displayed), which requires that aircraft marked as such in the FAA's database to be removed from the official data feeds used by the commercial flight radar sites.
Crowdsourced data isn't subject to LADD, so adsbexchange and other such sites can and do display such aircraft.
For flights within the US, there's also a private address program that allows an ADS-B equipped plane to broadcast an alternate address.
Yeah exactly, like that second article says, suddenly having to switch to a pretty archaic system that's now only used for backup (with a reduced number of VORs) is not fun, and the distraction can lead to build up of other situations that can really cause serious danger. It won't be the single cause of a crash, but crashes are rarely the cause of a single problem but rather a compound failure of many things going wrong in just the worst way.
Here in Europe VORs are also very rare now. Makes sense because they're hugely expensive to operate and when used only for backup it's not a very good investment.
The US has laws against interfering with GPS, but I don't think there's any global laws about GPS jamming, you'd need something from the UN but it doesn't seem like most countries would want to give up that ability - we can't even get people to stop making nukes and they have a much higher danger
Interesting - as 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. All the local services that rely on positioning via phones seemed to work fine as well.
I wonder how the jamming works - is it just for higher altitudes or maybe it only affects GPS and my phone also uses GLONASS or something?
On your phone the GPS is just one input to determine its position. It's most likely also triangulating cell phone towers. Get an app that only shows GPS data and check if you see coordinates jumping around.
Google maps (and your phone's location services) seldom rely only on GPS.
For one, accelerometer-based location has become pretty good. You can usually get by for a few kilometers on the average road.
For two, Google maps is aware that you are driving, and this it sticks to roads, especially ones that are on your itinerary, because of your GPS registers as the middle of a field, it's more likely that you're experiencing GPS issues rather than you driving at 130km/h in a potato field.
Finally, location services are amplified by nearby wifi signals, mapped by google with street view. Your phone can say "here is the Mac address of every wifi network I can see and a rough estimate of my position" and Google's services can very accurately triangulate where you are.
Does accelerometer-based location algorithm integrate the acceleration readings to get the phone displacement? Is it a part of the phone operating systems ?
It tries. Accelerometer-based positioning is best used with camera displacement, which isn't used in Google maps driving mode (though there was? Is? An experimental on-foot mode that showed directions in AR).
the accel-based positioning I'm pretty sure is implemented app-side, not os-side, but I could be mistaken.
Aircraft fly higher, which means they pick up ground radio signals from much further away - both good (ATC communication, ground-based navigation beacons) and bad (intentional jamming).
On the ground, the radio horizon is about 20-40 miles. In the air, the radio horizon is about 200-400 miles.
That spot in western Australia is interesting, I was looking at that earlier. My map doesn't show any indication of interference there, in fact from what I can tell there's plenty of evidence of _no_ interference. Eh, there are sometimes analysis or other artifacts, and it can be tricky to try to infer too much from one hex.
I crosschecked with google Maps and I belive the Jindalee Operational Radar Network in Laverton is stationed there. Maybe that has something to with the interference. A 560kw transmitter is no joke.
I guess south-west Texas is most likely also military. E.g. the Naval Air Station Kingsville is not far away.
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.
(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.
"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!
There have been close calls due to lack of GPS. It increases workload
for both pilots and controllers, which is a safety issue by
itself. Despite a lot of airlines and government aviation agencies
saying everything is fine, they're not really prepared for a world
with frequent GPS denial, and everything is not fine. Industry and
government are organizing emergency meetings about how to handle this
in a less ad hoc way than they have been so far (commercial aviation
is kind of the opposite of ad hoc).
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 n?e?a?r?-?c?o?n?s?t?a?n?t? 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.
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."
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.
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).
If people are claiming that a country is threatening nuclear war, they damn well better be able to back it up with something more than narrative-shaping sound bytes.
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.
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.
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
Biden did kind of the same. A few years ago he promised russia "devastating consequences if Navalny dies in prison". So Navalny did die in prison. What did Biden do? Right.
Yup. Promises and talking big works up until someone calls the bluff.
NATO in a certain way is based on that as well. If it fails a single test regarding article 5 after someone challenges it, it becomes instantly worthless.
The danger as I see it currently is that the West is tired of war and it’s an opportunity for Putin to challenge NATO. Attack a small village in a Baltic state. Are Americans and Germans and the British going to risk their lives for a small village in a Baltic country? I hope they would, but I realistically don’t see it. And that one non-response would make NATO worth less than the paper the agreement was printed on.
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.
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 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?
>> 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.
> I haven't the slightest idea what point you're trying to make
This human was criticizing other humans for "pretending", but they themselves are pretending (well, technically something more like engaging in ~hallucination, Naive Realism based cognition, Meme Magic, etc). They desire and recommend that others (the members of their various outgroups I suspect, purely coincidentally) think better, but if one was to ask them to do the same, they would assert that that is a false accusation / invalid request (because their thinking "is" without substantial flaw, ~"thinking perfectly is stupid, why are you suggesting it lol", not realizing that no such suggestion was made).
~All humans behave this way (I dare you to respond, so a demonstration can be made that proves my point (though it would be fairly pointless outside of having fun, at least at this point in time)), due to the conditioning we receive from birth, and every single day of our lives, all without our realization.
I was kinda making a joke, but it is a joke in at least two ways.
Check out the arguments made by John Mearshimer. His heart breaks for the Ukrainian people but he is focused on US policy missteps (because he is American and lives in the US) as the root cause of the problem.
No offense to you but that man’s argument has strong “I beat my wife because she deserves it” vibes.
The US has made more than its fair share of policy missteps. But to try and argue that the actions of the US somehow “forced” Russia to invade its neighbor and former satellite state to rid it of “nazis” (Putin’s quote not mine) is absurd.
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.
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.
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.
> but my understanding is that most aircraft are still using GPS.
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.
Consumer GNSS devices are developed a lot quicker than aviation GPS receivers due to high cost and strict certification requirements.
So your 100 dollar drone very likely has a receiver with more features than a 100 million dollar airliner. And that drone is probably made recently, but airliners fly for 30 years.
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.
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.
Avionics were designed with the opposite assumption. When a high accuracy location source provides a location (GNSS or DME/DME) the position is updated and it's assumed that could mean a significant jump for the INS.
Practically that was what happened all the time before GPS. You would fly for a few hours over the ocean with no ground based reference, having a reasonable but not perfect INS location. Then get close to the coast where a DME/DME fix was done which updated the INS position as a big jump of up to a few miles.
Filtering GPS updates that are too far "off" the INS state would be an almost opposite design to the original assumptions that DME and GNSS are highly accurate.
It seems like there’d be some use for something that correlates what it sees on the ground with known satellite imagery as a check? Especially for anything low-flying.
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).
You can look at the INS position (and compare the position from each INS separately), but practically you're always looking at the "FMS position" which is where the flight management computer thinks you are. That takes INS, GNSS/GPS and other nav beacons into account. So it's technically true that pilots don't often look at the specific screen that has the INS position(s) on it, but you are looking at the FMS position which is basically equal to the INS position if GPS is not updating and you receive no ground signals.
Modern aircraft will also set the known position based on the runway you're taking off from. And when airborne they'll pick up a DME/DME fix and update the location. So while it's procedure to set the known starting location at the gate, there are also other sources.
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.
I have lived in Kiev and I have seen how GPS jamming works on the ground. As soon as russian missiles or drones approached Kiev, our air defense typically turned on the GPS jamming. I could immediately see on my phone that I'm steadily moving in a straight line directly northeast at a high speed in a very different part of the city - all while sitting on the couch in my home not very high above the ground. A few times like that.
I was curious how powerful should a jammer be to completely actively substitute GPS coordinates in a city so large.
When I wait for relatives/friends to land in Turkey, I always get a mini heart attack because either plane drifts like Fast and Furious or disappears completely from map and ask myself, is this real this time? Sometimes I have nightmares about it, I see the planes just falling down from the sky spontaneously because of the stress that GPS jamming induced to me over the years.
I'm strongly believe sooner or rather later GPS/GNSS will be considered human right since the areas where their signals are mostly devoid of them are intentionally devoid by the prepetrators.
Currently I am working for a new wireless PHY technique that is more secure and robust against jamming, and also the first that able to propagate with limited non line of sight (NLoS). Hopefully soon we can overcome this anti human GPS/GNSS jamming shenanigans.
For an excellent example for anti jamming secure wireless network for GPS (not my work) please check this thesis by Cara Yang Kataria [1]. She is currently working at the infamous MIT Lincoln Laboratory.
[1] Antenna-driven methods for increased wireless network security:
This reminds me of when I looked at Starlink's coverage map ( https://www.starlink.com/map ) and at first I was super disappointed to see a big hole over WV, and I assumed it was political or some nonsense, but it's not!
There will never be Starlink service there. Or cell service for that matter. There might not even be GPS now that I think about it. WiFi and microwaves are restricted too.
The map implementation is not great, what I miss most is country borders and labels.
https://gpsjam.org has come out first and is a much better design IMHO.
Flightradar24 has _just_ the advantage of bigger sensors network and hence wider coverage.
Also: https://gpsjam.org/ | https://hn.algolia.com/?q=gpsjam
(am I missing any other GPS jamming mapping or data collection projects?)
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