I have an amateur built experimental airplane, and on my first flight, GPS wasn't working. It was working on the ground, so I figured a bad coax cable or something from the vibration. When I landed it started working again, but later in the day it wasn't. A few days later I found out that the nearby Air Force base was testing GPS jamming, and there was even a NOTAM about it.
Wanted to highlight how GREAT the FAQ section is on that page. It feels like each question on that list is one that the author actually received and answered in an easy to understand format.
Makes me wish for the early days of the Internet where FAQ writing was good practice and writing a great FAQ was considered something worth celebrating.
Ukraine is of course a huge hotbed of jamming, but every time I've looked, there's been jamming on the US/Mexico border and a bit north of Texas around an airbase.
The apparent interference in Texas is almost always fighter pilots doing training. During aggressive maneuvering the aircraft fuselage can mask the GPS antenna, causing the aircraft to lose GPS accuracy.
Go to https://globe.adsbexchange.com and once it loads, press "u" to show only military aircraft. You'll see bunches of helicopters, transports and tankers, trainers like T-6 Texans and T-38 Talons, and once in a while an actual fighter or ground attack aircraft.
Is it common practice to go flying without checking for a NOTAM that might impact your intended route? (I'm not trying to insult you or anything, I'm not a pilot and don't know the standard procedures for dealing with those.)
Should you brief the NOTAMs? Yes. Is it common to miss one? Also yes. Go look at the ATC YouTube channels and you will find lots of people being intercepted by fighter jets even though they use Foreflight.
Another problem is NOTAM spam; it seems like, in some areas, there are a bunch of NOTAMs that aren't very important but that you still have to read through to see if they're relevant. "We're testing GPS jamming" or "we will send a fighter jet if you fly into this rectangle" look a lot like the more common "taxiway T at Middle Of Nowhere Municipal Airport is out of service until 1/1/2038".
Here’s a critical NOTAM that was missed. Translated, it means, if you fly here, the Russians will shoot your ass down. And so they did. But nothing encodes that information in the NOTAM so there is nothing for an LLM to summarize and extract. Expecting an AI to compensate for poor system design is magical thinking.
A1492/14 NOTAM
Q) UKDV/QRTCA/IV/BO /W /260/320/4822N03807E095
A) UKDV
B) 1407141800 C) 1408142359EST
E) TEMPO RESTRICTED AREA INSTALLED WITHIN FIR DNIPROPETROVSK BOUNDED BY COORDINATES : 495355N 0380155E 485213N 0372209E 480122N 0370253E 471352N 0365856E 465018N 0374325E 465900N 0382000E 470642N 0381324E THEN ALONG STATE BOUNDARY UNTIL POINT 495355N 0380155E. RESTRICTION NOT APPLIED FOR FLIGHTS OF STATE ACFT OF UKRAINE.
F) FL260 G) FL320)
Besides that, would the developer of the LLM accept liability for accidentally filtering out important NOTAMS, or hallucinating NOTAMS that did not exist?
For those who can't read NOTAMs: This is a NOTAM that was in effect during the MH17 shootdown, closing the airspace from FL260 (26,000 feet) to FL320 (32,000 feet.) In the previous three months, 16 aircraft were shot down in Ukrainian airspace, including one three days before at FL210, which is what prompted the NOTAM. Ukrainian officials should have closed the airspace entirely, but chose to keep it open and issue this NOTAM instead. MH17 was at FL330, so in fact it did not violate this NOTAM at all.
And for some further context: the quote upthread of "NOTAMS are a bunch of garbage that no one pays any attention to" from NTSB chairman Robert Sumwalt came after Air Canada flight 759, which would have had >1000 fatalities if two airplanes were a few feet closer: https://en.wikipedia.org/wiki/Air_Canada_Flight_759
I mean, I just copy/pasted that into ChatGPT with no other instructions or context, and it seemed to handle it pretty well:
This NOTAM (Notice to Airmen) establishes a temporary restricted area within the Dnipropetrovsk FIR (Flight Information Region) in Ukraine. The restricted airspace is defined by specific geographic coordinates, forming a boundary for the restricted area.
Key details include:
- *Effective Dates:* From July 14, 2014, at 18:00 until August 14, 2014, at 23:59, with the "EST" indicating that the end date might be subject to change.
- *Altitude Limits:* The restricted area applies to flights between FL260 (Flight Level 260, approximately 26,000 feet) and FL320 (approximately 32,000 feet).
- *Exemptions:* The restriction does not apply to flights of state aircraft of Ukraine, meaning those aircraft can operate within the restricted area during the specified timeframe.
Pilots and airline operators should be aware that flights not exempted by this NOTAM must avoid this area or adjust flight levels accordingly to comply with the restrictions. For further guidance, they should consult official aviation authorities or current NOTAM listings, considering the potential for changes.
Perhaps. It would be easy to past in an arbitrary one and see how it does. I'm pretty sure it has information on how to decode these in general in it's training set.
That would be impressive because there isn't a standard format for NOTAMs. They are intended for humans, not machines. It's a major problem that safety critical information is often not available in machine readable format, so you can't have a plane's navigation system automatically give warnings if you program it to fly into restricted air space or to a navigation beacon or runway that is announced as offline for maintenance by NOTAM.
I have an AI-powered NOTAM mapper at https://notam-mapper.obliscence.com. It's just intended for fun, but you can try pasting arbitrary NOTAMs into it and check the results.
That looks less like poor system design (although I'm sure that's contributing) and more like understatement that's practically criminal. Who the hells hears "Russia may shoot down your plane if you go here" and thinks they should convey it via "tempo restricted area bounded by coordinates"? That's like posting a "do not enter" on a door with a bomb behind it. Is English so hard?
For pilots, "restricted area" is already synonymous with "absolutely do not even think about going here" and is used for things like military testing and training areas that regularly use live ammo, extremely sensitive military or bases, etc. As a concrete example, Area 51 is in a "restricted area".
> For pilots, "restricted area" is already synonymous with "absolutely do not even think about going here"
I don't buy it. How often do you hear of a passenger plane getting shot down for entering restricted airspace over peaceful territory like the US? What about over combat zones, like over Ukraine or Russia? Who in their right mind equates these as as equally severe? If you had to make an emergency landing would you seriously view these equally?
At least within the US, entering a restricted area without authorization can result in your own personal military air show, followed by lots of questioning, possibly prison, losing your license or both. You don't mess around with restricted areas unless you have a damn good reason.
>> I don't buy it. How often do you hear of a passenger plane getting shot down
> At least within the US, entering a restricted area without authorization can result in your own personal military air show, followed by lots of questioning, possibly prison, losing your license or both. You don't mess around with restricted areas unless you have a damn good reason.
You're not taking my point.
I don't know about you, but I would sure as hell prefer prison over myself and hundreds of other people falling from 40,000 feet.
When I'm flight planning and I see a restricted area along my route, I honestly don't need to know why. I'm not going there unless the controlling agency gives me authorization and I understand the danger. Because there is danger; otherwise it wouldn't be restricted.
If it makes you feel better, here's the current TFR over eastern Ukraine. It even explicitly says "danger" - does that make you feel better?
TEMPO DANGER AREA ACT WI COORD:
434800N0392400E-433000N0303500E-441500N0302500E-...
> ...I would sure as hell prefer prison over myself and hundreds of other people falling from 40,000 feet.
On the one hand, that would be ideal.
On the other hand, that appears to be a NOTAM restricting access to an active war zone. It is truly tragic, and should be avoided whenever reasonably possible, but sometimes civilians who enter war zones get killed.
So, (just so you know) the "they flew into an active war zone" bit is probably the reason why your point is being brushed aside. Restricted airspace is restricted airspace. Unless you're on the unrestricted craft list, you simply don't enter it.
To my reading it's very understated if that is the entire text of the NOTAM - I would have liked it to say WAR ZONE or GUIDED MISSILES in there somewhere.
Compare it to the DC SFRA[0] which specifically states "MAY USE DEADLY FORCE" even though that's extremely unlikely to happen.
When Flight Restrictions are active in FAA controlled airspace, ATC will often clear you through them if you're on an appropriate flight plan without you needing to ask. Even the 'deadly force' SFRA above is essentially handled for you so long as you file an IFR flight plan.
There are more risks than getting shot down. All sorts of dangerous activities may be going on in restricted areas: missile launches, dogfights between fighter jets, tests of unmanned vehicles, etc. You don't want to be a surprise guest at any of them. "Restricted" is a single, short word taught in pilot school to get the message across clearly. If a sudden emergency requires entering a restricted area, then air traffic controllers are there to coordinate it.
NOTAMS are a bunch of garbage that no one pays any attention to. That’s not my opinion, that’s the opinion of former NTSB chairman Robert Sumwalt. I’m sure the GPS NOTAM was buried somewhere in the 27 page NOTAM list and it probably said something like this actual current GPS NOTAM: !GPS 03/022 GPS NAV PRN 08 U/S 2503061847-2506050001
I was flying in and out of a private airport in uncontrolled airspace, so I didn't check. If was my first test flight so I was pretty much just circling around my airstrip.
If I'm flying cross country, in to controlled airspace, or an airport I'm not familiar with, I will. But this particular notam didn't show up when I looked at nearby airports.
Russia has been jamming GPS over Finland, Estonia, and Poland on and off for a couple years, and it's been at its peak now for several months. Sometimes flights have to be canceled. Tartu airport in Estonia was closed for a while[1] because the only instrument approaches it has were GPS-based.
Even worse than jamming is spoofing, which Russia also does. With jamming, you and the aircraft's systems both know what's happening. Spoofing isn't as easy to detect, as the GPS system can report the wrong location but think it's highly accurate. Spoofing (and to some extent jamming) can have a persistent effect on aircraft systems even after they move out of range of the jammer/spoofer, which can lead to degraded navigation accuracy for the rest of the flight.
It's a whole deal. Russia is messing with strategically important systems of many European countries, and decreasing civilian aviation safety, and they rarely get called on it. For a long time there was reluctance to even name Russia as the culprit.
> Russia has been jamming GPS over Finland, Estonia, and Poland on and off for a couple years, and it's been at its peak now for several months. Sometimes flights have to be canceled.
I feel like we had airports before we had GPS. If this is a regular thing, shouldn't we have ways of using the airport without hoping that the jamming is having an off day?
What do you mean "if" of course we do? Relying on older methods means narrowing the acceptable conditions for landing. It means reduced economic activity, reduced opportunities.
How about we treat enemies as actual enemies, rather than rolling over and letting them make our lives more difficult?
In comparison to the US's power, Russia is an annoying pipsqueak, but instead we are letting Russia boss around on everything. It's shameful and embarrassing.
Why in the world should we have to rely on inferior methods?
You're suggesting open war with Russia over GPS jamming? You do understand that the west also engages in sub-war, antagonistic activities with Russia, right? These aren't "inferior methods", they're part of spectrum of activities which have associated costs and risks.
Europe has about 5 functioning fighter aircraft and ~~20 operating tanks at any given moment. It is also completely controlled by a political system that considers conflict the same way it sees domestic abuse in a relationship. It's entire current zeitgeist is formed and controlled by the half of humanity that cant fight and will spend as much time as possible trying to talk their way out of it.
Your narrative on Europe is wrong. Poland has 1000 tanks and would completely wipe out Russia in a war. United, Europe could eliminate Russia's military with a few percent of GDP, full war footing is in no way essential.
They are nobles arguing about who has to take time away from the dinner party to shoo away a miscreant throwing tomatoes. Except for the Baltic States, who take it more seriously at the moment, but that will change as soon as the Vatniks on the political extremes are finally removed.
even assuming Poland could do this, what do you think Russia would do nuclear wise if they were faced with imminent destruction? Did you forget that we live under the sword of Damocles?
Additionally, good luck finding young men who want to fight for their country in the west of Europe. New arrivals will not lay down their lives as they often hate their host countries and people. Heritage Europeans are massively discriminated against by their own governments for speech crimes, on top of race and sex-based discrimination. A very small amount of men will fight to continue that state of affairs.
Second, Ukraine is invading Russian territory, occupies it, and no nukes yet! The supposed nuclear threat is empty and stupid.
Third, if you think for a fucking microsecond that 90% of Polish men are not ready to go to war and kill Russians you have never talked to a Polish person. They know what is at stake.
Fifth, fighting these completely made up narratives that have no basis in reality is exhausting. It's almost as if an entire population has decided that they misread the commandment to be "Though SHALL bear false witness."
Yes, I'm reminded of how woefully the teachers at my grade school tried to stop bullying by... making them sit together and talk through a script. Usually finalized by a knock on the head as they were walking out, having perfectly finished their "remediation". I'm also reminded of how quickly problems were solved when you simply disobeyed the adults and hit them back. It got results. You might say that a grade school is very different than the world state. You might
And other, far more wise people, might realize that appeasement of bullies throughout history has resulted in some of our very worst wars and the most horrific atrocities that humanity has ever committed. Weakness invites conflict and destruction from the bullies of the world, and when it comes to war, the bullies gain materials and conscripts when they are allowed to conquer.
(I think we are very much on the same page, thank you for the comment.)
There usually are other systems (e.g. ILS), but not always.
This post has several comments along the lines of "We used to fly without GPS and it was fine!" The fact is that aviation is so much safer than it used to be, and GPS is part of that. GPS helps aircraft navigate accurately even when they're not near an airport. It helps give situational awareness and avoid mid-air collisions (almost every aircraft these days has a traffic display that shows ADS-B positions of other nearby aircraft, and those positions come from accurate GPS).
Loss or spoofing of GPS isn't usually a critical safety issue on an aircraft, but it definitely removes layers of safety and adds additional risk. Pilots can lose that situational awareness of nearby traffic. They may have increased workload and distraction due to having to use a less familiar & less accurate means of navigation, trying to figure out why their systems aren't working correctly, and even getting bogus ground proximity warning system alerts. ATC may now have increased workload and distraction because some approaches or even runways are no longer usable.
We drove cars for a long time without seat belts and air bags, too.
> We drove cars for a long time without seat belts and air bags, too.
And if we were having problems with seatbelt jammers, everyone would instantly respond by just not using seatbelts in those areas. There would be no road closures and no trip cancellations. What are we supposed to learn from this analogy?
I don't even think that's true. Seatbelts are an improvement in safety regardless of context. But what you're arguing here is that a system that's designed to rely on GPS availability, and gets it, is safer than the same system during a GPS outage, not that GPS availability will make any airport management system safer.
It makes it safer to run aircraft closer together. Most airport capacity increases these days come from optimizing airspace, not from new runways or airports, which are time consuming, expensive, and controversial. We used to operate without them but we were also generally operating a lot fewer flights back then.
The more apt analogy is what would our roads look like if all traffic signals stopped working? People would still drive, but it would have to be at lower speeds, with more congestion, etc.
> The more apt analogy is what would our roads look like if all traffic signals stopped working? People would still drive, but it would have to be at lower speeds, with more congestion, etc.
This happens pretty frequently with single signals, so we know what that looks like.
An unattended broken signal gets treated like a stop sign (by law), and this immediately blocks traffic. It's a total disaster.
If it happens anywhere near a population center, a human will be dispatched to cover for the broken signal and dysfunctional law by manually directing traffic, and this gets you almost all the way back to normal.
If every signal failed at once, that would cause much bigger problems, but in the event that we know we're unable to repair the signals, which is the case here, we wouldn't just try to muddle through using the existing roads and systems. We'd define new systems that worked better in the absence of traffic lights.
I was mostly addressing the idea expressed in other places in this thread that aviation without GPS is fine, not your specific point. To address your question, the commercial aviation world is still in the process of figuring out how to deal with the new, current reality of GPS jamming and spoofing. They're developing new procedures, designing new equipment, and changing priorities and plans. While this happens they're downplaying the risks in press releases and statements to avoid spooking the public.
"If this is a regular thing, shouldn't we have ways of using the airport without hoping that the jamming is having an off day?" Yes. But it takes time and money. This level of GPS interference is relatively new, and for about the past 30 years you could basically assume GPS would be available.
Yes, airports in eastern Europe are now using the old ground based VHF radio beacons (VOR, DME and ILS).
However, they were not in use a few years ago. Some airports never had the ground based equipment installed, others still had the beacons functional but the procedures (STAR, SID) had been phased out in favor of the easier and cheaper satellite based GNSS RNAV procedures.
Some airports had brand new VHF equipment installed, others had the old procedures reinstated.
But aviation is a slow moving, risk averse, cost sensitive business so several airports were inaccessible (apart from visual approach) for a few months.
It's the default OpensStreetMap style, which was never intended as a cartographic basemap for visualizations. Its purpose is to facilitate editing of the underlying data... but it's also one of the "free" options out there and integrated into most map library examples. ("free" because it's community-supported and heavy usage is discouraged, https://operations.osmfoundation.org/policies/tiles/)
That's fair! While understandably it isn't probably a top priority, I'd highly encourage checking out https://docs.protomaps.com/pmtiles/maplibre . It can be nearly free to directly hit a single planet pmtile file, especially with cdn in front, and slightly more to put up a server in front of it (imo, not needed).
Anyway, awesome site regardless, and OSM tiles are fine if not abusing their hosting (this isn't I'm sure).
Myanmar, alias Burma. They're having a hot civil war since 2021. (They've had tensions and insurgencies for as long as they've been an independent state.)
Myanmar. Unstable autocracy, recent coup, ongoing uprising. A huge mess, and exactly where you'd expect the ruling party to be trying to eliminate navigation aids.
The article is a bit strange. While GPS can be used to receive accurate timing (phase correction once per second), for gps less navigation, even a picosecond accurate atomic clock wont really give any additional benefit compared to a wirst watch.
Using an accurate clock, you might be able to detect spoofing (by detecting small “jumps in time”).
However, the same should be possible even with a non accurate clock (a few ppms) by detecting conflicts between the different satellites timings (since the “fake” transmitter is on earth, it will never be able to accurately simulate the real satellites’ airtime delays from space to your specific reception location).
On the other hand, if you pair a very accurate clock with a very accurate gyroscope, you might be able to replace gps altogether (https://en.m.wikipedia.org/wiki/Inertial_navigation_system) But from my knowledge, these kind of gyros are not really available for sale (but this is already outside of my knowledge, so maybe something changed).
> On the other hand, if you pair a very accurate clock with a very accurate gyroscope, you might be able to replace gps altogether (https://en.m.wikipedia.org/wiki/Inertial_navigation_system) But from my knowledge, these kind of gyros are not really available for sale (but this is already outside of my knowledge, so maybe something changed).
Dead reckoning systems are available with varying degrees of accuracy and drift depending on your budget. It's common to use them to guess location during GPS dropouts, such as driving through tunnels.
More accurate systems are available as budget allows and the military has a lot of research on this topic. Error accumulates over time, so the longer you go without a GPS reset, the worse the precision gets.
You can't fully eliminate the error accumulation over time, so they can't completely replace GPS. You still need some way to periodically refresh your ground truth position.
The clock is not the hard part of this.
Oscillators doing 10mhz or 1pps with nanosecond accurate holdover for 24hours are easily available (for like 3k for chip-scale atomic clocks, and less for rubidium or whatever ).
Galileo et al also have publicly available cryptographic signatures so you can't actually spoof them, only jam them.
If you are trying to do navigation while jammed, the reckoning is the hard part of this, not the clock.
The first thing i said makes this sort of irrelevant, but to go down this path:
The replay attacks i'm aware of fall into two categories - cold start and warm start (mostly from https://arxiv.org/html/2501.09246v1, which has been in progress for a while)
The cold start replay attacks are irrelevant here - unless you can force-restart the gps receiver in cold start mode during flight. If you can do that, you probably don't need to spoof the signal. Especially since it requires precise timing to forge the new signal to the receiver at the right time (otherwise it detects it), etc. Seems like there are easier ways.
The warm start replay attack
A. Requires you replay valid, but out of date, signals, in real time. This is non-trivial, and also limited in effect as you can only arbitrarily spoof one receiver to a location of your choosing - maybe you can get a few receivers with really good high-signal strength directional beaming of different replays, but it requires real-time tracking and adjustment of the signal of the target anyway to be able to spoof the location accurately.
Spoofing the location inaccurately is sort of pointless in most cases.
B. The attack has to change the time (and thus location) slow enough to not trigger various protections, then keep changing it slowly enough to continue that.
C. The attack requires that your receiver is too stupid to notice that a forced revert to non-authenticated time occurred, doesn't notify you of this, and then doesn't notice that time or location jumped suddenly by more than any reasonable amount. It also has to not notice that the SNR of everything suddenly changed, etc.
Oh, also, they have to spoof all other sources of time, including local oscillators, etc, for you to not notice.
Given we just talked about how cheap and easy it is to have a high quality oscillator disciplined to time before takeoff, this kind of replay attack seems "practical" only in the sense that it is possible.
Are you aware of other replay attacks, if so, that'd be cool :)
Otherwise, yes, I agree you can spoof location in theory. I can't imagine a practical application of it in the scenario we are talking about.
Another thing that is being looked at are antennas (CRPA: Controlled Reception Pattern Antennas) which filter signals more, so that "GPS signals" that come from the ground and the sides are more likely to be rejected:
> Given that GPS/GNSS comes from satellites, ignoring signals from not-from-the-sky seems like a quick win.
You're right, but GPS antennas already have some rejection from the "bottom" hemisphere. So they're already rejecting not-sky.
CRPAs (of the type contemplated by ITAR) are electronically steerable antennas (phased arrays), that allow you to steer one or more nulls to the direction of the noise source(s). That gives much better rejection of point-source noise.
Also, the Doppler shift of jamming/spoofing will be all wrong, unless they’re specifically targeting your vehicle and accounting for its speed and direction in their attack.
… if you can get the precision to filter that out…
GPS signals from low attitudes improve accuracy (to a point) because they provide much better triangulation. You want low attitude GPS satellites. You also don't want to lose signal every time the receiver tips, like when going up/down slight hills.
They don't lose signal when the receiver tips (which would make it useless for planes). They use antenna arrays to filter signals coming from directions they don't expect, too strong, etc.
These systems have been used used in military aircraft for a long time.
Magnetic-anomaly based navigation (MagNav) is a real thing that can solve this problem, and has been shown to work with the accuracy of a few hundred meters. Perhaps the government and defense contractors should look into this technology more. With a few more years of funded R&D and FAA-certification, I think its pretty likely that we'll see some of these systems on planes soon. The military is already flying with it during their exercises.
disclosure - I do work on a team developing MagNav, but much of the seminal research has come out of the Air Force Institution of Technology. They performed it on an F16, paper results shown here https://ieeexplore.ieee.org/document/9506809
It’s not uncommon to fuse magnetometer with other sensors. We did that for indoor navigation at Apple. In fact, we had prototypes that used only magnetometer and it worked fairly well for what it was but the low update rate and poor resolution meant that it worked to like 10-30 meters which wasn’t usable for indoor by itself. Of course, for indoor there was a lot more “texture” indoors for the commercial magnetometer of the time to pick up whereas outdoor it gets trickier. Is that similar to how MagNav works just with higher quality more sensitive magnetometers?
So the role that magnetometers play in sensor fusion w/ IMU data is for yaw/heading/magnetic north estimation. In short, it aids your orientation (RPY estimate). However, with MagNav, they play a large role in supplying information that allows you to decrease your drift rate.
I find these sorts of alternatives to what I'll call 'adversarially contested technologies' super interesting. Jamming drone control and video links is another similar instance where alternatives like MagNav could prove useful by allowing autonomous fallback operation in the case of signal loss. I assume viable solutions will probably require a fusion of approaches like MagNav, optical terrain following, laser altimeter, etc
We're working on making MagNav a one stop shop backup for GPS. I think to cover ALL cases however, you'll need other technologies. TERCOM, visual, and celestial all have their niche use cases.
But for most cases, MagNav should do the job. Happy to answer more
1. Roughly how long does it take for MagNav to get a "lock". For example, GPS takes 10 or 15 seconds (at least consumer stuff I have access to). Also, with GPS the accuracy improves if you're moving. I assume it may be similar with MagNav but it would be an interesting advantage if MagNav got a lock super fast vs GPS and/or it was basically at 100% resolution without needing to move (and I understand MagNav's "100%" res is much lower than GPS).
2. What's your drive-by guesstimate on probable future evolution of MagNav tech on the 'Four Horsemen' of mobile tech (size, weight, power, cost)? For example, which of the four are more like "No reason it can't improve a lot if given sufficient time, funding and development with no new science required" and are more "Well, physics/materials are currently an unsolved, seemingly fundamental barrier to improving beyond X threshold." In a perfect world... (the one we don't live in), MagNav would be on a five year productization track that'll put it inside an Micro SD card footprint with negligible power budget at 25 cents/ea by the million and be common in small Costco drones as a fallback if GPS fails.
1. MagNav needs to be done continuously over a trajectory. Like GPS, it actually needs to be fused with INS data to work. Also GPS actually takes longer for a good lock on. What your phone is actually doing is sensor fusion (GPS + wifi, onboard accelerometer and gyro, etc.) and caching of the satellite information in order to produce a best estimate immediately. So when you first get a lock it takes a while even up to 15 minutes depending on the environment. Afterwards your phone/receiver tends to remember what satellites there were in the trajectory. It's a background process thats constantly running. We've experienced this first-hand in our experiments.
2. Since I work for a company in this area, I can't say too much, but SWaP is definitely going to decrease. Right now I think you could decrease size to a midsize cereal box. I don't think a super accurate version would exist for phones yet. Power consumption is somewhat low, but you need a serviceable GPU and RAM, like an Apple M3 to run things. Power consumption will improve with improvements in compute.
I think cost is the most prohibitive of them all, because quality magnetometers and INS are not cheap. > $20K per unit at least. i'm not talking MEMS grade stuff you see in phones and student projects, I'm referring to Tactical/Navigation grade—the stuff you see on military platforms. I think you'll see MagNav on military planes much faster, due to their mission-critical needs. For commericial planes to use them at scale, one needs FAA clearance which is a bottleneck for good and bad reasons.
We're not in a perfect world yet. MagNav will take some time to develop. What I think is missing is a larger community to work on this issue. There isn't that much motion in the space. Less than 5 serious players in the game, IMO. There also aren't that many suppliers who make the parts (magnetometers, etc.) you need for MagNav.
Lots of more thoughts here, but if anyone wants to chat more, contact me at sir.claude.shannon@gmail.com
Thanks for taking the time to answer. That was a perfect level of detail to give me a broad, high-level vibe on MagNav. And the answers are about as I expected. Approaches which serve as an alternative to a ubiquitous, cheap, COTS tech (like GPS), are interesting. They're usually driven by highly specialized use cases where the cheap COTS default isn't always quite adequate and there's a small but meaningful number of customers with challenging requirements and deep pockets.
I imagine larger military drones which need to navigate autonomously for extended periods over denied environments in all conditions are very interested in MagNav as a component in their sensor fusion suites. Even narrowing the current position to less than a square kilometer would make the identification problems faced by other sensors like optical much easier to solve.
Currently 20-40 pounds right now, but we're working to reduce the SWaP. MagNav does rely on having accurate magnetic anomaly maps, which the government and certain private companies have access to.
They change over geological timescales—so not anytime soon. We're talking millions of years, w/ movement of tectonic plates and such. So for right now, once an area is mapped, its mapped for good. HOWEVER. Maps may need to be redrawn if the quality of them sucks.
> The Boeing 737 MAX 8-200 had already descended to around 850ft (259m) when the disruption occurred. Instead of landing, the plane was forced to climb back into the sky and divert nearly 400km (250 miles) south to Warsaw, Poland. Lithuanian air authorities later confirmed the aircraft had been affected by "GPS signal interference".
GPS is incredibly flimsy. Normally it operates by taking the average of 1000 observations to generate a noisy signal. It's not that difficult to be louder than something shouting from space. You can pick up cheap GPS blockers easily about the size of a walkie-talkie (handheld radio).
> By carrying a group of atoms cooled to -273C on the plane itself, rather than relying on an external signal, the technology can't be interfered with by jamming.
Last year I was on a plane where if the engines were not running, it entirely went into darkness. They hooked the plane up to the airport and tripped the airport electrics too. Now imagine if your plane loses power momentarily, and suddenly your GPS stops working entirely.
> Henry White, part of the team from BAE Systems that worked on the test flight, told BBC News that he thought the first application could be aboard ships, "where there's a bit more space".
> Quantum clocks, gyroscopes and accelerometers are large, bulky and incredibly expensive, with an accurate quantum clock costing around £100,000. Yet military research is allowing the creation of smaller, better and cheaper systems.
Likely a minimum of 10 years from being viable. Mt White of BAE is politely saying as much.
Apparently they're not even export-protected, despite their obvious use in GPS validation schemes and in RTK.
> The SA.45s CSAC has an Export Commodity Control Number (ECCN) of EAR99. This means it is not ITAR-controlled and does not require a special license to ship to most nations. The SA.45s CSAC classification is controlled by the Bureau of Industrial Security (BIS) within the US Department of Commerce.
The article talks about quantum "optical clocks" but doesn't really explain the concept.
It’s true that optical clocks will improve the accuracy of our measurement of time, and it’s true that GPS depends on time, but there are several steps between primary frequency standards (ie, optical clocks) and GPS, and several more steps between GPS and navigation applications.
So optical clocks cannot, in fact, have any effect on the end-user perceived reliability of GPS.
For that, the best solution is to revive LORAN which is much less susceptible to jamming. (And would also benefit from better atomic clocks.)
You can do about 5x worse (in accuracy terms) than a Cesium clock in a smaller package using a rubidium atomic clock. Average ~4 of these and you get to the same accuracy as a cesium clock. They aren't export controlled because they aren't that special in terms of what you get.
To improve instrumental accuracy by 5x in a single dimension when fighting against random uncorrelated drift/noise, from what I recall of statistics you require 5^2 = 25x as many instruments.
Yeah, I think you're actually right. I was thinking you double them with 2 (experimentally), so you double that again to get 4x, but my curve was pretty off.
High quality dead reckoning over a long duration + an initial fix solves the reliable instantaneous absolute fix. So different technically but OP is correct it would be relevant to the problem of solving GPS jamming.
It absolutely does not. Dead reckoning has error that accumulates over time, and even "high-quality" dead reckoning will be beaten by a crappy GPS fix very quickly.
The dead reckoning I’m referring to (and I suspect op is too and seemingly you are as well), is the work being done by the military in the usage of submarines that stay submerged for extremely long periods of time. The error accumulated is many orders of magnitude less than traditional accelerometers + gyroscopes over the same time frame. The point is you can dead reckon within your error bounds even when GPS is unavailable and the accuracy from fusion will beat GPS by itself (not that that matters for the applications we’re discussing). For the duration of a flight it should be well within the capabilities of such sensors to dead reckon accurately from a last GPS fix before blackout and OP is correct this would be a complementary solution to more accurate clocks making it harder to jam GPS in the first place.
Indeed it’s being examined precisely for this application:
I don't really understand why the plane was diverted because GPS was jammed; I get that it's important for navigation, but not how it's required for landing when they're that close. There's (iirc) close range guidance systems, and of course visual ones (lamps, stripes, etc).
Not all types of approaches are available at all runways (or airports), and sometimes they are down for maintenance. Specific runways may be required due to wind, aircraft weight and runway condition and length. Most airlines ban "circling approaches" (using an approach to one runway end and then circling visually to land at a other) for safety reasons. ILS, which is probably the "close range guidance" you are thinking of, must be installed, maintained and calibrated individually per runway end. Visual aids cannot be used for approach if there is low cloud.
It is usual to be able to abort an approach and try again at the same airport using a different approach technology. But if the journalist wanted to find the most extreme example, it's not surprising that it happened at least once that an alternative wasn't available. This is probably "sampling bias"!
Note that final operational decisions are made by the aircraft commander. Aircraft do not "get diverted", except by decision of the "captain".
My understanding is it depends on the amount of visibility, plus what type of approach they were on. One type of approach, an ILS, has big radio transmitters pointing from the runway into the air and allows the plane (either pilots or autopilot) to get close enough to the runway without visibility, and with enough precision, to land. In many circumstances ILS isn't available and an alternative is Required Navigation Performance (RNP) which uses GPS plus a ton of other inputs to give some amount of precision to the same end. If they're on an RNP approach but suffer a reduction in navigation accuracy then I imagine it's a policy 'go-around'. Even if there's enough visibility it allows the pilots to brief a 'visual' approach before attempting it.
Considering it's below 1000 feet, losing GPS could indicate an "unstablized" approach and require a go-around, as opposed to losing it at a higher altitude where the pilot could have more time to safely switch to alternatives (other navigating aids or go to visual?).
Source: my guess after watching a lot of aviation YouTube videos......
For anybody who doesn't know, a "stabilized approach" is an approach with a constant angle and speed as the plane descends and lands. This allows the plane to keep consistent control settings (flaps, throttle, etc).
It's best practice/policy for all major airlines to use stabilized approaches and most/all require a go-around if the stabilized approach is interrupted (there are edge cases and exceptions).
Commercial air travel is very risk-averse. Best practice is that if something unexpected occurs, and you have plenty of fuel to spare, you go and and find someplace else to land.
> They think most devices talk back to the satellites somehow.
To be honest, I don't think most people realize GPS is coming from satellites in the first place. Most people simply don't think about how/why at all when using things.
Spoofing is different from jamming. Spoofing is when you trick the receiver into thinking the position is one you fed it vs jamming is you preventing it from acquiring a signal at all. Jamming is much easier while spoofing can be more difficult if there’s encryption on the signal. Unfortunately I think commercial signals aren’t signed with a private key to completely prevent spoofing but I’m not 100% sure.
... and this term only appears in the headline, not (anywhere!) in the body text. Wonder if the author of the article intended that term to be used, or whether the (sub)editors put it in to help get more clicks?
Detailed summary from Ops.group, which is for pilots and flight planners.[1]
It's really bad. They write:
Typical indications of Spoofing
Unlike jamming, a GPS signal is present, but it has fake information. False GPS position, time,
and date information will be processed by the GPS receiver as being valid. As soon as this is
fed to other systems, failure messages will begin.
• Rapid EPU or ANP increase
• GPS position and IRS or FMS position disagree caution message
• Aircraft Clock time changes, or difference between Capt/FO clocks
• Transponder failure: EICAS/ECAM “ATC FAIL”
• Autopilot turns aircraft unexpectedly
• ADS-B Failure/Warning
• Synthetic Vision reverting to blue over brown
• Loss of enhanced display, such as display of terrain on PDI
• Wind indication on ND is illogical or has a major shift - erratic groundspeed
• GPS position symbol on ND drifts away from the FMS and the IRS symbols
• Datalink (CPDLC, ADS-C) failure warning
• GPS information on sensor page shows unusual values: altitude, etc.
• Handheld GPS (e.g. Garmin, iPad) disagrees with aircraft GPS position
• EGPWS audible warning (‘Pull Up”)
• GPS 1 and 2 dramatically different i.e. more than 100 meters, which may also give an
ECAM/EICAS GPS miscompare warning.
• Spoofing Alerting app e.g. Naviguard gives alert
• ACARS message from ground/ops advises of spoofing (based on aircraft downlink
message with unusual values)
If you can't receive signals from the GPS satellites because some country's military is jamming them, how does having an accurate on-board clock help?
Are they somehow able to determine position via dead reckoning? How does that account for errors from wind, vibration, etc. and compounding of errors over time? (I'm pretty sure dead reckoning is not a closed-loop system)
"Miniaturize a very accurate clock" seems like a fairly straightforward engineering challenge. "I can give you clocks as precise as you need, now design me a system that can give your coordinates in thick fog without GPS or any other external radio signals" seems like a much harder one.
Historically ships at sea could determine latitude through sun-sighting or stars, but longitude was impossible because they did not have a clock which was accurate enough
I doubt they're navigating using the sun an stars, but if the airspeed indicator is accurate, and you know you're heading, all you need is an accurate clock to determine absolute position since the last known good position.
> if the airspeed indicator is accurate, and you know you're heading, all you need is an accurate clock to determine absolute position
Airspeed gives speed relative to the air, not the ground. To compute ground speed, you also need winds aloft, which can be huge if the aircraft is operating in the jet stream.
Getting good data for winds aloft is difficult because there are a relatively small number of actual measurements, and everything else is model output with all the usual caveats.
Indeed. The article is a bit confusing on details. At the end it talks about accelerometers and gyros, but aircraft have been using laser ring gyros for decades. They now use gps because it is much more accurate.
The article does a poor job explaining, but seems to imply that they are working on replacing GPS altogether with a local system that relies on an atomic clock and quantum engineering. From what I can find, there are many approaches to this, including quantum gravimetry, quantum accelerometers, etc.
Technically both techniques can be used for gps hacking. It also seems you can fake a gps signal altogether, because the public signal is not cryptographically signed, which surprises me (the only thing that makes sense to me is that the gps protocol doesn't have room for adding a signature, so it'd be a breaking change to the protocol).
When Israel was waiting for a retaliatory strike from Iran they jammed GPS in the region. I never found a clear explanation of how it was done technically, this would make total sense if their system also was targeting atomic clock signals rather than GPS itself to confuse incoming missiles or aircraft.
That does raise an interesting question though - do missles actually depend on the standard atomic clock signals? Maybe that isn't how they did it, that seems like a dependency you wouldn't want in a weapon.
GPS signals are atomic clock signals. The receiver triangulates its position by comparing the time delays between the signals originating from different satellites. The receiver itself doesn't require a good clock since it only compares signals with each other.
No. The US stopped degrading civilian GPS accuracy in 2001[1]. Although the US retains the ability to degrade civilian GPS in specific target areas.
Regardless, if you’re building a long range missile, you need some ability for it to navigate. If you’re not using GPS, then what would you use instead? Additionally there’s nothing preventing you from using multiple navigation systems in tandem and fusing the results together, which is almost certainly what these missile do.
Sensor fusion reduces the impact of stuff like GPS jamming, but certainly doesn’t eliminate it. The over all system will be less accurate with fewer inputs, and if you’re the one faced with a high speed missile flying at you, I suspect you’ll take every edge you can get, regardless of how small the impact might be.
>Regardless, if you’re building a long range missile, you need some ability for it to navigate. If you’re not using GPS, then what would you use instead?
US ICBMs and submarine-launched ballistic missiles use a combination of inertial and celestial navigation: in space of course there are no clouds to obscure the stars:
A error correction technique I learned as a young land surveying assistant is to put a gps antenna on a known fixed point location. The delta between the fixed point and the point of measurement is cancelled out to get a more accurate read.
We did this to trial some new (at the time) surveying equipment when the primary equipment was optical. It would save time for really long measurements through the forest and mountainous terrain .
You can even subscribe to services which do this for you! There are a few companies with large-scale networks of fixed receivers, and you can get the observed offset from a node near you via the internet, usually via "NTRIP".
Getting correction data from a node a few dozen kilometers away isn't quite as good as having your own fixed base station a stone's throw away, but it's way more convenient and for a lot of applications plenty accurate.
GPS Accuracy used to be limited, but that ended decades ago.
There are rules about GPS hardware that say that they should cease working above certain speeds and altitudes for guided missile purposes. But that is a firmware issue. I’m sure the Iranians have figured that out if the are even using off the shelf hardware.
GPS signals are relatively low power (American GPS broadcasts at 25 watts and the signal is a tiny fraction of a mW at sea level). In theory, it's easy to pump out noise over it, especially the civilian frequencies that Iran would in theory be using.
Depending on the receivers and what (combination?) of GPS/GLONASS/GALILEO/BAIDU Iran uses, you could easily overwhelm them.
There have been cases of delivery drivers using jammers to stop companies from tracking them, only to interfere with airport landing systems, which is a concern as a lot of warehouses are near airports.
> GPS signals are relatively low power (American GPS broadcasts at 25 watts and are ~10-15W at sea level)
Did you lose 16 orders of magnitude for the sea level values? GPS signal strength on the ground is usually below -135dBm per square meter. That gives you a couple of femtowatts with commonly used antenna, if you're lucky.
GPS (as well as most satellite) signals are weak because it's strong enough for line of sight even from so far away. They only transmit at 25W. Comparatively, an FM/TV signal will often broadcast at tens of thousands of watts and up.
I don't understand this article. If the GPS signals are jammed, what purpose does it serve to have an atomic clock on board your plane? You still need accurate signals with time data to measure against.
You can get a very accurate timestamp from GNSS. What lots of people do then is slave a PLL based on a local oscillator, to be able to get time between two GNSS captations. Or to be able to extrapolate when they have no GNSS signal.
Now suppose someone is spoofing your GNSS signals, it's pretty hard to replace a constellation with another one whilst maintaining time consistency for you. One way to detect spoofing is comparing what a local clock is saying to whatever the GNSS is giving. A local, unfudgeable, stable, accurate clock is a good reference for this.
The article is seriously confused.
What you are talking about is easy - chip scale atomic clocks are easy to get. I can have one shipped to me today.
Hell, i have one on a time card in my basement.
I was under the impression (and from experience too) that the very stable oscillators were finicky and sensitive to temperature swings and in general costly to use properly in "hard" environments.
I'm happy to learn this is not the case for every good oscillator. TIL.
As I read from book about gyroscopes, most sensitive achieve so fine accuracy, they detect daily Earth rotation and even yearly Earth rotation.
But when they speaking about near zero temperatures, looks like they talking about something like Rydberg atoms - extremely sensitive matter, which could be considered as nuclear scale gyroscopes, or quantum gyroscopes, or read more about quantum accelerometer.
And current inertial navigation could be used to calculate relative coordinates like automobile odometer, but from integrating accelerations. But classic accelerometer is just not fine enough, and at this place appear quantum accelerometer and quantum gyroscope.
And I agree, article is terrible. I don't know why they use so abstract language, when could just say, navy already tested quantum navigation.
To be more concrete, space rockets nearly all fly with inertial navigation, but they are extreme case, because most use only inertial navigation just few minutes (so all those classic gyros/accelerometers integrated errors are small enough to successful enter stable orbit, and then using some sort of radio or optical fine measurements and making corrections with fine engines).
Planes flights are much more lengthy than rockets - I think, typical ~40 minutes or more (most long I hear 20 hours), so INS could integrate huge mistake.
INS essentially was expensive and AFAIK once GPS became available started to drop off in use outside of military. And with GPS availability coinciding with switching to more modern integrated Flight Management System/Computer, a lot of planes simply don't have INS installed.
Your words are near to truth. Before GPS from nearly 1950s used LORAN navigation system, with similar to GPS principles, but used long waves and have relatively low precision - about kilometer at best.
Before LORAN, used radio beacon navigation and star navigation (from Newton time), and good human navigator could achieve about 50km precision.
You could easy see signs of star navigation on good preserved old planes - they all have some sort of fully glass dome, or blister, to provide good near semi-sphere view.
And sure, all those before-GPS era planes have separate navigator job position, sometimes shared with mechanic.
You could ask, how planes could fly with 50km precision? Answer is easy - at all plane routes built ground structures easy seen from air and last mile navigation become essentially visual flight, nothing more, nothing less.
On some places ground navigation structures preserved now, for examples:
LORAN was mostly long range over sea, on the ground we had NDB, DME, VOR, etc all ultimately linking into "airways" for higher altitude operations where earth might be not visible due to cloud cover for example
The INS unit is separate and often has its own set of gyros and has to be connected as separate input to FMS or other navigational computers, same as connecting GPSes or other radio nav components.
For example the current model of popular Universal Avionics UNS1 series of NCU (navigational computer part of FMS) come with built-in augmented GPS receiversz but do not mention INS functionality at all even in extended models. Don't have access to manuals at the moment, but I'd expect to see INS as optional to connect over one of the external connectors on the MCU, as it was on the older models without integrated GPS
I had assumed that the ADIRU’s inertial reference data from its gyroscopes and accelerometers would feed into the FMS to provide INS capabilities in case GNSS was unavailable.
Many small planes don't have INS in typical meaning, but their pilot is INS computer, calculated approximate nav from air data (air speed + weather data + compass or radio compass).
I believe submarines navigate long distances using INS. I don’t know how accurate it is, or how often they have to make corrections using other data. But ballistic missile submarines can’t really use active sonar or surface with any frequency, so I’m not sure what other method they’d use.
> ballistic missile submarines can’t really use active sonar or surface with any frequency
Detect semi-surfaced submarine at night is really hard, if don't have intelligence data that it will surface on some non-random position.
From experience of Ukrainian war, my country have success with eliminating surface military ships, because have constantly monitoring their moves with satellites, but I cannot remember any case when semi-surfaced submarine was hit.
Are they not easy to detect on radar? Even during WWII, radar got good enough to detect submarine periscopes. It's hard to imagine that a partially surfaced submarine wouldn't have a significant radar return. That doesn't mean that they're easy to detect at long ranges, but I would have thought that partially surfacing or raising a periscope would be a significant risk to a submarine if the enemy knew its rough location.
At a guess, Ukraine probably can't deploy naval assets with powerful radar close enough to where Russian subs are operating. But an adversary with a more powerful navy might be able to.
During WWII, submarines was just very special type of boat. You could check wikipedia about German u-boats - exist about TEN subtypes, from which only latest types have really significant underwater range, but all others was extremely limited in underwater activity.
But, surface ships of that time was even more limited, many could not achieve even half of surface speed of u-boat, so become easy prey.
But if you will try to find some artificial object on sea surface, that is really hard question. Just because sea is huge, so you need to check extremely large space in short time.
Radars are better to spot artificial object on sea surface than visual, just because radar easier to automate. But nothing more. Radar is also have problem of square distance, very similar to visual. So, as it is hard to spot partially surfaced submarine visually, it also hard to spot such sub with radar, because much less part will be on surface, so radar will have much less signal to detect.
Periscope size is nearly undetectable on surface, if it used carefully, just outside detection range of radar.
So, to conclude, Ukraine problem is, we cannot detect partially surfaced submarines on open sea, but they could fire missiles. Fortunately, Russians have very few submarines on Black sea, and after they was hit at harbors, their usage become very limited.
> But, surface ships of that time was even more limited, many could not achieve even half of surface speed of u-boat, so become easy prey.
Agree with most of what you said, but U-boats generally had top surface speeds under 20 knots and were thus slower on the surface than most naval vessels of the time. They could certainly move faster than most convoys, but they couldn’t outrun pursuing destroyers or corvettes.
> slower on the surface than most naval vessels of the time
That is point. I'm not agree about most, but will be agree if you say about many.
> they couldn’t outrun pursuing destroyers or corvettes
But problem was, navy have so huge deficit of ships, so some convoys was run without naval support.
Sure, if all convoys was supported with fastest ships with best commands, u-boats will be no problem anymore, and as I understand, once this was happen.
A big issue during WWII is that the submarines were trying to find and approach the ships in order to sink them - and the ships in turn were looking out for the submarines. The submarine is forced to be close to ships equipped with radar.
Ballistic missile submarines are a completely different story. They aren't chasing anyone. Their entire goal is to be unpredictable and stay hidden, so if there's anyone with a radar around they are just going to keep quiet and move somewhere else.
Finding a sub prowling a shipping route is quite doable. Finding a sub in the middle of the Pacific Ocean? Not a chance.
I must admit, I agree with nearly all you said. Problem is that Ukraine was weak, and nearly without navy, and civilian ships was unable to resist to Russian navy. And Ukrainian export was blocked, as civilian ships fear to run within range of fire of Russian navy.
When Ukraine got enough weapons to force Russian ships to stay at distance, situation changed dramatically, so export was unblocked.
I think, very similar things happen during WWII.
This is not about only submarines, this is about superiority.
I talked with captain of submarine. He said, in real life navigation was not reliable, so they have to go to surface and make adjustments with some classic navigation - radio beacons and star navigation.
And civilian education now close to forgot star navigation, but navy still train people to navigate with stars and learn Morse code.
Unfortunately, these numbers considered state of art for modern classic gyroscopes.
Better are quantum navigation systems, using quantum matter as sensor, but they was too bulky to be used on planes, only last years appear more compact systems, sized like common home fridge.
I didn't read the article, but: a GPS receiver must calculate/find both it's time and position to get a fix. So maybe by having the time already available really accurately it makes the job of finding position easier?
From my (very basic) understanding of GPS you need at minimum four satellites to calculate the time. If you had a local atomic clock in sync with the GPS satellites, you'd only need three satellites to get a position fix. It would (probably, maybe?) also speed up the time to first fix / time to a precise position fix.
Shameless self-plug: I had Ken Munro from PTP on my podcast [1] in the episode 'Hacking airplanes, ships and IoT devices with Ken Munro' where we dove into GPS hacking and spoofing at length.
GPS and other navigation systems are well worth the time to look into.
something like Decca or LORAN are really simple to understand: two or more base stations in a known location emitting phase locked signals. By counting the nodes/antinodes of the harmonics, you can work out how far away you are from the base stations. The downside is that you need a initial fix to work out absolute location.
The thing thats kinda touched on here is that GPS uses clocks to allow the receiver to work out how long the signal has been in flight (simplification) If you know where the satellites are (using the Almanac of satellite positions) you can get your location by fairly simple triangulation.
Now, you don't have an atomic clock on your receiver, so how can you accurately measure the time difference between signals?
for GPS you only need to know the relative time difference between each satellite, and even thought quartz clocks are only accurate to seconds a year, in the ~20-50ms it takes for the signal to arrive, its more than accurate enough.
However that means you are open to spoofing, because you sync your local clock to a satellite, you have no real way of detecting if the clock has skipped.
If you have an accurate clock source, you can then validate the clocks that are on the transmitters. I think, but can't confidently assert that calculating position becomes easier because you have an authoritative clock source, so don't need to piss about with clock sync using an unknown time offset.
I think the implication is that this provides a strong form of signal authentication.
However chipscale super-stable clock references also allow more autonomous styles of navigation. (ie celestial)
Planes have been flying for decades before GPS even existed, yet the article seems to make it sound like they wouldn't be able to without GPS. Unfortunately no mention of https://en.wikipedia.org/wiki/Inertial_navigation_system at all.
After the invention of GPS, aviation increased its capabilities due to the advantages GPS provides. Many modern flights depend on those capabilities to be economically viable, and are thus dependent on GPS.
Simply because it’s possible to fly without GPS doesn’t mean it’s commercially viable. Remember, before GPS, direct transatlantic flight weren’t generally possible because there’s no radar or radio coverage out there to help with flight navigation. Also for a long time, plane navigated by flying low and literally following giant arrows on the ground[1]. I doubt anyone is particularly keen to return to that kind of navigation.
We'd definitely need new hardware and/or infrastructure to work without GPS.
> before GPS, direct transatlantic flight weren’t generally possible
I'm not sure what you mean by this. Commercial transatlantic flight picked up after WW2 in the 50s. By the 1970s it was fairly common. A lot of that came from rocketry research and INS.
It is interesting to consider how many old mysteries in flying came down to "pilot didn't know where they actually were." This isn't much different from hikers getting stranded, even when they are within a mile of a marked trail.
Nonsense. There were decades of commercial transatlantic flights before the widespread adoption of GPS. No one painted giant arrows on the ocean. Airliners navigated using a mix of dead reckoning, ground signals, and sometimes even celestial observations.
Note those INS systems depend on some sort of navigational system to verify against due to drift and such, and those systems are GPS or VOR.. and VORs are being shut down or decommissioned as they fail (except for the ones declared required for national security).
Well, it's just bad journalism, cause what they are referring to is a quantum inertial navigation system, not a clock – it's just thousands of time more precise. The plan happen to also have an atomic clock (which is used to properly integrate inertia through time), without having to rely on external GPS (which is a clock).
INS accumulates error though. It comes in handy in the absence of any other navigation system, but generally an INS is supplemented by some sort of radio navigation aid such as VOR, LORAN, or GPS to correct it.
Except guess what! Many of the VOR stations in the USA have been shut down, due to the high availability of GPS!
The behavior will continue until a negative stimulus is introduced.
Which seems to be hard seeing as how the Russian government is good at convincing people (mainly their own, Europe's elite, and members of the Republican Party in the US) that it's okay to do what they do.
So this pertains to jamming so strong that traditional jam-proof GPS that uses signal phase shift to weed out GPS signals coming from "wrong" directions, are insufficient? 100db attenuation of jamming signal has been achieved around 15 years ago with those.
In the air, there are always more GPS satellites visible than necessary. So jam-proofing through signal processing methods is the way to go.
What I don't understand about this GPS spamming: we don't need to rely on GPS. We have Galileo, (GLONASS) and BAIDU. That is the reason we its now called GNSS.
Most of the chips and as such the receivers are supoorting all of these systems in parallel. While I understand that the Chinese use their own coordinate system, I don't if BAIDU is based on that or not. Galileo is available. Galileo is able to use authenticated signals. Galileo has much improved over GPS. I assume in (important) comercial applications like aircrafts, you could use the better Galileo service for which you have to pay for.
> Galileo was the ugly duckling for a very long time - but it turned into a shining one after it aged a bit.
Yeah, for some time I was also in the camp of "why we need our own expansive service". But the current development has shown, that it was a wise desicion to have our own system.
BTW: thanks for updating on some other details. I never followed up really, it was from the initial plans, that I was told there should be comercial service, that should pay. Also that for some emergency services there is a very limited possibility to have a back channel.
It has optional cryptographic signatures of the navigation message, i.e. the data indicating position of satellites.
Spoofing generally works not by altering the navigation message, but by altering the timing of arriving signals. I'd recommend this video for a publicly-available overview of the techniques: https://www.youtube.com/watch?v=sAjWJbZOq6I
A) you keep on using the word "almanac". That term only refers to the imprecise information about all satellites that every satellite broadcasts, mostly to improve TTFF. The actual position used for navigation is called "ephemeris", and each satellite only broadcasts its own.
B) none of that other stuff in the navigation message changes the pseudorange, which is what spoofers mess with. For a networking analogy - pseudoranges are calculated based on layer 1/2 properties of the network. (Specifically the code phase and Doppler shift.) Navigation messages are layer 7 information passed on top of that physical layer. You can change the timing and frequency characteristics of the PRN code without touching a single bit of the navigation message.)
The G/NAV message (note the G - government) is for a separate service - not OSNMA - where not only is the navigation message encrypted, but the PRN code is also encrypted (symmetrically, so it can't be done for the mass market or even untrusted commercial customers).
In other comments to this link people are describing GPS according to my mental model, which is hard to combine with cryptography making it un-spoofable.
If someone can re-broadcast the keystream and control the latency I perceive as a receiver, how would me checking that the MAC is correct help?
"GPS" is being used as a genericism in these articles. All the GNSS constellations work the same way, and all of the military-grade spoofers are multi constellation.
Authenticating signals for GNSS sound like an impossible cryptographic task. What stops a malicious actor from recording the signals coming off the satellites and replaying them louder with a delay?
If you pick the delay properly you can make the plane believe it is at an arbitrary point in space and time (although of course that time would always have to be at least a few `us` in the past).
The article mentions the UK Government Risk Register, which I've always thought was pretty interesting. They publish it each year (I think) as a PDF and it's very easy to access and read.
Mind you this only helps to tell you if the signal is authentic, you're still without that navigation system at that point, hence the search for a localized alternative.
Also, the Russians have been playing around with rebroadcasting legit signals with slight delays as well. The Ukraine war has been a very interesting time to observe these tricks.
If you have a good local clock (e.g. rubidium), you can now detect the signal is from the past and correctly conclude you are jammed and trust INS, starnav or whatever instead...
TESLA encryption is resistant against rebroadcasting. The idea is to use a PKI infrastructure to digitally sign the timestamp stream at fairly granular intervals.
This way, you'll be able to find a set of satellites that are not getting jammed.
Another option is to use the low-orbit satellites in addition to regular sats.
Can’t an attacker still start meaconing the original (i.e. locally captured) signal and then slowly selectively delay/advance each individual satellite component in the time and frequency domain?
Not sure how much latency that would introduce and how feasible that is in terms of tricking a receiver sensitive to any jumps/outages, and its definitely a weaker attacker capability than “simulate any time and location you want”.
The attacker can do that, but it will be immediately apparent for the receiver. The only thing you can do is a replay attack, which is useless, if the receiver has a clock that is accurate to within ~1 sec. It'll immediately recognize that the time stream is being tampered with when the next signature is out of whack.
You might be able to trick the receiver _once_ into not updating its position for a few seconds. After that, it'll mark the affected satellites as unreliable and will not use them.
It's functionally no different from just jamming them.
Why would the replay attack necessarily be immediately apparent if you start out synchronously and only very slowly build up a delay, especially if combined (as you suggest) with a momentary gap and re-acquisition to mask any unavoidable slight initial delay?
It does not work mathematically. If you delay signals from one satellite, then you need to simulate signals arriving _faster_ from another satellite (on the opposite side of the sky), assuming the receiver is not diving down into the Earth. And you can't do that because you can't predict the timestream.
The receiver should be able to detect this inconsistency and try to filter out the faulty signals.
To make this attack feasible, you need to "prime" the receiver by delaying ALL the signals, but that is only possible if you control the initial timestamp sync.
Hence first slowing down everything for a while so the attacker has some headroom for the signals they would need to speed up.
Alternatively, just slowing down some signals more than others would still amount to a global slowdown, with some signals being sped up and others slowed down relative to the sum. If all signals drift into the same direction simultaneously, a receiver would just interpret this as its own non-precision oscillator running slightly fast and adapting, right?
Even if feasible, this would still be a much weaker threat than that of a completely attacker-chosen location, velocity, and time, but it could still be catastrophic (imagine e.g. introducing a gradual shift to an aircraft's navigation system and nudging it across an international border that way).
This is true, but the Russians have demonstrated that combining this with jamming they can make this still possible (along with other tricks). Obviously there's going to be some back and forth movement via countermeasures and updates, but the west has only very recently woken up to these threats.
The key issue here is bypassing the time synchronization requirement during the cold start. This has always been a problem with OSNAM, and it's impossible to solve completely. The workaround is clear, the receiver just needs to do an external clock synchronization without relying on GNSS. Something like NTP is more than sufficient for that.
The attack in the paper also assumes that the attacker has complete radio control and can jam ALL the signals. If the receiver gets even one fully authenticated stream from an actual satellite, then the initial timestamp spoofing will fail.
Replay attacks on tracking receivers are not particularly powerful either, they will be apparent within 10-30 seconds.
Russia is like a kid playing with matches. I'm a noob when it comes to aviation, but AFAIK RNAV GPS approaches are quite common? Disrupting that is dangerous.
Russia keep seeing what they can get away with and then push harder. Since nobody is willing to apply enough meaningful punishment due to fear of escalation, and they successfully propagandized/bought the US Republican party, they're winning on this axis.
More sanctions should have been imposed when they shot down a passenger plane and killed several hundred Dutch civilians.
True, the cheapest option was always to hid hard with sanction on Russia as early as the first Chechen war and establish backup for Russian energy. But instead, Germany still build Nordstream after Georgia.
German politics was clearly heavily compromised as well, beyond the basic self interest of cheap gas. See Wirecard and Jan Marsalek.
The interesting question is how compromised British politics has been. Lots of very suspicious things (secret Boris Johnson meeting against the advice of security services; appointment of Lord Lebedev), but UK support for the Ukraine war has been unwavering.
Yeah, and its leadership held to account; for some reason the results of the investigation was that a number of individuals were marked as suspect, while IMO the entire military leadership all the way up the chain should be held accountable.
I really hope this war ends, and ends up with Russia paying for repatriations, including this case.
Unfortunately I don't see the reparations coming about without the war getting much, much larger first, like a EU-NATO ground invasion of Russia. Which violates a whole load of red lines and would get a lot of people killed. But maybe Russia will force it to happen regardless.
(what is happening is turning the asset freeze into asset seizure, but this is complicated - rightly - by human rights law, because most of the assets are nominally private)
And they have for years now. Invaded / occupied Crimea with a slap on the wrist at best. International cybercrime for at least 15 years now, probably longer, but they get plausible deniability because it's not officially state doing it (even though we know they are).
But outside of Ukraine, none of it crosses physical borders; the sabotage of undersea cabling is all done in international waters, the internet is some kind of free for all as well, etc.
What should have happened is that the international community stepped up and sent a clear message, like "Russia will be cut off from the internet if they do not stop their digital attacks". Boundaries mean nothing if there are no consequences to violating them.
RNAV are less common than people think, and given the limitations appear to mostly be used as secondary help in conditions where one could possibly go by vectoring.
Losing them however does drop capacity because now you need extra work to get planes to final.
Russia is playing with matches since NATO allows for this. It would be sufficient if in Kaliningrad Oblast or in Petersburg NATO forces jammed GPS/Glonas/Beidou and, as a bonus, also VAR system (much more important than GPS for aviation) and next day Russia would apologize and never try stupid games again.
I don't think there is any direct claim for this. But you will find lots of old research about optical flow measurement for navigation. Optical flow sensor part of https://en.wikipedia.org/wiki/Optical_flow seems like a good start.
Satellite guided approaches are used when there is no visibility, so I don't know how that would help. You could use terrain-matching radar for navigation, but that would require additional equipment on the airplane. Every plane already has GNSS receivers, so implementing RNAV is basically a software feature.
Before the GPS era (military) planes had inertial navigation systems, why can't civilian planes have something like that as a backup until you get in range of a terrestrial navigation radio tower - those are still in use, right?
Commercial airliners have this for a long time. Early 474 models have it.
And VOR (VHF Omnidirectional Range) beacons are still used.
Many of the systems used are much older than people realize. Airports had ILS (instrument landing systems) in the 1950s. Improved low visibility versions started coming out in the 1970s.
A lot of these systems are being phased out. Lots of airports now have GPS only approaches where they would have had an ILS systems in the past. The bigger airports still have more advanced ILS systems for landings in extremely limited/no visibility but also have GPS approaches.
A normal IFR approach has more relaxed minimums that you can get to with GPS so there are a lot of airports without any ILS system in place at this point. The GPS approach gets you down to minimums of something like 200 feet above ground at which you either have the runway in sight or abort the landing.
Likewise, VOR radios are slowly being retired and increasingly used as a fallback only. GPS systems in planes have been common for since end of last century. ILS and VOR infrastructure is kind of expensive to keep up and running and increasingly optional.
I wasn’t meaning to apply that ILS was a sufficient alternative . I was using it as an example of tech technologies that have been around for a long time.
Navigation without GPS is not a problem for a commercial airliner. Landing without it in poor visibility is a different issue.
I think we need to separate issues here namely the threat types, one is jamming and another is spoofing.
As of jamming most probably the new clock will not help. But for spoofing it probably can be prevented and mitigated with the new clock, but the root cause is the pseudo-orthogonality of the spread spectrum.
To put it simply, in housing property market the main criteria are three namely location, location, location. Similarly in communication and specifically in wireless the main criteria are also three namely orthogonality, orthogonality, orthogonality.
It's interesting to note that all mainstream GNSS systems including GPS, Galileo, GLONASS, and BeiDou are using spread spectrum modulation system, and they all affected by the pseudo-orthogonality of the spread spectrum system. There's a reason why the newer 4G/5G, and even Wi-Fi have moved away from spread spectrum modulation that's was being initially used by 3G and 802.11b, respectively, by fully embracing OFDM. The reverse-engineered Starlink modulation is reportedly using OFDM as well [1]. This mainly because of spread spectrum limitations but at the time it's not due to spoofing (security) but due to bandwidth scaling (performance) limitations. For GNSS on the other hand, don't care about the bandwidth because it's for location service not streaming video, but the limitations of being pseudo-orthogonal eventually got to them in the form of spoofing vulnerability.
The next generation GNSS designers perhaps need to bite the bullet, and should employ proper orthogonal modulation (OFDM or others), not pseudo one like spread spectrum. Having highly accurate on board clock is a hacked solution at best, not a proper solution, and it just unnecessarily increase the upfront cost and maintenance complexity by being overkill and over engineered.
[1] Reverse Engineered Signal Structure of the Starlink Ku-Band Downlink (2022) [PDF]:
This is entirely wrong. OFDM is necessary for WiFi etc. in order to maximize spectral efficiency (i.e., bps per Hz for a given unit of radio spectrum) and mitigate multipath.
The main purpose of the GPS spreading codes is to prevent self-interference from the other satellites and to increase the effective bandwidth for the cross ambiguity function (i.e., to get a nice, sharp cross-correlation peak in the time-domain). The pre-spreading data signal is only ~50 bits per second, so spectral efficiency is not a primary concern.
>For GNSS on the other hand, don't care about the bandwidth because it's for location service not streaming video, but the limitations of being pseudo-orthogonal eventually got to them in the form of spoofing vulnerability.
Please check my original comments as above.
Granted, it's still perhaps feasible to spoof OFDM system but it'll be much harder to pull off compared to the pseudo-orthogonal spread spectrum system [1],[2].
[1] Secure OFDM System Design and Capacity Analysis under Disguised Jamming (2019):
For one thing, the scale of Russia's interference is probably close to 100x as many aircraft being affected. Maybe 1000x or more if you consider the total number of aircraft affected over the past 3 years.
How bad is the best inertial navigation is? From what i see it would be pretty sufficient for civilian aviation (for fighter jets doing bunch of turns, etc. that would be different of course) to get into the vicinity of the destination airport. Add correction by stars/Sun - any plane on long flight would get above clouds any way - and you'd get the precision of a modern ICBM - like 30m or so. Who needs GPS then? :) May be it is the time to make a startup to produce such a navigational device?
As a particularly egregiously fragile aircraft, the Embraer Phenom 300 isn't certified to fly into areas without functioning GPS because it affects flight stability. QNS can't happen soon enough and hopefully the consumerization and miniaturization of strontium optical lattice clocks too.
be interesting to see, what just caused two large ships to collide off the English coast, in a known
and busy area
ships on fire, more than 30 rescued so far
The title is clickbait. It implies hacking the plane's hardware, which is not occurring.
GPS jamming is unfortunate, but relying on U.S. GPS is foolish anyway (as the article also points out).
Planes still have inertial navigation systems. It worked before GPS, why not now? GPS for tracking phone users should go away anyway. If you are in an unknown city, but a damn paper map. No tracking and you absorb the big picture much faster.
> GPS for tracking phone users should go away anyway. If you are in an unknown city, but a damn paper map. No tracking and you absorb the big picture much faster.
Regular GPS is receive-only. GPS receivers naturally cannot be tracked. Tracking happens much higher up the stack, such as with your map app downloading local map tiles for display. Technology-wise, it's trivial to have a smartphone based map that is tracking-free, and the privacy focused alternate phone OSes do this already.
I have an amateur built experimental airplane, and on my first flight, GPS wasn't working. It was working on the ground, so I figured a bad coax cable or something from the vibration. When I landed it started working again, but later in the day it wasn't. A few days later I found out that the nearby Air Force base was testing GPS jamming, and there was even a NOTAM about it.
There's a site that tracks GPS jamming: https://gpsjam.org/
Wanted to highlight how GREAT the FAQ section is on that page. It feels like each question on that list is one that the author actually received and answered in an easy to understand format.
Makes me wish for the early days of the Internet where FAQ writing was good practice and writing a great FAQ was considered something worth celebrating.
Thank you! I haven't updated that page in a long time, and there are a few things I should add. Some possibilities:
* Does this map show spoofing? No.
* How come sometimes I see aircraft flying over Ukraine? That's GPS spoofing.
* [Add Myanmar & Kashmir to the list of conflict zones.]
I wish that website had some kind of timelapse functionality. It would be very useful to see how jamming in an area changes over time.
I'm thinking about adding that. (Donations help, see the About page.)
There are multiple sites that try to infer whether jamming is happening.
https://gpsjam.org/
https://spoofing.skai-data-services.com/
https://www.flightradar24.com/data/gps-jamming
Ukraine is of course a huge hotbed of jamming, but every time I've looked, there's been jamming on the US/Mexico border and a bit north of Texas around an airbase.
There's also a lot of info available here: https://www.nstb.tc.faa.gov/
The apparent interference in Texas is almost always fighter pilots doing training. During aggressive maneuvering the aircraft fuselage can mask the GPS antenna, causing the aircraft to lose GPS accuracy.
Fighter jets emit ADS-B? I know it's only training, but I'm curious?
Go to https://globe.adsbexchange.com and once it loads, press "u" to show only military aircraft. You'll see bunches of helicopters, transports and tankers, trainers like T-6 Texans and T-38 Talons, and once in a while an actual fighter or ground attack aircraft.
adsb.exposed has a dedicated section on F-16: https://adsb.exposed/?zoom=5&lat=43.4805&lng=-110.7608&query...
Is it common practice to go flying without checking for a NOTAM that might impact your intended route? (I'm not trying to insult you or anything, I'm not a pilot and don't know the standard procedures for dealing with those.)
Should you brief the NOTAMs? Yes. Is it common to miss one? Also yes. Go look at the ATC YouTube channels and you will find lots of people being intercepted by fighter jets even though they use Foreflight.
Another problem is NOTAM spam; it seems like, in some areas, there are a bunch of NOTAMs that aren't very important but that you still have to read through to see if they're relevant. "We're testing GPS jamming" or "we will send a fighter jet if you fly into this rectangle" look a lot like the more common "taxiway T at Middle Of Nowhere Municipal Airport is out of service until 1/1/2038".
"One lamp out of 18 on this radio tower is operating at 75% brightness" repeated every day for years
Could be a good opportunity for using an LLM to summarize and extract anything important?
Here’s a critical NOTAM that was missed. Translated, it means, if you fly here, the Russians will shoot your ass down. And so they did. But nothing encodes that information in the NOTAM so there is nothing for an LLM to summarize and extract. Expecting an AI to compensate for poor system design is magical thinking.
A1492/14 NOTAM Q) UKDV/QRTCA/IV/BO /W /260/320/4822N03807E095 A) UKDV B) 1407141800 C) 1408142359EST E) TEMPO RESTRICTED AREA INSTALLED WITHIN FIR DNIPROPETROVSK BOUNDED BY COORDINATES : 495355N 0380155E 485213N 0372209E 480122N 0370253E 471352N 0365856E 465018N 0374325E 465900N 0382000E 470642N 0381324E THEN ALONG STATE BOUNDARY UNTIL POINT 495355N 0380155E. RESTRICTION NOT APPLIED FOR FLIGHTS OF STATE ACFT OF UKRAINE. F) FL260 G) FL320)
Besides that, would the developer of the LLM accept liability for accidentally filtering out important NOTAMS, or hallucinating NOTAMS that did not exist?
For those who can't read NOTAMs: This is a NOTAM that was in effect during the MH17 shootdown, closing the airspace from FL260 (26,000 feet) to FL320 (32,000 feet.) In the previous three months, 16 aircraft were shot down in Ukrainian airspace, including one three days before at FL210, which is what prompted the NOTAM. Ukrainian officials should have closed the airspace entirely, but chose to keep it open and issue this NOTAM instead. MH17 was at FL330, so in fact it did not violate this NOTAM at all.
And for some further context: the quote upthread of "NOTAMS are a bunch of garbage that no one pays any attention to" from NTSB chairman Robert Sumwalt came after Air Canada flight 759, which would have had >1000 fatalities if two airplanes were a few feet closer: https://en.wikipedia.org/wiki/Air_Canada_Flight_759
I mean, I just copy/pasted that into ChatGPT with no other instructions or context, and it seemed to handle it pretty well:
This NOTAM (Notice to Airmen) establishes a temporary restricted area within the Dnipropetrovsk FIR (Flight Information Region) in Ukraine. The restricted airspace is defined by specific geographic coordinates, forming a boundary for the restricted area.
Key details include:
- *Effective Dates:* From July 14, 2014, at 18:00 until August 14, 2014, at 23:59, with the "EST" indicating that the end date might be subject to change.
- *Altitude Limits:* The restricted area applies to flights between FL260 (Flight Level 260, approximately 26,000 feet) and FL320 (approximately 32,000 feet).
- *Exemptions:* The restriction does not apply to flights of state aircraft of Ukraine, meaning those aircraft can operate within the restricted area during the specified timeframe.
Pilots and airline operators should be aware that flights not exempted by this NOTAM must avoid this area or adjust flight levels accordingly to comply with the restrictions. For further guidance, they should consult official aviation authorities or current NOTAM listings, considering the potential for changes.
FWIW, this exact text was probably part of ChatGPT's training data, but the next important NOTAM might not be.
Perhaps. It would be easy to past in an arbitrary one and see how it does. I'm pretty sure it has information on how to decode these in general in it's training set.
That would be impressive because there isn't a standard format for NOTAMs. They are intended for humans, not machines. It's a major problem that safety critical information is often not available in machine readable format, so you can't have a plane's navigation system automatically give warnings if you program it to fly into restricted air space or to a navigation beacon or runway that is announced as offline for maintenance by NOTAM.
I have an AI-powered NOTAM mapper at https://notam-mapper.obliscence.com. It's just intended for fun, but you can try pasting arbitrary NOTAMs into it and check the results.
That looks less like poor system design (although I'm sure that's contributing) and more like understatement that's practically criminal. Who the hells hears "Russia may shoot down your plane if you go here" and thinks they should convey it via "tempo restricted area bounded by coordinates"? That's like posting a "do not enter" on a door with a bomb behind it. Is English so hard?
For pilots, "restricted area" is already synonymous with "absolutely do not even think about going here" and is used for things like military testing and training areas that regularly use live ammo, extremely sensitive military or bases, etc. As a concrete example, Area 51 is in a "restricted area".
> For pilots, "restricted area" is already synonymous with "absolutely do not even think about going here"
I don't buy it. How often do you hear of a passenger plane getting shot down for entering restricted airspace over peaceful territory like the US? What about over combat zones, like over Ukraine or Russia? Who in their right mind equates these as as equally severe? If you had to make an emergency landing would you seriously view these equally?
At least within the US, entering a restricted area without authorization can result in your own personal military air show, followed by lots of questioning, possibly prison, losing your license or both. You don't mess around with restricted areas unless you have a damn good reason.
>> I don't buy it. How often do you hear of a passenger plane getting shot down
> At least within the US, entering a restricted area without authorization can result in your own personal military air show, followed by lots of questioning, possibly prison, losing your license or both. You don't mess around with restricted areas unless you have a damn good reason.
You're not taking my point.
I don't know about you, but I would sure as hell prefer prison over myself and hundreds of other people falling from 40,000 feet.
When I'm flight planning and I see a restricted area along my route, I honestly don't need to know why. I'm not going there unless the controlling agency gives me authorization and I understand the danger. Because there is danger; otherwise it wouldn't be restricted.
If it makes you feel better, here's the current TFR over eastern Ukraine. It even explicitly says "danger" - does that make you feel better?
TEMPO DANGER AREA ACT WI COORD: 434800N0392400E-433000N0303500E-441500N0302500E-...
> ...I would sure as hell prefer prison over myself and hundreds of other people falling from 40,000 feet.
On the one hand, that would be ideal.
On the other hand, that appears to be a NOTAM restricting access to an active war zone. It is truly tragic, and should be avoided whenever reasonably possible, but sometimes civilians who enter war zones get killed.
So, (just so you know) the "they flew into an active war zone" bit is probably the reason why your point is being brushed aside. Restricted airspace is restricted airspace. Unless you're on the unrestricted craft list, you simply don't enter it.
To my reading it's very understated if that is the entire text of the NOTAM - I would have liked it to say WAR ZONE or GUIDED MISSILES in there somewhere.
Compare it to the DC SFRA[0] which specifically states "MAY USE DEADLY FORCE" even though that's extremely unlikely to happen.
When Flight Restrictions are active in FAA controlled airspace, ATC will often clear you through them if you're on an appropriate flight plan without you needing to ask. Even the 'deadly force' SFRA above is essentially handled for you so long as you file an IFR flight plan.
[0]: https://www.faa.gov/air_traffic/publications/us_restrictions...
There are more risks than getting shot down. All sorts of dangerous activities may be going on in restricted areas: missile launches, dogfights between fighter jets, tests of unmanned vehicles, etc. You don't want to be a surprise guest at any of them. "Restricted" is a single, short word taught in pilot school to get the message across clearly. If a sudden emergency requires entering a restricted area, then air traffic controllers are there to coordinate it.
NOTAMS are a bunch of garbage that no one pays any attention to. That’s not my opinion, that’s the opinion of former NTSB chairman Robert Sumwalt. I’m sure the GPS NOTAM was buried somewhere in the 27 page NOTAM list and it probably said something like this actual current GPS NOTAM: !GPS 03/022 GPS NAV PRN 08 U/S 2503061847-2506050001
https://www.ainonline.com/aviation-news/business-aviation/20...
I was flying in and out of a private airport in uncontrolled airspace, so I didn't check. If was my first test flight so I was pretty much just circling around my airstrip.
If I'm flying cross country, in to controlled airspace, or an airport I'm not familiar with, I will. But this particular notam didn't show up when I looked at nearby airports.
This map is great,very interesting. curious that GPS is jammed over Gdansk, Helsinki and Tallinn.
Russia has been jamming GPS over Finland, Estonia, and Poland on and off for a couple years, and it's been at its peak now for several months. Sometimes flights have to be canceled. Tartu airport in Estonia was closed for a while[1] because the only instrument approaches it has were GPS-based.
Even worse than jamming is spoofing, which Russia also does. With jamming, you and the aircraft's systems both know what's happening. Spoofing isn't as easy to detect, as the GPS system can report the wrong location but think it's highly accurate. Spoofing (and to some extent jamming) can have a persistent effect on aircraft systems even after they move out of range of the jammer/spoofer, which can lead to degraded navigation accuracy for the rest of the flight.
It's a whole deal. Russia is messing with strategically important systems of many European countries, and decreasing civilian aviation safety, and they rarely get called on it. For a long time there was reluctance to even name Russia as the culprit.
1. https://www.heise.de/en/news/GPS-jamming-no-more-flights-to-...
> Russia has been jamming GPS over Finland, Estonia, and Poland on and off for a couple years, and it's been at its peak now for several months. Sometimes flights have to be canceled.
I feel like we had airports before we had GPS. If this is a regular thing, shouldn't we have ways of using the airport without hoping that the jamming is having an off day?
What do you mean "if" of course we do? Relying on older methods means narrowing the acceptable conditions for landing. It means reduced economic activity, reduced opportunities.
How about we treat enemies as actual enemies, rather than rolling over and letting them make our lives more difficult?
In comparison to the US's power, Russia is an annoying pipsqueak, but instead we are letting Russia boss around on everything. It's shameful and embarrassing.
Why in the world should we have to rely on inferior methods?
You're suggesting open war with Russia over GPS jamming? You do understand that the west also engages in sub-war, antagonistic activities with Russia, right? These aren't "inferior methods", they're part of spectrum of activities which have associated costs and risks.
Europe has about 5 functioning fighter aircraft and ~~20 operating tanks at any given moment. It is also completely controlled by a political system that considers conflict the same way it sees domestic abuse in a relationship. It's entire current zeitgeist is formed and controlled by the half of humanity that cant fight and will spend as much time as possible trying to talk their way out of it.
Your narrative on Europe is wrong. Poland has 1000 tanks and would completely wipe out Russia in a war. United, Europe could eliminate Russia's military with a few percent of GDP, full war footing is in no way essential.
They are nobles arguing about who has to take time away from the dinner party to shoo away a miscreant throwing tomatoes. Except for the Baltic States, who take it more seriously at the moment, but that will change as soon as the Vatniks on the political extremes are finally removed.
even assuming Poland could do this, what do you think Russia would do nuclear wise if they were faced with imminent destruction? Did you forget that we live under the sword of Damocles?
Additionally, good luck finding young men who want to fight for their country in the west of Europe. New arrivals will not lay down their lives as they often hate their host countries and people. Heritage Europeans are massively discriminated against by their own governments for speech crimes, on top of race and sex-based discrimination. A very small amount of men will fight to continue that state of affairs.
First, Poland is a NATO member.
Second, Ukraine is invading Russian territory, occupies it, and no nukes yet! The supposed nuclear threat is empty and stupid.
Third, if you think for a fucking microsecond that 90% of Polish men are not ready to go to war and kill Russians you have never talked to a Polish person. They know what is at stake.
Fourth, even the UK is talking about boots on the ground and planes in the air over Ukraine, https://breakingdefense.com/2025/03/amid-us-rift-with-ukrain...
Fifth, fighting these completely made up narratives that have no basis in reality is exhausting. It's almost as if an entire population has decided that they misread the commandment to be "Though SHALL bear false witness."
Poland is a NATO member, but we're not going to war if they invade Russia and then get nuked.
UK is talking about boots on the ground. Wake me up when they actually have a sustained, large-scale presence.
Europe has paid Russia more (for their natural gas) than they have given aid to Ukraine during the duration of this war. Europe is totally cooked.
> How about we treat enemies as actual enemies, rather than rolling over and letting them make our lives more difficult?
Treating someone as an actual enemy means accepting that sometimes they're going to do things that are inconvenient for you.
> Why in the world should we have to rely on inferior methods?
Well...
treating someone as an actual enemy means accepting that sometimes they're going to do things that are inconvenient for you.
And they are going to also experience "inconveniences" for random bullying.
Ignoring what a bully does has predictable consequences.
Yes, I'm reminded of how woefully the teachers at my grade school tried to stop bullying by... making them sit together and talk through a script. Usually finalized by a knock on the head as they were walking out, having perfectly finished their "remediation". I'm also reminded of how quickly problems were solved when you simply disobeyed the adults and hit them back. It got results. You might say that a grade school is very different than the world state. You might
Yes, some might.
And other, far more wise people, might realize that appeasement of bullies throughout history has resulted in some of our very worst wars and the most horrific atrocities that humanity has ever committed. Weakness invites conflict and destruction from the bullies of the world, and when it comes to war, the bullies gain materials and conscripts when they are allowed to conquer.
(I think we are very much on the same page, thank you for the comment.)
There usually are other systems (e.g. ILS), but not always.
This post has several comments along the lines of "We used to fly without GPS and it was fine!" The fact is that aviation is so much safer than it used to be, and GPS is part of that. GPS helps aircraft navigate accurately even when they're not near an airport. It helps give situational awareness and avoid mid-air collisions (almost every aircraft these days has a traffic display that shows ADS-B positions of other nearby aircraft, and those positions come from accurate GPS).
Loss or spoofing of GPS isn't usually a critical safety issue on an aircraft, but it definitely removes layers of safety and adds additional risk. Pilots can lose that situational awareness of nearby traffic. They may have increased workload and distraction due to having to use a less familiar & less accurate means of navigation, trying to figure out why their systems aren't working correctly, and even getting bogus ground proximity warning system alerts. ATC may now have increased workload and distraction because some approaches or even runways are no longer usable.
We drove cars for a long time without seat belts and air bags, too.
> We drove cars for a long time without seat belts and air bags, too.
And if we were having problems with seatbelt jammers, everyone would instantly respond by just not using seatbelts in those areas. There would be no road closures and no trip cancellations. What are we supposed to learn from this analogy?
That aviation without GPS isn’t as safe as aviation with it.
I don't even think that's true. Seatbelts are an improvement in safety regardless of context. But what you're arguing here is that a system that's designed to rely on GPS availability, and gets it, is safer than the same system during a GPS outage, not that GPS availability will make any airport management system safer.
It makes it safer to run aircraft closer together. Most airport capacity increases these days come from optimizing airspace, not from new runways or airports, which are time consuming, expensive, and controversial. We used to operate without them but we were also generally operating a lot fewer flights back then.
The more apt analogy is what would our roads look like if all traffic signals stopped working? People would still drive, but it would have to be at lower speeds, with more congestion, etc.
> The more apt analogy is what would our roads look like if all traffic signals stopped working? People would still drive, but it would have to be at lower speeds, with more congestion, etc.
This happens pretty frequently with single signals, so we know what that looks like.
An unattended broken signal gets treated like a stop sign (by law), and this immediately blocks traffic. It's a total disaster.
If it happens anywhere near a population center, a human will be dispatched to cover for the broken signal and dysfunctional law by manually directing traffic, and this gets you almost all the way back to normal.
If every signal failed at once, that would cause much bigger problems, but in the event that we know we're unable to repair the signals, which is the case here, we wouldn't just try to muddle through using the existing roads and systems. We'd define new systems that worked better in the absence of traffic lights.
I was mostly addressing the idea expressed in other places in this thread that aviation without GPS is fine, not your specific point. To address your question, the commercial aviation world is still in the process of figuring out how to deal with the new, current reality of GPS jamming and spoofing. They're developing new procedures, designing new equipment, and changing priorities and plans. While this happens they're downplaying the risks in press releases and statements to avoid spooking the public.
"If this is a regular thing, shouldn't we have ways of using the airport without hoping that the jamming is having an off day?" Yes. But it takes time and money. This level of GPS interference is relatively new, and for about the past 30 years you could basically assume GPS would be available.
Yes, airports in eastern Europe are now using the old ground based VHF radio beacons (VOR, DME and ILS).
However, they were not in use a few years ago. Some airports never had the ground based equipment installed, others still had the beacons functional but the procedures (STAR, SID) had been phased out in favor of the easier and cheaper satellite based GNSS RNAV procedures.
Some airports had brand new VHF equipment installed, others had the old procedures reinstated.
But aviation is a slow moving, risk averse, cost sensitive business so several airports were inaccessible (apart from visual approach) for a few months.
We become reliant on technology so quickly. Alternatives may not be safe in extreme weather. We have also torn down previous systems like Omega.
https://en.wikipedia.org/wiki/Omega_(navigation_system)
> I feel like we had airports before we had GPS.
one of the things that made GPS available for civilian use was the Korean Air Lines Flight 007 incident.
https://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007
Here's one: https://en.wikipedia.org/wiki/Bubble_octant
They are surely doing that because they want to divert NATO expansion westward /s
It’s because they’re next to Kaliningrad, that weird Russian exclave
Another way to see that geography is as approaches into Russia. Gdansk borders Kaliningrad, Helsinki and Tallinn straddle St Petersburg.
I’ve never seen a map that has each locality in its primary language..
It's the default OpensStreetMap style, which was never intended as a cartographic basemap for visualizations. Its purpose is to facilitate editing of the underlying data... but it's also one of the "free" options out there and integrated into most map library examples. ("free" because it's community-supported and heavy usage is discouraged, https://operations.osmfoundation.org/policies/tiles/)
GPSJAM had a non-free map for years that didn't have this issue, but as the site got more traffic I could no longer afford to pay for it.
That's fair! While understandably it isn't probably a top priority, I'd highly encourage checking out https://docs.protomaps.com/pmtiles/maplibre . It can be nearly free to directly hit a single planet pmtile file, especially with cdn in front, and slightly more to put up a server in front of it (imo, not needed).
Anyway, awesome site regardless, and OSM tiles are fine if not abusing their hosting (this isn't I'm sure).
What is that area to the right of India?
Myanmar, alias Burma. They're having a hot civil war since 2021. (They've had tensions and insurgencies for as long as they've been an independent state.)
Myanmar, which is currently a conflict zone.
> to the right
*East
Myanmar. Unstable autocracy, recent coup, ongoing uprising. A huge mess, and exactly where you'd expect the ruling party to be trying to eliminate navigation aids.
The article is a bit strange. While GPS can be used to receive accurate timing (phase correction once per second), for gps less navigation, even a picosecond accurate atomic clock wont really give any additional benefit compared to a wirst watch.
Using an accurate clock, you might be able to detect spoofing (by detecting small “jumps in time”). However, the same should be possible even with a non accurate clock (a few ppms) by detecting conflicts between the different satellites timings (since the “fake” transmitter is on earth, it will never be able to accurately simulate the real satellites’ airtime delays from space to your specific reception location).
On the other hand, if you pair a very accurate clock with a very accurate gyroscope, you might be able to replace gps altogether (https://en.m.wikipedia.org/wiki/Inertial_navigation_system) But from my knowledge, these kind of gyros are not really available for sale (but this is already outside of my knowledge, so maybe something changed).
> On the other hand, if you pair a very accurate clock with a very accurate gyroscope, you might be able to replace gps altogether (https://en.m.wikipedia.org/wiki/Inertial_navigation_system) But from my knowledge, these kind of gyros are not really available for sale (but this is already outside of my knowledge, so maybe something changed).
Dead reckoning systems are available with varying degrees of accuracy and drift depending on your budget. It's common to use them to guess location during GPS dropouts, such as driving through tunnels.
More accurate systems are available as budget allows and the military has a lot of research on this topic. Error accumulates over time, so the longer you go without a GPS reset, the worse the precision gets.
You can't fully eliminate the error accumulation over time, so they can't completely replace GPS. You still need some way to periodically refresh your ground truth position.
There is a YC startup doing this right now: https://www.ycombinator.com/companies/theseus
https://youtu.be/i1QRqu3Cocw
yeah, i don't get it either.
The clock is not the hard part of this. Oscillators doing 10mhz or 1pps with nanosecond accurate holdover for 24hours are easily available (for like 3k for chip-scale atomic clocks, and less for rubidium or whatever ).
Galileo et al also have publicly available cryptographic signatures so you can't actually spoof them, only jam them.
If you are trying to do navigation while jammed, the reckoning is the hard part of this, not the clock.
We solved the clock enough already.
> Galileo et al also have publicly available cryptographic signatures so you can't actually spoof them, only jam them.
Replay attacks still work allowing one to spoof location.
The first thing i said makes this sort of irrelevant, but to go down this path:
The replay attacks i'm aware of fall into two categories - cold start and warm start (mostly from https://arxiv.org/html/2501.09246v1, which has been in progress for a while)
The cold start replay attacks are irrelevant here - unless you can force-restart the gps receiver in cold start mode during flight. If you can do that, you probably don't need to spoof the signal. Especially since it requires precise timing to forge the new signal to the receiver at the right time (otherwise it detects it), etc. Seems like there are easier ways.
The warm start replay attack A. Requires you replay valid, but out of date, signals, in real time. This is non-trivial, and also limited in effect as you can only arbitrarily spoof one receiver to a location of your choosing - maybe you can get a few receivers with really good high-signal strength directional beaming of different replays, but it requires real-time tracking and adjustment of the signal of the target anyway to be able to spoof the location accurately.
Spoofing the location inaccurately is sort of pointless in most cases.
B. The attack has to change the time (and thus location) slow enough to not trigger various protections, then keep changing it slowly enough to continue that.
C. The attack requires that your receiver is too stupid to notice that a forced revert to non-authenticated time occurred, doesn't notify you of this, and then doesn't notice that time or location jumped suddenly by more than any reasonable amount. It also has to not notice that the SNR of everything suddenly changed, etc. Oh, also, they have to spoof all other sources of time, including local oscillators, etc, for you to not notice.
Given we just talked about how cheap and easy it is to have a high quality oscillator disciplined to time before takeoff, this kind of replay attack seems "practical" only in the sense that it is possible.
Are you aware of other replay attacks, if so, that'd be cool :)
Otherwise, yes, I agree you can spoof location in theory. I can't imagine a practical application of it in the scenario we are talking about.
Another thing that is being looked at are antennas (CRPA: Controlled Reception Pattern Antennas) which filter signals more, so that "GPS signals" that come from the ground and the sides are more likely to be rejected:
* https://rntfnd.org/2025/02/26/faa-moving-toward-crpa-on-airc...
One tripping point is that in the US, CRPAs are on ITAR, so exports are difficult:
* https://www.gpsworld.com/first-fix-freeing-crpas/
Given that GPS/GNSS comes from satellites, ignoring signals from not-from-the-sky seems like a quick win.
> Given that GPS/GNSS comes from satellites, ignoring signals from not-from-the-sky seems like a quick win.
You're right, but GPS antennas already have some rejection from the "bottom" hemisphere. So they're already rejecting not-sky.
CRPAs (of the type contemplated by ITAR) are electronically steerable antennas (phased arrays), that allow you to steer one or more nulls to the direction of the noise source(s). That gives much better rejection of point-source noise.
They're taking CRPAs off the ITAR list later this year, supposedly.
https://insidegnss.com/crpas-to-be-removed-from-itar-list-op...
Also, the Doppler shift of jamming/spoofing will be all wrong, unless they’re specifically targeting your vehicle and accounting for its speed and direction in their attack.
… if you can get the precision to filter that out…
GPS signals from low attitudes improve accuracy (to a point) because they provide much better triangulation. You want low attitude GPS satellites. You also don't want to lose signal every time the receiver tips, like when going up/down slight hills.
They don't lose signal when the receiver tips (which would make it useless for planes). They use antenna arrays to filter signals coming from directions they don't expect, too strong, etc.
These systems have been used used in military aircraft for a long time.
> triangulation
*Trilateration
One measures the time of flight of the satellites signal, not the angle it arrives from!
https://en.wikipedia.org/wiki/Trilateration
Magnetic-anomaly based navigation (MagNav) is a real thing that can solve this problem, and has been shown to work with the accuracy of a few hundred meters. Perhaps the government and defense contractors should look into this technology more. With a few more years of funded R&D and FAA-certification, I think its pretty likely that we'll see some of these systems on planes soon. The military is already flying with it during their exercises.
disclosure - I do work on a team developing MagNav, but much of the seminal research has come out of the Air Force Institution of Technology. They performed it on an F16, paper results shown here https://ieeexplore.ieee.org/document/9506809
It’s not uncommon to fuse magnetometer with other sensors. We did that for indoor navigation at Apple. In fact, we had prototypes that used only magnetometer and it worked fairly well for what it was but the low update rate and poor resolution meant that it worked to like 10-30 meters which wasn’t usable for indoor by itself. Of course, for indoor there was a lot more “texture” indoors for the commercial magnetometer of the time to pick up whereas outdoor it gets trickier. Is that similar to how MagNav works just with higher quality more sensitive magnetometers?
So the role that magnetometers play in sensor fusion w/ IMU data is for yaw/heading/magnetic north estimation. In short, it aids your orientation (RPY estimate). However, with MagNav, they play a large role in supplying information that allows you to decrease your drift rate.
https://www.sagemotion.com/blog/how-does-imu-sensor-fusion-w...
I find these sorts of alternatives to what I'll call 'adversarially contested technologies' super interesting. Jamming drone control and video links is another similar instance where alternatives like MagNav could prove useful by allowing autonomous fallback operation in the case of signal loss. I assume viable solutions will probably require a fusion of approaches like MagNav, optical terrain following, laser altimeter, etc
We're working on making MagNav a one stop shop backup for GPS. I think to cover ALL cases however, you'll need other technologies. TERCOM, visual, and celestial all have their niche use cases.
But for most cases, MagNav should do the job. Happy to answer more
Well, since you were kind enough to offer...
1. Roughly how long does it take for MagNav to get a "lock". For example, GPS takes 10 or 15 seconds (at least consumer stuff I have access to). Also, with GPS the accuracy improves if you're moving. I assume it may be similar with MagNav but it would be an interesting advantage if MagNav got a lock super fast vs GPS and/or it was basically at 100% resolution without needing to move (and I understand MagNav's "100%" res is much lower than GPS).
2. What's your drive-by guesstimate on probable future evolution of MagNav tech on the 'Four Horsemen' of mobile tech (size, weight, power, cost)? For example, which of the four are more like "No reason it can't improve a lot if given sufficient time, funding and development with no new science required" and are more "Well, physics/materials are currently an unsolved, seemingly fundamental barrier to improving beyond X threshold." In a perfect world... (the one we don't live in), MagNav would be on a five year productization track that'll put it inside an Micro SD card footprint with negligible power budget at 25 cents/ea by the million and be common in small Costco drones as a fallback if GPS fails.
Also, nicely appropriate username :-)
1. MagNav needs to be done continuously over a trajectory. Like GPS, it actually needs to be fused with INS data to work. Also GPS actually takes longer for a good lock on. What your phone is actually doing is sensor fusion (GPS + wifi, onboard accelerometer and gyro, etc.) and caching of the satellite information in order to produce a best estimate immediately. So when you first get a lock it takes a while even up to 15 minutes depending on the environment. Afterwards your phone/receiver tends to remember what satellites there were in the trajectory. It's a background process thats constantly running. We've experienced this first-hand in our experiments.
2. Since I work for a company in this area, I can't say too much, but SWaP is definitely going to decrease. Right now I think you could decrease size to a midsize cereal box. I don't think a super accurate version would exist for phones yet. Power consumption is somewhat low, but you need a serviceable GPU and RAM, like an Apple M3 to run things. Power consumption will improve with improvements in compute.
I think cost is the most prohibitive of them all, because quality magnetometers and INS are not cheap. > $20K per unit at least. i'm not talking MEMS grade stuff you see in phones and student projects, I'm referring to Tactical/Navigation grade—the stuff you see on military platforms. I think you'll see MagNav on military planes much faster, due to their mission-critical needs. For commericial planes to use them at scale, one needs FAA clearance which is a bottleneck for good and bad reasons.
We're not in a perfect world yet. MagNav will take some time to develop. What I think is missing is a larger community to work on this issue. There isn't that much motion in the space. Less than 5 serious players in the game, IMO. There also aren't that many suppliers who make the parts (magnetometers, etc.) you need for MagNav.
Lots of more thoughts here, but if anyone wants to chat more, contact me at sir.claude.shannon@gmail.com
Thanks for taking the time to answer. That was a perfect level of detail to give me a broad, high-level vibe on MagNav. And the answers are about as I expected. Approaches which serve as an alternative to a ubiquitous, cheap, COTS tech (like GPS), are interesting. They're usually driven by highly specialized use cases where the cheap COTS default isn't always quite adequate and there's a small but meaningful number of customers with challenging requirements and deep pockets.
I imagine larger military drones which need to navigate autonomously for extended periods over denied environments in all conditions are very interested in MagNav as a component in their sensor fusion suites. Even narrowing the current position to less than a square kilometer would make the identification problems faced by other sensors like optical much easier to solve.
> Air Force Institution of Technology
I've never heard of that - what is it? What's it like to work with them (if you did)?
It's the Air Force's higher ed institution. They offer masters and PhDs. They have their own labs doing R&D.
If you had to break it down to the essential parts, how much would it weigh? Do you rely on having measured the area you are flying in previously?
Currently 20-40 pounds right now, but we're working to reduce the SWaP. MagNav does rely on having accurate magnetic anomaly maps, which the government and certain private companies have access to.
Are those anomalies change over time? Do you have to continuously update those devices with the latest maps?
They change over geological timescales—so not anytime soon. We're talking millions of years, w/ movement of tectonic plates and such. So for right now, once an area is mapped, its mapped for good. HOWEVER. Maps may need to be redrawn if the quality of them sucks.
> The Boeing 737 MAX 8-200 had already descended to around 850ft (259m) when the disruption occurred. Instead of landing, the plane was forced to climb back into the sky and divert nearly 400km (250 miles) south to Warsaw, Poland. Lithuanian air authorities later confirmed the aircraft had been affected by "GPS signal interference".
GPS is incredibly flimsy. Normally it operates by taking the average of 1000 observations to generate a noisy signal. It's not that difficult to be louder than something shouting from space. You can pick up cheap GPS blockers easily about the size of a walkie-talkie (handheld radio).
> By carrying a group of atoms cooled to -273C on the plane itself, rather than relying on an external signal, the technology can't be interfered with by jamming.
Last year I was on a plane where if the engines were not running, it entirely went into darkness. They hooked the plane up to the airport and tripped the airport electrics too. Now imagine if your plane loses power momentarily, and suddenly your GPS stops working entirely.
> Henry White, part of the team from BAE Systems that worked on the test flight, told BBC News that he thought the first application could be aboard ships, "where there's a bit more space".
> Quantum clocks, gyroscopes and accelerometers are large, bulky and incredibly expensive, with an accurate quantum clock costing around £100,000. Yet military research is allowing the creation of smaller, better and cheaper systems.
Likely a minimum of 10 years from being viable. Mt White of BAE is politely saying as much.
Chip-scale atomic clocks based on cesium were demonstrated in 2003 with DARPA/NIST funding, and entered commercial production in 2011.
https://en.wikipedia.org/wiki/Chip-scale_atomic_clock
Apparently they're not even export-protected, despite their obvious use in GPS validation schemes and in RTK.
> The SA.45s CSAC has an Export Commodity Control Number (ECCN) of EAR99. This means it is not ITAR-controlled and does not require a special license to ship to most nations. The SA.45s CSAC classification is controlled by the Bureau of Industrial Security (BIS) within the US Department of Commerce.
The article talks about quantum "optical clocks" but doesn't really explain the concept.
Which appears to be this:
https://en.wikipedia.org/wiki/Quantum_logic_clock
Which, like many things named "Quantum", still doesn't really explain how you get an IMU out of it.
The article is deeply confused.
It’s true that optical clocks will improve the accuracy of our measurement of time, and it’s true that GPS depends on time, but there are several steps between primary frequency standards (ie, optical clocks) and GPS, and several more steps between GPS and navigation applications.
So optical clocks cannot, in fact, have any effect on the end-user perceived reliability of GPS.
For that, the best solution is to revive LORAN which is much less susceptible to jamming. (And would also benefit from better atomic clocks.)
Much of Finland and Estonia are currently being jammed per https://gpsjam.org/?lat=58.53948&lon=24.82400&z=4.9&date=202...
Finland is reintroducing DME: https://www.reuters.com/business/aerospace-defense/three-fin...
Which seems to be a different concept from LORAN, but still useful for navigation when multiple base stations are in range.
https://en.wikipedia.org/wiki/Distance_measuring_equipment
You can do about 5x worse (in accuracy terms) than a Cesium clock in a smaller package using a rubidium atomic clock. Average ~4 of these and you get to the same accuracy as a cesium clock. They aren't export controlled because they aren't that special in terms of what you get.
To improve instrumental accuracy by 5x in a single dimension when fighting against random uncorrelated drift/noise, from what I recall of statistics you require 5^2 = 25x as many instruments.
Yeah, I think you're actually right. I was thinking you double them with 2 (experimentally), so you double that again to get 4x, but my curve was pretty off.
They’re probably talking about this for quantum navigation
https://www.theguardian.com/science/article/2024/jun/15/lond...
The diamond-based quantum IMUs are a completely different appliance and a different application (dead reckoning).
High quality dead reckoning over a long duration + an initial fix solves the reliable instantaneous absolute fix. So different technically but OP is correct it would be relevant to the problem of solving GPS jamming.
It absolutely does not. Dead reckoning has error that accumulates over time, and even "high-quality" dead reckoning will be beaten by a crappy GPS fix very quickly.
The dead reckoning I’m referring to (and I suspect op is too and seemingly you are as well), is the work being done by the military in the usage of submarines that stay submerged for extremely long periods of time. The error accumulated is many orders of magnitude less than traditional accelerometers + gyroscopes over the same time frame. The point is you can dead reckon within your error bounds even when GPS is unavailable and the accuracy from fusion will beat GPS by itself (not that that matters for the applications we’re discussing). For the duration of a flight it should be well within the capabilities of such sensors to dead reckon accurately from a last GPS fix before blackout and OP is correct this would be a complementary solution to more accurate clocks making it harder to jam GPS in the first place.
Indeed it’s being examined precisely for this application:
https://newatlas.com/aircraft/quantum-navigation-infleqtion-...
> Now imagine if your plane loses power momentarily, and suddenly your GPS stops working entirely.
Now imagine your plane loses power momentarily and switches to a backup system... The exact same GPS every plane is using today.
Even further, you can loose your super accurate special crystal and simply fall back to “normal” GPS.
I don't really understand why the plane was diverted because GPS was jammed; I get that it's important for navigation, but not how it's required for landing when they're that close. There's (iirc) close range guidance systems, and of course visual ones (lamps, stripes, etc).
Not all types of approaches are available at all runways (or airports), and sometimes they are down for maintenance. Specific runways may be required due to wind, aircraft weight and runway condition and length. Most airlines ban "circling approaches" (using an approach to one runway end and then circling visually to land at a other) for safety reasons. ILS, which is probably the "close range guidance" you are thinking of, must be installed, maintained and calibrated individually per runway end. Visual aids cannot be used for approach if there is low cloud.
It is usual to be able to abort an approach and try again at the same airport using a different approach technology. But if the journalist wanted to find the most extreme example, it's not surprising that it happened at least once that an alternative wasn't available. This is probably "sampling bias"!
Note that final operational decisions are made by the aircraft commander. Aircraft do not "get diverted", except by decision of the "captain".
My understanding is it depends on the amount of visibility, plus what type of approach they were on. One type of approach, an ILS, has big radio transmitters pointing from the runway into the air and allows the plane (either pilots or autopilot) to get close enough to the runway without visibility, and with enough precision, to land. In many circumstances ILS isn't available and an alternative is Required Navigation Performance (RNP) which uses GPS plus a ton of other inputs to give some amount of precision to the same end. If they're on an RNP approach but suffer a reduction in navigation accuracy then I imagine it's a policy 'go-around'. Even if there's enough visibility it allows the pilots to brief a 'visual' approach before attempting it.
Considering it's below 1000 feet, losing GPS could indicate an "unstablized" approach and require a go-around, as opposed to losing it at a higher altitude where the pilot could have more time to safely switch to alternatives (other navigating aids or go to visual?).
Source: my guess after watching a lot of aviation YouTube videos......
For anybody who doesn't know, a "stabilized approach" is an approach with a constant angle and speed as the plane descends and lands. This allows the plane to keep consistent control settings (flaps, throttle, etc).
It's best practice/policy for all major airlines to use stabilized approaches and most/all require a go-around if the stabilized approach is interrupted (there are edge cases and exceptions).
Commercial air travel is very risk-averse. Best practice is that if something unexpected occurs, and you have plenty of fuel to spare, you go and and find someplace else to land.
Personally, I find it comforting that the plane was able to fly 400km more!
Hacked doesn't seem like the right term. It's jamming, being overwhelmed, not infiltrated in any way. Curious if others use this term in such a way?
The vast majority of people don’t know that GPS is only a one-way transaction anyways. They think most devices talk back to the satellites somehow.
> They think most devices talk back to the satellites somehow.
To be honest, I don't think most people realize GPS is coming from satellites in the first place. Most people simply don't think about how/why at all when using things.
The term used in industry is typically "spoofing."
https://www.u-blox.com/en/blogs/tech/gnss-spoofing-new-secur...
Spoofing is different from jamming. Spoofing is when you trick the receiver into thinking the position is one you fed it vs jamming is you preventing it from acquiring a signal at all. Jamming is much easier while spoofing can be more difficult if there’s encryption on the signal. Unfortunately I think commercial signals aren’t signed with a private key to completely prevent spoofing but I’m not 100% sure.
> Hacked doesn't seem like the right term
... and this term only appears in the headline, not (anywhere!) in the body text. Wonder if the author of the article intended that term to be used, or whether the (sub)editors put it in to help get more clicks?
lol, good point. I wouldn't doubt this as a cause.
Detailed summary from Ops.group, which is for pilots and flight planners.[1] It's really bad. They write:
Typical indications of Spoofing
Unlike jamming, a GPS signal is present, but it has fake information. False GPS position, time, and date information will be processed by the GPS receiver as being valid. As soon as this is fed to other systems, failure messages will begin.
• Rapid EPU or ANP increase
• GPS position and IRS or FMS position disagree caution message
• Aircraft Clock time changes, or difference between Capt/FO clocks
• Transponder failure: EICAS/ECAM “ATC FAIL”
• Autopilot turns aircraft unexpectedly
• ADS-B Failure/Warning
• Synthetic Vision reverting to blue over brown
• Loss of enhanced display, such as display of terrain on PDI
• Wind indication on ND is illogical or has a major shift - erratic groundspeed
• GPS position symbol on ND drifts away from the FMS and the IRS symbols
• Datalink (CPDLC, ADS-C) failure warning
• GPS information on sensor page shows unusual values: altitude, etc.
• Handheld GPS (e.g. Garmin, iPad) disagrees with aircraft GPS position
• EGPWS audible warning (‘Pull Up”)
• GPS 1 and 2 dramatically different i.e. more than 100 meters, which may also give an ECAM/EICAS GPS miscompare warning.
• Spoofing Alerting app e.g. Naviguard gives alert
• ACARS message from ground/ops advises of spoofing (based on aircraft downlink message with unusual values)
[1] https://ops.group/blog/crew-guidance-published-by-gps-spoofi...
If you can't receive signals from the GPS satellites because some country's military is jamming them, how does having an accurate on-board clock help?
Are they somehow able to determine position via dead reckoning? How does that account for errors from wind, vibration, etc. and compounding of errors over time? (I'm pretty sure dead reckoning is not a closed-loop system)
"Miniaturize a very accurate clock" seems like a fairly straightforward engineering challenge. "I can give you clocks as precise as you need, now design me a system that can give your coordinates in thick fog without GPS or any other external radio signals" seems like a much harder one.
Historically ships at sea could determine latitude through sun-sighting or stars, but longitude was impossible because they did not have a clock which was accurate enough
I doubt they're navigating using the sun an stars, but if the airspeed indicator is accurate, and you know you're heading, all you need is an accurate clock to determine absolute position since the last known good position.
> if the airspeed indicator is accurate, and you know you're heading, all you need is an accurate clock to determine absolute position
Airspeed gives speed relative to the air, not the ground. To compute ground speed, you also need winds aloft, which can be huge if the aircraft is operating in the jet stream.
Getting good data for winds aloft is difficult because there are a relatively small number of actual measurements, and everything else is model output with all the usual caveats.
But quartz is accurate enough for that, let alone a properly calibrated oscillator. So why is the article focused on giving planes atomic clocks?
Indeed. The article is a bit confusing on details. At the end it talks about accelerometers and gyros, but aircraft have been using laser ring gyros for decades. They now use gps because it is much more accurate.
The article does a poor job explaining, but seems to imply that they are working on replacing GPS altogether with a local system that relies on an atomic clock and quantum engineering. From what I can find, there are many approaches to this, including quantum gravimetry, quantum accelerometers, etc.
https://en.wikipedia.org/wiki/Quantum_sensor
It's not white noise jamming it's replaying with a delay, so the receiver is getting a meaningful signal.
Technically both techniques can be used for gps hacking. It also seems you can fake a gps signal altogether, because the public signal is not cryptographically signed, which surprises me (the only thing that makes sense to me is that the gps protocol doesn't have room for adding a signature, so it'd be a breaking change to the protocol).
When Israel was waiting for a retaliatory strike from Iran they jammed GPS in the region. I never found a clear explanation of how it was done technically, this would make total sense if their system also was targeting atomic clock signals rather than GPS itself to confuse incoming missiles or aircraft.
That does raise an interesting question though - do missles actually depend on the standard atomic clock signals? Maybe that isn't how they did it, that seems like a dependency you wouldn't want in a weapon.
GPS signals are atomic clock signals. The receiver triangulates its position by comparing the time delays between the signals originating from different satellites. The receiver itself doesn't require a good clock since it only compares signals with each other.
And you can even update your clock info from the GPS signal. So the only dependency is GPS or similar.
But would Iranian missiles even use GPS? Isn't accuracy limited for civilian use for precisely this reason?
No. The US stopped degrading civilian GPS accuracy in 2001[1]. Although the US retains the ability to degrade civilian GPS in specific target areas.
Regardless, if you’re building a long range missile, you need some ability for it to navigate. If you’re not using GPS, then what would you use instead? Additionally there’s nothing preventing you from using multiple navigation systems in tandem and fusing the results together, which is almost certainly what these missile do.
Sensor fusion reduces the impact of stuff like GPS jamming, but certainly doesn’t eliminate it. The over all system will be less accurate with fewer inputs, and if you’re the one faced with a high speed missile flying at you, I suspect you’ll take every edge you can get, regardless of how small the impact might be.
[1] https://en.m.wikipedia.org/wiki/Error_analysis_for_the_Globa...
>Regardless, if you’re building a long range missile, you need some ability for it to navigate. If you’re not using GPS, then what would you use instead?
US ICBMs and submarine-launched ballistic missiles use a combination of inertial and celestial navigation: in space of course there are no clouds to obscure the stars:
https://en.wikipedia.org/wiki/Celestial_navigation#:~:text=I...
Many cruise missiles use terrain contour mapping. In principle at least it seems like it should work for airplanes too.
A error correction technique I learned as a young land surveying assistant is to put a gps antenna on a known fixed point location. The delta between the fixed point and the point of measurement is cancelled out to get a more accurate read.
We did this to trial some new (at the time) surveying equipment when the primary equipment was optical. It would save time for really long measurements through the forest and mountainous terrain .
You can even subscribe to services which do this for you! There are a few companies with large-scale networks of fixed receivers, and you can get the observed offset from a node near you via the internet, usually via "NTRIP".
Getting correction data from a node a few dozen kilometers away isn't quite as good as having your own fixed base station a stone's throw away, but it's way more convenient and for a lot of applications plenty accurate.
GPS Accuracy used to be limited, but that ended decades ago.
There are rules about GPS hardware that say that they should cease working above certain speeds and altitudes for guided missile purposes. But that is a firmware issue. I’m sure the Iranians have figured that out if the are even using off the shelf hardware.
GPS signals are relatively low power (American GPS broadcasts at 25 watts and the signal is a tiny fraction of a mW at sea level). In theory, it's easy to pump out noise over it, especially the civilian frequencies that Iran would in theory be using.
Depending on the receivers and what (combination?) of GPS/GLONASS/GALILEO/BAIDU Iran uses, you could easily overwhelm them.
There have been cases of delivery drivers using jammers to stop companies from tracking them, only to interfere with airport landing systems, which is a concern as a lot of warehouses are near airports.
EDIT: power at ground level is miniscule
> GPS signals are relatively low power (American GPS broadcasts at 25 watts and are ~10-15W at sea level)
Did you lose 16 orders of magnitude for the sea level values? GPS signal strength on the ground is usually below -135dBm per square meter. That gives you a couple of femtowatts with commonly used antenna, if you're lucky.
Easy to jam doesn't begin to describe it.
Shit, you're right. I blame the time change.
My understanding is you just flood the spectrum at the frequency that GPS is operating at
GPS signals are weak since they come from far away
GPS (as well as most satellite) signals are weak because it's strong enough for line of sight even from so far away. They only transmit at 25W. Comparatively, an FM/TV signal will often broadcast at tens of thousands of watts and up.
I don't understand this article. If the GPS signals are jammed, what purpose does it serve to have an atomic clock on board your plane? You still need accurate signals with time data to measure against.
Am I missing something?
You can get a very accurate timestamp from GNSS. What lots of people do then is slave a PLL based on a local oscillator, to be able to get time between two GNSS captations. Or to be able to extrapolate when they have no GNSS signal.
Now suppose someone is spoofing your GNSS signals, it's pretty hard to replace a constellation with another one whilst maintaining time consistency for you. One way to detect spoofing is comparing what a local clock is saying to whatever the GNSS is giving. A local, unfudgeable, stable, accurate clock is a good reference for this.
The article is seriously confused. What you are talking about is easy - chip scale atomic clocks are easy to get. I can have one shipped to me today. Hell, i have one on a time card in my basement.
Assume you want it even super accurate.
Great, 3k for an SA65 https://www.microchip.com/en-us/products/clock-and-timing/co...
Holdover would be fine for even a very long flight.
Hell, even a good rubidium oscillator doing 1PPS will stay within 200 nanoseconds over 12 hours.
If you are trying to do navigation while jammed, none of these help you.
You still need good reckoning, which is the hard part
We done solved the clock problem enough already :)
I was under the impression (and from experience too) that the very stable oscillators were finicky and sensitive to temperature swings and in general costly to use properly in "hard" environments.
I'm happy to learn this is not the case for every good oscillator. TIL.
Ahhhhh, that makes sense. Treating this as security mechanism rather than an anti-jamming one.
As I read from book about gyroscopes, most sensitive achieve so fine accuracy, they detect daily Earth rotation and even yearly Earth rotation.
But when they speaking about near zero temperatures, looks like they talking about something like Rydberg atoms - extremely sensitive matter, which could be considered as nuclear scale gyroscopes, or quantum gyroscopes, or read more about quantum accelerometer.
And current inertial navigation could be used to calculate relative coordinates like automobile odometer, but from integrating accelerations. But classic accelerometer is just not fine enough, and at this place appear quantum accelerometer and quantum gyroscope.
And I agree, article is terrible. I don't know why they use so abstract language, when could just say, navy already tested quantum navigation.
To be more concrete, space rockets nearly all fly with inertial navigation, but they are extreme case, because most use only inertial navigation just few minutes (so all those classic gyros/accelerometers integrated errors are small enough to successful enter stable orbit, and then using some sort of radio or optical fine measurements and making corrections with fine engines).
Planes flights are much more lengthy than rockets - I think, typical ~40 minutes or more (most long I hear 20 hours), so INS could integrate huge mistake.
INS essentially was expensive and AFAIK once GPS became available started to drop off in use outside of military. And with GPS availability coinciding with switching to more modern integrated Flight Management System/Computer, a lot of planes simply don't have INS installed.
Your words are near to truth. Before GPS from nearly 1950s used LORAN navigation system, with similar to GPS principles, but used long waves and have relatively low precision - about kilometer at best.
https://en.wikipedia.org/wiki/LORAN
Before LORAN, used radio beacon navigation and star navigation (from Newton time), and good human navigator could achieve about 50km precision.
You could easy see signs of star navigation on good preserved old planes - they all have some sort of fully glass dome, or blister, to provide good near semi-sphere view. And sure, all those before-GPS era planes have separate navigator job position, sometimes shared with mechanic.
https://www.reddit.com/r/WWIIplanes/comments/59xfkz/pby_wais...
You could ask, how planes could fly with 50km precision? Answer is easy - at all plane routes built ground structures easy seen from air and last mile navigation become essentially visual flight, nothing more, nothing less.
On some places ground navigation structures preserved now, for examples:
https://en.wikipedia.org/wiki/Airway_beacon
https://en.wikipedia.org/wiki/Transcontinental_Airway_System
LORAN was mostly long range over sea, on the ground we had NDB, DME, VOR, etc all ultimately linking into "airways" for higher altitude operations where earth might be not visible due to cloud cover for example
> a lot of planes simply don't have INS installed
Perhaps in general aviation, but I can't think of any modern commercial airliner without an INS via the air data inertial reference unit.
Except ADIRU isn't INS.
The INS unit is separate and often has its own set of gyros and has to be connected as separate input to FMS or other navigational computers, same as connecting GPSes or other radio nav components.
For example the current model of popular Universal Avionics UNS1 series of NCU (navigational computer part of FMS) come with built-in augmented GPS receiversz but do not mention INS functionality at all even in extended models. Don't have access to manuals at the moment, but I'd expect to see INS as optional to connect over one of the external connectors on the MCU, as it was on the older models without integrated GPS
In that case, I stand corrected.
I had assumed that the ADIRU’s inertial reference data from its gyroscopes and accelerometers would feed into the FMS to provide INS capabilities in case GNSS was unavailable.
Many small planes don't have INS in typical meaning, but their pilot is INS computer, calculated approximate nav from air data (air speed + weather data + compass or radio compass).
I believe submarines navigate long distances using INS. I don’t know how accurate it is, or how often they have to make corrections using other data. But ballistic missile submarines can’t really use active sonar or surface with any frequency, so I’m not sure what other method they’d use.
> ballistic missile submarines can’t really use active sonar or surface with any frequency
Detect semi-surfaced submarine at night is really hard, if don't have intelligence data that it will surface on some non-random position.
From experience of Ukrainian war, my country have success with eliminating surface military ships, because have constantly monitoring their moves with satellites, but I cannot remember any case when semi-surfaced submarine was hit.
Are they not easy to detect on radar? Even during WWII, radar got good enough to detect submarine periscopes. It's hard to imagine that a partially surfaced submarine wouldn't have a significant radar return. That doesn't mean that they're easy to detect at long ranges, but I would have thought that partially surfacing or raising a periscope would be a significant risk to a submarine if the enemy knew its rough location.
At a guess, Ukraine probably can't deploy naval assets with powerful radar close enough to where Russian subs are operating. But an adversary with a more powerful navy might be able to.
> if the enemy knew its rough location
In these words you hit bull eye.
During WWII, submarines was just very special type of boat. You could check wikipedia about German u-boats - exist about TEN subtypes, from which only latest types have really significant underwater range, but all others was extremely limited in underwater activity.
But, surface ships of that time was even more limited, many could not achieve even half of surface speed of u-boat, so become easy prey.
But if you will try to find some artificial object on sea surface, that is really hard question. Just because sea is huge, so you need to check extremely large space in short time.
Radars are better to spot artificial object on sea surface than visual, just because radar easier to automate. But nothing more. Radar is also have problem of square distance, very similar to visual. So, as it is hard to spot partially surfaced submarine visually, it also hard to spot such sub with radar, because much less part will be on surface, so radar will have much less signal to detect.
Periscope size is nearly undetectable on surface, if it used carefully, just outside detection range of radar.
So, to conclude, Ukraine problem is, we cannot detect partially surfaced submarines on open sea, but they could fire missiles. Fortunately, Russians have very few submarines on Black sea, and after they was hit at harbors, their usage become very limited.
> But, surface ships of that time was even more limited, many could not achieve even half of surface speed of u-boat, so become easy prey.
Agree with most of what you said, but U-boats generally had top surface speeds under 20 knots and were thus slower on the surface than most naval vessels of the time. They could certainly move faster than most convoys, but they couldn’t outrun pursuing destroyers or corvettes.
> slower on the surface than most naval vessels of the time
That is point. I'm not agree about most, but will be agree if you say about many.
> they couldn’t outrun pursuing destroyers or corvettes
But problem was, navy have so huge deficit of ships, so some convoys was run without naval support.
Sure, if all convoys was supported with fastest ships with best commands, u-boats will be no problem anymore, and as I understand, once this was happen.
A big issue during WWII is that the submarines were trying to find and approach the ships in order to sink them - and the ships in turn were looking out for the submarines. The submarine is forced to be close to ships equipped with radar.
Ballistic missile submarines are a completely different story. They aren't chasing anyone. Their entire goal is to be unpredictable and stay hidden, so if there's anyone with a radar around they are just going to keep quiet and move somewhere else.
Finding a sub prowling a shipping route is quite doable. Finding a sub in the middle of the Pacific Ocean? Not a chance.
I must admit, I agree with nearly all you said. Problem is that Ukraine was weak, and nearly without navy, and civilian ships was unable to resist to Russian navy. And Ukrainian export was blocked, as civilian ships fear to run within range of fire of Russian navy.
When Ukraine got enough weapons to force Russian ships to stay at distance, situation changed dramatically, so export was unblocked.
I think, very similar things happen during WWII.
This is not about only submarines, this is about superiority.
> Are they not easy to detect on radar? Even during WWII, radar got good enough to detect submarine periscopes.
They are, if you can get your radar on top of the periscope, e.g. mounted on a plane that flies above the sea.
I talked with captain of submarine. He said, in real life navigation was not reliable, so they have to go to surface and make adjustments with some classic navigation - radio beacons and star navigation.
And civilian education now close to forgot star navigation, but navy still train people to navigate with stars and learn Morse code.
https://news.ycombinator.com/item?id=43319923
> most sensitive achieve so fine accuracy, they detect daily Earth rotation and even yearly Earth rotation
Daily rotation is 360°/23.934h, so 0,25°/min, which is acutally quite a lot if you want to use a device to track your orientation.
Unfortunately, these numbers considered state of art for modern classic gyroscopes.
Better are quantum navigation systems, using quantum matter as sensor, but they was too bulky to be used on planes, only last years appear more compact systems, sized like common home fridge.
> daily Earth rotation and even yearly Earth rotation.
Minor FYI: the earth rotates daily, but it revolves around the sun yearly.
I took it to mean "able to measure a rotation rate of 1 turn per year".
> they detect daily Earth rotation
This is the principle gyrocompasses work on; when left running for a while they align themselves with true north; the axis of Earths rotation.
I didn't read the article, but: a GPS receiver must calculate/find both it's time and position to get a fix. So maybe by having the time already available really accurately it makes the job of finding position easier?
From my (very basic) understanding of GPS you need at minimum four satellites to calculate the time. If you had a local atomic clock in sync with the GPS satellites, you'd only need three satellites to get a position fix. It would (probably, maybe?) also speed up the time to first fix / time to a precise position fix.
Shameless self-plug: I had Ken Munro from PTP on my podcast [1] in the episode 'Hacking airplanes, ships and IoT devices with Ken Munro' where we dove into GPS hacking and spoofing at length.
[1] https://www.youtube.com/watch?v=rkhCN7taMK4
GPS and other navigation systems are well worth the time to look into.
something like Decca or LORAN are really simple to understand: two or more base stations in a known location emitting phase locked signals. By counting the nodes/antinodes of the harmonics, you can work out how far away you are from the base stations. The downside is that you need a initial fix to work out absolute location.
The thing thats kinda touched on here is that GPS uses clocks to allow the receiver to work out how long the signal has been in flight (simplification) If you know where the satellites are (using the Almanac of satellite positions) you can get your location by fairly simple triangulation.
Now, you don't have an atomic clock on your receiver, so how can you accurately measure the time difference between signals?
for GPS you only need to know the relative time difference between each satellite, and even thought quartz clocks are only accurate to seconds a year, in the ~20-50ms it takes for the signal to arrive, its more than accurate enough.
However that means you are open to spoofing, because you sync your local clock to a satellite, you have no real way of detecting if the clock has skipped.
If you have an accurate clock source, you can then validate the clocks that are on the transmitters. I think, but can't confidently assert that calculating position becomes easier because you have an authoritative clock source, so don't need to piss about with clock sync using an unknown time offset.
I think the implication is that this provides a strong form of signal authentication.
However chipscale super-stable clock references also allow more autonomous styles of navigation. (ie celestial)
Planes have been flying for decades before GPS even existed, yet the article seems to make it sound like they wouldn't be able to without GPS. Unfortunately no mention of https://en.wikipedia.org/wiki/Inertial_navigation_system at all.
After the invention of GPS, aviation increased its capabilities due to the advantages GPS provides. Many modern flights depend on those capabilities to be economically viable, and are thus dependent on GPS.
Simply because it’s possible to fly without GPS doesn’t mean it’s commercially viable. Remember, before GPS, direct transatlantic flight weren’t generally possible because there’s no radar or radio coverage out there to help with flight navigation. Also for a long time, plane navigated by flying low and literally following giant arrows on the ground[1]. I doubt anyone is particularly keen to return to that kind of navigation.
[1] https://www.dreamsmithphotos.com/arrow/
We'd definitely need new hardware and/or infrastructure to work without GPS.
> before GPS, direct transatlantic flight weren’t generally possible
I'm not sure what you mean by this. Commercial transatlantic flight picked up after WW2 in the 50s. By the 1970s it was fairly common. A lot of that came from rocketry research and INS.
Not to mention removal of the alternatives in favor of GPS, e.g. shutting down VOR beacons (see e.g. https://www.flightaware.com/squawks/view/1/24_hours/popular/...)
It is interesting to consider how many old mysteries in flying came down to "pilot didn't know where they actually were." This isn't much different from hikers getting stranded, even when they are within a mile of a marked trail.
Nonsense. There were decades of commercial transatlantic flights before the widespread adoption of GPS. No one painted giant arrows on the ocean. Airliners navigated using a mix of dead reckoning, ground signals, and sometimes even celestial observations.
https://www.smithsonianmag.com/air-space-magazine/707-flight...
GPS (and other GNSS) make civil aviation slightly safer and more efficient but it's hardly necessary for routine flight operations.
Note those INS systems depend on some sort of navigational system to verify against due to drift and such, and those systems are GPS or VOR.. and VORs are being shut down or decommissioned as they fail (except for the ones declared required for national security).
In the case of planes celestial navigation is a realistic alternative as they fly most of the time above the cloud cover...
Well, it's just bad journalism, cause what they are referring to is a quantum inertial navigation system, not a clock – it's just thousands of time more precise. The plan happen to also have an atomic clock (which is used to properly integrate inertia through time), without having to rely on external GPS (which is a clock).
You just have to get closer to the source and find better information: https://www.gpsworld.com/uk-government-tests-quantum-inertia...
INS accumulates error though. It comes in handy in the absence of any other navigation system, but generally an INS is supplemented by some sort of radio navigation aid such as VOR, LORAN, or GPS to correct it.
Except guess what! Many of the VOR stations in the USA have been shut down, due to the high availability of GPS!
Don't worry everyone, we have shut down our Russia cyber defense efforts:
https://www.theguardian.com/us-news/2025/feb/28/trump-russia...
Which implies that we don't need to worry about Russia jamming GPS on our planes, they are just trying to help. Just flow with it and stop panicking.
The behavior will continue until a negative stimulus is introduced.
Which seems to be hard seeing as how the Russian government is good at convincing people (mainly their own, Europe's elite, and members of the Republican Party in the US) that it's okay to do what they do.
I remember this from stackexchange. Real answer is here. https://aviation.stackexchange.com/questions/108154/how-is-q...
So this pertains to jamming so strong that traditional jam-proof GPS that uses signal phase shift to weed out GPS signals coming from "wrong" directions, are insufficient? 100db attenuation of jamming signal has been achieved around 15 years ago with those.
In the air, there are always more GPS satellites visible than necessary. So jam-proofing through signal processing methods is the way to go.
It can be done, but airplane GPS receivers aren't jamming resistant. This is expected to change in the next decades.
What I don't understand about this GPS spamming: we don't need to rely on GPS. We have Galileo, (GLONASS) and BAIDU. That is the reason we its now called GNSS.
Most of the chips and as such the receivers are supoorting all of these systems in parallel. While I understand that the Chinese use their own coordinate system, I don't if BAIDU is based on that or not. Galileo is available. Galileo is able to use authenticated signals. Galileo has much improved over GPS. I assume in (important) comercial applications like aircrafts, you could use the better Galileo service for which you have to pay for.
So how important is GPS spaming really?
> Galileo
Which has optional cryptographic signatures of its positioning data. It's not spoofable anymore (but still jam'able with strong transmitters).
Free for use.
(https://www.gsc-europa.eu/sites/default/files/sites/all/file...)
Same for the HAS (High Accuracy Service) which offers precision down to 30cm without additional correction data.
Also free for use. But requires a special receiver as it's using an additional band.
Galileo was the ugly duckling for a very long time - but it turned into a shining one after it aged a bit.
> Galileo was the ugly duckling for a very long time - but it turned into a shining one after it aged a bit.
Yeah, for some time I was also in the camp of "why we need our own expansive service". But the current development has shown, that it was a wise desicion to have our own system.
BTW: thanks for updating on some other details. I never followed up really, it was from the initial plans, that I was told there should be comercial service, that should pay. Also that for some emergency services there is a very limited possibility to have a back channel.
As far as I know all nav sats have emergency beacon payloads (Cospas-Sarsat). All providers (Beidou, GPS, Glonass, Galileo) joined this.
It has optional cryptographic signatures of the navigation message, i.e. the data indicating position of satellites.
Spoofing generally works not by altering the navigation message, but by altering the timing of arriving signals. I'd recommend this video for a publicly-available overview of the techniques: https://www.youtube.com/watch?v=sAjWJbZOq6I
tl;dr Galileo spoofers exist and work just fine.
Nope, the GNAV message is not only the position of the sateellites, the almanac https://gssc.esa.int/navipedia/index.php?title=Galileo_Navig...
Spoofing of Galileo was possible as long as the authentification was not enabled. https://www.septentrio.com/en/learn-more/insights/osnma-late...
A) you keep on using the word "almanac". That term only refers to the imprecise information about all satellites that every satellite broadcasts, mostly to improve TTFF. The actual position used for navigation is called "ephemeris", and each satellite only broadcasts its own.
B) none of that other stuff in the navigation message changes the pseudorange, which is what spoofers mess with. For a networking analogy - pseudoranges are calculated based on layer 1/2 properties of the network. (Specifically the code phase and Doppler shift.) Navigation messages are layer 7 information passed on top of that physical layer. You can change the timing and frequency characteristics of the PRN code without touching a single bit of the navigation message.)
The G/NAV message (note the G - government) is for a separate service - not OSNMA - where not only is the navigation message encrypted, but the PRN code is also encrypted (symmetrically, so it can't be done for the mass market or even untrusted commercial customers).
In other comments to this link people are describing GPS according to my mental model, which is hard to combine with cryptography making it un-spoofable.
If someone can re-broadcast the keystream and control the latency I perceive as a receiver, how would me checking that the MAC is correct help?
"GPS" is being used as a genericism in these articles. All the GNSS constellations work the same way, and all of the military-grade spoofers are multi constellation.
They receive these signals in parallel because they're sharing frequencies: https://novatel.com/support/known-solutions/gnss-frequencies...
You can jam 5-6 frequencies and knock out multiple constellations.
Authenticating signals for GNSS sound like an impossible cryptographic task. What stops a malicious actor from recording the signals coming off the satellites and replaying them louder with a delay?
If you pick the delay properly you can make the plane believe it is at an arbitrary point in space and time (although of course that time would always have to be at least a few `us` in the past).
https://gssc.esa.int/navipedia/index.php/Galileo_Open_Servic...
Can you point us to which part of that can deal with the scenario in question?
> What stops a malicious actor from recording the signals coming off the satellites and replaying them louder with a delay?
Do you mean it is specifically GPS that is getting spammed, or more generally are all of the GNSS systems getting spammed?
In the UK "GPS" is used as a general term for GNSS. I don't doubt that the aircraft already use multiple satellites.
I dont understand this yet.
GPS allows us to navigate, based on the timing of signals from several satellites.
GPS jamming would involve flooding the relevant frequecies with noise, or somehow making it harder to acquire the signals?
How does creating a more accurate clock at the GPS receiving end help
That sounds like the jamming interferes with the speed fo the signals from the satellites which I dont think it likely?
The article mentions the UK Government Risk Register, which I've always thought was pretty interesting. They publish it each year (I think) as a PDF and it's very easy to access and read.
https://assets.publishing.service.gov.uk/media/67b5f85732b2a...
Page 86 is the start of the "Loss of Positioning, Navigation, and Timing (PNT) services".
Galileo can use TESLA (no relation), see RFC 4082, to mostly protect from the issue. Getting away from GPS is actually the simplest way.
An explanation of how it works here: https://www.euspa.europa.eu/sites/default/files/expo/osnma_p...
Mind you this only helps to tell you if the signal is authentic, you're still without that navigation system at that point, hence the search for a localized alternative.
Also, the Russians have been playing around with rebroadcasting legit signals with slight delays as well. The Ukraine war has been a very interesting time to observe these tricks.
If you have a good local clock (e.g. rubidium), you can now detect the signal is from the past and correctly conclude you are jammed and trust INS, starnav or whatever instead...
TESLA encryption is resistant against rebroadcasting. The idea is to use a PKI infrastructure to digitally sign the timestamp stream at fairly granular intervals.
This way, you'll be able to find a set of satellites that are not getting jammed.
Another option is to use the low-orbit satellites in addition to regular sats.
Can’t an attacker still start meaconing the original (i.e. locally captured) signal and then slowly selectively delay/advance each individual satellite component in the time and frequency domain?
Not sure how much latency that would introduce and how feasible that is in terms of tricking a receiver sensitive to any jumps/outages, and its definitely a weaker attacker capability than “simulate any time and location you want”.
The attacker can do that, but it will be immediately apparent for the receiver. The only thing you can do is a replay attack, which is useless, if the receiver has a clock that is accurate to within ~1 sec. It'll immediately recognize that the time stream is being tampered with when the next signature is out of whack.
You might be able to trick the receiver _once_ into not updating its position for a few seconds. After that, it'll mark the affected satellites as unreliable and will not use them.
It's functionally no different from just jamming them.
Why would the replay attack necessarily be immediately apparent if you start out synchronously and only very slowly build up a delay, especially if combined (as you suggest) with a momentary gap and re-acquisition to mask any unavoidable slight initial delay?
It does not work mathematically. If you delay signals from one satellite, then you need to simulate signals arriving _faster_ from another satellite (on the opposite side of the sky), assuming the receiver is not diving down into the Earth. And you can't do that because you can't predict the timestream.
The receiver should be able to detect this inconsistency and try to filter out the faulty signals.
To make this attack feasible, you need to "prime" the receiver by delaying ALL the signals, but that is only possible if you control the initial timestamp sync.
Hence first slowing down everything for a while so the attacker has some headroom for the signals they would need to speed up.
Alternatively, just slowing down some signals more than others would still amount to a global slowdown, with some signals being sped up and others slowed down relative to the sum. If all signals drift into the same direction simultaneously, a receiver would just interpret this as its own non-precision oscillator running slightly fast and adapting, right?
Even if feasible, this would still be a much weaker threat than that of a completely attacker-chosen location, velocity, and time, but it could still be catastrophic (imagine e.g. introducing a gradual shift to an aircraft's navigation system and nudging it across an international border that way).
This is true, but the Russians have demonstrated that combining this with jamming they can make this still possible (along with other tricks). Obviously there's going to be some back and forth movement via countermeasures and updates, but the west has only very recently woken up to these threats.
Encryption is not widely used right now, so I don't believe it's been defeated.
There have been papers that successfully demonstrated spoofing attacks against OSNMA-enabled GNSS receivers like:
https://arxiv.org/abs/2501.09246
The key issue here is bypassing the time synchronization requirement during the cold start. This has always been a problem with OSNAM, and it's impossible to solve completely. The workaround is clear, the receiver just needs to do an external clock synchronization without relying on GNSS. Something like NTP is more than sufficient for that.
The attack in the paper also assumes that the attacker has complete radio control and can jam ALL the signals. If the receiver gets even one fully authenticated stream from an actual satellite, then the initial timestamp spoofing will fail.
Replay attacks on tracking receivers are not particularly powerful either, they will be apparent within 10-30 seconds.
Galileo offers optional cryptographic signatures for their positioning data.
It's a solved problem and free for use.
https://www.gsc-europa.eu/sites/default/files/sites/all/file...
Sadly this doesn’t solve the problem.
Spoofers simply receive the signed signal and re-broadcast it with a tiny delay. Signatures still intact.
If you ever received unspoofed data, and have a somewhat accurate local clock (rubidium is fairly cheap), you can detect the spoofing.
I love it when James Bond plots come to life.
https://en.wikipedia.org/wiki/Tomorrow_Never_Dies
https://archive.md/DvdcV
I cannot tell you how infuriating it is as a UK tax payer on a UK-based ISP, that pays for this content to be made, to be blocked from viewing it.
Worse still, if I view the article in 'Private' browser mode then I can see it all.
Russia is like a kid playing with matches. I'm a noob when it comes to aviation, but AFAIK RNAV GPS approaches are quite common? Disrupting that is dangerous.
Russia keep seeing what they can get away with and then push harder. Since nobody is willing to apply enough meaningful punishment due to fear of escalation, and they successfully propagandized/bought the US Republican party, they're winning on this axis.
More sanctions should have been imposed when they shot down a passenger plane and killed several hundred Dutch civilians.
True, the cheapest option was always to hid hard with sanction on Russia as early as the first Chechen war and establish backup for Russian energy. But instead, Germany still build Nordstream after Georgia.
German politics was clearly heavily compromised as well, beyond the basic self interest of cheap gas. See Wirecard and Jan Marsalek.
The interesting question is how compromised British politics has been. Lots of very suspicious things (secret Boris Johnson meeting against the advice of security services; appointment of Lord Lebedev), but UK support for the Ukraine war has been unwavering.
Yeah, and its leadership held to account; for some reason the results of the investigation was that a number of individuals were marked as suspect, while IMO the entire military leadership all the way up the chain should be held accountable.
I really hope this war ends, and ends up with Russia paying for repatriations, including this case.
Unfortunately I don't see the reparations coming about without the war getting much, much larger first, like a EU-NATO ground invasion of Russia. Which violates a whole load of red lines and would get a lot of people killed. But maybe Russia will force it to happen regardless.
(what is happening is turning the asset freeze into asset seizure, but this is complicated - rightly - by human rights law, because most of the assets are nominally private)
Since this year, the most likely reason to die in an consumer aviation accident is being hit by a Russian missile.
And they have for years now. Invaded / occupied Crimea with a slap on the wrist at best. International cybercrime for at least 15 years now, probably longer, but they get plausible deniability because it's not officially state doing it (even though we know they are).
But outside of Ukraine, none of it crosses physical borders; the sabotage of undersea cabling is all done in international waters, the internet is some kind of free for all as well, etc.
What should have happened is that the international community stepped up and sent a clear message, like "Russia will be cut off from the internet if they do not stop their digital attacks". Boundaries mean nothing if there are no consequences to violating them.
No, they are bullies trying to extort other kids. They fully know what they are doing, but they are trying to find what they can get away with.
RNAV are less common than people think, and given the limitations appear to mostly be used as secondary help in conditions where one could possibly go by vectoring.
Losing them however does drop capacity because now you need extra work to get planes to final.
Russia is playing with matches since NATO allows for this. It would be sufficient if in Kaliningrad Oblast or in Petersburg NATO forces jammed GPS/Glonas/Beidou and, as a bonus, also VAR system (much more important than GPS for aviation) and next day Russia would apologize and never try stupid games again.
Pardon my ignorance, but do you mean VOR instead of VAR? Or what does VAR stand for in your example?
Fun fact: optical mouse tech was developed for airplane navigation first. So it would not be very expensive to have this system as a backup.
> optical mouse tech was developed for airplane navigation first
Citation needed.
I don't think there is any direct claim for this. But you will find lots of old research about optical flow measurement for navigation. Optical flow sensor part of https://en.wikipedia.org/wiki/Optical_flow seems like a good start.
Satellite guided approaches are used when there is no visibility, so I don't know how that would help. You could use terrain-matching radar for navigation, but that would require additional equipment on the airplane. Every plane already has GNSS receivers, so implementing RNAV is basically a software feature.
The recent crash of two ships near the East coast of UK, could it have been caused by GPS hacking?
Doesn’t IRS take care of this? https://youtu.be/bFGwjPaxGM0
Before the GPS era (military) planes had inertial navigation systems, why can't civilian planes have something like that as a backup until you get in range of a terrestrial navigation radio tower - those are still in use, right?
Commercial airliners have this for a long time. Early 474 models have it.
And VOR (VHF Omnidirectional Range) beacons are still used.
Many of the systems used are much older than people realize. Airports had ILS (instrument landing systems) in the 1950s. Improved low visibility versions started coming out in the 1970s.
A lot of these systems are being phased out. Lots of airports now have GPS only approaches where they would have had an ILS systems in the past. The bigger airports still have more advanced ILS systems for landings in extremely limited/no visibility but also have GPS approaches.
A normal IFR approach has more relaxed minimums that you can get to with GPS so there are a lot of airports without any ILS system in place at this point. The GPS approach gets you down to minimums of something like 200 feet above ground at which you either have the runway in sight or abort the landing.
Likewise, VOR radios are slowly being retired and increasingly used as a fallback only. GPS systems in planes have been common for since end of last century. ILS and VOR infrastructure is kind of expensive to keep up and running and increasingly optional.
I wasn’t meaning to apply that ILS was a sufficient alternative . I was using it as an example of tech technologies that have been around for a long time.
Navigation without GPS is not a problem for a commercial airliner. Landing without it in poor visibility is a different issue.
INS is still the primary navigation system on most airliners with GPS providing correction data for drifting.
They still have this system. This video gives great insights into how GPS jamming affects planes:
https://www.youtube.com/watch?v=wm9B-oofY9g
I think we need to separate issues here namely the threat types, one is jamming and another is spoofing.
As of jamming most probably the new clock will not help. But for spoofing it probably can be prevented and mitigated with the new clock, but the root cause is the pseudo-orthogonality of the spread spectrum.
To put it simply, in housing property market the main criteria are three namely location, location, location. Similarly in communication and specifically in wireless the main criteria are also three namely orthogonality, orthogonality, orthogonality.
It's interesting to note that all mainstream GNSS systems including GPS, Galileo, GLONASS, and BeiDou are using spread spectrum modulation system, and they all affected by the pseudo-orthogonality of the spread spectrum system. There's a reason why the newer 4G/5G, and even Wi-Fi have moved away from spread spectrum modulation that's was being initially used by 3G and 802.11b, respectively, by fully embracing OFDM. The reverse-engineered Starlink modulation is reportedly using OFDM as well [1]. This mainly because of spread spectrum limitations but at the time it's not due to spoofing (security) but due to bandwidth scaling (performance) limitations. For GNSS on the other hand, don't care about the bandwidth because it's for location service not streaming video, but the limitations of being pseudo-orthogonal eventually got to them in the form of spoofing vulnerability.
The next generation GNSS designers perhaps need to bite the bullet, and should employ proper orthogonal modulation (OFDM or others), not pseudo one like spread spectrum. Having highly accurate on board clock is a hacked solution at best, not a proper solution, and it just unnecessarily increase the upfront cost and maintenance complexity by being overkill and over engineered.
[1] Reverse Engineered Signal Structure of the Starlink Ku-Band Downlink (2022) [PDF]:
https://radionavlab.ae.utexas.edu/wp-content/uploads/starlin...
This is entirely wrong. OFDM is necessary for WiFi etc. in order to maximize spectral efficiency (i.e., bps per Hz for a given unit of radio spectrum) and mitigate multipath.
The main purpose of the GPS spreading codes is to prevent self-interference from the other satellites and to increase the effective bandwidth for the cross ambiguity function (i.e., to get a nice, sharp cross-correlation peak in the time-domain). The pre-spreading data signal is only ~50 bits per second, so spectral efficiency is not a primary concern.
>For GNSS on the other hand, don't care about the bandwidth because it's for location service not streaming video, but the limitations of being pseudo-orthogonal eventually got to them in the form of spoofing vulnerability.
Please check my original comments as above.
Granted, it's still perhaps feasible to spoof OFDM system but it'll be much harder to pull off compared to the pseudo-orthogonal spread spectrum system [1],[2].
[1] Secure OFDM System Design and Capacity Analysis under Disguised Jamming (2019):
https://arxiv.org/abs/1804.07826
[2] OFDM-based JCAS under Attack: The Dual Threat of Spoofing and Jamming in WLAN Sensing (2025):
https://arxiv.org/html/2501.06798v1
There is solution to this called the ARM (Anti Radiation Missile)
Of course they called themselves Time Lords, what else would British scientists call themselves? The Kings of Lower Frequencies?
Could that incident 4 days ago in a South Corean maneuvre have anything to do with GPS manipulation? That was my first thought when i heard of it.
https://www.yahoo.com/news/south-korean-f-16s-just-162213039...
Replace the light beacons on radio towers with a line of sight laser triangulation system.
To replace the INS system we have now, for when GNSS spoofing etc is done? That clock?
It's bad when Russia is doing it, but no mention of Israel jamming a big part of the land during the war
For one thing, the scale of Russia's interference is probably close to 100x as many aircraft being affected. Maybe 1000x or more if you consider the total number of aircraft affected over the past 3 years.
But do planes not have these fancy laser gyroscopes- so accurate, they have to correct in software for earth and the solar system moving?
https://en.wikipedia.org/wiki/Ring_laser_gyroscope
Why is GPS relevant here?
How bad is the best inertial navigation is? From what i see it would be pretty sufficient for civilian aviation (for fighter jets doing bunch of turns, etc. that would be different of course) to get into the vicinity of the destination airport. Add correction by stars/Sun - any plane on long flight would get above clouds any way - and you'd get the precision of a modern ICBM - like 30m or so. Who needs GPS then? :) May be it is the time to make a startup to produce such a navigational device?
Are GBAS also affected by GPS hacks?
https://en.m.wikipedia.org/wiki/GNSS_augmentation
What happened to that attempt to use Starlink as a GPS system?
Not that we should build anything else that relies on it
But only two other sat networks are OneWeb and PlanetLabs with one tenth the sats
https://www.datocms-assets.com/53444/1666338747-every-satell...
As a particularly egregiously fragile aircraft, the Embraer Phenom 300 isn't certified to fly into areas without functioning GPS because it affects flight stability. QNS can't happen soon enough and hopefully the consumerization and miniaturization of strontium optical lattice clocks too.
be interesting to see, what just caused two large ships to collide off the English coast, in a known and busy area ships on fire, more than 30 rescued so far
[flagged]
The title is clickbait. It implies hacking the plane's hardware, which is not occurring.
GPS jamming is unfortunate, but relying on U.S. GPS is foolish anyway (as the article also points out).
Planes still have inertial navigation systems. It worked before GPS, why not now? GPS for tracking phone users should go away anyway. If you are in an unknown city, but a damn paper map. No tracking and you absorb the big picture much faster.
> GPS for tracking phone users should go away anyway. If you are in an unknown city, but a damn paper map. No tracking and you absorb the big picture much faster.
Regular GPS is receive-only. GPS receivers naturally cannot be tracked. Tracking happens much higher up the stack, such as with your map app downloading local map tiles for display. Technology-wise, it's trivial to have a smartphone based map that is tracking-free, and the privacy focused alternate phone OSes do this already.
GPS isn’t there to track you. It’s a tool for you to use to know where you are.