[HN Gopher] Planes are having their GPS hacked. Could new clocks...
       ___________________________________________________________________
        
       Planes are having their GPS hacked. Could new clocks keep them
       safe?
        
       Author : justin66
       Score  : 143 points
       Date   : 2025-03-07 13:31 UTC (3 days ago)
        
 (HTM) web link (www.bbc.com)
 (TXT) w3m dump (www.bbc.com)
        
       | anovikov wrote:
       | 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.
        
         | elchananHaas wrote:
         | It can be done, but airplane GPS receivers aren't jamming
         | resistant. This is expected to change in the next decades.
        
       | thesh4d0w wrote:
       | 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?
        
         | BenjiWiebe wrote:
         | 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?
        
           | gorbypark wrote:
           | 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.
        
         | simne wrote:
         | 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.
        
           | simne wrote:
           | 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.
        
             | p_l wrote:
             | 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.
        
               | scrlk wrote:
               | > 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.
        
               | simne wrote:
               | 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).
        
               | p_l wrote:
               | 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
        
               | scrlk wrote:
               | 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 as an inertial navigation source in case GNSS was
               | unavailable.
        
               | simne wrote:
               | 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_w
               | ais...
               | 
               | 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_Sys
               | tem
        
               | p_l wrote:
               | 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
        
             | foldr wrote:
             | 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.
        
               | simne wrote:
               | 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
        
               | simne wrote:
               | > 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.
        
               | foldr wrote:
               | 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.
        
               | maratc wrote:
               | > 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.
        
               | simne wrote:
               | > 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.
        
               | foldr wrote:
               | > 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.
        
               | simne wrote:
               | > 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.
        
               | crote wrote:
               | 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.
        
               | simne wrote:
               | 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.
        
           | magnetometer wrote:
           | > most sensitive achieve so fine accuracy, they detect daily
           | Earth rotation and even yearly Earth rotation
           | 
           | Daily rotation is 360deg/23.934h, so 0,25deg/min, which is
           | acutally quite a lot if you want to use a device to track
           | your orientation.
        
             | simne wrote:
             | 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.
        
           | RandomBacon wrote:
           | > daily Earth rotation and even yearly Earth rotation.
           | 
           | Minor FYI: the earth rotates daily, but it _revolves_ around
           | the sun yearly.                   revolve /ri-volv'/
           | intransitive verb         To orbit a central point.
           | "The planets revolve around the sun."
        
             | HPsquared wrote:
             | I took it to mean "able to measure a rotation rate of 1
             | turn per year".
        
           | lupusreal wrote:
           | > _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.
        
         | touisteur wrote:
         | 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.
        
           | thesh4d0w wrote:
           | Ahhhhh, that makes sense. Treating this as security mechanism
           | rather than an anti-jamming one.
        
       | harha_ wrote:
       | 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.
        
         | yetihehe wrote:
         | 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.
        
         | piokoch wrote:
         | 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.
        
           | harha_ wrote:
           | Pardon my ignorance, but do you mean VOR instead of VAR? Or
           | what does VAR stand for in your example?
        
         | p_l wrote:
         | 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.
        
         | pjc50 wrote:
         | 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.
        
           | looofooo0 wrote:
           | 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.
        
             | pjc50 wrote:
             | 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.
        
           | miohtama wrote:
           | Since this year, the most likely reason to die in an consumer
           | aviation accident is being hit by a Russian missile.
        
           | Cthulhu_ wrote:
           | 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.
        
             | pjc50 wrote:
             | 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)
        
         | Cthulhu_ wrote:
         | 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.
        
       | KaiserPro wrote:
       | 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)
        
       | looofooo0 wrote:
       | 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.
        
         | Eduard wrote:
         | > optical mouse tech was developed for airplane navigation
         | first
         | 
         | Citation needed.
        
           | looofooo0 wrote:
           | 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.
        
       | bArray wrote:
       | 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.
        
       | PinguTS wrote:
       | 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?
        
         | jstanley wrote:
         | Do you mean it is specifically GPS that is getting spammed, or
         | more generally are all of the GNSS systems getting spammed?
        
           | bArray wrote:
           | In the UK "GPS" is used as a general term for GNSS. I don't
           | doubt that the aircraft already use multiple satellites.
        
         | ElectRabbit wrote:
         | > 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.
        
           | PinguTS wrote:
           | > 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.
        
             | ElectRabbit wrote:
             | As far as I know all nav sats have emergency beacon
             | payloads (Cospas-Sarsat). All providers (Beidou, GPS,
             | Glonass, Galileo) joined this.
        
           | azernik wrote:
           | 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.
        
             | PinguTS wrote:
             | Nope, the GNAV message is not only the position of the
             | sateellites, the almanac https://gssc.esa.int/navipedia/ind
             | ex.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...
        
               | filleokus wrote:
               | 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?
        
               | azernik wrote:
               | 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).
        
         | sebzim4500 wrote:
         | 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).
        
           | PinguTS wrote:
           | https://gssc.esa.int/navipedia/index.php/Galileo_Open_Servic.
           | ..
        
             | marsovo wrote:
             | 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?
        
         | azernik wrote:
         | "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.
        
         | jotux wrote:
         | 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.
        
       | ElectRabbit wrote:
       | 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...
        
         | michaelt wrote:
         | Sadly this doesn't solve the problem.
         | 
         | Spoofers simply receive the signed signal and re-broadcast it
         | with a tiny delay. Signatures still intact.
        
           | brohee wrote:
           | If you ever received unspoofed data, and have a somewhat
           | accurate local clock (rubidium is fairly cheap), you can
           | detect the spoofing.
        
       | bArray wrote:
       | > 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 PS100,000. 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.
        
         | freddie_mercury wrote:
         | > 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.
        
           | SkyPuncher wrote:
           | Even further, you can loose your super accurate special
           | crystal and simply fall back to "normal" GPS.
        
         | Cthulhu_ wrote:
         | 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).
        
           | mapt wrote:
           | 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.
        
           | macguillicuddy wrote:
           | 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.
        
           | Gathering6678 wrote:
           | 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......
        
             | alistairSH wrote:
             | 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).
        
           | rlpb wrote:
           | 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".
        
         | mapt wrote:
         | 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.
        
           | pclmulqdq wrote:
           | 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.
        
             | mapt wrote:
             | 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.
        
               | pclmulqdq wrote:
               | 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.
        
           | fanf2 wrote:
           | 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.)
        
             | mapt wrote:
             | Much of Finland and Estonia are currently being jammed per 
             | https://gpsjam.org/?lat=58.53948&lon=24.82400&z=4.9&date=20
             | 2...
             | 
             | 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
        
           | Havoc wrote:
           | They're probably talking about this for quantum navigation
           | 
           | https://www.theguardian.com/science/article/2024/jun/15/lond.
           | ..
        
             | pclmulqdq wrote:
             | The diamond-based quantum IMUs are a completely different
             | appliance and a different application (dead reckoning).
        
               | vlovich123 wrote:
               | 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.
        
               | pclmulqdq wrote:
               | 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.
        
               | vlovich123 wrote:
               | 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-...
        
         | gbil wrote:
         | Personally, I find it comforting that the plane was able to fly
         | 400km more!
        
       | InDubioProRubio wrote:
       | 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?
        
       | h1fra wrote:
       | It's bad when Russia is doing it, but no mention of Israel
       | jamming a big part of the land during the war
        
         | jjwiseman wrote:
         | 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.
        
       | Iolaum wrote:
       | 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?
        
         | secondcoming wrote:
         | They still have this system. This video gives great insights
         | into how GPS jamming affects planes:
         | 
         | https://www.youtube.com/watch?v=wm9B-oofY9g
        
         | izacus wrote:
         | INS is still the primary navigation system on most airliners
         | with GPS providing correction data for drifting.
        
         | kayodelycaon wrote:
         | 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.
        
           | jillesvangurp wrote:
           | 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.
        
             | kayodelycaon wrote:
             | 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.
        
       | distantsounds wrote:
       | I love it when James Bond plots come to life.
       | 
       | https://en.wikipedia.org/wiki/Tomorrow_Never_Dies
        
       | lenerdenator wrote:
       | 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.
        
       | _heimdall wrote:
       | 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.
        
         | fsh wrote:
         | 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.
        
           | grotorea wrote:
           | 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?
        
             | avianlyric wrote:
             | 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...
        
               | hollerith wrote:
               | >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#:~:tex
               | t=I...
        
               | lupusreal wrote:
               | Many cruise missiles use terrain contour mapping. In
               | principle at least it seems like it should work for
               | airplanes too.
        
             | dghlsakjg wrote:
             | 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.
        
             | baskinator wrote:
             | 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 .
        
               | crote wrote:
               | 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.
        
         | SJC_Hacker wrote:
         | 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
        
           | hylaride wrote:
           | 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.
        
         | hylaride wrote:
         | 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
        
           | pbmonster wrote:
           | > 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.
        
             | hylaride wrote:
             | Shit, you're right. I blame the time change.
        
       | thwra wrote:
       | 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.
        
         | yimby2001 wrote:
         | GPS isn't there to track you. It's a tool for you to use to
         | know where you are.
        
         | rlpb wrote:
         | > 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.
        
       | userbinator wrote:
       | 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.
        
         | bitwize wrote:
         | 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!
        
         | avianlyric wrote:
         | 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/
        
           | marsovo wrote:
           | Not to mention removal of the alternatives in favor of GPS,
           | e.g. shutting down VOR beacons (see e.g. https://www.flightaw
           | are.com/squawks/view/1/24_hours/popular/...)
        
           | taeric wrote:
           | 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.
        
           | cogman10 wrote:
           | 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.
        
           | nradov wrote:
           | 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.
        
         | carreau wrote:
         | 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...
        
         | iamtheworstdev wrote:
         | 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).
        
       | cantrecallmypwd wrote:
       | 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.
        
       | teleforce wrote:
       | 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...
        
         | ooterness wrote:
         | 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.
        
           | teleforce wrote:
           | >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
        
       | throw0101c wrote:
       | 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.
        
         | burnerthrow008 wrote:
         | > 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.
        
         | jpm_sd wrote:
         | They're taking CRPAs off the ITAR list later this year,
         | supposedly.
         | 
         | https://insidegnss.com/crpas-to-be-removed-from-itar-list-op...
        
         | KennyBlanken wrote:
         | 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.
        
           | Aloisius wrote:
           | 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.
        
         | Scoundreller wrote:
         | 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...
        
       | kevin42 wrote:
       | 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/
        
         | ge96 wrote:
         | What is that area to the right of India?
        
           | inejge wrote:
           | 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.)
        
           | pixl97 wrote:
           | Myanmar, which is currently a conflict zone.
        
           | ajross wrote:
           | 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.
        
         | alphan0n wrote:
         | I've never seen a map that has each locality in its primary
         | language..
        
           | biker142541 wrote:
           | 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/)
        
             | jjwiseman wrote:
             | 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.
        
               | biker142541 wrote:
               | 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).
        
         | crote wrote:
         | 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.
        
           | KennyBlanken wrote:
           | 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/
        
             | jjwiseman wrote:
             | 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.
        
               | folli wrote:
               | Fighter jets emit ADS-B? I know it's only training, but
               | I'm curious?
        
           | jjwiseman wrote:
           | I'm thinking about adding that. (Donations help, see the
           | About page.)
        
         | KoolKat23 wrote:
         | This map is great,very interesting. curious that GPS is jammed
         | over Gdansk, Helsinki and Tallinn.
        
           | lawrenceduk wrote:
           | It's because they're next to Kaliningrad, that weird Russian
           | exclave
        
           | bitcurious wrote:
           | Another way to see that geography is as approaches into
           | Russia. Gdansk borders Kaliningrad, Helsinki and Tallinn
           | straddle St Petersburg.
        
           | jjwiseman wrote:
           | 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-...
        
             | thaumasiotes wrote:
             | > 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?
        
               | WorkerBee28474 wrote:
               | Here's one: https://en.wikipedia.org/wiki/Bubble_octant
        
               | jjwiseman wrote:
               | 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.
        
               | thaumasiotes wrote:
               | > 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?
        
               | jjwiseman wrote:
               | That aviation without GPS isn't as safe as aviation with
               | it.
        
               | thaumasiotes wrote:
               | 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.
        
               | bobthepanda wrote:
               | 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.
        
               | epistasis wrote:
               | 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?
        
               | thaumasiotes wrote:
               | > 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.
        
               | epistasis wrote:
               | And they are going to also experience "inconveniences"
               | for random bullying.
               | 
               | Ignoring what a bully does has predictable consequences.
        
             | ithkuil wrote:
             | They are surely doing that because they want to divert NATO
             | expansion westward /s
        
         | nradov wrote:
         | 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.)
        
           | jrockway wrote:
           | 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".
        
             | jameslk wrote:
             | Could be a good opportunity for using an LLM to summarize
             | and extract anything important?
        
               | buildsjets wrote:
               | 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?
        
             | dmd wrote:
             | "One lamp out of 18 on this radio tower is operating at 75%
             | brightness" repeated every day for years
        
           | buildsjets wrote:
           | 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...
        
         | alexpotato wrote:
         | 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.
        
           | jjwiseman wrote:
           | 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.]
        
       | mvip wrote:
       | 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
        
       | lawlessone wrote:
       | There is solution to this called the ARM (Anti Radiation Missile)
        
       | csense wrote:
       | 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.
        
         | brohee wrote:
         | It's not white noise jamming it's replaying with a delay, so
         | the receiver is getting a meaningful signal.
        
           | Salgat wrote:
           | 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).
        
         | cpncrunch wrote:
         | 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.
        
         | SJC_Hacker wrote:
         | 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.
        
           | Dylan16807 wrote:
           | But quartz is accurate enough for that, let alone a properly
           | calibrated oscillator. So why is the article focused on
           | giving planes atomic clocks?
        
         | Salgat wrote:
         | 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
        
       | brohee wrote:
       | 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...
        
         | Salgat wrote:
         | 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.
        
           | hylaride wrote:
           | 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.
        
             | brohee wrote:
             | 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...
        
             | cyberax wrote:
             | 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.
        
               | hylaride wrote:
               | 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.
        
               | cyberax wrote:
               | Encryption is not widely used right now, so I don't
               | believe it's been defeated.
        
               | lxgr wrote:
               | 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".
        
       | metalman wrote:
       | 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
        
       | biker142541 wrote:
       | 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?
        
         | jotux wrote:
         | The term used in industry is typically "spoofing."
         | 
         | https://www.u-blox.com/en/blogs/tech/gnss-spoofing-new-secur...
        
           | vlovich123 wrote:
           | 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.
        
         | logifail wrote:
         | > 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?
        
           | biker142541 wrote:
           | lol, good point. I wouldn't doubt this as a cause.
        
         | asynchronousx wrote:
         | 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.
        
           | diggan wrote:
           | > 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.
        
       | ck2 wrote:
       | 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...
        
       | Frederation wrote:
       | To replace the INS system we have now, for when GNSS spoofing etc
       | is done? That clock?
        
       | shannonclaude wrote:
       | 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
        
         | mmooss wrote:
         | > 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)?
        
           | shannonclaude wrote:
           | It's the Air Force's higher ed institution. They offer
           | masters and PhDs. They have their own labs doing R&D.
        
         | vlovich123 wrote:
         | 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?
        
           | shannonclaude wrote:
           | 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...
        
         | mrandish wrote:
         | 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
        
           | shannonclaude wrote:
           | 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
        
       | reflexe wrote:
       | 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).
        
       | Animats wrote:
       | 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...
        
       | epistasis wrote:
       | 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.
        
       | neuroelectron wrote:
       | Replace the light beacons on radio towers with a line of sight
       | laser triangulation system.
        
       | manosyja wrote:
       | Of course they called themselves Time Lords, what else would
       | British scientists call themselves? The Kings of Lower
       | Frequencies?
        
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       (page generated 2025-03-10 23:01 UTC)