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Why are these pilots getting terrain warnings while cruising at 37,000 feet? I have talked about GPS jamming in other videos, but what you see here is more complicated than that - and it can sometimes affect more aircraft systems than just the GPS. How?
Stay tuned!
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Below you will find the links to videos and sources used in this episode.
• A milestone first flig...
• GPS How It Works
• Boeing: Building A Bet...
• APL Defining Innovatio...
• What is Galileo?
• 777-300ER Take Off
• 777-300ER Take Off
• U S Space Force - Ori...
• History of GPS
• Transit: The World's F...
• Military GPS at BAE Sy...
• Russia Shoots Down Kor...
• Airport Stuff You Shou...
• Pilote
• The ILS Critical Area
• The Wide Area Augmenta...
• Ground Based Augmentat...
• Understanding the ADIRU
• Inside flydubai's Boei... .
• Delivery of our 1,700t...
• We are Air France
• Microwave Landing Syst...
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Russia did NOT "escalate its attack against Ukraine". It was British Prime Minister Boris Johnson who flew to Kiev and convinced Zelensky to withdraw from the peace negotiations. That's what this turned into a war. And for those who will present the supposed "argument": "Ukraine should be free to decide whether it wants to be part of NATO and host US missiles", they should first answer the question why wasn't Cuba allowed to do the same back during the Cuban missile crisis. I understand that you come from the West, but either try to be objective and factual on what you say or just stay on what you do stunningly well and talk about aviation.
And some more facts. When on September 1, 1983, Korean Air flight 007 was shot down by the Soviet Sukhoi Su-15, a) The Soviets were running a major *Airforce* exercise that same evening b) There was also a US RC-135 spy plane circling the area and c) The Soviets recovered tons of special equipment from the sea in the wreckage, which also explains why it was only carrying 269 passengers. This flight had been intentionally sent there. If it made it through, then that's great, CIA could get their high-resolution photos of the USSR territory. If it didn't and the soviets shot it down, so what. This was all about the US obtaining as much spying data as they could. Not that this was the first, or the last, time that the US treated commercial flights this way. When on 03 of July 1988 USS Vincennes shot down an Iranian passenger jet killing all 290 souls onboard, US President Reagan called this "an understandable accident". Operation Northwoods was CIA's submission to Kennedy, which envisioned the shoot down of a passenger jet over Cuba. The intend was to accuse Cuba of terrorism and give them an excuse to invade the island. You may also want to read this: www.telegraph.co.uk/news/2018/03/19/ukrainian-pilot-blamed-mh17-kills/
I love your plant. Do you know what it is called? (Random question, I know 😅)
@@uslaserguideddemocracyseed1039 warra warra, blah blah.
I work as an Software Engineer with maritime GNNS and fiber gyro navigation systems. At least Galileo and perhaps all but GPS has authentication, meaning you can't spoof the signal. Naturally this won't prevent jamming, but at least incorrect data won't be fed into the IRS system.
Maybe we should not be decommissioning VOR, ILS, and NDBs so quickly. AM radio stations, too. They can be used by an ADF receiver and you can catch the latest baseball scores at the same time.
Agreed. NDB is now not even required nor taught in FAA instrument rating. I just got one.
No more NDB?! I FEEL OLD
Sometimes the old ways are the best…
Preach! I've been saying this. There's a reason why the doomsday planes (E4B) still have a navigational sextant.
Seriously? SO they are dumping the working stuff for stuff that does not work? Ah well, humans They think they are intelligent but a shrimp has more intelligence than most maggots. Eh, humans.
About a year ago, I got those same terrain warnings 2 days in a row, in a Challenger 300 over the northeastern continental United States, at 45,000 feet. Not a pleasant experience at all, even though I knew we were well above any terrain on the planet.
Very unpleasant indeed!
Thanks to open American border, spoofing equipments can easily come into the country.
Well there are two occasions where solid matter could be that high up but I think the warning chime would then be the least of your problems. 😅
Would that happen to coincide with a certain balloon overflying the US?
@@jerseyshoredroneservices225 He wrote Challenger 300!
I remember hearing a story from my college aerial photography professor about how she’d been out working an archaeological site in the US using GPS. She said she’d been checking her GPS location to note down the location of an artifact when suddenly her GPS location skipped from generally accurate to EXACTLY accurate. She’d been looking at the GPS date the exact day and time the US government allowed the GPS to be exact. It was a cool story.
Selective availability was on regularly in the 1990s. Went from 300m accuracy to 5m.
It still IS a cool story. As the story exists today. ONLY when the story ceases to exist can it ever be ' Was a cool Story ' Undertake an advanced reading program to better educate yourself and learn Correct English Learn also how to format text into narrow paragraphs. Your level of education is below that of my youngest students age 8 - who are academically more advanced than you. You have been successful at showing how uneducated you are -
Back in 1992/93 I was crew on a round the world yacht race. GPS was really helpful in the far southern latitudes when compass deviation was really high - a tack of 140 degrees would sometimes move the compass just 20 degrees. And at the end, when heading back to the UK, off the Portuguese coast we passed by a large freighter heading South. After some chit chat on the VHF the navigator on the freighter asked if we would like to verify our position. On learning we had 2 GPS systems on board he sheepishly admitted we had better kit than he did and asked us to verify his position…
See my comment.
You cannot see my comment, because it is deleted. Make it short - it is AWACS burst of signal on all frequencies.
The good old days of chatting in VHF, aye? We Portuguese always find a way to desenrascate
What @@Tvrtko1995
The Ocean Race? My brother put me onto the Volvo Ocean Race in 2018. Exciting stuff!
The phrase "This is why we can't have nice things." comes to mind.
Si vis pace para bellum
@@konstantinschubert2094uh, no.
A society that has homeless and starving children cannot complain when those children grow up and want to burn it all down. That's why we can't have nice things.
@@haydentravis3348 Putin isn't a starving child. I agree that wealth differential is a problem. Crazy leaders are also a problem. We wouldn't just fixate on one problem there when there are multiple and each requires a different approach
Yeah, all navigation systems have their strengths, weaknesses, and failure modes. In 1973 I was in the US Navy navigating a ballistic missile submarine. We relied on NAVSAT, the predecessor to GPS. At night we would extend a mast out of the water and get a fix from one of a set of satellites in polar orbit. As each satellite passed over a ground station it would get its location updated and would use that to track its orbit and position. One night we got a satellite fix, decoded it, did some math and were given two positions we could be at -- one was in the middle of the gobi desert, the other was in the Altiplano in the Andes mountains. Since a submarine under way was unlikely to be in either area, we chose not to feed that into the SINS navigation computer. Twelve hours later we received a radio alert informing us that particular satellite had gone crazy and not to use any positions we got from it. I'm not surprised that GPS has its own weaknesses.
At least it didn't claim location was some Mt. Everest... But pretty slow response if it took twelve hours for someone important enough to notice that satellite was malfunctioning and get warning about it out. That faulty data could have caused some major danger situation. Though would have needed to be not excessive error. Besides ground surface being out of question there's also limit in possible traveled distance from previous check... Especially with SSBNs usually moving slowly to stay silent.
@@tuunaes As far as time goes, you have to remember that this was one of a small number of satellites in a polar orbit, long ago, well before the GPS system was installed. It was broadcasting an encrypted signal that could only be used by a military vessel that was equipped to decipher it. A submarine was not going to break radio silence to report the satellite being down. Even if a surface ship did report the problem, the people responsible would need to wait for it pass over the ground station to verify that something was wrong, before issuing the warning. As far as navigation goes, an SSBN relied on a SINS system with three gyroscopes and accelerometers to feed a computer which calculates the location, a sophisticated means of dead reckoning that was usually accurate to within about 50 yards over the space of several weeks. The satellite fix was just a means of providing another data point to the computer. Also, the QM, who was analyzing the data, would look at what was already in the computer and would have thrown out anything from the satellite that was unreasonably far off. That's why, as good as the electronics are, you still need a savvy person in the mix.
@@paulcooper3611 Very, very, right.
I used the Transit navigation system for yacht navigation in the early '80s. You generally only got a fix every few hours and it took maybe 20 minutes for the receiver to calculate a position after acquisition of a satellite, using Döppler shift calculations. wwhat was really good though was the receiver also took data from a flux gate compass and hull water speed sensor every few seconds so that an automatic dead reckoning position was calculated between fixes. By comparing dead reckoning with an updated fix it was easy to calculate the speed and leeway the yacht was making. This allowed a new course to be set taking this into account. Very useful in off shore navigation where trends in changes of current could be estimated allowing a better heading to counteract set and drift to be set after each fix.
@paulcooper3611....I thought our subs used inertial. Was there a second sytem as a backup?
the European constellation, Galileo, implemented a system which works with the current receivers and has authenticated positioning, OS-NMA. This will mitigate spoofing and is free to use. The GNSS receiver manufacturers have to implement this in the firmware. P.S.: maybe it's worthwhile to do a related episode about ADS-B spoofing 😅
ADS-B spoofing is very easy to do in comparaison to GPS spoofing but at the same time there is almost no practical reason to do it - you can try but they will find you while the best you can achieve is to create problems for some airport. GPS spoofing and jamming though is a big industry now with many people and even whole countries being interested in the gear. That is why the latter is a much more pressing issue.
Several years ago around 2008 while at FL370 in an EMB-145 I got that exact warning. Since the highest terrain in the world was well below FL370 I continued the flight. We started our descent to Savanah, GA after about 5 minutes and since the entire area was VMC there was no problem and after about 10,000 feet of descent the warning went away and it never happened to me again. Great video and very interesting.
A related company was investigating the use of GPS jammers to prevent drones from operating around airfields and other sensitive sites. We had to point out that jamming GPS on an airfield was all kinds of bad - for navigational reasons, because the locals would be really pissed, and because a huge number of equipments use GPS instead of internal atomic clocks for essential timing systems.
It's shocking that a company working on GPS jammers would be so ignorant of the issues around GPS jamming.
@@jerseyshoredroneservices225 yeah... if the drone is a problem where it is, kn0ck it d0wn (pr0jectiles or laser or water jet etc.) Chase drone with another drone.
@@jerseyshoredroneservices225 You'd think... but sounds par for the course. I'm betting management, er, manglement, is insisting that it's not an issue, one or two engineers are saying "it is, you have to listen to us!", and the rest of the engineers are heads-down just trying to get their jobs done. And, uh, I do hope that they actually listened rather than proceeding further...
@@erichusmann5145 They probably listened, either the easy way or the hard way. The FCC doesn't play games...
Just jam the controlling transmitter and 𝑵𝑶𝑻 gps!
GBAS is also used in construction, a good example is the Millau Viaduct in France which used multiple GBAS sources to be certain that the two sides of the Viaduc would line up perfectly when meeting.
When engineering bridges, tunnels, or viaducts et al, it almost seems like magic to me when they meet ! And when it fails, it's terribly embarrassing...
@@Naptosisbridges and viaducts are "easy" when you can see the target. Tunnels are more impressive, and you can't use GPS underground.
@@NaptosisI remember the pre-GPS days, when the St Louis Arch was a big thing due to precision measurements. 1/128th of an inch off, the arch wouldn't have met in the middle. And I still ponder my cable humping days, when one discussed getting a cable stretcher... ;)
@@spvillano Well, from what I learned from the arch's history they had problems in making the two halves meet. But that was due to different temperatures the sun had heated the structures up to. The arch goes from north to south which makes the two halves susceptible to different amounts of radiation from the sun. So they used a kind of pry bar and water showers to adjust the temperatures.
@@user-sm3xq5ob5d well, water showers in the form of fire hoses. I can just picture their head slapping as they realized they didn't account for expansion of steel with heat. That's a hell of a lot of pressure to dissipate every day!
We're pretty much just turning the GPS updating off in the gulf, black sea and near the Myanmar/Chinese boarder right now. INS and ground based navaids do plenty to update the FMC position in those areas. You still get pretty good ANP with DME-DME updating, more than enough for en-route RNPs.. Always good to review the systems effected, but the company published a document for quick reference that reviews spoofing/jamming, the degradation of systems and mitigation. It's really not a big issue if you know what you're doing going in. It's actually kind of fun to go back to flying via ground based navaids with their limitations. It actually takes some piloting.
If they can spoof GPS, they'll soon start spoofing VORs.
I was a GPS engineer before there was a full constellation of US satellites. We tried telling the military how vulnerable it is. The signal is at -130dbm. That is such a small signal that you can’t use a regular spectrum analyzer to see it. You have to hop it by 60 dbm to get it above the noise floor on a regular spectrum analyzer. That makes it easy to over power. But normally it’s so expensive to try to fool the GPS receiver that it’s not worth doing, outside an engineering experiment. The way people got around the limiting features of code phase gps was by carrier phase. By counting the number of cycles from the satellite to the receiver. There’s a lot of math involved to do so. Inertial systems have come way down in cost and maybe the answer to the gps issue. Now you can have multiple inertial systems and use a Kalman filter to take out drift errors
A directed attack on a single plane feeding it "nudging" data to bias it on a slow basis to mimic INS creep is scary. Possibly EGI should log all GNSS Kalman filter inputs over a flight so they can be retroactively filtered out if they're detected/suspected to be wrong. Perhaps periodic updates from ground monitoring (ATC radar updates, VORs) can keep tabs on EGI accuracy. Those signals are subject to security risk as well but harder to mess with. Finally terrain matching is robust but not always practical. This video is scope perfect. It's just as detailed as it needs to be no more no less. This is an A+ presentation.
Terrain matching tomahawk style!
"A directed attack on a single plane using nudging data", do you mean like if a country wanted something (or someone) aboard a plane (or a drone) really badly and made it enter a hostile territory without knowing it using spoofed data, where it could be forced to land? Or could you explain any other attack you're visualizing in your head? Interesting topic.
"The plane knows where it is at all times"
@@kazansky22👍👌👍
Someone has been watching too many Bond films (this is basically the plot of Tomorrow Never Dies but with a ship instead of a plane).
GPS jamming and spoofing in northern Sweden and Norway has been happening for years before 2022.
Russians or reckless EW enthusiasts?
It is not necesarily jamming, GPS doesn't have optimal coverage on higher latitudes.
@@fifi23o5 So you know better than our military 😂😂😂
Finland too. And it's pretty clear which one of our neighboring countries is behind it...
@@ulf5738 Why can't it be instances of both? Instances of deliberate action and/or limitations of the technology and it's implementation.
As an A320/321 pilot, I experienced false pulup warning over UAE at an altitude of 27,000 feet. In other case, again false pull up while on short final at Tahran ILS approach.And similar a couple of cases in various areas all due to GPS signal jamming
I fly over Iraq a few times a month these days, and we get spoofing almost every single time. It's pretty crude and only spoofs a fixed position, always in the same place. On the airplane I fly (B787) we haven't had to take any actions because of it. once the GPS-IRU position loses enough accuracy, the FMC simply reverts to radio navigation (DME-DME usually), without any action required from the crew. Some airplanes types are a lot more susceptible to navigation issues because of it though, there have been reports of some airplanes not even displaying a correct zulu time in the area. As far as the terrain warnings are concerned, it has been very rare on the 787 so far. We do brief in advance not to carry out any terrain recovery procedure, as doing so at 41,000ft is unnecessary and would add more risk.
That reminds me; don't go to wedding celebration anywhere in the "middle-east", or given the known friendly-fire capabilities, any wedding anywhere (even your own).
@@SubTroppo Unless those wedding celebrations fire SAMs now, there's really no risk to an airliner at cruising altitude. Not even close.
@@unvergebeneid Not SAMs, but ASMs or laser guided munitions or such-like. The military origin of GPS reminded me of the "liberators" who regard themselves as "good guys" and past destruction of wedding parties. One should keep in mind the famous ally quote attributed to Henry K.
Recent actions have turned Iraq and the local region "hot" again. I wonder whether it is wise to take the risk. Keep in mind Malaysia 17 which was downed in a nascent war zone in 2014.
Does your airline require you to submit a report when that happens? I'm curious, I'm avionics mx at an airline with regular 777 flights over that region and we often get jamming writeups, but never terrain spoofing.
I've worked on satellite simulators for testing GPS systems, mainly for AGPS related to phones, and the lack of security is a big issue. It's time to rethink how GPS signals are sent and received, as the security layers that are ordinary in TCP/IP communications are missing from GPS. The industry needs to design a new security layer to guarantee the signals are coming from the correct satellites, and not being spoofed.
Actually, that would be really simple with digital signatures. Just digitally sign the GPS signal with EC, call is SGPS and you're done. The correction data too, of course.
In this case, spoofing is a MITM (man in the middle) attack, so your best bet is having settled on correct encryption methods, and sharing the encryption data across multiple sattelites as the plane is cruising. This will be tough but not impossible, mitigating a large portion of these attacks.
Security layers won't help a bit against jamming, because it's all about power levels and when your transmitter is in orbit it is automatically at a disadvantage.
@@onenote6619 Yes, but jamming doesn't have any potential to affect the INS or make the airplane generate false terrain alerts. So, a digital signature on the GPS data would still be a massive step forward.
@@pihi42 The trick in anti-spoofing like that is how to create a signature that cannot be duplicated. Most secure connections involve handshaking so that the application at the consumer end can set up a secure connection. That would be a huge demand for the satellite, with a potential for many billions of connections. There truly are no simple solutions.
I was in the vicinity of White Sands test range at FL310, my aircraft GPS system thought I was in Wyoming doing 1000kts ground speed. What was interesting was that my Garmin wristwatch knew exactly where I was. "They" do GPS spoofing there frequently. ...
3:48 I never forget that GPS started with the US Military. I worked on the Tomahawk and what used to be the ALCM and GLCM varients - and while they didn't rely on GPS entirely, it was ONE of their options on targeting and pathfinding.
I once got told that early Tomahawk used RCA 1802 microprocessors for its radar terrain following subsystem. I'd love to know if that was really true! An impressive thing to be able to do on such a humble CPU. Regardless, TLAM was / is a very impressive system. They also got used in British Telecom pay phones of the 1980s apparently.
Inertial and DSMAC if I remember my ESWS correctly.
@@dcviper985 Inertial was the final backup system, as I recall. Terrain Matching (that might be what you're thinking of as ESWS?) was the primary - GPS was later ADDED as the primary backup, due to resolution limits, and I don't know if it ever got the "tricks" to make it precise enough to become the primary.
@@abarratt8869 I think it more likely that they used a 6502 version, which I've seen Mil-Spec options for out of (I think) Raytheon. But fairly close on performance.
@@bricefleckenstein9666 You wouldn't do that anyway, consider the current situation in the middle east. 2/6/2024.
As an airline pilot from Russia, I do not see anything new in this episode 😅 This became a routine operation, with corresponding bulletins and actions needed. After takeoff you experience total loss of all gps signals and fly in such conditions for an hour or even more. We use dme/dme or vor/dme correction all the time flying in Moscow FIR. It usually does not drop ANP below 0,4 nm But what is really interesting is that after flying under spoofed gps signals, irs accumulates such strange error that the plane becomes unable to establish itself on a localizer. Sometimes, the plane flies parallel to the runway track with a big offset to the localizer with all green indications. That is really strange.
Could you maybe ask your compatriots to stop doing this please?
@@GorgeDawes unfortunately, this is beyond my capabilities
@@GorgeDawesGPS is being used to guide missiles and bombs that injure and kill people. Civilian airlines won't be targeted on purpose but they won't be given priority over military objectives either.
No wonder Russians crash so much.
@@GorgeDawes Then ask your government to stop using GPS and spy on Russia and starting wars all over the world
Woah! One of our planes made it in the video. 10:25 N32009 a amphibious Caravan that flys the world's only LPV approach to the ocean.
my father told me about one of his first transatlantic flights aboard a 707. He was an observer in the cockpit for civilian aviation and was observing the firts inertial units performances. The 707 arrived at NewYork from Europe with much less than a mile of error. The navigator was a little bit upset: he new at that time, this was the end of his career. Nowadays there are metric precision IMUs and atomic clocks that allows similar precision as gps.
high precision IMUs cost a lot. May be an option for airliners, but not for small aviation
@@adrianalexandrov7730 according google "Today, all commercial aircraft use inertial reference systems to get passengers safely from Point A to Point B. Honeywell's inertial systems can also be found on business jets, military aircraft and helicopters, remotely piloted vehicles, spacecraft, and land vehicles"
GPS technically trilaterates, not triangulates. It determines distances, not angles. Otherwise, an excellent description of how GPS works.
I’d like to see you do a video on ring laser gyroscopes and their use in the inertial guidance systems. They’re fascinating.
He already made a video on this: kzhead.info/sun/fZxypbaHhmp9pps/bejne.html
That works at principle of time delay between two lasers. At the end, there is a sensor to measure light interference which is changing due to delays caused by acceleration. Thats all...
Yes, a few orders of magnitude better than the original 747 peanut gyro units, that gave it originally the ability to fly around the planet, with Decca acting as backup and correction, and a star guide and sextant as the final arbitration.
Already done it
@@m0llux Nice. Thanks for the link.
MLS was installed and may still be installed at LHR (no longer used) - The system was only mainly used by BA because they had there aircraft’s retrofitted to be able to do them approach types. I remember hearing the old ATC “cleared microwave” and made me investigate the type a while back now
I was flying using a brand new first gen Garmin aviation GPS. Normally I had back up route plan on paper/sectional. This time I decided to wing it on a new route to test the capabilities of my new GPS. Half way along the military switched off the system (I later heard it was for maintenance). That's the last time I depended solely on the GPS.
In the early days of GPS I was working in the North Sea off of NorfolkUK. This was July 1990, just prior to the first Gulf War. We were close to an airfield where the USAF were practising airfield attack runs in A10 aircraft. Periodically our GPS equipment was totally shut down likely by burst radar. On another note, the removal of Selective Availability around 2000? May (Bill Clinton era) was more about the fact that about this time the USA did not have a sufficient stock of precise-code military GPS receivers, and were forced in effect to use commercially available sets
Given the size of commercial airliners, it should be possible to have the signals received from multiple GPS antennas physically spread out across the plane (at nose, tail, each wingtip) determine whether an apparent GPS signal originates from a direction consistent with its self-described location. There would be no way for a spoofed signal to fool such a system, since the only way to have a signal arrive at each receiver with the right delays is to have come from the direction the satellite is in.
provided there is some way to distinguish between signals coming from 'above' & 'below', that might work.
Possibly so. Reflected signals are a problem for ground-based receivers. Digital signatures would be much better without increasing hardware complexity.
@@alanhat5252: There exist millimeter-scale phased array antennas that are directional. The difference in arrival times to the top and bottom of the aircraft would be great enough to determine directionality with 99.999999% confidence.
Russia, and many other countries, have satelites in space.
Hallo. The GPS system uses multiple satellite signals from multiple directions simultainously AND the GPS antennas are not "directionally" sensitive, so the GPS receiver does not know from which "direction" the GPS signal comes, it only compares timing and position signals from multiple satellites to establich "relative position" and Geodatic (GPS) altitude, from which ground speed and track (not heading) can be calculated. So more antennas would be of no help against Jam or spoof. Best regards and wishes.
The US GPS system's name is NAVSTAR. Also, the time signals from GPS are used to sync power put on the electrical grid to ensure it is in phase. Seems like it would be pretty easy to spoof a couple of remote power plants and cause all sorts of problems.
NOW you've told them! But, the GPS is used to sync a Quartz/Rhubidium/Cesium standard, so difficult to steer quickly.
That used to be its name. It's just called GPS now.
Grid was in sync well before GPS existed. Only mechanism of syncing has changed
Good idea!
Kriss, the GPS input is almost always filtered and referenced against at least one if not more time references including local clocks and remote time services. The Network Time Protocol, despite being over 30 years old is pretty damn robust, and that's not easily spoofed.
@Petter: Another excellent video, thank you! Just FYI, the normal pronunciation for Phishing is with an F sound, so Phishing sounds identical to Fishing. 🎣 Pronouncing it 'Pishing' (with a soft/silent H) will make many people (especially Scottish people) think you're talking about going for a number 1 🚽🟡 I almost didn't want to flag it to you, because it makes me chuckle every time 😂
I've worked on avionics test equipment for 40 years and have been wondering why I've been seeing so many of these obsolete IFR MLS-800 testers the last few years. I had two of them in just last week. These haven't been produced in decades (built-in CRT display and two huge 12V lead-acid battery packs) and now big names in the business are scrounging for used ones and desperately trying to get them fixed. I thought MLS was dead, slayed by GPS, but it seems to be making a comeback and this video explains why.
As usual, a great, well thought out video. About 10 years ago, I had some involvement with ADS-B development in the US. Originally, the thought was to totally replace radar, for the reasons you are discussing, the military said no. One of the initial challenges was fusing the data with the existing radar data using an algorithm to give greater weight to what was considered the most accurate source for a given AC position though this was more important to radar returns at the time. I think in NY for example, there were 7 radar installations operating at perhaps different speeds. Speed and distance from the AC affected accuracy to some extent. I do think technology will evolve to encrypt this date further and in the US at least, radar will continue to be a back up though less accurate in some cases.
Some day I will understand Kalman filters. It seems the tool but I have weak understanding.
The data doesn't need to be (and shouldn't really be) encrypted, but it should most definitely be signed. We already have a public key infrastructure in place for the internet and there's really no reason why ADS-B couldn't use a similar setup for authentication. And that really goes for GPS and similar systems, too.
In nat airspace I usually found ads as having a long delay. Or at least it’s relation with cpdlc. We ask for wx deviation and sometimes there is no answer or ver delayed answer forcing us to contingency procedure.
@@amunak_ GPS & ADS-B are considered life safety technologies and are largely meant to inform a human so that human can make decisions (ignoring how military GNSS is different). These technologies use radio modulation technologies which are already fairly robust for their intended purpose. Attempting to change those protocols isn't going to happen as one does not just modify life safety systems the way one updates a cellphone. In addition adding an additional failure mode just doesn't make sense. The messages aren't even long enough to safely use public key authentication in many cases.
Due to the rising importance of drones and GMLRS in warfare, which depend on GPS (though GMLRS have IRS backups), advancements in spoofing are going to come thick and fast.
The satellites are doing my taxes too?!
@@Flumphinator IRS stands for Inertial Reference System
Drones depend on GPS in varying degrees. Some are highly dependent while others are independent. the FPV drones that they've been using don't require GPS at all, the remote pilot needs to know where he's at and where he's going. Well actually doesn't need to know where he's at because those drones are usually on a one way trip...
Hello, regarding MLS, I'm a retired ATP-Rotary-wing & Commercial-Fixed-wing aviator and in the late 70's I was a Captain on a Bell 212 IFR helicopter flying to off-shore oil rigs in the Beaufort Sea, Canada. These rigs were not on jacks standing on the bottom of the ocean but were the floating style of oil rig. They decided to try out a MLS installation on the helideck. I remember clearly how while on approach and having the CDI centered, the glide slope indicator was moving consistently full scale top to bottom due to the drill ship rolling in the waves. We had ground mapping weather radar, radar altimeter and an IVSI, it gave us the ability to do an emergency zero zero landing which was done on one occasion rescuing a day VFR helicopter pilot that could not get back to base due to heavy fog and nightfall. Watch all your content, cheers.
Ohhhh a rare mistake in a Mentour video :D 2:40 GNSS systems use trilateration and NOT triangulation. The later uses angels the first uses distance. GNSS satellites send their time so that the resiever can use their current time to calculate how long the signal traveld, which gives the distance to the sender. This distance is then used with the position of the satellites to determine the resivers position.
*Almost* correct. The GPS receivers themselves would also need an atomic clock if they used "their current time to calculate how long the signal traveld, which gives the distance to the sender". No, it's even more clever than that. GPS receivers aren't trilaterating only in 3 spatial dimensions, they're doing it also in the fourth dimension of time, so in 4D space-time in total, in order to find *their* 4D space-time position. Yes! They find out *when* they are as well! This means they don't need to have *any* idea of the current time for it to work. It's just taking the calculations up another dimension. You can perform trilateration in any number of dimensions. It's easiest to start with examples in only 2 spatial dimensions in order to get an idea of how it works, particularly with taking some uncertainty into account.
Air France 447 report provided full explanation of the Airbus cockpit philosophy: When instrumets do not agree, the flight computers issues an error message and stops any flight protection services that relies on the faulty instrument. So basically "Sorry Mr Pilot, I can't prevent you from stalling aircraft because I can't trust the instruments i need to detect a stall". This is part if pilot training. (for 447, because sensors came on and off constantly, pilotts ignored all the errors including the "you are stalling" ones which occured while computer saw valid sensors. ) In the case of the 737-Max, in order to remain just a simple vacuum tube era derivative of 737, they could not issue new messages to pilots about disagreeing sensors since not part of existing 737 training. So when sensors disagreed, the secret MCAS computer took matters into its own hands and chose what data to beleive and for the 2 initial crashes pitched the plane down to avoid a stall). This difference is important in the case of the video you showed. I would like to have a real version of the video shwng the GPWS alarm in question, not the one cropped to portrait designed and edited to go viral. If the plane was at altitude, it should be flying based on barometric altitude with 101.3 as base pressure. As long as Airbus saw 2 of 3 sensors agreeing , it would use their values. And in fact, despite left screen showing "primary GPS lost" the right screen still indicated altitude near FL 37. Calculated GPS altitude is based on distance from centre of Earth minus the radius of Earth at latitude where you are. The WGS84 model provides for a 21.4km difference in radius between the pole and equator. (which is why accepting Earth is flat would simplify things so much!). A plane flying 10km above sea level at Pole whose latitude is magically changed to 0° would end up being calculated at -11.4km under sea level having lost 21.4km despite flying level because it is the sea that rose 21.4km based on WGS84. The difference in elevation between Saudi Arabia and Equator would not be that great. At Riyahd, the radius is 6374km a difference of 4km in radius to equator at 6378. So a plane at over 10km alttitude whose computer suddently thinks it is at latitude 0 would calculate altitude above sea level of 6km or 19,500 feet, so plenty of space to fly without ground proximity. A plane over Saudi Arabia at 10km FL 33 altitude that is magically transported near Everest gains 1km in calculated elevation above sea level since radius of Earth is about 1km less at Everest vs Riyahd. So GPS would think it was at 11km altitude above sea level, and if you subtract the 8849m elevation of Everest above sea level there would yield 2151m or just under 7000 feet clearance between plane and tip of Everest. Not sure a computer would declare GPWS with that much clearance, although the distance between plane and grould would quickly go down as mountain rises steeply. So not sure it is plausible that just falsifying plane's location is enough. Moving you from Saudi Arabia to Equator reduces your calculated altitude just a bit, and moving you to Everest area still gives you plenty of clearance if you start at 10km or FL 33. What is strange is that despite the Airbus computer detecting loss of GPS, it would still try to generate alarms instead of simply generating th GPS LOST alarms and no longer computing anything based on GPS. Also, except for landing where GPS+GBAS can be used, a plane would never use GPS calculated elevation. This is why I am not sure this video was in a commercial flight. Perhaps simulator or development centre to debug software way before it is released. This is unlike the Airbus thinking in cockpit, especially as there is no place on earth where the aircraft's own altitude estimate of FL 37 could possibly hit terrain, no matter the shape of the planet. Perhaps fake Earth DEM models were loaded with some mountains higher than 37k feet. (so again simulator or software development centre). There are some different SBAS systems. WAAS covers north america. EGNOS covers western Europe and verty northern tip of Africa. SDCM covers Russia GAGAN covers India BDSBAS covers China MSAS covers Japan It is unclear to me whether a GPS in Saudi Arabia would process any of the SBAS messages it might receive from any of those satellites since it is outside the coverage area for any of the approved SBAS satellites. A WAAS message about North American corrections would be useless to a GPS in middle East. I the video you posted, since the plane detects LOSS of primary GPS, I have to assume this is more jamming than spoofing. Spoofing is a lot harder to do than jamming because a single "odd" satellite would likely be omitted from calculations by GPS receiver. And spoofing the SBAS signal from ground, assuming the Plane's anGPS antenna(s) see it, would be harder and not sure to what extent the quantum of values allowed for corrections would move aircraft in significant amounts while on level flights. The other problem I have with that video is that if the Airbus plane really behaves that way, it is terrible CRM issue because it creates false distraction when the only message that should appear is loss of GPS signal and listing disabled functions instead of allowing such functions to contiue to oeprate and genate alarms with erratic data. While Everest is highest point on the planet above sea level, it is not the highest point above centre of planet. Kilimanjaro is actually higher than Everest because its base is further from centre of the planet. Location= radius at latitude + height of mountain above radius (sea level) Everest = 6373km + 8849m 6381.8 km above centre of Earth. Kilimanjaro: 6378km + 5895m = 6384km so in fact 2000m higher than Everest !!!! I seem to recall it is a mountain in south america that has the title of being highest above centre of earth, but couldn't find it in writing this comment.
Fascinating stuff!
Thanks a lot for taking your time to write that comment!
Google Chimborazo. Or maybe it’s Lluillaillaco- if I spelled that right.
Or, Aconcagua?
It IS Chimborazo.
Years ago I saw a presentation at a conference suggesting that ADS-B was also vulnerable to spoofing and even presented a demo, in a simulated environment, where they very simply could "inject" phantom traffic into the system. Also no encryption or authentication...
I think almost none of the systems in use today were developed with any kind of security in mind, which makes sense when the underlying technologies predate the Internet for the most part. You can spoof ACARS, ground and space based navaids, plus even ATC radio comms with minimal equipment. That nobody did enough of this to affect significant commercial traffic until now is probably more amazing than anything else, as the doors and windows have been wide open for decades...
ADS-B is not really a navigational system. It is a technologi for broadcasting information about position and other flight parameters. So if the position being broadcasted is derived from GNSS, then that information is no better than the information presented to the pilots.
@@henrikvr2721 Yeah, but I recall a DEFCON talk I watched on KZhead talking about ADS-B and one of the concerns was what'd happen if you spoofed a plane flying on a path that would cause it to collide with a real plane, and potentially cause that plane's computers to trigger an evasive response. I can imagine that would be bad.
@@matthewmiller6068There are protections in place to help prevent spurious "ghost" planes from triggering a TCAS warning-and it remains the pilot's job to interpret that warning and act appropriately.
Ed & "Y.M." I'm afraid you underestimate the difficulty of implementing an authentication mode into a "fail safe" communications channel. It is vastly more difficult than you seem to think it is. Even implementing basic CRC32 over RF is not as easy as it seems. (I've done it.)
It was incredibly reassuring to hear how utterly accurate your short explanation to GPS was, simplified yet not dumbed down. This makes me even more confident in your aircraft-related explanations, where I don't have existing knowledge. Thank you!
Most gnss firmware are updatable. The location sent by the GNSS chipset is a computed location based on the various values of the various GNSS constellations and bands. Most chipset acept ephemerids of satellite to speed up the initial position fixing (from minutes to seconds) this is the Assisted GPS (AGPS). Some chipset also accept differential data computed on a land station (DGPS) and some other chipset also accept side chanel of data (speed, angle) to check the GNSS update for consistency or interpolate a position in case of a loss line of sight (cas of car in a tunnel ) or a global failure of the emiters. The algorithm used can be improved if needed 😅 Thanks for the video 👍
I love the head nod to General Relativity! It’s one of my favorite details about GPS (or GNSS)
Yes, the accuracy demands are so great that the speed of the satellites affects the timing of the clocks and has to be taken into account.
I'd like to see you cover the current and potential inertial navigation systems for alleviating issues with GPS jamming/spoofing. Great videos!
As someone who studied comsci I wanted to thank you for giving an excellent explanation of these systems! I will add that you discussed a spoof will suddenly change and there’s a good chance that it’ll be picked up as an error because the sudden change, this is true for aircraft that are straying into an area using spoofing. However far scarier would be an attack targeted at a specific aircraft. In this situation you get/work out the target aircraft’s position. You start by spoofing a perfect signal so nothing wrong, and progressively transition to a very incorrect position. This can result in the aircraft updating its imu and other components on the false signal, continuously, making it much harder for a pilot to diagnose and adapt to the issue.
Turning off Selective Availability caused disappointment in at least one science museum. I remember reading about a museum that had a robot that did what it had to do to maintain its location, based on GPS. While SA was still on it would zigzag around the room, much to the enjoyment of the public. When SA was turned off it would creep around within a one-meter circle and wasn't nearly as amusing. Early adopters of GBAS, specifically, Differential GPS, were surveyors and construction companies. Those systems did a really good job correcting for SA. My phone uses both GPS and GLONASS for its navigational solutions. It also receives WAAS but, unfortunately, doesn't make use of it.
I think this is a well-known issue and a good reason to have human pilots onboard. I remember stories of drones being diverted by Iranian GPS manipulation. Hell, there was even a James Bond movie about it, though that was with ships.
"Tomorrow Never Dies".
@@wyskass861 They have that most useful thing: a brain.
Yeah, it is a well known issue. ADS-B spoofing is less well known and could be much more catastrophic as while a pilot won't react to a terrain warning, they'll react to a plane appearing suddenly at the same flight level, heading towards them at the same speed, especially if it's squawking a mayday or hijack at the same time. Which can all be done using the same stuff used to spoof GPS.
It has been proposed for several years to implement enhanced LORAN as a GPS backup. So far, nothing has been done.
Why would human pilots do better than automated systems using the same set of information?
Strange how you didn't mention that MLS was used at Heathrow for some time. They were the first to use it for low vis approaches as well.
Did that result in planes diverting to Gatwick if they had unopened soda cans on board? Just asking because of microwave.
Business class got free hot popcorn@@linvesel
@@linvesel Unsure if this is a joke, but you should probably take a look at the Microwave Wikipedia entry. Airplanes already uses microwaves for Radar btw.
@@user-to7ds6sc3p The invention of the magnetron was actually motivated by the need of compact microwave sources on planes during WW II.
Yes it was a joke.
I've seen a video from a cargo ship captain showing similar situatiion. They now have some virtual bouys that can only be located by GPS(or other GNSS), similar to RNAV, and sometimes the satellite signal gets jammed or spoofed.
Interesting comment especially with the recent incident in which a ship collapsing a bridge is being blamed on anything but the systems. Something is very wrong with GPS and the planet as of late. No one wants to discuss it.
I remembered a case happened to me 10 years ago. One day we were experimenting with GPS spoofing in the lab. Then I meet my unaware boss during lunch time who was complaining from his new iphone. He told that the time and location being distorted time to time during the meeting. He runs the meeting in the room right below our lab room. 🙂
Fun fact, these GPS satalites have to adjust their clocks constantly, as their atomic clocks are affected by time dialation, and they run a bit quicker realtive to ones on the ground. It is an integral part of how this triangulation occurs.
Probably more accurate to say the clocks on the satellites are less affected by time dilation than the ones closer to the surface, so they need a correction to slow them down a bit. (Gravity causes time dilation. Less gravity in orbit due to further distance from the center of the Earth means less relativistic effects.)
@@Khetroidactually the time correction is just for the crappy clock in the receiver. The satellite clocks are good.
@@Khetroidgravitational force does,not cause time dilation, so the strength on orbit being weaker is not the cause. Time dilation is strictly due to different in potential energy. E.g, there is no gravity at the center of the earth, but is the most dilated place in the planet. For weak fields…I.e, far from the Schwarzschild radius,the time dilation formula is the same as the Lorentz factor formula, just replace the term for Newtonian kinetic energy Per mass, with Newtonian gravitational potential energy, per unit mass. Seems too simple for GR, but it works. Ofc that means the gravitational time dilation btw two heights is the same as the Lorentz factor the high one would gain falling to the lower one.
@@DrDeuteron that isn't how any of that works. Time dilation has two causes, speed, and gravity. As your approach the speed of light, time slows down. Similarly as you approach a massive object time slows down due to the greater gravitational force, something that might be noticeable as one were to approach a black hole. When it comes to GPS satellites, it's the difference in gravitational forces that dominates. The time difference isn't much, but the precision required for the system to work requires accounting for it. Also, I'm pretty sure GPS doesn't rely on your device time, but rather by comparing the time as reported by the various satellites in range. So the satellite time is the important one to have right.
Not quite. They run their clocs pre-adjusted as time dialation factor for each orbit is already figured out and accounted for at satelite design stage.
I worked for a major avionics OEM before I retired. We were developing nav systems for GPS denial of service environments. One of these was an automated celestial system. Yes you can use this in the day time. Interesting and very topical video. I used to fly in the south west region of the US and GPS interference was a fairly frequent situation especially in the KABQ area.
The SR71 was navigated using "R2D2", a star tracker which was located just behind the RSO's cockpit.
@@t67m Ha!
One potential problem with the MLS (Microwave Landing System): Since the time it was being investigated, the microwave spectrum has been partitioned and doled out to a LOT more uses (4G, 5G, WiFi, 5 GHz WiFi, etc.). Is there even any part of the microwave spectrum LEFT to use for MLS?
The obvious solution for me as programmer is to have the INS system store all the corrections and allow you to quickly swap between what actual correction is applied, till you find the last one that makes any sense. Like for example, if you realize your position info is wrong after flying 30 mins, and see the last "correction" was at 25 mins, and the one before that at the takeoff strip, you just press "previous" to go back to only calculating the INS result as if only the first calibration/correction was done. It's less accurate than ideal but not intentionally spoofed. An UI showing the differences in position caused by the different corrections would ease this problem fixable by the combinations of human and computer smarts too.
No single navigation system is infallible. That is why mariners are required to learn celestial navigation just in case their electronics are damaged, jammed, the power fails, etc. On airplanes, the older systems should be retained even if there is a bit of redundancy. It is nearly impossible to simultaneously jam multiple radio signals, and the older systems are very hard to spoof. Inertial navigation, due to its strictly internal nature, can never be jammed or spoofed. The Mark I eyeball is also jam and spoof proof.
There are ICAO standardized simple radio navigation beacons and directional beacons, with and without active distance measurement transponders and modern avionics can derive quite precise position using the signals and for even more precisision during approach a pair of localiser transmitters are used. So modern commercial airplanes can perform completely instrumental flights even without GPS at all. But the problem is that all the ground stations required are quite expensive as they require constant power supply and maintenace. That is why just throwing it all away and just relying on GPS for everything is so tempting as the economy would be just as huge as the risks.
The Mark 1 Eyeball is anything but jam proof. That's why idiots with laser pointers are such a hazard. As for spoofing, our senses get fooled _constantly._
Another great video, thank you. Let’s keep the ILS as long as we can, especially while the Rad Alt and GPS have frequency and jamming issues. MLS may well be the way forward and it has the benefit of Cat lll or better minima. ✅
Interesting. My 2 cents: I've been a helicopter pilot in the military for about 20 years (10 years in operational units part and 10 years as an experimental test pilot, to put it simple). In my country we were working on these GPS issues since the early 90s and to be honest we were very suspicious with regards to the use of the GPS in the civilian aviation industry. First, as you mentioned it, it's basically a military system, second it's an American system so that, although it's technically very seducing so to speak, this system is not usable without restriction since, like it or not, it belongs to a foreign power (you understood that I'm not American). At the time the accuracy was not the current one (it was around 200m or so) which was available only on request from government to government for military purposes through the so-called P-Code (P standing for Precision). Anyway we were also already working on the "gbas" solution which we called "differential GPS" to improve the precision on airfields and why not in the middle of nowhere using a portable system but ... the main issue was that the GPS as such was not "reliable" since it was depending entirely on the goodwill of the master of the system i.e. the US. As you say the system is technically based on time measurement via 1 atomic clock on each satellite but the satellites constellation must be coordinated and controlled (to make it simple) by reference clocks on the ground. Where are these clocks? One in the US mainland (Vandenberg if I remember correctly) and Hawaï. We were also considering the jamming of the GPS signal (not the spoofing since I'm not sure it was feasible at the time) but our main concern was the capability for the US to stop or degrade the signal depending on a political context, a war zone, whatsoever, against which we would have been powerless. Eventually we used the GPS but carefully and never as a prime system. For the record, during the Gulf War we implemented "some" civilian GPS receivers on "some" helicopters for "some" missions and you know what? On January the 16th, 1991 in the early morning started the Desert Storm phase (the air campaign) and all our GPS receivers stoppped working suddenly and definitely while the US forces didn't have obviously any problem (and we were on the same side!). QED On closing I'm just surprised to find that it took 30 years to come more or less to the same conclusion: to bet everything on the GPS remains risky to say the least. Why do you think "European Union" lauched Galileo (a civilian system which, for the moment, is not yet really working properly) and the Russians use the Glonass (a military system based on the same principle as the GPS and whose the Ground Control Segment is on Russian territory ...)? Regards
* At a recent job, I was the lead engineer investigating a combination of ILS and GPS to get to CAT II. One problem, according to the FAA, was that there was a six second delay to notify the pilot if WAAS became unavailable. (I never understood how the WAAS signal could change that fast.) Also, not all CAT I ILS installations were accurate enough for CAT II or better. And there are variations from "standard" localizer angular width with very short of very long (KDEN) runways. * MLS is line of sight, as are GBAS. Curvature of the earth means that 30 miles away, signals are not available below 3,000 AGL. In other words, you need a ground system at each airport. * The original MLS concept would have allowed curved approaches, etc. * I've read that it is possible for an appropriately sophisticated GPS receiver to know what kind of jamming is being employed. Don't remember any details.
Military gps we can load information from our ANCD that loads in encryption and can verify coordinates by adding additional encrypted satellites. Maybe airplanes just need access to that. Not only does it give the encryption keys but can do frequency hop to help with gps jamming. With such an important industry you think we could do that just with a civilian version.
There's a lot of things--some relatively simple--that you'd think would have been done by now.
My father moved to Titusville Fla back in the late 1980s. He liked fishing and I gave him a boat with 115hp motor I had at the time. A little later in the 1990s I bought him a GPS unit he could use on his boat. It was pretty expensive back then, but I loved him and it was worth to me. At least I felt better about him getting where he was going and getting back home again from his fishing trips. Now it is even in most cars and cell phones. How things change.
I remember lobster fishing with my dad in the 70's of the west coast of Newfoundland in a 18 foot dory. We were not often more than a couple miles offshore but some times the fog would come in so quick and heavy you could hardly see the other end of our dory. I can still see my dad one hand on the outboard and the compass in the other try to peer ahead. I would be up forward listening for the breakers on the rocks beside our beach. Man I love the GPS on my sailboat, not that we get much fog here on Lake Ontario.
Thank you Petter for keeping us informed. I purchased some merch this morning🎉 keep up the good work
The scarier part is that this shows you "GPS PRIMARY LOST". I had an incident once that I got back the GPS and it was Primary and monitored the GPS Monitor and it had all the wrong information with LAT/LONG and height and eventually got all the warnings on final approach, thankfully it was CAVOK and day time and it was a known airfield with no terrain around the area. Some colleagues had even incorrect wind information on the ND.. It's really hard to say how this can affect the aircraft and what kind of bulletins we will need to operate safely.
I did some library research on GPS for the Dutch Time institute during my study Electrotechnical Engineering TU Delft in 1982 - interesting subject to say the least. At that time GPS receivers were 19" racks...
Still used in them. Modern network cards are so fast that they use the GPS clock to synchronize real time protocols. The system clocks are not accurate enough.
Which is why when I was in the Navy we still had paper charts and old school celestial navigation and a compass. And we frequently practiced using them.
It's not about navigation. There are tons of smaller airfields with only RNAV approaches and if you're not in VMC, superior chart reading skills are of no use.
Thank you Petter for another very concise and informative video. All the best from Sydney Australia 🇦🇺
Updating IRS by other sources in-flight sounds like a terrible idea for me. And spoofing is the perfect reason why. Also keep in mind, that not only GPS can be spoofed. There was at least one example somewhere in Africa, when a plane was deliberately crashed by NDB/VOR spoofing! A fake beacon was installed, that completely outsignalled the correct one, and this fake beacon guided aircraft to the mountain during the approach.
I fly in northern germany and recently saw this NOTAM: "GPS UNRELIABLE AND MAY BE NOT AVBL IN EASTERN PART OF FIR EDWW." Being a VFR Pilot this isn´t a big deal for me but still it is really concerning knowing how much planes can rely on the GPS system.
Ja, aber um ehrlich zu sein - es ist nach wie vor automatisch ein Mix aus GPS und VOR (zwecks Kalibrierung). Wo es eng wird ist die Navigation über Waypoints, weil diese häufig nicht über Kreuzpeilung genau bestimmt werden können. Auf gewisse Anflugverfahren wird man auch verzichten müssen. Nun ist, bei Ausfall, der Flugbetrieb navigstorisch eben wie vor der Jahrtausendwende. Ging wunderbar.
Modern commertial planes have advanced avionics with charts inside so they can autamatically derive their locations from various types of radio beacons so it is not like they can get lost in such densely populated areas. And somewhete far over the ocean GPS jamming should not be an issue unless some idiot passenger decides to jam GPS signal while staying onboard. So this should net be a critical issue although it can indeed be a big annoyance especially for older airplanes.
Hi Petter - When flying a GLS Approach, the B787 sets itself up for a 3B Autoland with all required FMA and PFD indications such as ‘LAND 3’. So it looks as though the 3B Autoland Capability on the 787 is there, we just can’t use it yet. I’ve checked it several times in the FFS and all functionally such as FLARE/ROLLOUT are there. We do fly GLS approaches to CAT 1 where available, such as KEWR/EDDF.
I view this as primarily just creating a need for better software and hardware to deal with how GPS/GNSS and INS data are used. As an engineer, I would NEVER discard the actual INS data or the ability to display and use it. Basically, you want to keep access to the uncorrected INS data which is TOTALLY independent of any GPS jamming or spoofing that the flight encounters. As soon as jamming and spoofing are detected, just turn a selector switch from using GPS-corrected INS data, to using uncorrected INS data. Add in a few safeguards about checking that the position used when initializing the INS is correct (and not itself a false location) and you're 99% of the way to being unaffected by jamming or spoofing. Just use INS to get near your destination, and use other methods to descend and land. Knowing the drift specs of the INS, and the terrain anywhere within that radius (or several times it) on your approach, you can decide whether to completely ignore INS during descent, or correct it via any of a long list of methods, while again retaining access to the uncorrected INS. If GPS is completely down, you could even recalibrate by having another plane that just took off, fly alongside you with fresh, undrifted INS data to transfer.Or something as crude as using barometric altimeter and passing over a waypoint, and some weather correction, could put you back in business. Maybe not to spot-on accuracy, but to something usable. Even if the initial location when initializing INS is incorrect, if the plane is at rest and all velocities and rotation rates are correctly set to zero, and the correct airport elevation is entered, you will be in decent shape. If lat/lon are close to correct, so much the better. If lat/lon are precise, then the INS is doing exactly what it needs to do. The INS accuracy will drift, but hey, INS using much less precise hardware (electromechanical accelerometers mounted on gimbals/bearings more precise than a Swiss watch, and angular acceleration sensors) rather than the modern laser ring gyro hardware. In the 1990s, I was working on a project in a Honeywell facility where they worked on laser INS. I wasn't even allowed to go to the Men's Room without an escort with the proper security clearance to keep track of visitors. It was tighter security than I'd encountered even at a customer who builds nuclear submarines. Of course, that was back when precision use of GPS in real time was only for the military. Land surveyors could get some precision by placing a device in one place for hours at a time, and post-processing the data for that location plus some known ground stations. Not of much use to someone aiming a missile at us, like they can now using our GPS or their own GNSS.
Typo: at end of paragraph 3, add "got us to the moon and back, albeit with an occasional update using a sextant."
I'll note that GPS spoofing isn't a problem for US military aircraft, as they still have an encoded military system only accessible to the military so there's no way to reproduce it for spoofing.
In addition to the systems you mentioned, remember that ADS-B is usually dependent on GPS. So in many cases of GPS spoofing, air traffic control is also seeing the false location of the aircraft.
Which in theory is good, as there could be a Secondary Radar/ADS-B disagree alarm, and ATC could alert the pilots.
As a captain at sea i always wondered about the reliance on gps signals. I had multiple gps blocks only due to weather. Let alone its a system with a build in error from the start. 100 mtrs mostly but.. yes i do fly in simulators and this reliance always intugued me i always always would choose a VOR approach over a gps but than again i sail at sea where things go slow. Back rule i teach all Navigators dont rely on one system always always back check with another like radar or your eyes... Hard in adverse weather but that will be the time you need it most
I'm a recreational sailor and have been wondering the same thing. So I recently bought a sextant and started learning how to do celestial nav. As I was researching which model to buy, I ran into way too many "captains" online insisting that it's a complete waste of time since "you'll ALWAYS have GPS". So, now I'll have to add widespread jamming and spoofing to the list of reasons to carry a sextant on a long passage.
Thanks Petter, great as always. I was flying 747 classics long before anyone considered GPS, and doing “manual” INS updates by tuning ground stations. Then we went to laser ring gyros and much better accuracy (and reliability), and then in the 90s we started having GPS systems to update inertial reference systems automatically, and finally in the early 2000s we (Qantas) were the first operator in the Southern hemisphere doing RNP approaches. And now, with this sort of evil around, we might end up in a really troubled scenario again, as this has the potential to kill people. I’m glad I’m retired- you young blokes (and my son!) will have to deal with this. It’s sad.
Petter your sessions are clear and informative. Thank you. I was crossing the big island of Hawaii with the GPS in my car running. There is only one road, called the saddle road, over the island. As I approached the army post there I realized that according to my GPS I was actually in the crater of Mauna Kea. Fortunately it was a clear sunny day.
I remember riding a Twin Comanche from a uncontrolled field to LHR many years ago- well pre GPS! We started at about 6am and arrived just before LHR's jet curfew opened. We started as a night instrument takeoff from a dark runway and navigated by beacon into the airways system to do a full instrument approach and landing at Heathrow. My return flight was the reverse, full control and instruments out of LHR then leaving airways for a route to a non radio airport. Sadly now no-one wants to pilot a plane by beacons and when the rolling map says the wrong thing everything STOPS.
Well, a lot of the reason that nobody wants to fly an aircraft with beacon based navigation is that a lot of those beacons are being turned off and/or otherwise decommissioned because of budgetary reasons. So it's not just that nobody wants to put in the effort anymore, for some routes it's simply not possible anymore because there are too many beacons missing along the flight path. I agree with you, it's a shame all the same, but I have no idea what to do about it aside from properly funding the FAA and FCC. That would also solve many other issues, like ISP's that have "Only one company providing a relevant high-speed option in your area" (but the FCC says you have DSL and dial-up options too so it's "not a monopoly" and "their hands are tied"), and the (now seemingly constant) issues with Boeing. IMO Boeing is currently hamstrung by its shareholders, who demand constant and infinite unsustainable growth. The solution is to re-assume control of the company by engineers, for aviators. This would happen by buying back all the stock with a "take the deal or it's worth nothing" style stock split, current shareholders that are forced to cash out would get a "fair but non-negotiable" price. Then fire anyone in a leadership position that doesn't have an aerospace-engineering-related degree. Replace the people in those positions with only people that have aerospace-engineering-related degrees. Boeing rose to greatness because it was wholly owned and operated by engineers. When they merged with MDD there was a huge culture shift that happened, and if you ask anyone who works on or pilots airliners, they'll tell you that Boeing hasn't been the same (in a bad way) since that merger.
When I retired from aviation as a senior Captain GPS was not used in any aircraft. What is this all about? What has changed?
Didn't realise before that IRS is a rapid electronic 3D version of dead reckoning with regular updates from other sources similar to that used decades ago by ships. Which then used compass, heading times and wind and current directions with updates using a sextant and an accurate time piece. Thank you for the explanation and clear grafix.
Another excellent episode. Our airline has introduced formal procedures to mitigate this increasingly common problem, which is now a virtually permanent issue in the areas you mention. The most irritating problem is the introduction of a large time error to the aircraft „ master clock“. Once introduced, on our aircraft, it is impossible to correct until corrected by receiving correct time again from the GPS system when reactivated after disabling it exiting areas of known interference. This means that we must disable the GPS before entering any area of suspected GPS spoofing to avoid an uncorrectable false time being introduced to the FMC with all the related complications this causes.
FWIW, SBAS is still often referred to as WAAS (Wide Area Augmentation System) and the GBAS associated with airports is still often referred to as LAAS (Local Area Augmentation System). DGPS (Differential GPS) is the GBAS often used at construction sites, farms, and for scientific research and it uses a different method of communications than the airport-associated SBAS & GBAS (WAAS & LAAS) systems.
WAAS is the north american implementation of SBAS. So they are not synonymous but SBAS is the hypernym of WAAS, EGNOS, GAGAN, MSAS etc. LAAS is the former FAA term for GBAS.
@@FoxtrotSierra Those names are still often used in GPS "client" device documentation. That's the only reason I mentioned them. I have zero reason to believe that you aren't right otherwise.
A better receiver could listen simultaneously to all satnav constellations from different countries, and fuse the results with some rules for discarding outliers. So one would have to spoof all constellations in order to be undetectable. There is probably also room for improvement in antenna design, GPS signals should always come from above, so installing multiple antennas that have stronger directionality, and more complicated receivers could also help reject ground-based spoofing. Probably something like a large phased-array GPS receiver on top of the aircraft would be best.
your phone combines GNSS constellations.
Good receivers are already designed that way. The one on my phone defaults to GPS, but if it sees data that doesn't make sense it switches to Galileo, and if it still sees data that doesn't make sense, it switches to GLONASS. And if _THAT_ information doesn't make sense, it restarts, throwing a "GPS Not Found" alert until it can make sense of the data. There are enough regular GPS satellites that normally if it sees data from one or two satellites it is using for the fix that doesn't make sense, then it throws those out and swaps to the next best satellite. While GPS needs 4 satellites to get a fix, there are usually around 8 visible to a receiver on the ground at any given time, even more in the air
@@richardmillhousenixon Yes, a phone does that. But a plane is probably subject to all kinds of red tape and political issues where a plane flying under FAA rules would "not be allowed" to receive GLONASS or Beidou. Maybe Galileo, or not even that.
@@Rob2 They're generally allowed to use whatever gets the best fix, because aircraft fly all over the world. Usually that's Galileo or Navstar, but sometimes it's GLONASS. Don't know about Beidou though, but I assume it's the same way
@@richardmillhousenixon planes should be allower to combine GPS, Galileo, Beidou and Glonass together as that does increase accuracy above what each individual system of those 4 is capable of. Additionally, GPS uses L1, L2 and L5 frequencies, as outher 3 do so even more data to combine together (like modern smartphone do)
In the early 90s, i was surveying for forestry. I had a huge backpack, and a tall aerial smacking into the back of my head, and I'd walk a flag line. The intentional error was 10 meters, but a straight line could be drawn between the points. But, when i hit a corner, i had to wait for 25 pings to average an accurate point.
👏👏 quality of your videos are so good! I remember in the old days I liked your videos but you’ve upped your game. Lillebror Norge er stolt! Jätte bra!!
One can spoof GPS (in a small area) with a ~$200 HackRF or similar transmit capable SDR (software defined radio). I'd imagine that the spoofing could be extended over a larger area much the same as my legal transmissions are, with an external power amplifier and some filtering (for GPS, likely a band-pass filter).
An updated form of GPS is needed that encrypts both the military and civilian signals. That would allow us to use certificate validation to authenticate whether the signal we’ve received really is coming from a GPS satellite. It would also open up the possibility of a shared standard for how these systems work, where the only difference between civilian signals would be the root certificate authority used to sign the signal. This would further allow airports etc to broadcast *true* GPS signals with their own certificate signing them, and each operator to choose a set of root certs that they trust.
apparently Galileo is already updating to something related & should be operational in a couple of years.
How would you encrypt the civilain signal? For that to work, you would have to give the encryption to the public which would defeat the purpose.
I've been a long time out of IT. So may be wrong, but I believe the signal from the satellite would be signed by its Private Key which only said satellite would have and the Public key for that satellite would be freely available to all would be used to verify the signal signed by said Private Key. The signal need not be encrypted, just signed. @@Kriss_L
@@Kriss_L No, you give your public encryption key to the public, and sign your messages using your private encryption key (that you don't reveal to anyone). The way that PKE works is such that someone who receives your message can use your public key to verify that only the owner of the corresponding private key could have signed it.
@@Kriss_L no asymmetric encryption exist. The sat would have a private key it uses to encode the message. All receivers would use the public key to decode the signal. And you would rotate keys every so often.
There are always counter measures from longer, perhaps assisted correlations (not on approach) to phased array antennas (which for GPS are cheaper than you probably think). Upgrading the quality of basic GPS receivers would help a lot. I am retired RF and systems engineer who often had to overcome GPS problems.
I've seen a large number of comments asking why Public Key Infrastructure (PKI) based Massage Authentication is not used with GPS (and other GNSS). Being a person who has implemented the TRUSTED side of PKI-based systems I can say with 100% certainty it isn't as easy as it may seem. Not only that, but keeping malicious devices from getting valid private keys assigned to them and keeping those keys from being trusted would be extremely difficult-especially in an aviation environment. As for implementing PKI for ADS-B, that would be even harder than doing it for GPS…and in both cases I'm intentionally ignoring the changes to the protocols (which are baked into millions of devices at this point) which would be nearly impossible to make the way many people are considering.
That only solves HALF of a problem. Exact timing of a messages is crucial and that can be can be messed up with by a sufficiently clever attacker (for example retreansmitt signals coming into antenna located somewhee else). Attacker with sufficiently advanced beamforming capability - recieve signal from all visible satelites, separate all those signals via knowing where satelites are, MIMO antennas and a lot of math (i9 14900k or R9 7950x - overkill amount of fast enought), apply appropriate amount of delay to each signal and retransmitt combined output into transmission antenna and GPS spoofing works even with encryption.
@@volodumurkalunyak4651 I think you might want to look up the actual signal delays before you explain anything to anybody. I'll leave it at that.
Just an idea, I don't know if this is practical, since this is not my field - if you had a GPS antenna which consisted of a cluster of directional horns, mounted to the top of the aircraft, it could pick up the GPS signals & know the approximate direction of each of those signals. A secondary or re-transmitted signal would be coming from the wrong direction, and could be filtered out. A phased-array antenna might be able to do the same thing. It just feels like there's a technical solution possible given that the spoofed signals would be inconsistent with their direction of arrival.. It also ties into the 'single pilot cockpit' ambition of aircraft manufacturers. For their vision to be realistic, the autopilot should be good enough to land on it's own if the pilot is incapacitated - despite spoofing etc.
Just use a satelite to spoof the signal.
@@Kriss_LIt'd need to be a satellite in a similar orbit to the original, and you'd need enough spoof satellites to mirror a significant fraction of the GPS constellation. And their positions would be known to all the military satellite tracking systems, so it'd be kind of obvious to those observers.
all satellites are in orbit so a receiver pointing down should detect spoofed signals in most situations.
@@alanhat5252 Not if the spoofed signal comes from another satelite.
@@WyndStryke So adding an additional capability to GLONASS birds would do the trick.
Transmitting corrections to GPS signals was actually a big thing when civilian GPS was intentionally inaccurate
Turned off for Gulf war 1, because the US military needed so many GPS units they had to go buy off the shelf ones, and use them there. Then really never turned it on again.
Actually SA, "selective availability" or also called "spoofing," was finally removed from the signals in L1/L2 and CA codes at the end of 1999. Civi and even military use back in the early 90's was pretty limited for any kind of precision, due to lack of satellites in the constellation.
In a long line of excellent videos, this is a particularly excellent one. Great content wonderfully explained. Thank you
The software needs to be designed to spot and handle failures like this. By logging the corrections and using data from different sensors you should be able to detect jumps in position and/or corrections that are outside of reality and act on it. You can make use of other GNSS systems, turn off ground based corrections, employ other navigation systems to detect these intentional errors. Just as MCAS didn't have an error detection subroutine and let bad data change the correction beyond what was is possible in reality. In software you can never trust the data fully. You need to check that the data doesn't lead to a conclusion outside of reality.
Same for ADS-B, Mode S, Mode AC, and many systems that can be spoofed with $200 worth of radio hardware.
Not to mentioned anyone with a handheld radio can get on Tower frequency and start issuing fake clearances. Clickbait title for sure.
Great video! Maybe it‘s time to implement some kind of encryption and authentication into GPS data?
Military receivers already do this, but I'd imagine civilian ones would need to be totally replaced with models that can handle the increased power consumption of decryption as well as somehow get updates for those digital keys when they expire or get compromised and revoked.
Fascinating subject and excellent description of how it works. Thank you
I have also experienced it , it started around 10,000ft , and eventually got a terrain warning at 300ft on finals on a very marginal wx conditions.Since I was visual around 400ft and knew the airport had no terrain any where nearby ,went ahead with landing
Nice video! 1. Simple solution to the spoofing problem is using public key cryptography and signing the GPS data with a public key. The long-term problem however is quantum computers. There're already PQC algorithms but which of these will stay secure in future is an open area of research. This is mostly a problem if dealing with nation-state level adversaries not random small actors. Any update though would require updates to both satellites and airplanes, which would definitely cost something. 2. Jamming is another much more harder problem. There's also research into pulsar-based navigation. Terrain-based navigation is one thing but even it doesn't reach GPS and doesn't work over ocean that well. Pulsars are extremely accurate but because of huge distances, the accuracy of measurement is still a lot less than GPS (in kilometers). Now dish in inertial navigation and you got at least something. 3. Internal clocks probably shouldn't use GPS. Rather use some sort of secure dual-way link at airport to sync and just run internally. The drift with (several) modern clocks over a single flight is too small to make a difference. Same goes for inertial navigation reset (the airport SHOULD know where it is :-). In fact you could just have it pre-loaded on iPad or paper and reset it after landing (hopefully at the right airport). Airports don't usually move that much.
On point 1, there are already practical encryption algorithms that are immune to quantum computing attacks, thankfully.
Unfortunately public key encryption wont save you here. Unless you have a session pke is still vulnerable to replay attacks. Since a session requires bi direction communication that is not possible for GPS. Of course it will make attacks harder but by no means protect against it.
Yes, digitally signing the GPS data seems like the logical move. I don't know whether this can be done using existing satellites via a software update, but I doubt that the existing satellites in the GPS constellation have what's needed to continuously sign the data stream unless the USSF has been planning for this eventuality for some time (which is absolutely possible of course! - For all I know this capability is already available since clearly the US military wants to ensure its precision weapons aren't susceptible to spoofing) I don't think it's especially concerning that quantum computers might be used to break this signature, since we're looking to counter a fairly low-end threat model here. There are more practical ways to bypass this particular countermeasure than bruteforcing the key and using it to generate fraudulent signed GPS data, especially for state-level or well-funded terrorist group type threats.
@@CodingRays Replay attacks do not work well when you have the timestamp inside of the package like the GPS package. You could dismiss the one that are repeating or differ too much from an internal clock. Of course you can replay messages from another location but that kind of routing it will add detectable time delays.
The internal clock the GPS uses ideally should be synced from the satellites themselves. This is to keep the error circle as small as possible. The satellites are syncing with each other, and then they sync with the ground. But that means that while they can be very accurate to each other, they may have a very small variation to the real time on the ground. And since GPS uses time-of-flight to gather positional data, even a 1 microsecond variation means an error circle of nearly 300 meters.
I think a "GPS Error!" audible warning should be implemented when the plane (according to GPS) suddenly teleports somewhere else and it should automatically stop the IRS from updating from GPS until the pilots confirm the GPS data is accurate again.
I had spoofing myself yesterday departing from Paphos, in my case I even had the RA showing zero! Position was unaffected but elevation was ‘thinking’ we were on the ground (including EGPWS call-outs). The Garmin 3000 is HEAVILY (basically solely) GPS based so it’s always interesting to have spoofing/jamming on the Phenom… in fact 2 hours later, on the same flight, over the Black Sea we had jamming and in that case everything goes on the navigation part, since the aircraft does not have proper IRSs (only 2 AHRS systems). All you can do is ask for vectors or track radials 😅. Great little aircraft but this is its one big flaw (no DME/DME either)!
When traveling on an airline (as a passenger) that doesn't have any screens that display a map then I result to IFR (I Follow Roads). Of course this is easier for me since I'm a truck driver with 9 years experience and travel all of the lower 48 states and love looking at maps/ satellite view. I'm very familiar with the countries road network and can recognize all the landmarks/ cities to aid in navigating. Of course when there is cloud cover this becomes more difficult and knowing the approximate route, expected flight time and elapsed time helps quite a bit in determining location. Personally I can't stand not knowing my current location and how to get back to where I need to go
I'd love to know: 1) At what altitude (below) does the barometric altimeter require use of the ground QNH? The barometric altimeter, I'd assume, uses the standard QNH in cruise. 2) At which altitude does the radio altimeter start being used? 3) GPS provides altitude data (though it's not terribly accurate) -- it seems that the EGPWS is using the GPS altitude to check against its database 4) Given the 3 discrete sources of altitude data, what is displayed on the instruments in the cockpit?
1) Varies from country to country. In USA and Canada its 18,000ft/FL180, in Europe it's usually 5000/6000ft but ATC will determine the TL. Netherlands is 3000ft 2) Typically 2500ft above the ground 4) Barometric is always shown on the PFD unless aircraft has an alternate source. In that IG video, to the right of the PFD is a BKUP SPD/ALT button. Press that and altitude uses GPS (not as accurate) and airspeed uses the AOA sensors to calculate a safe speed zone. This is for A320's, A330s and A350 has slightly different version. 787 also has a synthetic system
The EGPWS Geometric Altitude is computed using a blending algorithm that looks at all altitude sources including GPS. So it’s hard to give a definitive answer.
1 depends on where you are. See Transition Altitude. In the US and Canada it is 18,000 feet. Last time I was in the UK it was 5,000 feet. New Zealand used to 11000 feet and now is 13000 feet. If you need to navigate in the flight levels, above transition altitude, you will see that on your flight plan. 2 Radio altimeters are only good for about 2500 feet, partly because they are cheap garbage, which is why some cell phone signals well outside of the rad alt band have to use low power. 3 GPS altitude accuracy is better than it used to be, but it wouldn't be my choice. Military receivers are much more accurate, but that doesn't help aircraft. Currently I am at 80 feet and the GPS on my phone says -20. 4 Pressure altitude, because that's what everyone else is using, and for commercial aircraft hitting other aircraft is much more likely than hitting unexpected ground.
1. When below the Transition Altitude. In the USA this is 18000’, in the UK it is 6000’. Above the Transition Altitude altimeters are set to 1013 HPA or 29.92 inches of mercury. 2. Radio altimeters will show a value if the aircraft is 2500’ or less above terrain. 3. In some cases such as when BARO ALT may be in error (eg Blocked STATIC PORTS) some aircraft (eg 787) will automatically switch to displaying GPS ALTITUDE. 4. In normal operations, the altimeters display altitude from BAROMETRIC sources. The Height above ground will be displayed on the Radio Altimeters when the aircraft is at or below 2500’ above the ground. NOTE: When the Altimeter subscale is set to 1013mb/29.92”Hg the value displayed is Flight Level. When QNH is set, the altimeters will display Altitude above Sea Level.
@@tomstravels520 Good comments but I disagree with " uses GPS (not as accurate)". Using the barometric altitude based on STP (standard temperature and pressure) is not as accurate as GPS, that's why the airports ATIS publishes the offset from STP to local STP. In cold and warm fronts the local STP can vary hundreds of feet while the GPS is better than 45 feet 95% of the time and typically within 20 feet 50% of the time.
I thought it said "Spooning at work" You had my attention
Isn't that how everyone works that isn't customer facing?! 🤣
Oh, my!
@@Naptosis hahaha good one!
@@flagmichael don't pretend like you didn't notice michael you little joker
Kind of old discussion. Remember back when B767 was new, GPS was kind of nice to have when lining up IRS. If US it was a MEL item. Main source for updating IRS was DME. GPS was under military control and could not be used as primary nav source, while VOR system was controlled by aviation authorities. That is what we learned at courses. For decades Widerøe operating near Russian border occasionally looses GPS due Russian military exercise with jamming. Ends up with delay when they have fly old fashion VOR navigation.
I enjoy how you explain complex subjects in easily understandable terms.