Subscribe
Share
Share
Embed
"The Wing Wag" is a podcast for all things general aviation. Are tailwheel or nosewheel airplanes better? What is it like to own an airplane? How do you pick the right flight school? All these and more will be answered on "The Wing Wag".
Your pilot will be Jack Olinde, an aviator and owner of an aviation company and flight school in Central Florida. Each episode, Jack will navigate an aviation topic either flying solo or with a copilot.
Join us as we take to the skies in each episode, and if you're out flying make sure to give someone a wing wag!
Welcome to The Wing Wag. I'm your host Jack Olinde. I'm an instrument rated pilot and the owner of an aviation company and flight school here in Central Florida. This podcast is for informational purposes only and is not guaranteed to be accurate or complete. While we research each topic, we are humans and occasionally make mistakes.
Speaker 1:For the most up to date information on regulations, check out the official federal aviation regulations, also known as the FARS, or consult an aviation attorney. Lastly, the opinions expressed on this podcast are the guests' opinions and are not necessarily the opinions of the host or podcast. Imagine that you're an airline pilot doing your standard red eye route. You've done this route dozens of times before with very little variation, and tonight seems to be no different. All of a sudden, your primary flight display begins to show a red alert flashing, and an automated voice fills the cockpit.
Speaker 1:From experience, you know that there should be no obstacles on this route, but your instinct takes over, your training kicks in, and you begin a high performance climb out of habit, out of muscle memory. After a few seconds you begin to feel that something isn't right. You're still climbing but the alert is still blaring. You know that there are no obstacles on this route, and you look at your altitude and it's 35,000 feet, and there's no way any terrain could possibly be in our way, be close anywhere near the plane. Then you notice that the GPS is showing you in a location hundreds of miles from your planned route.
Speaker 1:ATC then calls you up and asks why you've busted your assigned altitude. Welcome to this week's episode of the wing wag. Today we're gonna be talking about GPS spoofing. So the story I told the beginning is a hypothetical situation of how it might feel to be a pilot flying through a known GPS spoofing region. So let's begin by talking about what exactly GPS spoofing is and the related phenomenon GPS jamming.
Speaker 1:So GPS jamming is when a malicious actor simply sends out random signals with the same frequency as GPS signals to drown out the the real GPS signals, and so any receivers in that area will just see the noise from the jammer without being able to pick up the real signals and so their GPS won't be able to calculate a location. GPS spoofing on the other hand is when the malicious actor sends out falsified GPS signals that are stronger than the real ones and so the receivers in the area will hear those falsified signals in calculating incorrect location. GPS spoofing can come in a couple of different flavors. One is where the spoofer will spoof all GPS receivers in the same area to a single point. There are some where this GPS spoofer will send all GPS receivers into a pattern, for example a circle or figure eight, and there are more complex versions of GPS spoofing where the spoofers will send the receivers along a realistic looking route that might be harder for the receiver to realize that spoofing is taking place.
Speaker 1:So GPS spoofing first was reported in late twenty twenty three but then experienced a sharp increase in 2024. Up until in one month in 2024, there were 41,000 flights where GPS spoofing was reported. So something interesting. So they were saying the first time airliners were reporting GPS spoofing was around the 2023. When I was doing my flight training at Yellow Jacket Flying Club at Georgia Tech, there were some reports of some of the students noticing weird GPS signals when they would fly over military bases in that area near Atlanta.
Speaker 1:And this was probably late twenty nineteen, early twenty twenty, so so a few years before GPS spoofing was was more of a known problem, so the military had been experimenting with this for a while. Thankfully, there's very little GPS spoofing in the Continental United States besides maybe some one off instances like the one I mentioned near Atlanta. The vast majority of the spoofing cases that we see occur in one of just a few regions, the Middle East, the the Eastern Mediterranean, the Baltics, Russia, and Ukraine. Real quick, I want to talk about how GPS actually works and what's going on when a receiver is being spoofed. So GPS refers to a constellation of satellites that provide global location services.
Speaker 1:There are other constellations like this like there's one for Russia called Galonaz and I believe there's also one for Europe and Japan. These satellites are constantly sending signals that contain various information but in particular it contains the time that the satellite is sending it. So when a receiver picks up that signal it can see the time the satellite sent it and it can compare it to its own internal time to figure out how long that message must have been in transit. Since we know the speed of light and we know the time that that message was in transit we can calculate the receiver's distance from that satellite. Then the receiver does this for at least four satellites and so now we have our distance relative to four different satellites.
Speaker 1:The receiver can look at an internal table of satellite locations, so now it knows where the satellites are and it knows its distance from each of these satellites, it can pinpoint exactly where it is located. And so this internal table of satellite locations is stored in the receiver but it's updated every so often from the satellites. They'll send down a copy the latest copy of the satellite locations. So like I said, four satellites is the minimum for a receiver to calculate its location, but with every satellite that you add, it adds redundancy one, and two, it improves the accuracy of the calculation. GPS receivers also use the satellites to set their own clocks.
Speaker 1:So when somebody wants to spoof a receiver, the most basic thing that they can do is simply send out a signal that has the same frequency as a known satellite signal but with a stronger power so that it overpowers the true signal, and that signal should include an incorrect timestamp so that when the receiver calculates the the time in transit, it will calculate an incorrect distance to one of the satellites and throw off the location calculations. If a spoofer wants to be a little bit more sophisticated, they can actually send an updated copy of the table of satellite locations and what you can actually do with this is the receiver stores not only this table of locations but they store an expiry date that comes from the satellite that tells you for how long is this table valid. For example, a satellite might send out a copy of the table and give an expiry date of five minutes in the future, meaning that this table is valid for five minutes. After that you'll need to request another one from the satellite. So the the malicious actor could send a falsified copy of this location table but set the expiry date to be far in the future.
Speaker 1:And before we talk about what the implications of that we need to talk a little about RAIM. So RAIM stands for receiver autonomous integrity monitoring and it is a software that's inside of some GPS receivers that allows it to detect when there is a problem with a satellite and occasionally correct that error. So if you remember, a GPS receiver needs at least four satellites to calculate its location, but if you have more than that that adds redundancy. So if you have more than four satellites, what RAIM will do is it will take different subsets of all of the visible satellites and calculate locations based on just that subset. So for example, if you can see 10 satellites in this moment it'll calculate your location using all the subsets of four and then all the subsets of five and then all subsets of six and so now you have a whole bunch of location calculations and it will do some statistical methods on these to figure out which are outliers and then once it's identified which are outliers you can go look at which subsets generated these outliers and sometimes pinpoint which satellite is causing the problems.
Speaker 1:So in general if you have five satellites that's when error detection becomes possible and once you have six satellites that's when air isolation becomes possible. These are not guaranteed by RAIM though. The more satellites you have the more likely it is going to be able to correctly detect and fix the error. So back to our example about the malicious actor who has sent to our receiver a falsified table of locations with an expiry date far in the future. So let's say that we're flying and we currently have 10 satellites overhead that are visible.
Speaker 1:We'll call them one through 10. So what the spoofer can do is it can send us an updated table that has the locations for satellites 11 through 20, which are currently not in sight, but they will be in a few hours as we keep flying. So in that moment we don't notice any issues with GPS spoofing. Our satellites one through 10 have correct location information so we're correctly calculating our location but as we move first satellite 11 comes into view and it gives us a falsified reading but thanks to RAIM it's able to isolate that one satellite and exclude it and we're still able to calculate our location. We fly a little bit longer, satellite 12 comes into view.
Speaker 1:Now we have two incorrect locations and RAIM is still able to exclude but one by one each of the incorrect satellites or each of the satellites that can that contains an incorrect location in our location table comes into view and with each one added RAIM has a harder and harder time isolating all of the incorrect satellites and our estimation of our location is degrading. And because the expiry date on that table is so far in the future, our receiver is never replacing it with the correct table from the satellites. We're continually using that incorrect table until eventually we hit a point where overhead we only see satellites from that incorrect table and we are unable to calculate our location correctly at all. And so in this case we were spoofed hours ago but we never even saw the effects until we were hours down the road. And so what can you do about this?
Speaker 1:Really at this point the only thing you can do is just do a full reset of your GPS system. Maybe you can do that in the air but you might have to do that on the ground as well to make sure that you've cleared the location table and accept a new one from the satellites before you continue on with your next flight. As you can imagine encountering GPS spoofing while you're flying can be very dangerous. At the very least, it can cause a lot of inconveniences. The most obvious dangers are things like controlled flight into terrain, see fit.
Speaker 1:Right? Flying into a mountain because you thought according to your GPS there were no mountains nearby when there really was. Flight into dangerous or restricted area when you didn't know about it and these dangers are way worse during IFR flight as you can imagine. ADS B and ELTs also use your GPS location when they when they broadcast so those will be broadcasting incorrect information while you're being spoofed and the ELT one is is especially scary because that is kind of your lifeline in the event that you crash in like a rural area or in the ocean. Thankfully there are ways to calculate your true location based on your ELT signal even if the ELT is broadcasting an incorrect location.
Speaker 1:So for example, by by measuring aspects of the signal itself, you can estimate the location of the ELT even if what's in the signal, the location in the signal is incorrect. But still it's kind of scary to think that, you know, the the thing that's supposed to save you in the event of a crash could be broadcasting an incorrect location. Some of the inconveniences are surprise climbs like we mentioned that story at the very beginning of the podcast where you you start climbing very fast to avoid terrain that's non existent. This can lead to separation loss with traffic around you, which in turn leads to excessive workloads for ATC. Because if you're a controller in a region that has GPS spoofing going on, you now have to you now have to consider the fact that any of the aircrafts in your region might be affected by the spoofing and therefore their own navigation can't be trusted and you basically have to give vectors to every single person in your region.
Speaker 1:So that's just that's a huge amount of workload for for a single controller. And then not to mention as a pilot, if you are constantly seeing GPS spoofing, you're gonna begin to have a loss of trust in your equipment and you might begin to ignore real alerts when you're not in a spoofing region because you see the, for example, you see the pull up alert so frequently that you're kind of immune to it. So when you see it in a situation where it's real, you just ignore it. It's like, yeah. I see that all the time.
Speaker 1:So how worried should we actually be about this? So I guess that depends on where you're flying and what you're doing. If you're an airline pilot who's constantly doing night or IFR flights into The Middle East to Russia, then maybe this is a big concern for you. If you're a general aviation pilot in The United States, then maybe you don't have to worry about this at all. Right?
Speaker 1:There's very little GPS spoofing going on in the Continental United States at least right now, but there is the possibility that this could expand out of its current regions and become a lot more widespread worldwide because each year the equipment needed to do GPS spoofing becomes cheaper, smaller, more effective. It's definitely reasonable to think that there could be a day in which a terrorist or someone could bring one of these devices into a big city in The US and spoof all the flights in a certain radius. While I'm not personally worried about it right now being here in Florida, it's definitely on my radar as something that I need to consider in the future and start planning for now. And thankfully, there are a lot of very effective solutions to GPS spoofing out there, and those solutions fall into three, like, general kind of ideas. The first is, like, software solutions, hardware solutions, and pilot solutions.
Speaker 1:So software solutions are things like algorithms to better detect satellite outliers. Like RAIM we were talking about earlier is a great system, but RAIM was never meant to fight GPS spoofing. It was meant to fight like little errors that might arise from disturbances in the atmosphere. So while it's being used to fight GPS swooping a little bit, it's not optimized for that. So there could be a new algorithm that's devised that's better for identifying what malicious signals.
Speaker 1:I'm sure you could there could be like an AI or machine learning component there. For hardware, you could have a device that analyzes the incoming signals like tries to find out where they're coming from. If you see a signal that's coming from the ground it's clearly not a GPS satellite and so it should be excluded. You could also have receivers that are able to pick up signals from all the different location constellations in the world, not just the American GPS but also the Russian glow that has an European one because the more satellites that you can see the more fidelity your location will have and it's also the more signals that a spoofer would have to spoof in order to make you have an incorrect reading. You could also have a GPS system that takes in GPS as a single input but not the only input.
Speaker 1:It would also take in things like the altimeter, it could take in a VOR if you have that installed, a DME, other more traditional means of navigation, and combine all of these together into a single location reading. And so if something is wrong with one particular satellite or GPS in general, it can fall back onto the other sources. These are cool to think about and try to, like, come up with ideas to fight GPS spoofing, but the only real solution that is going to be always effective is the pilot behaviors solutions. Right? And that is in our training, we're we're taught a variety of ways of navigating.
Speaker 1:The first one being just like visual navigation with a dead reckoning. Right? For our PPL cross country, they have us fill out a flight plan, like a paper flight plan. On these flight plans, you you put down your flight legs, you put down how long each leg will take you, what your heading should be, and then while you're flying, you are timing each leg. You are making sure that your heading indicator, your compass, is showing the correct heading that you estimated, and you're looking out the window for your waypoints.
Speaker 1:Obviously, you can't do this when you're flying IFR, but this method of navigation requires no signals from a GPS and cannot be spoofed. It always works in VFR flying. Additionally, we throw in things like VOR, DME, other radio sources of navigation, that gives us another thing we can fall back on. And we we don't have to give up on the GPS entirely. If we use GPS as simply just one of the tools in our bag of tricks along with the radio navigation, the visual navigation, the dead reckoning, paper flight plan, if it it will be very apparent if one of them is being spoofed right?
Speaker 1:If the GPS is being spoofed it will be very apparent because it won't match up with any of the other sources of navigation that we're using and so this is why I think it's so valuable for students to continue learning kind of what some people might call the old school way of flying of doing paper paper navigation, learning how to tune VORs and DMEs because GPS, while it is an amazing tool that has has really increased safety in flying and allowed things that that probably old pilots never thought were possible like IFR approaches down to very low minimums. So while this is all true, GPS spoofing in the last couple of years has shown us that it is not foolproof. It has its own weaknesses like every other system, and it cannot be relied on entirely. And so when a student is learning to fly, learning how to use the GPS should just be one aspect of their training. And once they get their license, they start flying, it should continue to just be one aspect of their navigation because pilots have a habit of learning these things in their training, but then once they actually get their license and start doing their own cross countries, just relying on the GPS, just relying on the iPad.
Speaker 1:And I myself fell into this too. Once I got my license, I just started using the GPS entirely. Completely forgot about VORs, never tuned to them. And now I'm trying to get back into that. Now that we started to lend aerospace, we're trying to instill some of these virtues from old school aviation, and I still find myself kind of fighting with this when I'm doing a cross country not to just trust the GPS blindly.
Speaker 1:But I think that that learning about GPS spoofing has really motivated me to to go back to that to those old school methods such as VORs and visual navigation really out of necessity. Like, not just because it's kind of cool and and vintage, but also because it could very well be the only way to navigate, you know, in a more dystopian future. But, yeah, let's land the plane here, and thanks for listening to this week's episode. Thank you for listening to the wing wag. If you like this episode, please consider subscribing.
Speaker 1:And if you're out flying today, make sure to give somebody a wing wag.