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Comment by Animats | Hacker News Reader

This used to be mostly a military problem. No longer. GPS is no longer reliable enough for civilian aerial navigation in much of eastern Europe and the Middle East.[1] "Most recently, for the one-month period from July 15 - August 15, 2024, a total of 41,000 flights experienced spoofing. Because modern aircraft have incorporated GPS into a large number of aircraft systems, the impact of a spoofed GPS signal has had severe and cascading effects. These include the FMS, Hybrid IRS, the aircraft clock, GPWS, Weather Radar, CPDLC, ADS-B and ADS-C, as well as numerous other systems." GPS is so low power that spoofing signals now take out a large area of service.

[1] https://ops.group/blog/gps-spoofing-final-report/

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There are many frequent flyers travelling on routes going through those regions, dozens of times each in the last year.

And they haven’t reported any noticeable issues caused by GPS spoofing, at least not that I’ve heard of.

So I’d be surprised if modern planes are designed such that the loss of GPS for an hour or two would cause issues severe enough to be noticed by even seasoned travellers.

Not to be a jerk, but you would be wrong. GPS spoofing is a growing problem in commercial aviation. So far it has not led to any fatalities, but it has led to a significant number of system malfunctions which degrade the safety features available to pilots.

One example that made the rounds on social media a few months back was a crew flying above 30,000 ft receiving "Terrain - Pull Up!" advisories. They ignored them, because there is no terrain on earth at 30k ft. If that had happened at a lower altitude, they would have likely had to do a terrain escape maneuver, which would definitely be felt by passengers, though it would likely not introduce a lot of additional safety risk.

The real risk comes when pilots begin to doubt that their safety systems are working correctly and thus ignore true warnings. Or when a bungled GPS leads pilots to fly into military airspace and get shot down.

Pilots can be instructed to ignore GPS related warnings and not trust GPS based systems for the one or two hour duration while they are transiting the jammed airspace.

Better yet they can be disabled temporarily since presumably the same proof can be shown to the relevant regulators, airline HQ, etc…

They aren’t automatons that must obey every single system installed in the plane regardless of how absurd the outputs are.

Yeah, I would guess that a spoofed signal wouldn't be that hard to detect - though you'd presumably need the GPS receiver to be capable of this. A spoofed signal would have to be stronger than the real thing in order to drown it out, no? So as a first guess - if a signal is unreasonably strong, the signal is probably spoofed, so warn the operator.

Read the Ops Group report. It is a very real problem. They explain it clearly. Many highly qualified people are concerned about GPS spoofing.

(Ops Group is a professional group for international pilots, flight planners, or, as they say, people who have a callsign or answer the phone "Ops".)

Of course, but these systems are installed and active with the intention of providing a safety barrier. If they are disabled while transiting jammed airspace, then they are not providing that safety barrier at that time, which is itself a vulnerability.

Besides, it is hard to determine when and where jamming will happen, and it can start and stop at any time. Imagine a truck driver trying to bypass their company tracking using a small jammer, and driving down the coastal highway near SFO. Any planes coming in for landing might lose GPS or even worse, get inaccurate results, but only for a moment or two. Is that a problem? It depends on exactly what the plane is doing in that moment and whether everything else is going right.

When I was a war pilot this was common practice. Shut off radio. You'd know they were going to mess with you in creative and twisted ways. So much simpler to put it on mute. Usually works best in situations where radio silence is also a mission parameter

> Because modern aircraft have incorporated GPS into a large number of aircraft systems

Aviation is slow. It wasn’t until recently that GPS-based landing approach became common, and even then you’re double checking with ground radar. No commercial airliner would use IMU—if ground-based radar is not operating or coöperating, you get out of that airspace.

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