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Air travel is not ready for electronic warfare

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Re: Air travel is not ready for electronic warfare

#41

Post by AlotOfReading »

jandrewrogers wrote: post #23
realcertify wrote: post #17

For the past 10 years I've been travelling to Russia occasionally. Normally during a flight I like opening up my GPS app to check the location, altitude and speed of the aicraft. About a year ago I noticed that shortly after crossing Russias border the GPS stopped working. Initially I thought it was a glitch, but after a few flights it became obvious that something was going on, probably the signal was baing jammed.…

Planes have used inertial navigation for a long time. Adding GPS to that mix is relatively recent. GPS was never really intended to be used for navigation even though it can be and often is. There was no need for it to be particularly reliable when it was designed since the Soviets could easily kill it if they wanted to. It had a different purpose.

Can you elaborate on what you mean by "not intended for navigation"? GPS was intended as a replacement for TRANSIT and LORAN, which have navigation literally in their names. It's also the textbook example on Wikipedia's satellite navigation page, and I can't imagine how precise geolocation somehow wouldn't be useful for navigation.

Also, the general analysis after KAL007 was that GPS should be made publicly available specifically to aid civilian navigation. They even identify what we call RAIM today to make it suitable for eventual usage as a primary navigation system.

Re: Air travel is not ready for electronic warfare

#42

Post by burnerthrow008 »

kelnos wrote: post #2

Perhaps I just don't understand how this works all that well, but shouldn't it be easy to defeat GPS spoofing when you're 30,000+ feet in the air? Presumably the spoofed GPS signals are all coming from the ground, or close to it. I would think it would work to use a semi-directional antenna that is on top of the aircraft, pointing upward. Even an antenna that has a 180-degree field of view should reject fake GPS sign…

> Presumably the spoofed GPS signals are all coming from the ground, or close to it.

I think that's a good presumption when operating in, say, Iraq or Afghanistan. Maybe less so when operating near Russia (which has its own GNSS system)?

> I would think it would work to use a semi-directional antenna that is on top of the aircraft, pointing upward. Even an antenna that has a 180-degree field of view should reject fake GPS signals from the ground, no?

GPS receivers already do this to reject ground reflections that could give false position readings (and the GPS signal is circularly-polarized so it can reject odd-ordered reflections off building and the ground). However, any kind of steerable (electronically or otherwise) directional GPS antenna is considered an ITAR no-no.

The other problem is that GPS signals are incredibly weak (actually below the thermal noise floor), and rely on processing gain from the CDMA chipping to raise the SNR to something useful. So even an antenna with very very good rejection from the lower hemisphere will easily pass a jamming signal from the ground which is both many times closer and probably of higher power.

> Only thing I can think of that would invalidate this is if the fake GPS signals bounce off the atmosphere above the planes and come back down. What else am I missing here?

Any country with a space program could transmit the jamming signal from above.

Re: Air travel is not ready for electronic warfare

#43

Post by minetest2048 »

mikewarot wrote: post #22
chii wrote: post #5

Earlier quoted context omitted.

the gps receivers are probably not going to be able to detect the direction a signal comes from.

You're right, a cheap GPS isn't going to do that.. however, it is well within then realm of possibility to design a GPS receiver system that uses beamforming to lock onto satellites and ignore everything else for orders of magnitude better jamming resistance.

Its called controlled reception pattern antenna (CRPAs), which unfortunately is an ITAR restricted thing because of insane paperwork required, so no one wants to build it for civilian receivers. Which is stupid because beamforming (or null-steering) algorithms are not that difficult to implement, and so we already have Chinese and Iranian receivers with CRPAs.

So PNT National Advisory Board is trying to convince US government to stop putting CRPAs under ITAR: https://www.gps.gov/governance/advisory/meetings/2023-05/mur...

Re: Air travel is not ready for electronic warfare

#44

Post by jandrewrogers »

AlotOfReading wrote: post #41
jandrewrogers wrote: post #23

Earlier quoted context omitted.

Planes have used inertial navigation for a long time. Adding GPS to that mix is relatively recent. GPS was never really intended to be used for navigation even though it can be and often is. There was no need for it to be particularly reliable when it was designed since the Soviets could easily kill it if they wanted to. It had a different purpose.

Can you elaborate on what you mean by "not intended for navigation"? GPS was intended as a replacement for TRANSIT and LORAN, which have navigation literally in their names. It's also the textbook example on Wikipedia's satellite navigation page, and I can't imagine how precise geolocation somehow wouldn't be useful for navigation. Also, the general analysis after KAL007 was that GPS should be made publicly available…

GPS was trivially attackable from inception, that was not a design requirement given its purpose. The purpose of GPS was to precisely measure the planet in peacetime. A unique core capability of the US military is extremely precise INS technology, the capabilities and precision of which are closely guarded secrets and under continuous R&D. The precision of INS is dependent on the precision of your world model. GPS allowed extremely precise world models to be built globally, which provided the data model INS needs to be maximally effective. In wartime the GPS system can be killed by any near-peer adversary, but the damage has already been done to the extent inertial targeting systems have a precise model of the world.

No US military system relies on GPS for navigation. Military navigation systems use GPS as an untrusted source for fine-tuning inertial navigation within tight error bounds. Against US military systems, successfully spoofing GPS might buy you several meters of deviation. This only affects the cheapest US guidance systems, since most weapons have active terminal guidance. It is worth noting that GPS corrections are being phased out in US weapon systems, purportedly due to improvements in INS tech that moot the value of GPS corrections.

The tl;dr: GPS was developed to build a precise model of the world in peacetime that could be fed to inertial targeting and navigation systems in the complete absence of GPS. In that, it has been a massive success. US military systems have never relied on GPS for anything important. Contrary to popular media, the US has never produced GPS-guided weapons, even the cheapest systems are INS at their core.

Civilian systems use GPS for navigation, against its design, because they can mostly ignore its trivial susceptibility to hostile actors.

Re: Air travel is not ready for electronic warfare

#45

Post by mikewarot »

minetest2048 wrote: post #43
mikewarot wrote: post #22

Earlier quoted context omitted.

You're right, a cheap GPS isn't going to do that.. however, it is well within then realm of possibility to design a GPS receiver system that uses beamforming to lock onto satellites and ignore everything else for orders of magnitude better jamming resistance.

Its called controlled reception pattern antenna (CRPAs), which unfortunately is an ITAR restricted thing because of insane paperwork required, so no one wants to build it for civilian receivers. Which is stupid because beamforming (or null-steering) algorithms are not that difficult to implement, and so we already have Chinese and Iranian receivers with CRPAs. So PNT National Advisory Board is trying to convince US g…

I figured there was going to be some ITAR thing if I kept going with the brainstorm.... and you confirmed my hunch.

There are so many things these days which are almost trivial to build and somehow fall under ITAR.

Re: Air travel is not ready for electronic warfare

#46

Post by numpad0 »

glitchc wrote: post #33
coredog64 wrote: post #19

Earlier quoted context omitted.

GPS isn’t the only navigation tool. INS is pretty accurate if you zero it correctly, and VOR is good enough to keep to a specific airway.

All INSes require periodic GPS updates to limit the growth of positional error. Usually it's once per second or once every 10th of a second.

That sounds way too frequent, isn't typical holdover like 12 hours?

Re: Air travel is not ready for electronic warfare

#47

Post by MiddleEndian »

kelnos wrote: post #29
MiddleEndian wrote: post #14

Earlier quoted context omitted.

No, but assuming most of your friends and family haven't been murdered, we may assume murder is unlikely to be the cause of your death.

Whether or not my friends and family have been murdered shouldn't be correlated with whether or not I've been murdered. Unless we're all in the same place most of the time, I guess?

I'd say it's an indicator.

For instance: You may hang out with a crowd who is inclined to engage in dangerous criminal activities. You may live in a place with high crime. You may live in a place where most people are left alone, but there are a few families with Montague/Capulet style feuds that the police have chosen to leave alone while they kill each other lol

So if I have no other information, I would say someone who has a lot of family and friends who get murdered is more likely to be murdered than someone who doesn't.

Re: Air travel is not ready for electronic warfare

#48

Post by thfuran »

MiddleEndian wrote: post #14
thfuran wrote: post #9

Earlier quoted context omitted.

>The evidence shows that the contrary. Has a plane ever gone down from “electronic warfare?” Does the fact that no one has killed me yet indicate that I'm immortal?

No, but assuming most of your friends and family haven't been murdered, we may assume murder is unlikely to be the cause of your death.

But, sticking with this analogy, several of my cousins have recently been shot while going about their day.

Re: Air travel is not ready for electronic warfare

#49

Post by AlotOfReading »

jandrewrogers wrote: post #44
AlotOfReading wrote: post #41

Earlier quoted context omitted.

Can you elaborate on what you mean by "not intended for navigation"? GPS was intended as a replacement for TRANSIT and LORAN, which have navigation literally in their names. It's also the textbook example on Wikipedia's satellite navigation page, and I can't imagine how precise geolocation somehow wouldn't be useful for navigation. Also, the general analysis after KAL007 was that GPS should be made publicly available…

GPS was trivially attackable from inception, that was not a design requirement given its purpose. The purpose of GPS was to precisely measure the planet in peacetime. A unique core capability of the US military is extremely precise INS technology, the capabilities and precision of which are closely guarded secrets and under continuous R&D. The precision of INS is dependent on the precision of your world model. GPS al…

Most of the basic attacks against GPS also worked against TRANSIT, LORAN, OMEGA, and others, which were clearly used for military navigation. I'm not seeing the design differentiation with the systems that were guiding ships and missiles.

Re: Air travel is not ready for electronic warfare

#50

Post by jccooper »

realcertify wrote: post #17

For the past 10 years I've been travelling to Russia occasionally. Normally during a flight I like opening up my GPS app to check the location, altitude and speed of the aicraft. About a year ago I noticed that shortly after crossing Russias border the GPS stopped working. Initially I thought it was a glitch, but after a few flights it became obvious that something was going on, probably the signal was baing jammed.…

If you know GPS is unreliable in specific areas, it's not hard to get around with rough accuracy. There's still a compass, after all.
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