Russia expected to ditch GLONASS for Loran in Ukraine invasion | Hacker News Reader

Russia expected to ditch GLONASS for Loran in Ukraine invasion

gpsworld.com

38 pointsthrow0101a28 comments

Interesting but I don’t understand why Russia would disturb/spoof its own Glonass system. What’s the point? EU has the Galileo and USA GPS, so why not use Glonass?

They make the assumption that someone will disrupt it or spoof it. Same for Galileo and GPS. Might be them, might be someone else, but they're so easy and effective to spoof/disrupt that it'd be stupid to assume they could rely on any such system.

They also suspect that other people might make use of it, and that denying its use to those others would be a good idea.

This is legit also because it’s already happening in the sea/boats, but it’s the same for every other position system, maybe they put less trust in Glonass? In this case every states/military should use a hidden/unknown position system because the “official ones” could be hacked.

I don't think that GLONASS, at least the military-grade stuff, can be hacked or spoofed, but since radio frequencies are well-known any adversary can just pump enough noise to make the system unusable. This vulnerability is not limited to GLONASS - any satellite positioning system is vulnerable to "pump too much noise and it's unreadable without space-grade stationary equipment", which is already demonstrated by Iran versus satellite television and radio.

All three systems are incredibly easy to jam. The signals from the satellites are very low power by the time the reach Earth, and in fact are below the noise floor. Recievers use processing gain tricks in order to see them at all.

I don't remember the RF energy decay rate but there is a X^2 term in there, which means the energy decays exponentially with distance. So a jammer 10 miles away doesn't have to try very hard to drown out a satellite 13000 miles away.

Not exponentially, that would be 2^X

That's why RF loss equations use dB instead of ratios or percentage. GPS is anti-jam in nature due to it's spread spectrum method but a wideband jammer could make it difficult for a receiver to build the link. Jamming mitigation includes things like using highly directional antennas and smart receivers that can recognize jammers and null them out dynamically. Additionally there is a new encrypted M-code that allows military users access to a much harder to jam signal. A smart jammer works by not just putting noise into the GPS signal bands but by mimicking the GPS signal. You don't need much power and can use an antenna array to point at planes like radar systems do. Using an encrypted code would totally prevent someone from broadcasting a fake signal because the receivers would not lock onto it and would instead lock onto the weaker, correct signal. Although encrypted M-code has just come out so I doubt Ukraine has access to it. Maybe NATO countries will have access but that's not the reality for Ukraine now.

Encrypted GPS jammers/spoofers just use replay attacks. It's very effective.

I would think that the encryption would prevent replay. Galileo's (proposed?) system certain seems to:

* https://berthub.eu/articles/posts/galileos-authentication-al...

Based on:

* https://datatracker.ietf.org/doc/html/rfc4082

Naive replay attacks of course won't spoof because of encryption. However, by replaying, it will be harder for the receiver to find the actual good signal amongst masses of inauthentic ones.

If you want to spoof via replay you need to do it subtly and progressively - think by only a few ms, and it only works for a specific target. But that's not what I'm talking about here.

> EU has the Galileo and USA GPS, so why not use Glonass?

There's a good chance that the non-Russians in the area do not have Loran equipment. Further, all GNSS systems basically use the same set of frequencies (E1/L1, L2, E5/L5):

* https://gssc.esa.int/navipedia/index.php/GNSS_signal

* https://gssc.esa.int/navipedia/index.php/GLONASS_Signal_Plan

So they can jam these small number of frequencies, and take out their own system (along with everyone else's), but they are ready for this, and the opponent(s) may not be.

They could also just turn it off. Or change encryption so it will work for Russia but not others.

They'd have to turn it off selectively for just that region, as they may want to keep it working in other places (Siberia, Vladivostok).

Maybe be easier to just set up some jammers around the area of operations.

Jamming would also probably take out all the other GNSS systems, which could be an operational benefit to them if they're better prepared; which is probably why they run a Chayka/Loran system in the first place—as does China:

* https://www.gpsworld.com/china-expanding-loran-as-gnss-backu...

"War, what is it good for, absolutely nothing!"

If the US/UK are so he'll bent continuously crying wolf and not wiling to negotiate NATO expansion (Ukraine will never join because you need a unanimous vote from all members and even Germany would not vote for such an expansion. It's a mute point.) then impose the damn sanctions already. The only ones it really hurts is Europe but that is why the US government wants them isn't it?

The amount of posts on /r/worldnews saying Russia did this Russia did that is incredible. Western propaganda mostly out of anonymous sources is completely drowning out Russian propaganda which is amazing.

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