7 ms·

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 Glona

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?

EliRivers 5y ago
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.
- giuliomagnifico 5y ago
  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.
  - zinekeller 5y ago
    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.
rthomas6 5y ago
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.
- beecafe 5y ago
  Not exponentially, that would be 2^X
- wildzzz 5y ago
  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.
  - sudosysgen 5y ago
    Encrypted GPS jammers/spoofers just use replay attacks. It's very effective.
    - throw0101a 5y ago
      I would think that the encryption would prevent replay. Galileo's (proposed?) system certain seems to: * https://berthub.eu/articles/posts/galileos-authentication-algorithm-part-1/ https://berthub.eu/articles/posts/galileos-authentication-al... Based on: * https://datatracker.ietf.org/doc/html/rfc4082 https://datatracker.ietf.org/doc/html/rfc4082
      - sudosysgen 5y ago
        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.
throw0101a 5y ago
> 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/GNSS_signal * https://gssc.esa.int/navipedia/index.php/GLONASS_Signal_Plan 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.
- LatteLazy 5y ago
  They could also just turn it off. Or change encryption so it will work for Russia but not others.
  - throw0101a 5y ago
    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-backup/ https://www.gpsworld.com/china-expanding-loran-as-gnss-backu...

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?

EliRivers 5y ago

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.

giuliomagnifico 5y ago
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.
- zinekeller 5y ago
  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.

rthomas6 5y ago

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.

beecafe 5y ago
Not exponentially, that would be 2^X
wildzzz 5y ago
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.
- sudosysgen 5y ago
  Encrypted GPS jammers/spoofers just use replay attacks. It's very effective.
  - throw0101a 5y ago
    I would think that the encryption would prevent replay. Galileo's (proposed?) system certain seems to: * https://berthub.eu/articles/posts/galileos-authentication-algorithm-part-1/ https://berthub.eu/articles/posts/galileos-authentication-al... Based on: * https://datatracker.ietf.org/doc/html/rfc4082 https://datatracker.ietf.org/doc/html/rfc4082
    - sudosysgen 5y ago
      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.

throw0101a 5y ago

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

LatteLazy 5y ago
They could also just turn it off. Or change encryption so it will work for Russia but not others.
- throw0101a 5y ago
  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-backup/ https://www.gpsworld.com/china-expanding-loran-as-gnss-backu...