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United States has the capability to degrade or deny GPS based on location. Russia has also demonstrated the ability to spoof GPS signals. Either is a likely cause here.

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The United States do not have the ability to degrade or deny a gps signal based on location unless that particular location has a physical GPS jammer. I don't see what the US would gain from disrupting civilian airtraffic navigation. Just stop with your "either is a likely cause here"-spiel.

> The United States do not have the ability to degrade or deny a gps signal based on location

This was a feature designed into GPS from the beginning. They just stop transmitting the C/A code from satellites visible to the battlespace and a device can't bootstrap or maintain a location fix. Approved devices entering the battlespace (say a ballistic missile fired from a ship over the horizon) can continue to maintain high precision location using the P code.

Block III sattelites have also started transmitting M code, which is a second generation of military only GPS that claims to be unjammable and unspoofable.

In a major departure from previous GPS designs, the M-code is intended to be broadcast from a high-gain directional antenna, in addition to a wide angle (full Earth) antenna. The directional antenna's signal, termed a spot beam, is intended to be aimed at a specific region (i.e., several hundred kilometers in diameter) and increase the local signal strength by 20 dB (10× voltage field strength, 100× power). A side effect of having two antennas is that, for receivers inside the spot beam, the GPS satellite will appear as two GPS signals occupying the same position.

https://en.m.wikipedia.org/wiki/GPS_Block_III#Military_(M-co...

That's an ability to improve service for users of M-code receivers, which AFAIK are only available to the military (and it's new technology, so I'd expect it to be unsupported even by most military receivers currently in use).

The M-code is transmitted in the same L1 and L2 frequencies already in use

Nothing says that they have to transmit M-codes from the spot beam antenna.

In fact, since the M-codes are hardly used, it's pretty certain they're using that antenna for something else. How very convenient that those antennae are designed to transmit on the same frequency as the "ordinary" antenna.

Today I took the time to have a closer look. Turns out, the directional antenna for M-code is only present on Block III GPS satellites, and only four of those are currently in service:

https://en.wikipedia.org/wiki/GPS_Block_III

So this is definitely not the correct explanation.

Besides, even if there were enough Block III satellites in orbit to provide constant cover of the affected area, it would still make little sense to tie up their most advanced capabilities to jam their own legacy signal, when you could just turn off the legacy signal when transiting the target area and provide your own military with continued service using the directional antenna.

And of course, Russia has its own satellite navigation system

https://en.wikipedia.org/wiki/GLONASS

so you'd also have to explain what the US and NATO could hope to gain from turning off GPS.

> The M-code is transmitted in the same L1 and L2 frequencies already in use

Let's quote the whole thing, shall we?

The M-code is transmitted in the same L1 and L2 frequencies already in use by the previous military code, the P(Y) code. The new signal is shaped to place most of its energy at the edges (away from the existing P(Y) and C/A carriers).

Explain why only the "Russia did it"-spiel is allowed here.

> Explain why only the "Russia did it"-spiel is allowed here.

Because

A) Absolutely nobody fucking else would have any reason to? and/or

B) They're the one with a decades-long habit of doing shit like that? but,

C) Hey, "allowed"?!? Is anyone deleting your alternative (=P-burg Factory) "spiels"? only,

D) Be prepared for them to be laughed all to Hell like they deserve. and...

E) ...to be categorised as a Putler-propaganda troll. To paraphrase a great philosopher, Putler-troll is as Putler-troll does.

In 2000, Bill Clinton has banned the use of Selective Availability. Newer satellites, decided in 2007, first launched in 2018 don't even have the capability anymore.

This is different than selective availability, which kept the signals on at regular power but rounded off numbers/degraded them them. Starting with GPS 3 (or maybe even Block II-F?), the satellites have multiple antennas so they can just turn themselves on and off for specific regions. No cap. They can also adjust the SNR more granularly for the individual signals.

What would be the United States's interest to mess up with GPS now?

To deny access to Russia is one reason. Not saying it's the only reason, or that it's not more likely that Russia has done this.

Its a stupid reason. Russian military equipment uses GLONASS. Granted, GLONASS is just barely limping along, but it does work.

It's possible that GLONASS isn't working well for them for some reason. They've been using relatively few precision munitions. And of those few, many of them them seem to be missing by quite a lot. Some of the ballistic missiles they threw at runways look like they were probably under inertial guidance, judging by how badly they missed.

Jamming and spoofing GPS poses less risk than imposing a no fly zone.

> a no fly zone.

Uhm... Finland is several countries north of Ukraine. This is about the eastern Baltic region. I guess you are referring to the rejected NATO-maintained no-fly zone over Ukraine? Or do you mean a no-fly zone imposed by Russia for its Baltic region neighbors??

> According to reports, the interference isn't limited to Finland but also affects Poland, Lithuania, Latvia, and the broader Baltic region.

Also, a jammed GPS has little impact on flying, especially not on Russian military flying. They have their own system GLONASS (https://en.wikipedia.org/wiki/GLONASS).

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