> for use in distributing the keys for accessing the military GPS signals
It’s common knowledge that the military has access to a separate, encrypted, higher-precision GPS signal. “Numbers station” implies that they’re distributing unrelated encrypted information, but they’re not; it’s not surprising that GPS signals would be used to deliver information related to GPS, even if only military receivers have any use for it!
>It’s common knowledge that the military has access to a separate, encrypted, higher-precision GPS signal.
The most militarily-valuable aspect of the military GPS signals is actually the anti-spoofing qualities, rather than the higher precision. Survey-grade GPS gear has been able to achieve centimetre-level precision from the regular civilian signals for several years now, using RF fuckery like tracking the phase angle and other techniques.
To be sure, you want the precision too. NATO countries have M982 Excalibur GPS-guided artillery rounds that are precise enough that you can select not just the building you want to hit but the specific window you want the round to enter.
But the primary benefit of the encrypted signal is that it provides cryptographic assurance that the signal is not spoofed and one can be confident that one's GPS-guided cruise missile or other munition is not being diverted off-course.
Nowadays the military GPS signal has moved from transmitting the legacy "P(Y) code", which is a Cold War-era design, to the "M code" which incorporates several decades' worth of lessons learned in terms of spoofing resistance, cryptographic authentication, etc.
"Numbers station" is a weird analogy, because the idea of a numbers station was to broadcast messages to undercover operatives in a way that can be received using unmodified (and therefore non-suspicious) household radio receivers.
Here, it appears to be a rekeying system for specialized military gear.
“Every receiver in the world decodes Subframe 4, Page 17,” Murdoch said in his new article. [...] “Every GPS satellite is a numbers station,” he concluded.
I disagree? The point of a numbers station is that it broadcasts in the clear and anyone with a receiver can get it, but only people with the appropriate decryption key can make any use of it. Since it's broadcasting all the time, there's no need for steganography or covert transmission. That's exactly what a numbers station is.
Where the article loses me is the implication that this is somehow sinister or beyond the pale: it's just piggybacking on a global transmitter network that exists anyway, why not?
This implication is purely in your head. The article and the scientist whose work it describes are just pointing out the identification of some data that's been transmitted across a public channel for years without anyne noticing.
> Since it's broadcasting all the time, there's no need for steganography or covert transmission.
Well, you could look at it that way, or you could say that the fact that it's broadcasting all the time is the steganography. That constant transmission of nonsense that nobody wants is what makes it fail to be suspicious when you send a message that somebody does want.
Its all comes down to what we buy as the definition for a number station. For me a number station needs sends a message to be a number station, not a key.
>For me a number station needs sends a message to be a number station, not a key.
We don't know that it's a key that's being sent. For all we know, it could be just random data. Obviously it's most likely not random data, but ciphertext. Either way, we have no idea what the message is.
Indeed. i have some GPS receiver modules and had wondered about this data, I had assumed it was imprecision in my device or something to do with a satellite moving around. I'll have to plug it in and go back for another look.
GPS was always a dual use system. This is very detailed and specific, but not interesting or surprising. Research has been study GPS signal data, found parts that are encrypted and he doesn’t understand. The end. Article seems only intended to generate an emotional response of “how dare they use GPS for war, man!”
Even better, thanks for clarifying. It’s that kind of omission from the article that makes the rest of it hard to swallow. Even if it is technically correct. Which is sadly the case for most “journalism” these days.
Anyone have a good source to read up on the current state of the art for daytime celestial navigation? Maybe there isn't too much in the public domain, because things like GPS work so well. But I'd guess that since you can't easily artificially jam celestial navigation there would be military research on this. But I suppose clouds also limit the practicality as well.
The part they kept out of the headline:
> for use in distributing the keys for accessing the military GPS signals
It’s common knowledge that the military has access to a separate, encrypted, higher-precision GPS signal. “Numbers station” implies that they’re distributing unrelated encrypted information, but they’re not; it’s not surprising that GPS signals would be used to deliver information related to GPS, even if only military receivers have any use for it!
The most militarily-valuable aspect of the military GPS signals is actually the anti-spoofing qualities, rather than the higher precision. Survey-grade GPS gear has been able to achieve centimetre-level precision from the regular civilian signals for several years now, using RF fuckery like tracking the phase angle and other techniques.
To be sure, you want the precision too. NATO countries have M982 Excalibur GPS-guided artillery rounds that are precise enough that you can select not just the building you want to hit but the specific window you want the round to enter.
But the primary benefit of the encrypted signal is that it provides cryptographic assurance that the signal is not spoofed and one can be confident that one's GPS-guided cruise missile or other munition is not being diverted off-course.
Nowadays the military GPS signal has moved from transmitting the legacy "P(Y) code", which is a Cold War-era design, to the "M code" which incorporates several decades' worth of lessons learned in terms of spoofing resistance, cryptographic authentication, etc.
Here, it appears to be a rekeying system for specialized military gear.
Where the article loses me is the implication that this is somehow sinister or beyond the pale: it's just piggybacking on a global transmitter network that exists anyway, why not?
Well, you could look at it that way, or you could say that the fact that it's broadcasting all the time is the steganography. That constant transmission of nonsense that nobody wants is what makes it fail to be suspicious when you send a message that somebody does want.
We don't know that it's a key that's being sent. For all we know, it could be just random data. Obviously it's most likely not random data, but ciphertext. Either way, we have no idea what the message is.
What's interesting to me is how out of date US GPS system is compared to China's BeiDou
and while most US GPS receivers will use Russia's GLONOSS, China's BeiDou is blocked
https://news.ycombinator.com/item?id=47849174
It wasn't. It was going to be a military-only system, until KAL007 presented the obvious life-saving civilian case.
But yes, the title of this article might as well read "Satellite system developed for military use is being used for a military purpose."
https://youtu.be/tz23G_UXCGA
Theory is that Russia is constantly practicing to totally disrupt GPS and GNSS (and the Chinese system) across all of Europe.
https://www.scientificamerican.com/article/how-to-see-stars-...