The theory that they broadcast communication on a band near GPS in order to discourage jamming of their early warning system sounds likely. Flexing the ability to jam GPS is pointless, since it's obvious that any state actor who has military satellites in orbit has considered this option or have the capability already. Therefore, the disruptions must either be regular tests of the capability, or just actual communication. Right?
> The theory that they broadcast communication on a band near GPS in order to discourage jamming of their early warning system sounds likely.
Is it? If it is an early warning system, could it be jammed briefly so it would fail to warn, couldn't it? It will be a global disruption of GPS, but a brief one and I'm sure people wouldn't be concerned of it due to other news.
> Flexing the ability to jam GPS is pointless
Do you believe that cutting sea cables is a sensible action? Or sending drones to neighbors? It is what they call "hybrid asymmetric warfare", I'm not sure how it is supposed to work, but presumably it may let them take over the world or something.
Probably they just strive to normalize deviations, to boil frog slowly. When people become used to some stupid actions they widen their repertoire, until everything short of tanks crossing the borders became just normal news noise nobody reads twice.
Presumably the missile needs GPS to hit the target so if you jam right when the missile is coming in the missile will miss so you can't really jam the warning
Also if you broadcast noise when your missile is about to hit then your own jamming signal acts as an early warning as well, although I guess it wouldn't provide location.
US weapon systems have never relied on GPS for guidance. Some will accept GPS corrections to the primary inertial guidance system but those corrections will be rejected if they deviate more than a few meters from the inertial guidance. US missiles in particular use precision terminal guidance which doesn't involve GPS at all; in these systems GPS would only be used to correct mid-course guidance.
There has been anecdotal evidence for years suggesting that the latest US inertial guidance technology is sufficiently precise and accurate that GPS correction no longer adds value.
ICBMs don’t rely on GPS. They are typically self-guided and use a blend of their known launch location, inertial navigation using gyroscopes, celestial navigation (yes, looking at stars), and a few other techniques.
> Flexing the ability to jam GPS is pointless, since it's obvious that any state actor who has military satellites in orbit has considered this option or have the capability already.
Forget "state actors", truck drivers have taken out entire airports with GPS jammers:
The US still has a fairly robust network of VOR's / VOR with DME / VORTAC stations. Good for navigation, but there's no timing component, beyond what's inherent in how they operate.
Admittedly, that'll never be of use outside aviation as its line-of-sight only. But if the sun threw a Carrington event (or worse) at us, I think a lot of western aviation could carry on.
> The US still has a fairly robust network of VOR's / VOR with DME / VORTAC stations. Good for navigation, but there's no timing component, beyond what's inherent in how they operate. Admittedly, that'll never be of use outside aviation […]
I'm aware of the FAA's MON, Minimum Operating Network.
Exactly: that doesn't help boats. Or people in cars. Or farmers:
There is definitely value in having a demonstrated as opposed a simply supposed capability, though. And actions that are 'almost-certainly-but-not-completely-provably-us' is very much something Russia likes to do.
(One question I would have about the comms theory is whether the amount of power being used would be reasonable for that use-case. Jamming tends to be much higher power than just communicating, but also GNSS signals are very low bandwidth as comms channels go)
> One question I would have about the comms theory is whether the amount of power being used would be reasonable for that use-case. Jamming tends to be much higher power than just communicating, but also GNSS signals are very low bandwidth as comms channels go
GPS is suprisingly low power. I believe the satellites themselves transmit between 20W and 50W, and in general the signal is quieter than the background noise threshold. It's only by correlating with the PRNG stream [1] that the data signal can be detected at all [2].
[1] The PRNG stream is 1023 bits at 1.023Mbps, so repeats every 1ms, and only autocorrelates with the correct stream when they are aligned. When the streams are not aligned, the data looks like random noise, and each transmitter has a different LFSR configuration to provide a different sequence such that each stream has a low level of correlation with another.
[2] The PRNG stream bits at 1.023Mbps are exclusive-or'd with the data stream at 50bps, so when the decoder is using the correct PRNG and sequence offset, exclusive-or'ing with that produces detectable long pulses at the expected 50bps.
FWIW this is how almost every communication system works. They're all weaker than background noise (e.g. sunlight) but you extract them by correlating with some kind of carrier signal (often but not always a sine wave)
You do generally need a tuned filter before the rectification, unless you have an extremely large signal dominating the local airwaves. Which is precisely the parent poster's point: with RF you are almost always doing something to demodulate the signal. Whether you are doing it with a sine wave or something more complicated is not that fundamentally different. (and if you're looking at a spectrum analysis, that is looking at the radio signal from the point of view of that sinusoidal modulation scheme, so you will see such signals 'above' the noise floor more readily than something using a different modulation).
Why these capabilities, if they exist, were not used to send Iranian drones to a wrong target? Maybe because they do not exist. Israel definitely would be happy if thousands of drones were rerouted to a neighbour country or into the sea.
yeah, I have to admit I was commenting on possibilities here without having gone into the article yet -- having now looked for real, I agree that the disruptions don't seem very useful for actual jamming and repeatedly like this for years across satellites and bands in this specific way doesn't make sense for some mistaken targeting either.
There is a very good reason to do this. Suppose you had a device that would make the shoplifting detectors at stores go off. The first time you did it everyone would get hassled. And the second time and so forth. But if you kept doing it eventually the employees would stop caring. Then you just walk out the door with your stuff.
Even if that's for communication, repurposing it for mass jamming shouldn't be that hard. It already has this effect. Unless it's low power satellites that wouldn't be able to sustain radio signal in anything longer than short bursts.
