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> those able to decode the still-military-only encrypted signals How? I was under the impression that military-only signal was encrypted. And if someone breaks

> those able to decode the still-military-only encrypted signals How? I was under the impression that military-only signal was encrypted. And if someone breaks that encrpytion, blame should go to the poor handling of encryption rather than the person breaking it? Analogy : if you leave a classified document on the train and a passenger reads it, whose fault is it?

cmsj 2y ago
I'm relatively certain that the US government will be unmoved by your argument that it would be their fault if you built a GPS receiver that could decrypt the precise positioning signals ;)
dheera 2y ago
Actually you can use the phase information in the encrypted signals to improve RTK stability, without decrypting them.
j16sdiz 2y ago
Technological restrictions and Legal restrictions not always aligns. That's where the "restrictions have largely been lifted" part comes in. You can decrypt most of them, but it is illegal to export without a license.
tverbeure 2y ago
The Kraken RF project, which has multiple SDR radios next to each other, had demo code of a passive radar: the slight time delay by which signals arrived at the antennas could be used to detect large metal bodies (IOW: planes) in the sky. They took down the demo code they were informed that they were violating ITAR regulations. https://www.reddit.com/r/RTLSDR/comments/yu9rei/krakenrf_pulls_passive_radar_code_from_github_due/ https://www.reddit.com/r/RTLSDR/comments/yu9rei/krakenrf_pul...
solidsnack9000 2y ago
Well, consider another analogy: a person leaves their door unlocked and another person goes in their home. It is still trespassing, even though the physical barrier has been intentionally disabled. I'm not sure even what section of US code to check but it is certainly plausible that you can (for example) find a surplus device that decodes the signals on EBay and it's actually illegal to do it. You can find radios on EBay that broadcast on bands that are unlawful to use (or unlawful without certain licenses, &c).

cmsj 2y ago

I'm relatively certain that the US government will be unmoved by your argument that it would be their fault if you built a GPS receiver that could decrypt the precise positioning signals ;)

dheera 2y ago

Actually you can use the phase information in the encrypted signals to improve RTK stability, without decrypting them.

j16sdiz 2y ago

Technological restrictions and Legal restrictions not always aligns. That's where the "restrictions have largely been lifted" part comes in. You can decrypt most of them, but it is illegal to export without a license.

tverbeure 2y ago

The Kraken RF project, which has multiple SDR radios next to each other, had demo code of a passive radar: the slight time delay by which signals arrived at the antennas could be used to detect large metal bodies (IOW: planes) in the sky. They took down the demo code they were informed that they were violating ITAR regulations. https://www.reddit.com/r/RTLSDR/comments/yu9rei/krakenrf_pulls_passive_radar_code_from_github_due/ https://www.reddit.com/r/RTLSDR/comments/yu9rei/krakenrf_pul...

solidsnack9000 2y ago

Well, consider another analogy: a person leaves their door unlocked and another person goes in their home. It is still trespassing, even though the physical barrier has been intentionally disabled. I'm not sure even what section of US code to check but it is certainly plausible that you can (for example) find a surplus device that decodes the signals on EBay and it's actually illegal to do it. You can find radios on EBay that broadcast on bands that are unlawful to use (or unlawful without certain licenses, &c).