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GPS messages for civilian use are unencrypted. The US Military has access to another set of signals that ARE encrypted.
by engi_nerd 8y ago
GPS messages for civilian use are unencrypted. The US Military has access to another set of signals that ARE encrypted.
- isostatic 8y agoCan still be jammed of course, but hacking GPS was the plot of the Bond Film "Tomorrow Never Dies", where Rupert Murdoch attempts to instigate a global war to sell more newspapers
- paulsutter 8y agoSigning messages is completely separate from encryption. Also there is no longer separate quality gps for military vs civilian use: https://www.cnet.com/news/celebrating-10-years-of-gps-for-the-masses/ https://www.cnet.com/news/celebrating-10-years-of-gps-for-th...
- engi_nerd 8y agoFair point on signed vs encrypted, I was simply pointing out that the ordinary civilian GPS isn't all there is. And while that L1 GPS signal has had selective availability turned off, that can always be turned back on again. Plus, using the military parts of L2 GPS in combination with L1 do give a higher accuracy than civilian GPS units can achieve.
- gsich 8y agoNavstar claimed that this would not be possible anymore, but I find that hard to believe.
- Kadin 8y agoThere is presently no difference in accuracy between military and civilian GPS signals. The civilian / unencrypted stream is no longer intentionally degraded, as it once was (via "Selective Availability"). But there are still multiple datastreams, and the military one is still encrypted, and the military retains the ability to degrade or disable or degrade the civilian/unencrypted signal if circumstances require it, although it is hard to imagine a circumstance where this would be desirable, given the proliferation of civilian GPS receivers among military personnel, disruption to civil aviation / airlift capability, etc. The military GPS signal from the Block III satellites is called "M-Code": https://en.wikipedia.org/wiki/GPS_signals#Military_(M-code) https://en.wikipedia.org/wiki/GPS_signals#Military_(M-code)
- slededit 8y agoSelective availability is no longer available on newer satellites. I assume they can still shut off the stream though.
- erik_seaberg 8y agoCrappy firmware could ignore signatures but would definitely notice if no key could be found to successfully reverse mandatory encryption.