----- Original Message ----- > From: "Forrest Christian (List Account)" <[email protected]>
> Let me address your points: [ ... ] > Let's assume you have a typical GPS-derived NTP server using a typical > commercially available timing GNSS module. To convince that receiver that > it was a different time, I'd need to have an SDR that would operate in the > GPS band. These are widely available for under $500. You'd also need a > laptop and a download of a GPS simulator from GitLab. With a total > investment of $500 (assuming I already have a laptop), I now have a system > that can generate a GPS signal to convince your GPS receiver that it's any > time at all. If you're a tech neophyte, there are youtube videos on how to > do this. > > All I need to do now is add appropriate antennas and/or amplifiers to > overcome the official GNSS signals. As you pointed out, depending on the > location and directivity of your antenna, this is either trivial or becomes > slightly more difficult. If I can see your antenna, it becomes a lot > cheaper as I just need a relatively low-powered amplifier and a highly > directional antenna. If I can't see your antenna, I would opt for a > higher-power amplifier and a less directional transmit antenna to blanket a > wide area with the spoofed signal. If I'm trying to get time out of a NAVSTAR (yes, I know, shut up) receiver, it can see like 8-20 birds, right? Is there not some voting and such inside such a receiver? Just letting it see one 'bird' with spoofed time doesn't seem like it ought to work, to me; what don't I know? Cheers, -- jra -- Jay R. Ashworth Baylink [email protected] Designer The Things I Think RFC 2100 Ashworth & Associates http://www.bcp38.info 2000 Land Rover DII St Petersburg FL USA BCP38: Ask For It By Name! +1 727 647 1274
