3 ms·

Every GPS chip in every GPS-enabled device includes the clock — by design, it can't work without it. So perhaps it is possible to quickly hack something from a

Every GPS chip in every GPS-enabled device includes the clock — by design, it can't work without it. So perhaps it is possible to quickly hack something from a cheap Android phone placed somewhere near the window?

nickpsecurity 9y ago
That was sams idea I had. I found that SparkFun even had a guide on it: https://www.sparkfun.com/pages/GPS_Guide https://www.sparkfun.com/pages/GPS_Guide
- detaro 9y ago
  Better resources: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts (I don't understand a lot discussed there, but many interesting links and info about current deals to be found) There also are differences between the quality of the timing output of different GPS modules, with some being optimized for timing applications (as opposed to location finding)
  - nickpsecurity 9y ago
    Appreciate it as I am wanting timing-focused ones.
timelol 9y ago
Using GPS as your time source is a fabulously good way to trash your entire database during a leap second. See this paper for a discussion on how essentially everybody but Google gets this wrong: http://crin.eng.uts.edu.au/~darryl/Publications/LeapSecond_camera.pdf http://crin.eng.uts.edu.au/~darryl/Publications/LeapSecond_c...
- mastax 9y ago
  GPS time does not have leap seconds: http://www.oc.nps.edu/oc2902w/gps/timsys.html http://www.oc.nps.edu/oc2902w/gps/timsys.html > GPS Time is a uniformly counting time scale ... The word "uniformly" is used above to indicate that there are no "leap seconds" in this time system. > The GPS message contains information that allows a receiver to convert GPS Time into Universal Time In fact the article you linked corroborates this, because they used GPS time to show how inaccurate NTP servers are.

nickpsecurity 9y ago

That was sams idea I had. I found that SparkFun even had a guide on it: https://www.sparkfun.com/pages/GPS_Guide https://www.sparkfun.com/pages/GPS_Guide

detaro 9y ago
Better resources: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts (I don't understand a lot discussed there, but many interesting links and info about current deals to be found) There also are differences between the quality of the timing output of different GPS modules, with some being optimized for timing applications (as opposed to location finding)
- nickpsecurity 9y ago
  Appreciate it as I am wanting timing-focused ones.

timelol 9y ago

Using GPS as your time source is a fabulously good way to trash your entire database during a leap second. See this paper for a discussion on how essentially everybody but Google gets this wrong: http://crin.eng.uts.edu.au/~darryl/Publications/LeapSecond_camera.pdf http://crin.eng.uts.edu.au/~darryl/Publications/LeapSecond_c...

mastax 9y ago
GPS time does not have leap seconds: http://www.oc.nps.edu/oc2902w/gps/timsys.html http://www.oc.nps.edu/oc2902w/gps/timsys.html > GPS Time is a uniformly counting time scale ... The word "uniformly" is used above to indicate that there are no "leap seconds" in this time system. > The GPS message contains information that allows a receiver to convert GPS Time into Universal Time In fact the article you linked corroborates this, because they used GPS time to show how inaccurate NTP servers are.