nanog mailing list archives
Re: GPS rollover
From: "Eric S. Raymond" <esr () thyrsus com>
Date: Mon, 11 Mar 2019 05:00:54 -0400
Matthew Petach <mpetach () netflight com>:
On Sun, Mar 10, 2019 at 8:04 PM Stephen Satchell <list () satchell net> wrote:So far as I can tell with NTP, there was no issue with time sources becoming false-tickers, including my local GPS appliance. FWIW.I believe the rollover is *next* month, in April. :) https://ics-cert.us-cert.gov/sites/default/files/documents/Memorandum_on_GPS_2019.pdf "This paper is intended to provide an understanding of the possible effects of the April 6, 2019 GPS Week Number Rollover on Coordinated Universal Time derived from GPS devices."
I'm a domain expert in this area - lead of NTPsec and GPSD. Everything said in that memo is correct. I would add only that it is more normal now than not for GPSes to have a hidden pivot date. "For example, a particular GPS device may interpret the WN parameter relative to a firmware creation date and would experience a similar rollover event 1024 weeks after that firmware creation date." Yes, exactly. It is therefore unlikely that your GPSes will become falsetickers on 6 April. That's the good news. The bad news is that they *will* go poof some unpredictable number of weeks later. -- <a href="http://www.catb.org/~esr/">Eric S. Raymond</a> My work is funded by the Internet Civil Engineering Institute: https://icei.org Please visit their site and donate: the civilization you save might be your own.
Current thread:
- GPS rollover Stephen Satchell (Mar 10)
- Re: GPS rollover Matthew Petach (Mar 11)
- Re: GPS rollover Eric S. Raymond (Mar 11)
- Re: GPS rollover Matthew Petach (Mar 11)