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0
votes
1answer
69 views

Setting ntp time from gpsd

I'm trying to configure ntpd to source it's time from a gps receiver (BU-353S4) but I'm getting some errors. I'm using ntpd 4.2.8.p6-3 and gpsd 3.16-2 on Arch Linux Arm. I've been following the ...
4
votes
2answers
226 views

Getting gpsd address for ntpd

I'm working through some tutorials for setting ntpd clock from gpsd. The guides that I'm working from list adding something like this: server 127.127.46.0 fudge 127.127.46.0 time1 0.0 time2 0.0 ...
1
vote
1answer
130 views

NTP using GPS and PPS as clock, PPS is marked as falseticker

I am attempting to add a GPS-based clock source to my network, using a GPS which emits a 1-PPS clock pulse. This is connected to a GPIO pin. After allowing ntpd to run for 30 minutes or so, the PPS ...
9
votes
1answer
188 views

Linux ntpd leap second preparation

There will be a leap second on June 30, 2015 at 23:59:60 UTC. I have a Linux based stratum 1 NTP server which uses GPS as a reference clock. The server is using the "default" ntp.org ntpd. How ...
2
votes
1answer
929 views

configuration to use gps time with no internet connection

I use ntp with a GPS device with PPS on port /dev/ttyS0. All seems to be fine if the machine is connected to the internet. Output looks correct. But if there is no internet connection I get: $ ntpq -...
1
vote
1answer
669 views

Access NMEA reference clock and GPS position simultaneously

I noticed two approaches to get an accurate time from GPS (with PPS). Using ntpd either with NMEA reference clock or Shared Memory Driver My problem: I want to have a very accurate time and access ...
2
votes
1answer
556 views

udev rule running setserial low_latency don't work

My server runs Ubuntu 14.04.1. I created udev rules in /etc/udev/rules.d/09-pps.rules to get GPS with PPS support work. KERNEL=="ttyS0", SYMLINK+="gps0", MODE="0666" KERNEL=="ttyS0", RUN+="/bin/...
6
votes
3answers
4k views

Seemingly poor quality of NTP time synchronization using a GPS clock

I have a Linux server which has its time synchronized to a GPS-based NTP appliance located close by. Ping times from the server to the appliance are circa 1ms, with very low jitter: --- x.x.x.x ping ...
30
votes
12answers
15k views

Is anyone using GPS for time sync?

I've come across a handful of GPS NTP servers, as well as some inexpensive solutions using off-the-shelf receivers and software. Right now I'm just using NTP with a list of servers over the Internet. ...