How to achieve that ntpd synchronizes time from GPS? I have adafruit ultimate gps (without battery). It is connected to raspberry and i got fix. PPS pin not connected. I configured ntpd to use GPS http://www.catb.org/gpsd/gpsd-time-service-howto.html#_feeding_ntpd_from_gpsd

fudge time1 0.350 refid GPS

also changed ntp init script to run ntpd as root RUNASUSER=root. if i run ntpq -p, i got:

     remote           refid      st t when poll reach   delay   offset  jitter
 SHM(0)          .SHM.            0 l    -    8    0    0.000    0.000   0.000

so, there is no update from GPS and reach is 0.

Here http://blog.petrilopia.net/linux/raspberry-pi-set-time-gps-dongle/ is how to do it without ntp. But then i first must know that gps has fix.

Also in some sites i seen, that some configurations is used address But in official documentation is mentioned

Is it possible to get it work without PPS pin?

ipcs -m

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status
0x4e545030 0          root       600        80         2
0x4e545031 32769      root       600        80         1
0x4e545032 65538      root       666        80         1
0x4e545033 98307      root       666        80         1

ntp version = ntpd [email protected] Fri May 18 20:30:57 UTC 2012 (1)

  • Yes, you can get it without PPS - RPi needs some patch to use PPS. Did you check using the gpsd commands that GPS is indeed working? Also checkout satsignal.eu/ntp/Raspberry-Pi-NTP.html
    – d586
    Jan 21, 2015 at 8:50

1 Answer 1


I found solution (not clean but it works). I added battery to gps, so date and time is saved. In gps chip specification page 22 $GPRMC contains time and date $GPRMC,191822.247,A,2907.1856,N,19016.4938,E,0.03,165.48,031214,3.05,W,A*2C

And here is /etc/rc.local

#start GPSd
gpsd /dev/ttyAMA0 -F /var/run/gpsd.sock
# read date & time from GPS
/bin/bash /date_set_from_gps.sh

cat /date_set_from_gps.sh


# $GPRMC,191749.247,V,,,,,0.17,0.00,031214,,,N*4C
r=`gpspipe -R | head -10 | grep GPRMC | head -1 | awk -F"," '{print $10" "$2}'`
# 031214 191822.247
D="20${r:4:2}-${r:2:2}-${r:0:2} ${r:7:2}:${r:9:2}:${r:11:2}"
# I added prefix 20 to year (to get year with 4 digits ex: 2014)

# set date in UTC format.... -u 
DD=`date -us "$D $T"`

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