我正在使用yocto 开发AM335x定制板，其中“u-blox LEA-M8F”用作 gps 模块。基本上我想使用“ntpd deamon”所以在通过互联网时我发现我想链接 gpsd 和 pps 这样做，我已经配置了ntp.conf文件如下
#/etc/ntp.conf, configuration for ntpd
driftfile /var/lib/ntp/ntp.driftlogfile /var/log/ntp.log
logfile /var/log/ntp.log
#statistics loopstats peerstats clockstats
#filegen loopstats file loopstats type day enable
#filegen peerstats file peerstats type day enable
#filegen clockstats file clockstats type day enable
# You do need to talk to an NTP server or two (or three).
#server ntp.your-provider.example
# pool.ntp.org maps to more than 300 low-stratum NTP servers.
# Your server will pick a different set every time it starts up.
# *** Please consider joining the pool! ***
# *** ***
#server 0.rhel.pool.ntp.org iburst
#server 1.rhel.pool.ntp.org iburst
#server 2.rhel.pool.ntp.org iburst
#server 3.rhel.pool.ntp.org iburst
#server ntp0.pipex.net
#server ntp1.pipex.net
#server 127.127.1.0
#fudge 127.127.1.0 stratum 10
# By default, exchange time with everybody, but don't allow configuration.
# See /usr/share/doc/ntp-doc/html/accopt.html for details.
#restrict default kod notrap nomodify nopeer noquery
#restrict -6 default kod notrap nomodify nopeer noquery
#restrict otherntp.server.org mask 255.255.255.255 nomodify notrap noquery
#restrict ntp.research.gov mask 255.255.255.255 nomodify notrap noquery
# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict -6 ::1
# Clients from this (example!) subnet have unlimited access,
# but only if cryptographically authenticated
#restrict 192.168.123.0 mask 255.255.255.0 notrust
restrict 200.1.2.0 mask 255.255.255.0 nomodify notrap
# If you want to provide time to your local subnet, change the next line.
# (Again, the address is an example only.)
#broadcast 200.1.255.255 minpoll 1
#server 127.127.1.0 # local clock
#fudge 127.127.1.0 stratum 10
# If you want to listen to time broadcasts on your local subnet,
# de-comment the next lines. Please do this only if you trust everybody
# on the network!
#disable auth
#broadcastclient
restrict default kod nomodify notrap nopeer noquery
restrict -4 default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery
#tinker step 0.4 stepback 0.4 stepfwd 0.4
server 127.127.28.0 minpoll 4 maxpoll 4
fudge 127.127.28.0 flag1 1 time1 -0.875 refid GPS stratum 1
server 127.127.22.0 minpoll 4 maxpoll 4
fudge 127.127.22.0 refid PPS
driftfile /var/lib/ntp/drift
pidfile /var/run/ntpd.pid
当我使用以下命令重新启动板后
ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
SHM(0) .GPS. 0 l - 16 0 0.000 0.000 0.000
PPS(1) .PPS. 0 l - 16 0 0.000 0.000 0.000
如上所示，偏移值始终为零。谁能帮我理解我在 ntp.conf 文件中到底做错了什么？