我正在尝试设置 stratum-1 时间服务器。我有一个Navisys GR-701GPS 能够发送 1 PPS 信号。根据规格表和来源比如这个，我以为使用 ntpd 应该可以获得 ~1ms 的精度。但是，我的ntpq输出总是类似于以下内容：
$ ntpq -pncrv
remote refid st t when poll reach delay offset jitter
==============================================================================
x127.127.22.0 .PPS. 0 l 10 16 377 0.000 -0.204 0.277
o127.127.20.0 .GPS. 0 l 11 16 377 0.000 -0.201 0.277
us.pool.ntp.org .POOL. 16 p - 64 0 0.000 0.000 0.000
pool.ntp.org .POOL. 16 p - 64 0 0.000 0.000 0.000
132.163.96.2 .NIST. 1 u 42 64 377 41.279 103.302 0.576
198.137.202.56 216.218.254.202 2 u 42 64 377 12.813 104.505 0.736
96.244.96.19 192.168.10.254 2 u 39 64 377 83.023 101.028 19.775
216.187.142.202 204.123.2.72 2 u 33 64 177 53.911 104.458 7.406
69.10.161.7 204.26.59.157 3 u 36 64 177 23.968 104.162 3.718
129.6.15.29 .NIST. 1 u 59 64 77 83.782 101.719 0.298
204.2.134.164 199.233.236.226 3 u 38 64 37 12.489 103.279 3.668
129.6.15.30 .NIST. 1 u 32 64 37 83.723 101.487 0.319
108.61.73.244 128.59.0.245 2 u 40 64 37 94.283 109.618 4.261
66.172.10.184 199.102.46.72 2 u 34 64 33 20.098 104.790 0.421
72.5.72.15 162.213.2.253 2 u 33 64 37 12.271 103.247 0.163
204.9.54.119 .CDMA. 1 u 29 64 17 61.895 102.250 1.371
198.206.133.14 58.180.158.150 3 u 60 64 3 70.588 103.281 0.451
129.250.35.250 249.224.99.213 2 u 60 64 3 12.579 102.302 0.611
216.6.2.70 195.219.14.21 2 u 61 64 3 82.862 104.402 0.366
198.55.111.50 45.79.111.114 3 u 56 64 3 22.114 104.099 0.728
216.228.192.52 207.171.7.151 3 u 28 64 3 37.095 97.609 0.214
associd=0 status=04f8 leap_none, sync_uhf_radio, 15 events, no_sys_peer,
version="ntpd [email protected] Mon Oct 9 10:54:36 UTC 2017 (1)",
processor="amd64", system="FreeBSD/11.1-RELEASE-p2", leap=00, stratum=1,
precision=-24, rootdelay=0.000, rootdisp=1.150, refid=GPS,
reftime=dda36229.ea4158ca Tue, Oct 31 2017 13:57:13.915,
clock=dda36234.1c1f0bc5 Tue, Oct 31 2017 13:57:24.109, peer=28141, tc=4,
mintc=3, offset=-0.200797, frequency=53.398, sys_jitter=0.276969,
clk_jitter=0.014, clk_wander=0.008
ntpd 配置文件
tinker panic 0
# Orphan mode stratum
tos orphan 12
# PPS Setup
server 127.127.22.0 minpoll 4 maxpoll 4 prefer
fudge 127.127.22.0 flag3 0
# GPS Setup
server 127.127.20.0 mode 16 minpoll 4 maxpoll 4 prefer
fudge 127.127.20.0 flag1 1 flag3 1
# Upstream Servers
server time-b-b.nist.gov iburst maxpoll 9
pool us.pool.ntp.org iburst maxpoll 9
pool pool.ntp.org iburst maxpoll 9
enable stats
statistics clockstats
statsdir /var/log/ntp
logconfig =syncall +clockall +sysall
driftfile /var/db/ntpd.drift
restrict default kod limited nomodify nopeer notrap
restrict -6 default kod limited nomodify nopeer notrap
restrict source kod limited nomodify notrap
interface ignore all
interface listen igb0
ntpd 是否真的表示我的时钟比其他时钟“慢”约 100 毫秒？如果是这样，为什么会这样？我该怎么办？