我正在尝试使用发射1-PPS时钟脉冲的GPS来为我的networking添加一个基于GPS的时钟源。 这是连接到一个GPIO引脚。
允许ntpd运行30分钟左右后，PPS时钟仍然没有使用，并标记为坏，但我不明白为什么。
ntpq> opeer remote local st t when poll reach delay offset disp ============================================================================== -127.127.28.0 127.0.0.1 2 l 5 16 377 0.000 17.704 2.125 x127.127.22.0 127.0.0.1 0 l 4 16 377 0.000 6.546 0.260 +50.116.36.122 10.42.134.1 3 u 33 64 377 43.017 2.337 5.208 +52.0.56.137 10.42.134.1 3 u 33 64 377 52.022 -6.430 3.944 -2001:418:8405:4 _d58f:78d0:fd39 3 u 30 64 377 85.262 13.465 4.929 *104.156.99.30 10.42.134.1 2 u 32 64 377 63.671 -0.166 5.484 ntpq> assoc ind assid status conf reach auth condition last_event cnt =========================================================== 1 2139 933a yes yes none outlier sys_peer 3 2 2140 9134 yes yes none falsetick reachable 3 3 2141 9424 yes yes none candidate reachable 2 4 2142 9424 yes yes none candidate reachable 2 5 2143 9324 yes yes none outlier reachable 2 6 2144 963a yes yes none sys.peer sys_peer 3 ntpq> rv 2140 associd=2140 status=9134 conf, reach, sel_falsetick, 3 events, reachable, srcadr=127.127.22.0, srcport=123, dstadr=127.0.0.1, dstport=123, leap=00, stratum=0, precision=-20, rootdelay=0.000, rootdisp=0.000, refid=PPS, reftime=da584969.00b5c330 Sun, Jan 31 2016 8:50:49.002, rec=da584969.0f2551bb Sun, Jan 31 2016 8:50:49.059, reach=377, unreach=0, hmode=3, pmode=4, hpoll=4, ppoll=4, headway=0, flash=00 ok, keyid=0, ttl=0, offset=9.551, delay=0.000, dispersion=0.260, jitter=2.148, filtdelay= 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00, filtoffset= 9.55 9.97 10.46 10.98 11.49 11.95 12.46 12.91, filtdisp= 0.03 0.27 0.51 0.75 0.99 1.23 1.47 1.71 PPS来源本身似乎非常干净和规则：
# ppstest /dev/pps0 trying PPS source "/dev/pps0" found PPS source "/dev/pps0" ok, found 1 source(s), now start fetching data... source 0 - assert 1454230928.995087804, sequence: 7552 - clear 0.000000000, sequence: 0 source 0 - assert 1454230929.995115719, sequence: 7553 - clear 0.000000000, sequence: 0 source 0 - assert 1454230930.995144056, sequence: 7554 - clear 0.000000000, sequence: 0 source 0 - assert 1454230931.995173388, sequence: 7555 - clear 0.000000000, sequence: 0 source 0 - assert 1454230932.995202464, sequence: 7556 - clear 0.000000000, sequence: 0 source 0 - assert 1454230933.995230660, sequence: 7557 - clear 0.000000000, sequence: 0 source 0 - assert 1454230934.995258966, sequence: 7558 - clear 0.000000000, sequence: 0 source 0 - assert 1454230935.995287693, sequence: 7559 - clear 0.000000000, sequence: 0 source 0 - assert 1454230936.995317675, sequence: 7560 - clear 0.000000000, sequence: 0 source 0 - assert 1454230937.995345684, sequence: 7561 - clear 0.000000000, sequence: 0 source 0 - assert 1454230938.995375052, sequence: 7562 - clear 0.000000000, sequence: 0 source 0 - assert 1454230939.995403851, sequence: 7563 - clear 0.000000000, sequence: 0 source 0 - assert 1454230940.995433228, sequence: 7564 - clear 0.000000000, sequence: 0 source 0 - assert 1454230941.995463497, sequence: 7565 - clear 0.000000000, sequence: 0 source 0 - assert 1454230942.995491843, sequence: 7566 - clear 0.000000000, sequence: 0
2140被误报为Falseicker，它不在时钟selectalgorithmselect的区间内。 排列的错误间隔使得所选的候选人不包括它。 由于超过一半的候选人时钟被认为是正确的。
虽然它看起来适用于抛弃假发之后，还有一个喜欢关键字的同龄人 。
考虑在似乎性能良好的对等方上使用ntpdate，并使用不同的对等方重新启动ntpd以获得第二种意见。 如果它更喜欢networking对等体，并且它们的延迟和抖动相对较低，那也不算太差。