Hi,
I started using gpsd three years ago, to interface with NTP servers I am running for the pool. The issue I had, repeatedly, was to check if my devices (all cheap consumer stuff) reported a PPS, and if this was being passed to NTP in a usable fashion.
Unfortunately, there seemed to be no way to even know reliably if the device was sending a PPS. The list provided lots of advice, including looking at SHM segments, tuning, calibration, etc. Note the problem: not that PPS did not work, but I did not know if it was working.
Over the last couple of months, PPS display support has become a non-brainer. Thanks to the developers (I am looking at you, Mr Miller), I have been meeting local enthusiasts, plugging their devices into my laptop, and in every case, seeing both a PPS display in PPS, and NTP locking onto it. Note that all these devices are "unbranded", bought off eBay.
killall gpsd
gpsd -n /dev/ttyUSB0
/etc/init.d/ntp restart
gpsmon
(go for a smoke)
ntpq -pn
Could someone who has a wider range of devices see if this item still needs to be in the TODO ?
==
**** In gpsmon's PPS Offset field
Presently PPS Offset is displayed in direct mode for NMEA, SiRF, and
UBX devices. Others should probably do likewise, notably the
Motorola Oncore and Garmin drivers.
==
Thank you, thank you, thank you