Quoting sandip gangakhedkar (sandipfl...@gmail.com): > Any suggestions/comments on my approach are much appreciated.
Try using real serial ports, avoid USB-serial. I'm using the Garmin GPS18x LVC puck, it has a PPS signal and talks RS232 serial. Sells on eBay for $50/$75. You can either try and use NTPs own NMEA/PPS clocks or use GPSd to provide the SHM-segments for NTPs SHM-clock. You'll probably need to tweak (fudge) some parameters to get a stable clock but when it does, it's rock solid. It might also help to change the baud-rate of the puck's output: higher is not always better, but i've seen improvements in stability with baud rates >4800bps. Relevant config parts for my GPS18x LVC: | # NMEA http://doc.ntp.org/4.2.6/drivers/driver20.html | server 127.127.20.0 mode 2 minpoll 4 maxpoll 4 prefer | fudge 127.127.20.0 time1 0.000 time2 0.684076 | fudge 127.127.20.0 flag1 1 flag2 0 flag3 0 flag4 0 | | # PPS http://doc.ntp.org/4.2.6/drivers/driver22.html | server 127.127.22.0 minpoll 4 maxpoll 4 | fudge 127.127.22.0 time1 0.000 | fudge 127.127.22.0 flag1 0 flag2 0 flag3 1 flag40 Also take a look at 'pps-tools' from http://linuxpps.org to get better insight in your kernel PPS-setup (FYI, i've also used this GPS18x LVC connected to a PL2303 USB-serial dongle, this worked fine, even the PPS, but the accuracy is so much better with real serial, because of, well, what has been said already on the list) -Sndr. -- | Don't worry about life, you're not going to survive it anyway. | 4096R/20CC6CD2 - 6D40 1A20 B9AA 87D4 84C7 FBD6 F3A9 9442 20CC 6CD2 _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions