> Does anyone run gpsd with the Garmin GPS 18 LVC and have it successfully > read both PPS and GPS time? I'm interested to know, as I would rather go > that route. >
Hi Dennis, I have my GPS 18 LVC feeding ntpd via gpsd on a stock CentOS 4 install with no problems. I didn't want to recompile the kernel either as the server is running other apps with certain kernel dependencies I didn't' want to mess up! I did compile gpsd from source with the --disable-reconfigure so it would stop messing around with the configuration every time it started up. I setup the GPS using the Garmin SNSRCFG configuration program. If memory serves, I had set the following: NMEA Sentences on: $GPRMC $GPGGA $GPGSA $GPGLL Baud: 38.4K PPS Length: 240 PPS Auto Off Mode: ENABLED Everything else should be factory default. I just followed the configuration outlined under NTP near the bottom of this page: http://gpsd.berlios.de/gpsd.html and it worked great: remote refid st t when poll reach delay offset jitter ============================================================================== +132.246.168.164 132.246.168.3 2 u 7 64 377 30.521 1.361 39.667 - 199.212.17.22 18.26.4.105 2 u 5 64 377 29.211 -3.905 0.702 +198.82.1.201 198.82.247.40 2 u 30 64 377 52.541 3.364 2.372 +209.51.161.238 .CDMA. 1 u 59 64 377 41.550 7.450 33.173 -127.127.28.0 .GPS. 0 l 5 16 377 0.000 -3.692 6.086 * 127.127.28.1 .PPS. 0 l 7 16 377 0.000 0.070 0.010 The only thing strange is that the poll times go up and then they keep dropping back down to 64 (as you can see). Not sure why... My ntp.conf for my GPS is as follows: server 127.127.28.0 minpoll 4 fudge 127.127.28.0 time1 -0.340 refid GPS server 127.127.28.1 minpoll 4 prefer fudge 127.127.28.1 refid PPS gpsd is started using: gpsd -n /dev/ttyS0 And of course, you did properly solder the PPS line to the correct pin on the db9 and verified its output? I just used a volt meter and saw the needle pulse ever second. As a foot note - the GPS is located in my office, on the top floor of a 2 story wood frame construction building. The GPS actually works better on top of my book shelf (near the ceiling) in the middle of the buliding then it does sitting close to the window facing south! I guess the wood roof struts are more RF friendly then the aluminum soffits! I ran a logging script for 2 days and had less than 1% total loss of satellite lock. Most ticks were with 7 birds and I've seen it go up as high as 11. Not bad for an indoor antenna! Thanks, -Rob
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