[ntp:questions] help with setting up NTP on windows with a USB GPS

jack j.jack.wang at gmail.com
Thu Nov 26 16:56:02 UTC 2009


Hi all,

I am trying to setup NTP on Windows XP with a USB GPS at "COM1". I can
verify that the GPS is outputing $GPRMC strings at 1Hz with some other
strings occasionally (eg at startup).

I installed the Meinberg NTP server and then overwrote ntpd.exe with
Dave Hart's executable. I disabled all internet servers and add the
following line:

# NMEA GPS driver
server  127.127.20.1 mode 1   prefer

NTP can see COM1 but it always reports an error. Below is the log from
the system event logger. The most important line is:

NTP	Error	None	1	N/A	JACKXPS	configuration of 127.127.20.1 failed

---------------------------------------------------------------------------------------------------------------------------------------
11/26/2009	11:31:43 AM	NTP	Information	None	3	N/A	JACKXPS	synchronized
to LOCAL(0), stratum 10
11/26/2009	11:30:11 AM	NTP	Information	None	3	N/A	JACKXPS	interp_time
thd 3ec mean -7.3285 spread 14.6574 msec
11/26/2009	11:30:11 AM	NTP	Information	None	3	N/A	JACKXPS	interp_time
thd 58c mean -7.3304 spread 14.6573 msec
11/26/2009	11:28:30 AM	NTP	Error	None	1	N/A	JACKXPS	configuration of
127.127.20.1 failed
11/26/2009	11:28:30 AM	NTP	Information	None	3	N/A	JACKXPS	frequency
initialized 0.000 PPM from C:\Program Files\NTP\etc\ntp.drift
11/26/2009	11:28:30 AM	NTP	Information	None	3	N/A	JACKXPS	Listening on
interface #2 IP Interface 2, 192.168.1.121#123 Enabled
11/26/2009	11:28:30 AM	NTP	Information	None	3	N/A	JACKXPS	Listening on
interface #1 Loopback Interface 1, 127.0.0.1#123 Enabled
11/26/2009	11:28:30 AM	NTP	Information	None	3	N/A	JACKXPS	Listening on
interface #0 wildcard, 0.0.0.0#123 Disabled
11/26/2009	11:28:30 AM	NTP	Information	None	3	N/A	JACKXPS	precision =
0.500 usec
11/26/2009	11:28:28 AM	NTP	Information	None	3	N/A	JACKXPS	HZ 64.000
using 43 msec timer 23.256 Hz 64 deep
11/26/2009	11:28:28 AM	NTP	Information	None	3	N/A	JACKXPS	Wiring to
processor 2 (0 means all) affinity mask 2
11/26/2009	11:28:28 AM	NTP	Information	None	3	N/A	JACKXPS	substituting
RDTSC for QueryPerformanceCounter() with 2400.040 MHz frequency
11/26/2009	11:28:28 AM	NTP	Information	None	3	N/A	JACKXPS	System time
precision 15.625 msec, min. slew 6.400 ppm/s
11/26/2009	11:28:28 AM	NTP	Information	None	3	N/A	JACKXPS	Clock
interrupt period 15.625 msec
11/26/2009	11:28:28 AM	NTP	Information	None	3	N/A	JACKXPS	Performance
counter frequency 2400.040 MHz
11/26/2009	11:28:28 AM	NTP	Information	None	3	N/A	JACKXPS	MM timer
resolution: 1..1000000 msec, set to 1 msec
11/26/2009	11:28:28 AM	NTP	Information	None	3	N/A	JACKXPS	Raised to
realtime priority class
11/26/2009	11:28:28 AM	NTP	Information	None	3	N/A	JACKXPS	ntpd
4.2.4p6 at DLH-QPC-o Mar 15 21:30:20.47 (UTC)  2009  (239)

Please help. I've tried to read all documents available. The GPS I
have is from ublox and it can output 1PPS signal, which I instend to
use later with an RS232 port.

Thanks in advance.


jack




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