[ntp:questions] Motorola Oncore Surveyed Position
mail at miguelgoncalves.com
Tue Sep 6 15:32:13 UTC 2011
Thanks for the help!
My /etc/ntp.oncore.0 file is this (I disabled SHMEM)
HT 146.72 M
DELAY 25 NS
I'm getting one strange thing:
oncore# ntpq -p
remote refid st t when poll reach delay offset
xGPS_ONCORE(0) .GPS. 0 l 4 16 377 0.000 -15045.
canon.inria.fr .GPSi. 1 u 69 64 377 49.013 -15043.
ptbtime1.ptb.de .PTB. 1 u 52 64 377 66.784 -15043.
ntp.inrim.it .CTD. 1 u 56 64 377 52.119 -15043.
The GPS is off by 15 secs. Is this the GPS-UTC delta? Why is this happening?
Can anyone help?
On 6 September 2011 15:31, Thomas Laus <lausts at acm.org> wrote:
> On 2011-09-06, Miguel Gon?alves <mail at miguelgoncalves.com> wrote:
> > I switched again to mode 4 and started again to see if I missed
> something. I
> > believe I'll only have to wait 10000 seconds = 2 hours and 46 minutes...
> > much. :-)
> > Unfortunatelly clockstats doesn't show position, only time. I believe
> > is because it's in position lock (0D?) mode. Here's a sample:
> > By the way... I was looking at the clockstats file and noticed that when
> > switched to mode 4 as I said earlier I got this
> > 55810 40560.366 127.127.30.0 ONCORE: Loading Posn from SHMEM
> > 55810 40560.367 127.127.30.0 ONCORE: Setting Posn and Time after
> > Almanac
> > 55810 40562.091 127.127.30.0 ONCORE: Posn:
> > 55810 40562.091 127.127.30.0 ONCORE: Lat = N 41.1745319deg, Long =
> > W 8.6560764deg, Alt = 146.72m (481.36ft) GPS
> > 55810 40562.091 127.127.30.0 ONCORE: Lat = N 41deg 10.4719m, Long =
> > W 8deg 39.36458m, Alt = 146.72m ( 481.36ft) GPS
> > 55810 40562.091 127.127.30.0 ONCORE: Lat = N 41deg 10m 28.32s, Long =
> > W 8deg 39m 21.88s, Alt = 146.72m ( 481.36ft) GPS
> > 55810 40564.365 127.127.30.0 ONCORE: Waiting for Almanac
> > 55810 40567.365 127.127.30.0 ONCORE: Have now loaded an ALMANAC
> > 55810 40567.365 127.127.30.0 ONCORE: state = ONCORE_RUN
> > It seems this is my location... :-) Now you know where I live! :-)
> > So the position is stored in the shared memory and when I reset the unit
> > (mode 4) it uses the position stored in there.
> > Anyone help care to comment this?
> This is from the refclock_oncore.c file.
> * If we don't find any then we don't have the cable delay or PPS
> * offset and we choose MODE (4) below.
> * Five Choices for MODE
> * (0) ONCORE is preinitialized, don't do anything to change it.
> * nb, DON'T set 0D mode, DON'T set Delay, position...
> * (1) NO RESET, Read Position, delays from data file, lock it in,
> * go to 0D mode.
> * (2) NO RESET, Read Delays from data file, do SITE SURVEY to get
> * position, lock this in, go to 0D mode.
> * (3) HARD RESET, Read Position, delays from data file, lock it
> * in, go to 0D mode.
> * (4) HARD RESET, Read Delays from data file, do SITE SURVEY to
> * get position, lock this in, go to 0D mode.
> * NB. If a POSITION is specified in the config file with
> * mode=(2,4) [SITE SURVEY] then this position is set as the INITIAL
> position of the
> * ONCORE. This can reduce the time to first fix.
> * Note that an Oncore UT without a battery backup retains NO
> information if it is power cycled, with a Battery Backup it remembers the
> etc. For an Oncore VP, there is an eeprom that will contain this data,
> along with the option of Battery Backup.
> * So a UT without Battery Backup is equivalent to doing a HARD RESET
> on each power cycle, since there is nowhere to store the data.
> If we open one or the other of the files, we read it looking for
> MODE, LAT, LON, (HT, HTGPS, HTMSL), DELAY, OFFSET, ASSERT, CLEAR,
> HARDPPS, STATUS, POSN3D, POSN2D, CHAN, TRAIM then initialize using
> method MODE. For Mode = (1,3) all of (LAT, LON, HT) must be present
> or mode reverts to (2,4).
> Your ntp.oncore.0 file will need to list your location:
> This is from my file
> MODE 1
> LON -84.2017844758
> LAT 40.7762210511
> HT 223.445
> DELAY 92.1 ns
> This skips the receiver reset and loads my coordinates. Once the
> receiver has a valid almanac, it will serve time. I am also using
> FreeBSD, but don't use SHMEM. You should be able to just link your
> serial port to the correct device using devfs.conf
> oncore.pps.0 ->cuau0
> oncore.serial.0 ->cuau0
> Public Keys:
> PGP KeyID = 0x5F22FDC1
> GnuPG KeyID = 0x620836CF
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