[LinuxPPS] Oncore section of the LinuxPPS NTPD support web page. Improve docmumentation.

[Hal V. Engel]

On Wednesday 18 February 2009 11:07:43 pm clemens at dwf.com wrote:
> <snip>
>
> > and the 'option'
> >
> > 	Posn3D
>
> I have never been able to figure out why this causes problems on Hal's
> machines.

I am not sure how widely Posn3D and Posn2D have been tested.  In a private 
note to me in Dec. Reg wrote: 

"All of the early (VP UT GT) receivers seem to be able to do this fine, the 
later (M12 M12T) receivers dont.  When switching back to position hold, they 
have lost something, and take more than the next 15sec to try to stabalize 
again."

I am not sure that the Posn3D/Posn2D code has been tested with any + models 
like the UT+ and perhaps these are more like the M12T in this regard.  What I 
am seeing is that the GPS does not stabilize in the 15 second period after the 
mode change and because of this it will almost never start outputting 
messages.  It does on occasion stabilize quickly enough for it to start 
working but this only happens about every 5 to 15 minutes if Posn3D/Posn2D is 
enabled and then it only outputs 1 or 2 messages before it goes off line again 
with the next mode switch.  So this sounds like my UT+ is acting more the the 
M12T.  Perhaps others here with various Oncore models could test this?

>
> > By the way I am using a modified version of the latest OncorePlot code
> > that displays the signal to noise data when satellite information is
> > enabled.   It is a simple mod that only adds perhaps 8 or 10 lines of
> > code.   If you are interested I can create a patch and get this to you.
>
> send me the change and Ill add it before I replace the old version of
> OncorePlot
> on ntp.org

Reg,

I have attached two patches.  The first of these I sent earlier but I don't 
know it you have it or have applied it yet.  

sat_path2-useconfig.patch 

Will use the /etc/<ntp/>npt.oncore<.X> files to locate the SHMEM file.  It 
uses an optional command line arg that must be 0 .. 9 to specify which 
ntp.oncore<.X> config file to use.  If no arg is specified it will look in the 
/etc and /etc/ntp directories for ntp.oncore and ntp.oncore.0.  It uses the 
same basic logic as is used in the oncore ntp driver to find and parse the 
config files.    So if you only have one Oncore and the config file is either 
ntp.oncore or ntp.oncore.0 you do not need to use a command line argument and 
it will just work.

This also places OncorePlots SAT_MAP files in ~/.OncorePlot and names them 
SAT_MAP<.X> so that it is possible to run concurrent copies of the software if 
users have more than one Oncore.

The last feature added is that the title of the application window is changed 
to reflect the device such that if you are using the ntp.oncore.0 config file 
the application window will have "Plot for Oncore 0" as the window title.

sat_path2-sigtonoise.patch

Adds a set of lines that are output in the lower left corner of the 
application window that displays the s/n of all satellites that the Oncore has 
a lock on.  

The s/n info is very handy since it allows you to see at a glance how good 
your reception is and how this is affected by changing conditions and 
different satellite locations in the sky.  For example my Oncore is currently 
locked onto 8 satellites (there are 9 in the sky) and the s/n values are all 
between 42 and 51 right now.  We just recently had some fairly hard rain and 
during that weather it appeared that s/n was degraded by about 3db compared to 
what I see with clear skies.

These patches should be applied on top of the first patch I sent which I 
believe that you have already applied.

>
> > You are correct that with a setting of MODE 2 or 4 that the ntp Oncore
> > driver will do a site survey at startup.

>
> Once a user has his Oncore running, I would only suggest doing a mode 2 or
> 4 once to
> get the position, and then use Mode 1 from then on out.

Does using mode 2 or 4 output the position data somewhere so that users can 
update the oncore config file or does this happen automatically?

Hal
-------------- next part --------------
A non-text attachment was scrubbed...
Name: sat_path2-sigtonoise.patch
Type: text/x-patch
Size: 1853 bytes
Desc: not available
Url : http://ml.enneenne.com/pipermail/linuxpps/attachments/20090219/fb9c5108/attachment-0002.bin 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: sat_path2-useconfig.patch
Type: text/x-patch
Size: 11748 bytes
Desc: not available
Url : http://ml.enneenne.com/pipermail/linuxpps/attachments/20090219/fb9c5108/attachment-0003.bin