GPS as a source of time like NTP

Joerg Reisenweber joerg at openmoko.org
Sun Jul 27 03:28:19 CEST 2008


Am So  27. Juli 2008 schrieb Daniel Willmann:
> Hi,
> 
> On Sat, 26 Jul 2008 19:42:43 -0500
> "Dale Schumacher" <dale.schumacher at gmail.com> wrote:
> 
> > On Sat, Jul 26, 2008 at 6:28 PM, Daniel Willmann
> > <daniel at totalueberwachung.de> wrote:
> > > Yeah, currently a signal is emitted if the current
> > > location/accuracy/whatever packet contains a different value than
> > > before. So If nothing changes you wont get a Signal either. The one
> > > exception is time because I don't want to send that every second for
> > > nothing. The idea at the moment is to just send a TimeChanged signal
> > > once as soon as the time is valid. After that you can request the
> > > time if you so desire.
> > 
> > Is the GPS time used as a source for the system, like an NTP server?
> 
> There's no code for it yet, but yeah, that is being taken into
> consideration. Basically I want to send a TimeChanged signal once after
> I got the valid time from GPS (and not every second as gypsy specifies
> as that is just wasting resources - although that probably matters if
> we really route accelerometer through dbus...) and whenever a program
> asks for it via a method.
> Then you would have a program listening on dbus for the TimeChanged
> signal and set the system clock (and rtc) according to that.
> 
> > That seems like it would be a very useful option.  It would take
> > advantage of the special capabilities of the FreeRunner beyond a
> > typical Linux box.
> 
> That and auto timezone selection based on your location will be some
> nice features, yes.
> 
> Regards,
> Daniel Willmann
> 

please consider using ntpd. There should be standard "modules" for using GPS 
for a timeserver.
see:
man ntpd
http://www.mpipks-dresden.mpg.de/~mueller/docs/suse10.3/opensuse-manual_de/manual/sec.netz.xntp.normal.html
xntp-doc
/etc/ntp.conf


/jOERG
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