openmoko at mazikeen.demon.co.uk
Mon Jul 14 14:41:12 CEST 2008
On Monday 14 July 2008, BlueStar88 wrote:
> Russell Sears schrieb:
> > That sounds like a different problem than I have.
> > People have reported many different failure modes:
> > - Everything "works". The phone gets a reliable fix in ~5-15 minutes
> > if you baby it enough. (This might be improved w/ better drivers...)
> The GPS-module talks NMEA to the serial. I'm no GPS-expert, but where
> exactly should a 'driver' step in, to assist in basic technical procedures?
The module talks NMEA but also a ublox binary format. Among other things this
allows time and location estimates, ephemeris and almanac data to be fed to
the module to give it an initial state, and should reduce time to first fix.
Likewise it can be used to request this data from the module so it can be
saved before shutdown. 'Driver' probably isn't the right word.
> > - The software is somehow messed up, and there are never any fixes.
> > (People report GPS breakage after installing some combination of the GPS
> > packages...) Reflashing the phone does not seem to help(!)
> Ignore the software, just look at the NMEA output!
> If you get a communication to the module established, all depends on the
> facts coming from the NMEA output. There should be no
> 'misunderstandings' from any software involved.
> This poor (?) signal is just not enough, to get any fix:
> > - Actual antenna troubles. (See message "GPS issue related to GPS
> > antenna selector ?")
> Yepp, I assume this as the right (and only) direction it goes.
> > TangoGPS problems:
> > - TangoGPS says "no gps found". Run "opkg install gpsd".
> > - The GPS device usually works, but sometimes tangoGPS sees zero
> > satellites after > 5 minutes. If you to power down the GPS device, then
> > power it back up, it starts seeing satellites.
> GPS UI 0.20 is used by me to do the diagnostics. Is there a cause not to
> trust it, even by looking at the pure NMEA output of it?
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