[debian & gps] How to check gps

-stacy slm3095om at Millions.Ca
Wed Sep 24 19:41:11 CEST 2008

Christian Weßel wrote:
> Thanx for the detail explaination, but I am still a little confused.
> After installation of Debian I followed the tangogps guide from OM wiki.
> I installed fso-gps and tangogps, both with <apt-get install fso-gps
> tangogps> and it doesn't work together. Neither 'location' nor 'tango'.
> After a selfmade confusion with my servers iptables I installed also
> netutils-ping and dnsutils. Thats all.

So that means you have the tangogps that uses gpsd not the version that 
has been modified for gypsy, thus you need fso-gpsd, which you have. So 
far so good.

> So, please give me a hint what to de-install and which combination to
> install and how to configured it. Maybe also the startup with zhone gui,
> currently I need to start tangogps by xterm.

As I said in my previous email, I think your software is configured and 
working properly; you just don't have a fix and no combination of 
software will help that. To help clarify, follow along with this:

Here [1] is a screen shot of the tangogps trip page when there is no 
gpsd for tango to talk to. As you can see, everything is blank.

Here [2] is a screen shot when there is a gpsd to talk to, but the gps 
is powered off so gpsd can't talk to it. Now everything is zero instead 
of blank, with the exception of GPS Time which is epoch incorrrectly 
converted from my local time to GPS Time.

Here [3] is a screen shot when the gps is powered on but there is no 
fix. Now that satellite count has changed to 14/0, which means the gps 
can see 14 satellites in the sky but has not locked on to any of them. 
The GPS Time is now correct as well which means that gps has received 
time from at least one of the satellites.

And finally, for completeness sake, here [4] is a screen shot of 
everything working. The satellite count is now 14/7; 14 in view, 7 used 
in calculating position.

[1] http://www.millions.ca/~stacy/neoFreeRunner/no-gpsd.png
[2] http://www.millions.ca/~stacy/neoFreeRunner/no-gps.png
[3] http://www.millions.ca/~stacy/neoFreeRunner/no-fix.png
[4] http://www.millions.ca/~stacy/neoFreeRunner/fix.png

Based on your description of what showed on your screen, you are in 
situation 3, your gps can see satelites, ogpsd is talking to your gps, 
fso-gpsd is talking to ogpsd and tangogps is talking to fso-gpsd. All 
you need now is a fix.

I would suggest you go outside, sit in an open space with a good view of 
the sky, have a beer (or two :-) and see what happens.

If you still can't get a fix, then I would suggest there is a hardware 
problem. There are two possibilities that I know of. The most likely is
the SD Card [5] I don't know if debian includes the driver fix for this 
or not. The other one is an issues with the connector for the internal 
antenna [6]. Using an external antenna will bypass both of those issues.

[5] http://wiki.openmoko.org/wiki/GPS_Problems
[6] http://wiki.openmoko.org/wiki/FreeRunner_GPS_antenna_repair_SOP

> BTW, I checked my process list and couldn't find any other gpsd except
> fso-gpsd:

ogpsd will not show up as a process under that name, it will show up as 
python. I would recommend you install lsof and then if you type

lsof /dev/ttySAC1

you will see what process has the gps device open.


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