Hello,
In the last days (nights :-)) I did some tests with GPS on my FR and
here are the results in compact form;
HIH
matthias
...
12. GPS
Install the following packages:
# opkg install gpsd
# opkg install http://www.tangogps.org/downloads/tangogps_0.9.3-r1_armv4t.ipk
# opkg install openmoko-agpsui
# opkg install gpsdcontrol_0.3_all.opk
The last one (gpsdcontrol) removes the starting of the 'gpsd' from the boot
run-level, which is a good idea at all for saving power;
One must edit the /etc/default/gpsd to point it to the correct serial device
of the GSM antenna:
# vi /etc/default/gpsd
GPS_DEV=/dev/ttySAC1
gpsdcontrol as well powers on the GSM antenna by writing '1' to the drivers
file; you could do this as well (and you should if you don't use gpsdcontrol)
in the gpsd start script /etc/init.d/gpsd in the start/stop sequence, writing
'1' on start and '0' on stop;
echo 1 /sys/class/i2c-adapter/i2c-0/0-0073/neo1973-pm-gps.0/pwron
in any case you must correct a bug in the /etc/init.d/gpsd which tries to
kill
the gpsd, but kills to the running script itself;
change:
killall gpsd
by:
pgrep -x gpsd | grep -v $$ | xargs -r kill
The installed tool openmoko-agpsui allows you to check if your GSM antenna
and chip work fine; some notes about this, GSM and TTFF:
- openmoko-agpsui does not need the 'gpsd' to be started and it goes out of
the
way if some application (like tangoGPS) instructs the 'gpsd' to read the
GSM chip;
- the internal radio antenna of the GSM chip is in the upper part of the
Freerunner, above the loudspeaker; while waiting for TTFF (Time To First
Fix) use the FR in upright position (and with nothing above it, no
building,
no trees, no hand or other parts of your body);
- I managed TTFF between 23 seconds and 400 seconds which is good enough if
you
keep in mind the small antenna; the Wiki explains about TTFF for cold start
(and the FR do this) about ~15 minutes:
http://en.wikipedia.org/wiki/Time_to_first_fix
- in the 'SS' menu of the openmoko-agpsui you can check after TTFF very good
the number of the satellites and the strength of their signals; any value
greater then -145 dbm should be fine; I normally manage average values
around
-130 dbm;
- I normally use openmoko-agpsui to get the First Fix and after this I start
the gpsd and tangoGPS which find the GSM chip already well located on
earth;
- some screenshoots of openmoko-agpsui can be seen here:
http://www.unixarea.de/GPS-test01.jpg
http://www.unixarea.de/GPS-test02.jpg
http://www.unixarea.de/GPS-test03.jpg
http://www.unixarea.de/GPS-test04.jpg
Some notes about tangoGPS:
- my cached maps are now stored in the SD card:
# mkdir /media/card/osm
# rm -rf OSM
# ln -s /media/card/osm OSM
- I pre-fetched maps with some tool from
http://www.millions.ca/~stacy/osmtiles.tgz
which let me define the two points of a rectangle, generate the URL's of
OpenStreetMap and fetch down the *.png files which I store below
/media/card/osm
where tangoGPS will pick them up; see the README of the tar-ball for more
details; for example the complete city of Munich inside the Highway-Ring
A99
are some 3000 files for zoom level 11-16 and occupy only ~32 MByte;
- I run tangoGPS as well in my FreeBSD laptops and connect it to the 'gpsd'
which runs on the Freerunner, i.e. using the Freerunner as the GSM device
for my laptop; this give you better view to the maps with tangoGPS, of
course :-)
more information:
Wiki: http://wiki.openmoko.org/wiki/Neo_FreeRunner_GPS
...
--
Matthias Apitz
Manager Technical Support - OCLC GmbH
Gruenwalder Weg 28g - 82041 Oberhaching - Germany
t +49-89-61308 351 - f +49-89-61308 399 - m +49-170-4527211
e [EMAIL PROTECTED] - w http://www.oclc.org/ http://www.UnixArea.de/
b http://gurucubano.blogspot.com/
A computer is like an air conditioner, it stops working when you open Windows
Una computadora es como aire acondicionado, deja de funcionar si abres Windows
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