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The Neo 1973 device contains an integrated GPS. The particular device is marketed as an AGPS, and there is some discussion available as to what significance that "A" might have.
The external antenna for the GPS is using an MMCX connector. It is located inside the battery compartment, to the left of the battery, and directly above the SD card. More information about external antennas on the GPS antennas page.
Note that the GTA02 GPS device contains the u-blox ANTARIS 4 ATR0635.
A critical problem with early (current) GTA02s is that they can take a long time (10min+) to get first GPS data. This problem has been traced to interference with the SD card, see this page for more discussion and suggested fixes.
Assisted GPS performance requirement also defined in GSM/GPRS 3GPP TS 25.171, CDMA 3GPP2 C.S0036-0
Main article - gllin
The GPS driver is available here: http://3rdparty.downloads.openmoko.org/gllin/. It is a command line tool that after starting writes the positioning data so that they can be read as if they were written to the file.
And here the Mail from Michael Shiloh http://lists.openmoko.org/pipermail/community/2007-November/011916.html
There was an effort to write a Free Software program that could be used instead of this binary-only program, but this stalled after the decision to change GPS chips in GTA02. The Iphone 3G also uses the same GPS chip. It's not inconcievable that this might lead to further effort.
See Hammerhead/Protocol for details and the latest status.
Some scripts for those with the binary are on Manually_using_GPS
Please see the important information on Gllin!
To turn on the GPS, echo 1 to the file /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/neo1973-pm-gps.0/pwron
To read from the GPS, simply read /dev/ttySAC1.
gpspipe -r 127.0.0.1 2947
gpspipe is in package gps-utils
NOTE:
cat /dev/ttySAC1 Produces the unknown msg*58 this doesn't happen with gpspipe |
Before getting a fix, the GPS spits out lots of "$GPTXT,01,01,01,NMEA unknown msg*58", though these stop once a fix is obtained.
A position without a fix looks like:
One with a fix:
0515,*7A
(central Scotland)
--Speedevil 11:52, 7 April 2008 (CEST)
If you are having GPS problems with your freerunner, please document these on the page GPS Problems. FreeRunner_GPS_antenna_repair_SOP documents a possible solution.
In Openmoko projects, you could find a GPS test program that could provide graphical and text dump of GPS information. See Howto Test Your GPS with agpsui. This project called Openmoko AGPS UI project.
As people develop more sophisticated GPS applications, please note them here.
Here are some ideas for possibilities:
To make your neo appear like a regular bluetooth GPS: