[Gta04-owner] Modem's GPS

Christoph Mair christoph.mair at gmail.com
Mon Nov 5 18:25:38 CET 2012

On Mon, Nov 5, 2012 at 6:15 PM, Denis 'GNUtoo' Carikli
<GNUtoo at no-log.org> wrote:
> Hi,
> I found on the net how to activate the Option Modem's GPS:
> http://www.option.com/en/support/faq/article/getting-gps-information
> http://developer.att.com/devices/OPTION_GPS_AT_Command_Reference.pdf
> The goal was to verify if the Modem's GPS can get a fix or not without
> the antenna.
> If it can't it's better because that way the Network
> can't use RRLP and has to use a less precise estimation of where I am.
> I didn't test if it can get the fix or not yet.
> Simple howto:
> On one ssh terminal do:
> picocom -b 115200 /dev/ttyHS_GPS_Control
> ATE //for the echo
> AT_OGPS=2 //for enabling the GPS for more than 1 fix.
> on another ssh terminal do:
> picocom -b 115200 /dev/ttyHS_GPS
> And you get NMEA.

I tried once and it didn't get a fix even with some piece of wire
soldered to the pin. You probably have to attach some kind of antenna
and a matching pre-amplifier with filters to get something meaningful.

It works (as expected) if you add a coax-cable and connect it to the
GPS-Switch chip so that you can use the real GPS antenna.


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