GPS newbie needs help with antenna

Hi, I'm new here.

I have a Fujitsu Siemens U9200 - this laptop was designed and sold with Option GTM378 (which supports GPS) but FS never marketed the GPS functionality, so I'd like some help in clearing up a few things:

• Is there a way to know if the built-in WWAN antenna is (also) able to receive GPS? (I can open up the laptop and take a look, but what do I know...
• If not, can anyone suggest a way of adding a GPS antenna without compromising on the Rx diversity feature of the 3G modem (ie. should I be looking for a "combined" antenna, or do I just solder a lead to a separate GPS antenna to the WWAN antenna's cable?

 

there you go

Option - How to enable and use the GPS functionality on your GTM378 module?

 

I know how to do that and have done so quite a while ago (but thanks anyway) - I'm not getting any fix though, just empty sentences:

Code:

$GPGSV,4,1,16,32,,,,31,,,,30,,,,29,,,*70
$GPGSV,4,2,16,28,,,,27,,,,26,,,,25,,,*74
$GPGSV,4,3,16,24,,,,23,,,,22,,,,21,,,*7D
$GPGSV,4,4,16,20,,,,19,,,,18,,,,17,,,*7B
$GPGGA,,,,,,0,,,,,,,,*66
$PQXFI,,,,,,,,,,*56
$GPVTG,,T,,M,,N,,K,N*2C
$GPRMC,,V,,,,,,,,,,N*53
$GPGSA,A,1,,,,,,,,,,,,,,,*1E

That's why I'm looking for someone who has added GPS to a laptop that didn't come with one, what the GPS antenna should look like - it's quite possible the antennae in U9200 aren't GPS-ready but I just can't tell the difference.

EDIT: Oh, btw: GTM378 is what other models of the laptop were sold with, I installed GTM382.

 

well, i'm pretty sure a normal wifi aerial can act as a gps antenna. At least, the last time when I took apart my (previous) GPS-equipped phone, I could only see one. GPS frequensy is about 1.5GHz, which is not too far from 2.4GHz of modern wifi networks. Seriously, why not?

 

Well, circular polarization for one, and the radically different-looking GPS-specific antenna I saw on the EeePC-hack wiki (and other places). I'd love to hear from people who have GPS (real, satellite-based, not GSM/WiFi cell triangulation) on their laptop running from the internal 3G card, what antennas do they have in their laptops (and what cards are they using). The thing is that I can't get a fix with either of the two frimware versions available for GTM382 so I'm starting to suspect the antenna.

 

well, yeah, it's better to hear from people actually owning one. Let's hope there are some here)

Good luck!

 

Interesting. I would peek at your module to see how many of your SMA connectors are filled, out of two. I suggest you check your data sheet and or call Fujitsu support but would guess that you do need separate antenna.

I found this;

Most branded 3G/HSDPA cards have GPS function disabled by provider(don't ask me why )

to enable GPS function on GTM378 connect to your card via Hyperteminal and type

AT_OIFC=3,1,1,2

then type

AT_OGPS=2

Reboot.

On next startup you will have an aditional com port in device manager

GlobeTrotter Module HSxPA - GPS Interface (COMx)

where COMx is your interface port (mine is COM4).

Connect you GPS software to this port in setting, works with Garmin MobilePC, IGO 8.

 

To make myself clear and expand on the background:

• My laptop came with nothing - it was a budget model that had an empty mini-PCIe slot but DID have two WWAN antennas in the lid.
• I bought the GTM382 (ie. NOT the GTM378 sold by Fujitsu) module separately from the laptop and installed it myself. Do note that cables are installed in reverse - this is intentional, as the GTM378 has the connectors the other way around compared to GTM382 - not swapping them makes any difference to my GPS problems.
• Configuration and all that is mentioned at Option's site (including the pdf) is all done at this point - I'm just getting empty sentences (see above) - there's no point in trying GPS-aware software if I don't have position info - I can see that with catting the GPS data port. On a related note, if any linux user has a hint on telling which ttyHSn port is which, I'd love to know - I already learned through trial/error but still..