Open moko GPS pin connection

[Alexander Lehner]

On Wed, 9 Nov 2011, RANJAN wrote:

> Hi,
>
> Does any one know about the OpenMoko GPS chipset pin connection. After I
> opened it I could find only one grey wire which appears to be the antenna.
> Where are the Vcc,Gnd and Rx-Tx pins?

I guess you mean this part:
http://wiki.openmoko.org/wiki/Disassembling_Neo1973#Removing_PCB_from_case_frame

The grey cable is a 2-wire coaxial cable. I once ripped it off and tried 
to re-solder it without success. It is too tiny to handle it with fingers.

The actual antenna is (from my understanding) the big light-brown piece of 
plastic in the top of the phone, while the GPS chip is soldered on the 
board itself. I think this is so because there is also a second 
external GPS antenna connector on the side of the phone. Also, plenty of 
shielding metal next to the GPS antenna connector lets me assume, that 
there is some high-frequencey electronics working under ;)

I guess it works similair to a TV satelite receiver (LNB) which is also 
powered and data-exchanged with a 2-line coax cable.
No idead how they do this technically.

Roughly, there is power and some commands to justify the satelite receiver 
to a certain frequency. But IMHO the actual logic to interpret GPS data is 
not inside 'that brown plastic piece'.


Alex.