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Tips and questions relating to the GPS modules from SFE
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By SebaS
Hello everybody!

I'm having this problem... I buy a MG-S01SP SiRFstarIII Module and I can't get valid GPS position.
This module has an internal antenna.

I 've connected the power supply (3.3v), the Vbat also to 3.3v and Reset with a Pull-Up resistor also to 3.3v.
Then I have a LED in the GPS Status pin (the manual says that this LED will blink when GPS is fixed otherwise it will remain on) . And finally the Tx/Rx signals with a MAX232 to the PC.

I'm at the balcony, and I turn it on... The LED (GPS Status) lights up. And I get invalid position (I see it in the PC)...
Then SOMETIMES the LED begin to blink, so it means that at least find 1 satellite so it's syncronized... at least that is what I understand for "GPS fixed"
And invalid data keep coming.... And only ONE TIME I get valid position... I've done several test and never again get valid position... Sometimes the LED doesn't even blink.

I don't think that it's a matter of visibility with the sky because I'm at the balcony and there is plenty of sky, lol....

I wonder if it could be the internal antenna... Because since I'm just doing some tests I plug it to a proto-board... So the proto-board my interfere... But the manual says it has high sensitivity: -159dBm

Another thing that I notice is that the datasheet says that in cold start the Acquisition Rate is 42 sec average.... I've waited minutes and nothing...

Any suggestion? Please help!!!!!!! ANYTHING!!! :cry:
By rtxo
Hello from California!

When you first plug in any GPS it must do a site survey
which can take hours and more hours. So, if you can let
the GPS sit and do its site survey overnight, you should
get good results in the morning.

User avatar
By SebaS
Hello there!!

Thanks for your reply! A couple of week ago I managed to make it work. Actually it works by its self... Maybe because unconsciously I do as you said... Thanks Anyway for you concern...

I 'll let you know if i encounter any new problem

Thanks Again! :D