GPS is dead after some time


#1

Hello Every body,

We are facing dificult situation

We have ordered 1000 pices of 2501b module and the problem they are giving us is following

We are observing the gps data every 10 seconds and it is being displayed on uart 1 so we can observe it on hyperterminal

What we observe is gps is giving correct data for some time and then it suddenely vanishes for some time and this time ranges from few minutes to hours.

we have provision to restart the application by giving internal commnad at+cfun=1 which is linked to some timer and it works after some time but the situation is not recovered and gps is still dead

Then we switch on and off our system and GPS is alive again like nothing has happened (ofcource after some 30 sec)

We have some 40 systems on which we are testing and all are behaving like this and behaviour is totaly random.

We are running the system on 4.2 volt and antena we are using is of 3-5 volts.

The voltage on antena connector, we have observed is 2.99 volts

There is a pin on module to provide external voltage to the gps antena in case we are using 5 volt antena we have connected it to supply voltage of module as recomended in the manual

but we have observed the behaviour of gps is quite the similar if we keep this pin floating

Pls help since this a grave situation for us!


#2

Hello,

What do you mean by that? Doesn’t provide a fix anymore?
I assume you use it in internal mode, and you send some position info through UART1.

Look at the AT+WGPSANT command description and configure the gps module according your hardware setup. Do not provide external voltage to antenna when the module configured for internal 3V antenna power!!!
What is the answer for the AT+WGPSANT=2 command when the gps looks like “vanished”?
What kind of GPS antenna do you use? Is the gain of the antenna not too much? What is the consumption of the antenna? How long cable do you use?

And finally you should write down your firmware version.

Please provide us as much info as you have, and hopefully somebody will give you a solution.

Cheers,
tom


#3

yes it doesn’t provide a fix anymore.

yes I use it in internal mode, and send some position info through UART1.

we are providing external voltage(4.2v) to antenna when the module configured for internal 3V antenna power!!! could this be the reason for GPS blackout??

AT+WGPSANT=2 command gives 2,1,1,2978

cable is 5 m long, it is an antena with voltage range from 2-5 volt

And finally you should write down your firmware version.

firmware is 6.57 and os version is 3.12