SIM39EA GPS signal acquisition problem

I’m building a tracker using SIM800C GSM and SIM39EA GPS. Everything works fine but one small problem I’m facing is the GPS signal acquisition. Sometimes even in an open area GPS is not able to get the location nor the GPS time is updated. I tried placing GPS away from other components and also a good ground plane but this does make any difference for me. Please help me if I’m missing something and also give advice to get good GPS signal reception.

Hello and welcome!
I’ve never heard of this GPS chip, but checking on the documentation, some things I see you can check are:

  • In this document on page 18 the manufacturer specifies how the antenna should be mounted on a system. Check to see if you find something you’ve missed.
  • On page 19 of that same document, check to see if you are working according to the recommended electrical values.
  • How are you interfacing the SIM800 and the SIM39EA?

May be a picture of the setup would help us understand the problem

Hi Ravi, Please find attached image.

@RaviPujar Please tell me If something is wrong with the components placing.

Why is GPS not soldered properly?

@RaviPujar Firstly GPS was properly soldered on PCB but was not able to get the location data. So to check with the issue, I tried placing the GPS module outside the board by extending it with wire and it works fine. I tried again soldering GPS on PCB but it did not work. I’m totally confused now and could not find the exact issue. GPS position on PCB might be causing the issue or something else.

The image above shows connected wires to test GPS outside the PCB board.

To get the location sync sooner, you need to have a uninterrupted ground plane below the GPS module. Otherwise it wont work, or takes too long to get the sync

@RaviPujar I tried placing a larger ground plane but no difference in GPS signal reception. I connected FTDI to GPS and this time GPS is solder on PCB when I keep MCU in reset by pressing reset button GPS signal gets acquired in no time and I can see coordinates on serial monitor via FTDI. I tried to see if location get acquire without MCU on reset and the result was no location coordinates. I de-soldered MCU and got the same result as MCU in reset with fast coordinates printing on serial monitor. Could you help me with this issue? I don’t know what problem is caused by MCU that results in GPS performance degradation.

May be MCU is sending some wrong commands and resetting the GPS repeatedly and prevening GPS signal sync