We have 6 raspberry pi’s with the 3G/4G Base HAT, we have a unit that works OK during some hours, but sometimes answers an error when asking for a new position (we get a serial read error), also sometimes the ttyUsb2 changes to ttyUsb3.
We developed a Python code that checks which of the two ports are available and is able to manage that scenario, but in some cases even if we get the right port we get an error like: cannot open /dev/ttyUSBX: Device or resource busy.
Please also note that we are using the AT+QGPSLOC command every second to get a new position update.
Is there a way to reset the GPS or another recommended way to use the unit in order to mitigate this issue? The only fix that we currently have is to reboot the Pi.