Sorry, my Samsung S4 has onboard GPS and it was found automatically..
The Options > Connections > Data Connections has
On Type:GPS Port: Internal Priority 1 I/O Input
Built in GPS is selected, Control Checksum is checked. Accept only sentences is checked.
I have also used my S4 GPS on a PC via Bluetooth so I believe the reverse is possible.
I notice that you can "Add" a "Serial" and there is a dropdown for adding com ports, but perhaps the Android system does not do this. There is also selection for "Network" and "Built-in Bluetooth" that would be the most likely way to gain GPS signal, depended on your GPS device.
PS: Just read this. " If I run a terminal on my Android it sees the incoming NMEA
messages. It all looks good, but OpenCPN doesn't seem to see the port, and it certainly isn't reading any sentences. The terminal program never asks which port to connect to, it just does. But the DataPort selection box in OpenCPN contains no information (although I have tried typing in several numbers etc). Nothing seems to go. I am running it fast (115200), but the Windows/Navigatrix versions can take this with no problem."
Try slowing it down to 4800 baud. Is there no way to determine which Com port Terminal is using? I haven't done that yet.
Android is like Linux
and uses dev/tty50, dev/tty51 etc.
I did a search on Android Com Ports
Perhaps there are some other better suggestions?
Certainly please post the answer so it can be recorded in documentation