If you use fairly common gps mouse it should be recognized by gpsd and
OpenCPN you can create connection to gpsd.
you can create connection to gpsd in SignalK and another one from OpenCPN to SignalK. You can also use KPlex instead of SignalK for it. It’s all up to you. First you need to find out if your gps mouse is recognized. lsusb. Then see tty device created for it. The system comes with rules to recognize most common gps devices by vendor and product id and it will create tty device aliases. How you
route NMEA traffic inside the system is up to you. You can use
serial to gpsd to OpenCPN, you can use serial to KPlex to OpenCPN,
Serial to SignalK to OpenCPN. And with each connection transport options are udp or tcp. In case of SignalK you also can choose
NMEA sentences or JSON based SignalK protocol. OpenCPN understands both but needs to be told which to use. With my gps mouse it just gets recognized after I
plug it in. I run gpsmon and gpsd already sees it.
Thanks,
—MG