the unknown messages is the GPS unit telling you that it is receiving data on the serial port, but it doesn’t know when it is.
Try to disable echo on the serial port.
stty -F /dev/serial0 -echo
Peter --OzzMaker.com --
Reply To: NMEA unkown msg*46
the unknown messages is the GPS unit telling you that it is receiving data on the serial port, but it doesn’t know when it is.
Try to disable echo on the serial port.
stty -F /dev/serial0 -echo
Peter --OzzMaker.com --