GPS data would normally be wired in on J2 - Pin 3 (+) and Pin 4 (-) from a 0183 NMEA data source. If you have existing NMEA 0183 data on the boat you could wire it with some simple twisted pair wire. If you need a GPS, I would suggest the Furuno GP39 using the WHITE (+) and BLUE (-) NMEA output wires to the FCV1150.