All I need to do now is find rules for adding a GNSS (GPS, GLONASS, BeiDou, Galileo, etc) receiver module and software to a portable computer. Maybe by TL8 the cost and weight are negligible, and the software is either /0 or /1, granting a +1 or +2 DM to Navigation checks?
I see that the CSC (p128) says under the Navigation Toolkit:
although it might be good to temper that by law level/government type to see if public access is allowed, or what granularity is permitted to non-military users