My question was for Andrea, who was asking how to hook it up.
Yes, there are any number of sources for adapters, from the cheap
and cheerful Chinese ones to "professional" equipment
at eye-watering prices. There really is no reason to deal with RS-232 for NMEA
as long as there is a USB port available. Personally I use a Keyspan adapter (now Tripp Lite) which had drivers for the Mac. Works a champ.