Do you mean stream the serial output from the GPS unit to a file?

Yes.

If that can be done with some kind of softare on the player, I'd be happy to do it.

Well, I could write something, but if you wait for that it will probably be a bit. Basically the simple way involves installing gpsd, making it get run by hijack, then installing "nc" (netcat) and a script which runs netcat, connects to gpsd, sends 'R' to enable raw mode, and writes output to a file... but you'll have to pick a partition on your player to mount read-write to do it.

Don't ask me to script it, at least not today.