I'm in the same boat (pun intended). AIS is ground-based with roughly a 40 mile range from each ground station. I picked up the Don Juan by accident a couple days ago as it run an altered course near Angra do Heroísmo in the middle of the Atlantic.
There actually IS satellite-based tracking, but it's not free like the AIS. I think it's only about $15K for an annual subscription if you want to track the balance of your car's journey. Maybe we can go halfsies?